preliminary environmental assessment report and … · action workplan proposed mangini ranch...

PREPARED FOR:

FOLSOM CORDOVA UNIFIED SCHOOL DISTRICT1965 BIRKMONT DRIVERANCHO CORDOVA, CALIFORNIA 95742

PREPARED BY:

GEOCON CONSULTANTS, INC.3160 GOLD VALLEY DRIVE, SUITE 800RANCHO CORDOVA, CALIFORNIA 95742

GEOCON PROJECT NO. S1376-03-02

Proposed Mangini RanchElementary SchoolFolsom, California

PRELIMINARYENVIRONMENTAL ASSESSMENT REPORT

AND REMOVAL ACTION WORKPLAN

APRIL 2019

Project No. S1376-03-02 April 23, 2019 José Luévano Hazardous Substances Engineer Northern California Schools Unit Site Mitigation and Restoration Program Department of Toxic Substances Control 8800 Cal Center Drive Sacramento, California 95826-3200 Subject: PRELIMINARY ENVIRONMENTAL ASSESSMENT REPORT AND REMOVAL

ACTION WORKPLAN PROPOSED MANGINI RANCH ELEMENTARY SCHOOL ASSESSOR PARCEL NUMBER: 072-3370-008 14640 SPARROW DRIVE FOLSOM, CALIFORNIA Mr. Luévano: In accordance with the Environmental Oversight Agreement (Docket No. HSA-FY18/19-093, dated January 23, 2019) between the California Department of Toxic Substances Control (DTSC) and Folsom Cordova Unified School District (the District), we have prepared this Preliminary Environmental Assessment (PEA) Report and Removal Action Workplan (RAW) for the proposed Mangini Ranch Elementary School site (the Site) in the Mangini Ranch residential development in Folsom, California. The school project design includes construction of a new approximately 66,000-square-foot, two-story school building and associated improvements. The PEA was performed to assess if naturally occurring hazardous materials (i.e., naturally occurring asbestos) are present in soil at concentrations that could pose a threat to children’s health and learning abilities, public health, or the environment (California Education Code, Section 17210, Subdivision h). The accompanying PEA Report/RAW describes the methodologies, procedures, and findings of the PEA, which was performed in general accordance with the DTSC’s PEA guidelines and DTSC-specific direction based on specific site conditions and findings. The document also provides a human health risk assessment, an evaluation of removal action alternatives to mitigate health risk, and a description of the selected alternative and associated operations and maintenance. Please let us know if you have any questions or comments regarding this report and if we may be of further service. Sincerely, GEOCON CONSULTANTS, INC. John Pfeiffer Jim Brake, PG Senior Geologist Senior Geologist

IDENTIFICATION FORM

Document Title: Preliminary Endangerment Assessment Report and Removal Action

Workplan Proposed Mangini Ranch Elementary School Site Location: 14640 Sparrow Drive

Folsom, California 95630

Docket No.: HSA-FY 18/19-093

Site Code No.: 104797-11

Prepared by: Geocon Consultants, Inc. 3160 Gold Valley Drive, Suite 800 Rancho Cordova, California 95742 Ph: 916.852.9118

Geocon Project Number: S1376-03-02

Geocon Project Manager: John Pfeiffer, CEG [email protected] 916.852.9118

Geocon Project Manager:

Approval: Date: April 23, 2019 John Pfeiffer, CEG No. 2372

Geocon Program Manager:

Approval: Date: April 23, 2019 Jim Brake, PG No. 5753 This document has been prepared for the California Environmental Protection Agency (CalEPA), Department of Toxic Substances Control (DTSC). The material herein is not to be disclosed to, discussed with, or made available to any person(s) for any reason without prior express approval of the appropriate responsible DTSC officer.

DISTRIBUTION LIST

José Luévano, Project Manager (e-copy and two bound copies) California Environmental Protection Agency Department of Toxic Substances Control

Matt Washburn (e-copy and one bound copy) Chief Operations Officer Folsom Cordova Unified School District John Pfeiffer and Jim Brake, Project/Program Managers (project file) Geocon Consultants, Inc. Folsom Public Library (one bound copy)

TABLE OF CONTENTS

PRELIMINARY ENDANGERMENT ASSESSMENT REPORT AND REMOVAL ACTION WORKPLAN PAGE

1.0 INTRODUCTION ........................................................................................................................... 1 1.1 Removal Action Objectives ................................................................................................ 1 1.2 Project Description .............................................................................................................. 2 1.3 Responsible Agency ............................................................................................................ 2

2.0 PURPOSE, OBJECTIVES, AND SCOPE ....................................................................................... 3 2.1 Purpose and Objectives of the PEA .................................................................................... 3 2.2 Purpose and Objectives of the RAW .................................................................................. 3 2.3 Scope of the PEA and RAW ............................................................................................... 3

3.0 BACKGROUND ............................................................................................................................. 4 3.1 Site Location and Description ............................................................................................. 4

3.1.1 Site Name, Address, and Size ................................................................................ 4 3.1.2 Contact Person, Mailing Address and Telephone Number .................................... 4 3.1.3 Environmental Consultant’s Contact Information ................................................. 4 3.1.4 Assessor’s Parcel Number (s) and Zoning ............................................................. 5 3.1.5 Ownership .............................................................................................................. 5 3.1.6 Township, Range, Section and Meridian ............................................................... 5

3.2 Operational History and Status ........................................................................................... 5 3.3 Topography ......................................................................................................................... 5

3.3.1 Original Topography .............................................................................................. 5 3.3.2 Post-grading Topography ....................................................................................... 5

3.4 Geology and Hydrogeology ................................................................................................ 6 3.4.1 Regional Geology .................................................................................................. 6 3.4.2 Site Geology ........................................................................................................... 6 3.4.3 Soil ......................................................................................................................... 7 3.4.4 Naturally Occurring Asbestos ................................................................................ 7 3.4.5 Groundwater .......................................................................................................... 7

3.5 Land Uses, Sensitive Receptors, Ecosystems, and Cultural Resources .............................. 8 3.5.1 Land Uses ............................................................................................................... 8 3.5.2 Sensitive Receptors ................................................................................................ 8 3.5.3 Ecosystems ............................................................................................................. 9 3.5.4 Cultural Resources ................................................................................................. 9

3.6 Climate ................................................................................................................................ 9 3.7 Previous Site Actions ........................................................................................................ 10

3.7.1 Phase I ESA - 2007 .............................................................................................. 10 3.7.2 Limited Phase II Soil Investigation - 2007 .......................................................... 11 3.7.3 Phase I ESA - 2012 .............................................................................................. 12 3.7.4 NOA Assessment - 2013 ...................................................................................... 12 3.7.5 Geotechnical Engineering Study – July 2014 ...................................................... 12 3.7.6 NOA Assessment – August 2014 ......................................................................... 12 3.7.7 Rough Grading Plans ........................................................................................... 13 3.7.8 Supplemental Geotechnical Study ....................................................................... 13 3.7.9 Geologic Hazards Evaluation and Geotechnical Investigation ............................ 13 3.7.10 Summary .............................................................................................................. 14

4.0 PEA ................................................................................................................................................ 15 4.1 Soil Sampling Rationale .................................................................................................... 15

4.1.1 ISM Soil Sampling Methodology ........................................................................ 15 4.1.2 Discrete Sampling ................................................................................................ 16

4.2 Soil Sampling Procedures ................................................................................................. 16 4.2.1 Field Screening .................................................................................................... 17 4.2.2 ISM Soil Sampling Procedures ............................................................................ 17

TABLE OF CONTENTS (Continued)

4.2.3 Discrete Soil Sampling Procedures ...................................................................... 18 4.2.4 Decontamination Procedures ............................................................................... 18 4.2.5 Disposal of Residual Materials ............................................................................ 19 4.2.6 Sample Documentation and Shipment ................................................................. 19

4.3 Laboratory Analysis .......................................................................................................... 19 4.3.1 Analytical Laboratory .......................................................................................... 19 4.3.2 Analyses ............................................................................................................... 20

4.4 Findings ............................................................................................................................. 21 4.4.1 Field Observations ............................................................................................... 21 4.4.2 Laboratory Analysis Results - Asbestos .............................................................. 22 4.4.3 NOA Summary .................................................................................................... 24 4.4.4 Laboratory Analysis Results – Arsenic and Mercury .......................................... 24

4.5 Conclusions and Recommendations ................................................................................. 25

5.0 HUMAN HEALTH SCREENING EVALUATION ..................................................................... 27 5.1 Chemicals of Potential Concern ........................................................................................ 27 5.2 Receptors and Exposure Pathways .................................................................................... 27 5.3 Uncertainty Analysis ......................................................................................................... 27

5.3.1 Sampling Uncertainty .......................................................................................... 28 5.3.2 Laboratory Methods and Detection Limits .......................................................... 28

5.4 Conclusions ....................................................................................................................... 28

6.0 ECOLOGICAL SCREENING EVALUATION ............................................................................ 29

7.0 CONCEPTUAL SITE MODEL ..................................................................................................... 30 7.1 Primary Source Media ...................................................................................................... 30 7.2 Primary Release Mechanism ............................................................................................. 30 7.3 Secondary Source Media .................................................................................................. 30 7.4 Transport Mechanism ....................................................................................................... 30 7.5 Exposure Media and Routes.............................................................................................. 30 7.6 Potential Receptors ........................................................................................................... 31

8.0 NATURE, SOURCE, AND EXTENT OF CONTAMINANTS .................................................... 32

9.0 ENGINEERING EVALUATION/COST ANALYSIS .................................................................. 33 9.1 Removal Action Scope and Objectives ............................................................................. 33 9.2 Identification and Evaluation of Removal Action Alternatives ........................................ 33

9.2.1 EE/CA Alternative Evaluation Criteria ................................................................ 33 9.2.2 Description of Removal Action Alternatives ....................................................... 34 9.2.3 Evaluation of Removal Action Alternatives ........................................................ 34 9.2.4 Removal Action Alternative Selection ................................................................. 36

10.0 APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS .............................. 37 10.1 Chemical-Specific ARARS ............................................................................................... 38

10.1.1 Screening Levels .................................................................................................. 38 10.1.2 Air Quality Management ..................................................................................... 38 10.1.3 Health and Safety Plan ......................................................................................... 39

10.2 Action-Specific ARARs .................................................................................................... 40 10.2.1 Hazardous Waste Management ............................................................................ 40 10.2.2 California Environmental Quality Act and Mitigated Negative Declaration ............ 40 10.2.3 Stormwater Discharge .......................................................................................... 43 10.2.4 Endangered Species Act ....................................................................................... 44 10.2.5 Quality Assurance Project Plan ............................................................................ 44

10.3 Location-Specific ARARs ................................................................................................ 45 10.3.1 Public Participation .............................................................................................. 45

10.4 Other ARARs .................................................................................................................... 47


11.0 MITIGATION MEASURES/ENGINEERING CONTROLS ....................................................... 48 11.1 Hardscape and Structures .................................................................................................. 48 11.2 Landscape.......................................................................................................................... 48 11.3 Import Fill Material ........................................................................................................... 49 11.4 Embankment Protection .................................................................................................... 49

12.0 REMOVAL ACTION IMPLEMENTATION ............................................................................... 50 12.1 Site Preparation and Security Measures ............................................................................ 50

12.1.1 Pre-Construction Planning and Notification ........................................................ 50 12.1.2 Security Measures ................................................................................................ 50 12.1.3 Contaminant Control ............................................................................................ 51 12.1.4 Cultural Resources Consideration ........................................................................ 51 12.1.5 Biological Resources Consideration .................................................................... 51 12.1.6 Noise Control ....................................................................................................... 52 12.1.7 Permits and Plans ................................................................................................. 52 12.1.8 Field Oversight and Documentation .................................................................... 52

12.2 Earthwork Activities ......................................................................................................... 52 12.2.1 Soil Segregation Operations ................................................................................. 53 12.2.2 NOA-Containing Soil Stockpiling ....................................................................... 53 12.2.3 Disposal of NOA-Containing Soil ....................................................................... 53 12.2.4 Import Fill Material .............................................................................................. 54 12.2.5 Documentation of Construction Activities ........................................................... 55

12.3 Air Monitoring .................................................................................................................. 55 12.3.1 Meteorological Monitoring .................................................................................. 55 12.3.2 Dust Monitoring ................................................................................................... 55 12.3.3 Perimeter and Personal Air Monitoring ............................................................... 56

12.4 Dust Control Plan .............................................................................................................. 56 12.5 Transportation Plan for Off-Site Disposal ........................................................................ 57 12.6 Decontamination ............................................................................................................... 58 12.7 Field Documentation ......................................................................................................... 58 12.8 Variance or Explanation of Significant Difference ........................................................... 59

12.8.1 Fundamental, Significant, or Minor Changes ...................................................... 59 12.8.2 ESD Process ......................................................................................................... 59

13.0 OPERATION AND MAINTENANCE PLAN .............................................................................. 60

14.0 REMOVAL ACTION COMPLETION REPORT ......................................................................... 61

15.0 PROJECT SCHEDULE ................................................................................................................. 62

16.0 LIMITATIONS .............................................................................................................................. 63

17.0 REFERENCES ............................................................................................................................... 64


FIGURES Figure 1 – Vicinity Map Figure 2 – Site Plan Figure 3 – Site Development Plan Figure 4 – April 2018 Sampling Layout and Analysis Results Figure 5 – July 2018 Sampling Layout and Analysis Results Figure 6 – September 2018 Sampling Layout and Analysis Results Figure 7 – Site Conceptual Exposure Model Figure 8 – Cross Section A-A’ Figure 9 – Cross Section B-B’ TABLES Table 1 – Summary of Laboratory Analysis Results – Soil, Asbestos Table 2 – Summary of Laboratory Analysis Results – Soil, Arsenic and Mercury Table 3 – Summary of Cap Components SITE PHOTOGRAPHS 1 through 18 APPENDICES Appendix A – Site Parcel Map Appendix B – Prior Reports Appendix C – Laboratory Analysis Reports Appendix D – Asbestos Dust Mitigation Plan Appendix E – Health and Safety Plan Appendix F – Mitigated Negative Declaration Appendix G – Stormwater Pollution Prevention Plan Appendix H – Quality Assurance Project Plan Appendix I – Operations and Maintenance Plan

LIST OF ACRONYMS

ADMP Asbestos Dust Mitigation Plan APN assessor’s parcel number ARAR applicable or relevant and appropriate requirement BMP best management practices CAC Certified Asbestos Consultant CARB California Air Resources Board CGS California Geological Survey CalEPA California Environmental Protection Agency CEQA California Environmental Quality Act Cal-OSHA California Occupational Safety and Health Administration CCR California Code of Regulations COC chain of custody

CMIST Cold Regions Research and Energy Laboratory multi-increment sampling tool

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act

CFR Code of Federal Regulations CIH Certified Industrial Hygienist COPC contaminant of potential concern CPR Community Profile Report DQO data quality objectives DTSC Department of Toxic Substances Control EE/CA Engineering Evaluation/Cost Analysis EIR Environmental Impact Report ESD Explanation of Significant Differences H&SC Health and Safety Code HSP Health and Safety Plan HERO Human and Ecological Risk Office HSCA Hazardous Substance Control Act HWCA Hazardous Waste Control Act IS Initial Study ISM incremental sampling methodology IDW investigation-derived waste mg/kg milligrams per kilogram mm millimeter MND Mitigated Negative Declaration MSL mean sea level NCP National Contingency Plan NPDES National Pollution Discharge Elimination System O&M operations and maintenance OMP Operations and Maintenance Plan OSHA Federal Occupational Safety and Health Administration PLM polarized light microscopy PEA Preliminary Endangerment Assessment PE Professional Engineer PEL Permissible Exposure Limit PG Professional Geologist QAPP Quality Assurance Project Plan RWQCB Regional Water Quality Control Board

RAO removal action objective RAW Removal Action Workplan RACR Removal Action Completion Report RCRA Resource Conservation and Recovery Act REC Recognized Environmental Condition ROD Record of Decision SCEM Site Conceptual Exposure Model SMAQMD Sacramento Metropolitan Air Quality Management District SOP standard operating procedures STLC Soluble Threshold Limit Concentration SWPPP Stormwater Pollution Prevention Plan SWRCB State Water Resources Control Board TCLP Toxicity Characteristic Leaching Procedure TEM transmission electron microscopy TTLC Total Threshold Limit Concentration USEPA United States Environmental Protection Agency USGS United States Geological Survey WET Waste Extraction Test YCG Youngdahl Consulting Group

Geocon Project No. S1376-03-02 - 1- April 23, 2019

1.0 INTRODUCTION

Geocon Consultants, Inc. completed a Preliminary Endangerment Assessment (PEA) and has prepared this Removal Action Workplan (RAW) to address naturally occurring asbestos (NOA) in soil at the Folsom Cordova Unified School District’s (the District) Proposed Mangini Ranch Elementary School (the Site) located at 14640 Sparrow Drive in Folsom, California. The Site is in the Mangini Ranch residential development south of US Route 50, north of White Rock Road, and between Scott Road to the west and Placerville Road to the east. This PEA Report/RAW was prepared in general accordance with the California Environmental Protection Agency (CalEPA), Department of Toxic Substance Control (DTSC) PEA Guidance Manual (2015). The mitigation measures set forth in the RAW have been conducted in general accordance with the California Health and Safety Code Chapter 6.8, Sections 25323.1 and 25356.1, the Code of Federal Regulations (CFR) Title 40 - Protection of the Environment Part 300 National Oil and Hazardous Substances Pollution Contingency Plan (NCP) (United States Environmental Protection Agency [USEPA], 1990), and the DTSC Memorandum: Removal Action Workplans, dated September 23, 1998, unless otherwise noted. This document includes an Engineering Evaluation/Cost Analysis (EE/CA) as required under section 300.415(b)(4)(i) of the NCP for all non-time critical removal actions.

1.1 Removal Action Objectives

Removal action objectives (RAO) are developed to mitigate impacts to human health and the environment due to a planned disturbance. Removal actions are subject to a different set of regulatory requirements than “remedial” actions. Therefore the term “removal” is used throughout this PEA/RAW in reference to the measures taken to mitigate potential exposure to NOA in soil at the Site. Because NOA exists naturally in soil and bedrock beneath the Site, it is impractical both physically and financially, to completely remove NOA from the Site. Therefore, the RAOs detailed in this RAW are to:

minimize site users’ (e.g., students, teachers and administrative staff, school maintenance workers, third-party workers, and site visitors) potential exposure to NOA in soil at the Site;

minimize the spread of NOA to adjacent properties via the air pathway;

facilitate site development for school use;

maximize confidence in the success of the removal action;

minimize long-term liability resulting from the removal action;

maximize public acceptance of the removal action; and

minimize the cost of removal actions.


1.2 Project Description

The District is proposing to acquire and develop the Site as an elementary school. The proposed elementary school will be part of the larger residential Mangini Ranch development that will include a park and additional school sites. Various phases of earthwork and construction are currently underway throughout the Mangini Ranch development. The school’s design plans include construction of a new approximately 66,000-square-foot, two-story school building of conventional steel-framed construction supported by conventional shallow foundation systems with concrete slabs-on-grade. Other site improvements will include retaining walls, underground utility infrastructure, asphalt-paved driveways and parking areas, concrete flatwork (quads and walkways), and landscaping. Existing and proposed site configurations are shown on the Site/Development Plan, Figure 3.

1.3 Responsible Agency

The DTSC is the responsible agency for the oversight of the characterization of the nature and extent of hazardous substances (NOA) on the Site and approval of a removal action to meet the removal action objectives stated herein. There has been no prior regulatory agency involvement with the Site.


2.0 PURPOSE, OBJECTIVES, AND SCOPE

2.1 Purpose and Objectives of the PEA

Previous assessment of the Site determined that no anthropogenic contaminants of potential concern (COPCs) are present on the Site, but that a geologic formation known to contain NOA is present in the northeastern portion of the Site, making NOA the primary COPC for the Site. The NOA-containing formation and associated soil in the northeastern portion of the Site were excavated to a depth of approximately 5 feet below the planned school development pad elevation and removed from the Site for use as fill elsewhere within the Mangini Ranch development. Clean fill material from the property (the future park site) adjacent to the west of the Site was then placed on the Site covering the NOA-containing rock and soil in the northeastern portion of the Site. The PEA was performed after the NOA-containing soil removal and placement of clean fill. Therefore, the primary purpose of the PEA was to perform a “confirmation assessment” of the fill for asbestos. The objective of the PEA was to collect a sufficient number of representative soil samples from the fill and have them analyzed for asbestos to achieve the purpose of the PEA. During a PEA scoping meeting with the DTSC on January 30, 2019, the DTSC requested that the fill material also be assessed for the metals arsenic and mercury. Therefore, for the purposes of the PEA, arsenic and mercury were also considered COPCs for the Site.

2.2 Purpose and Objectives of the RAW

The purpose of the RAW is to evaluate potential removal alternatives and select and describe the most appropriate one to mitigate exposure to asbestos on the Site. The objectives of the RAW are multifold and generally include: 1) to describe the Site, the planned school project, and the findings of the PEA; 2) establish RAOs that are protective of human health and the environment and enable the school to be constructed and safely occupied; 3) evaluate various removal action alternatives (including no action) against the criteria of long-term effectiveness and permanence, implementability, and cost; and 4) to select the most appropriate removal action and describe its implementation.

2.3 Scope of the PEA and RAW

The scope of the PEA is described in Section 4. Following the description of the site setting and the findings of the PEA, the scope of the RAW consists of an EE/CA (Section 9), a summary of applicable or relevant and appropriate requirements (ARARs - Section 10), and descriptions of the selected removal action and its implementation (Sections 11, 12, and 13).


3.0 BACKGROUND

3.1 Site Location and Description

The Site is located on the south side of Mangini Parkway between Scott and Placerville Roads and north of White Rock Road in Folsom, California, in the County of Sacramento (Figure 1). The Site is situated within the central portion of the new Mangini Ranch residential development, adjacent to the east of the proposed park site.

The site coordinates are 38.6271°N latitude and 121.1024°W longitude (WGS84 datum). Ultimately, the Site will be bounded by streets to the south and east, and residential development beyond the streets to the north, east, and south. Access is via Mangini Parkway from Scott Road, approximately 0.5 mile west of the Site, or from Placerville Road, approximately 0.3 mile east of the Site. The Site is depicted on the United States Geological Survey’s (USGS) Clarksville, California, 7.5-minute topographic map (USGS, 2012) in the southern quarter of Section 16 and the northern quarter of Section 21 in Township 9 North, Range 8 East, Mount Diablo Base and Meridian.

3.1.1 Site Name, Address, and Size

Site Name: Proposed Mangini Ranch Elementary School

Address: 14640 Sparrow Drive Folsom, California

Size: 8 acres

3.1.2 Contact Person, Mailing Address and Telephone Number

Contact Person: Geri Wickham, Planning/Project Manager

Mailing Address: Folsom Cordova Unified School District Facilities and Planning 1965 Birkmont Drive Rancho Cordova, California 95742

Telephone Number: 916.294.9000 ext. 103310

3.1.3 Environmental Consultant’s Contact Information

Contact Person: Jim Brake, PG

Mailing Address: Geocon Consultants, Inc. 3160 Gold Valley Drive, Suite 800 Rancho Cordova, California 95742

Telephone Number: 916.852.9118


3.1.4 Assessor’s Parcel Number (s) and Zoning

Sacramento County assessor’s parcel number (APN): 072-3370-008-0000. A parcel map is in Appendix A.

Zoning: AG80 - AGRICULTURE 80 ACRES MINIMUM

3.1.5 Ownership

Mangini Improvement Company, Inc.

3.1.6 Township, Range, Section and Meridian

Township 9 North, Range 8 East, Section 21 - Mount Diablo Base and Meridian

3.2 Operational History and Status

The historical land use of the Site appears to have been undeveloped grazing land from sometime prior to 1937 (earliest available information) until approximately 2017, when construction grading and excavation commenced. We did not identify information from historical resources of any prior development or mining on the Site or crop cultivation-type agricultural operations on the Site.

3.3 Topography

3.3.1 Original Topography

The original topography of the Site was characterized by low-relief hills with a low northeast-to-southwest-draining swale through the central portion of the Site and topographic highs near the northeastern and northwestern corners. Original elevations ranged from approximately 440 feet above mean sea level (MSL) near the northeastern corner of the Site to approximately 405 feet above MSL in the southwestern portion of the Site.

3.3.2 Post-grading Topography

From August through October of 2017, the project developer graded the Site to a relatively flat configuration as part of the overall mass grading of Mangini Ranch. The post-grading, rough pad elevation is approximately 431 to 432 feet above MSL. Additional remedial grading of the northern and eastern edge areas of the Site was performed in August of 2018. Geocon observed grading/fill placement at the Site on behalf of the District. Site grading included cuts up to approximately 10 feet and placement of up to approximately 20 feet of engineered fill to attain rough site grade. All fill material for the Site was derived from the non-NOA containing Salt Springs Slate and associated soil excavated from the future park area adjacent to the west.


3.4 Geology and Hydrogeology

3.4.1 Regional Geology

The Site is situated in the lower foothills, near the western edge of the Sierra Nevada geomorphic province of California. The foothills of the Sierra Nevada are typified by a belt of northwest-trending metamorphic, volcanic, and igneous rocks that have been sheared, deformed, and intruded during periods of tectonic and volcanic activity. Published geologic mapping (California Geological Survey [CGS], 1981) depicts the site vicinity as underlain by Jurassic-age Salt Springs Slate and Gopher Ridge Volcanics (map symbols Jss and Jgo, respectively), which generally consist of moderately to highly weathered, fractured rock with clay, silt, and sand infilling. Degree of weathering of the rock generally decreases with depth, with zones that are more resistant to breaking down.

3.4.2 Site Geology

We observed soil and geologic conditions on the Site in surface exposures, exploratory test pits excavated on July 21 and August 2, 2017 (before grading/fill placement), and exploratory borings performed on March 14, 2018 (after grading and initial fill placement).

3.4.2.1 Engineered Fill Derived from Salt Springs Slate

Engineered fill derived from Salt Springs Slate has been placed across the Site up to approximately elevation 431 to 432 feet above MSL. The engineered fill has a maximum depth of approximately 20 feet near the southwestern corner of the Site and minimum depth of approximately 3 feet in the northwestern corner of the Site. Geocon observed excavation and placement of the fill, derived from the Salt Springs Slate from the adjacent (future) park to the west, during August to October 2017 and August 2018.

3.4.2.2 Engineered Fill of Mangini Parkway

The embankment adjacent to the northern site boundary (north slope area) consists of engineered fill placed for the construction of Mangini Parkway and consists of mixed metavolcanic and metasedimentary rock and associated soils derived from various locations within the Mangini Ranch development. This material was not characterized for NOA content in conjunction with the PEA. It is assumed likely to contain low levels (<1%) of NOA based on the findings of various NOA assessments performed on metavolcanic materials in the area by Geocon and others (e.g., YCG, 2013).

3.4.2.3 Salt Springs Slate

Below the engineered fill, the Site is underlain predominantly by metasedimentary Salt Springs Slate. The slate is generally decomposed to intensely weathered at and near the surface, becoming less weathered with increasing depth. In borings B3 through B5 advanced during our investigation on


March 14, 2018, we encountered highly to slightly weathered slate that generally excavated as very dense, clayey/silty sand with weak to moderately strong, angular gravel and cobble. Salt Springs Slate is generally considered not likely to contain NOA.

3.4.2.4 Gopher Ridge Volcanics

Metavolcanic rock of the Gopher Ridge Volcanics underlies the engineered fill in the northeastern portion of the Site (Figure 2). At the Site, the Gopher Ridge Volcanics consists predominantly of variably weathered and moderately to intensely fractured andesitic metavolcanic rock. Gopher Ridge Volcanics is considered by the CGS as likely to contain NOA (CGS, 2006). Therefore, the northeastern portion of the Site underlain by Gopher Ridge Volcanics was overexcavated to a depth of at least 5 feet below finish grade and covered with orange filter fabric (“warning barrier”) before the area was covered with the engineered fill. Site photographs that follow the report figures and tables show the grading of the Site, placement of the warning barrier, and placement of fill on the Site.

3.4.3 Soil

According to the United States Department of Agriculture, Natural Resources Conservation Service, Web Soil Survey (https://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm), surface and near-surface soil at the Site consists of Whiterock loam formed on 3 to 30 percent slopes. This soil unit is described as somewhat excessively drained and formed on hills derived from residuum weathered from metasedimentary rock. The typical soil profile consists of loam from the surface to approximately 8 inches, underlain by unweathered bedrock from approximately 8 to 12 inches. The soil type is not considered to be prime farmland.

3.4.4 Naturally Occurring Asbestos

As described above, the northeastern portion of the Site is underlain by metavolcanic Gopher Ridge Volcanics and the remainder of the Site by Salt Springs Slate (Figure 2). Past studies of various properties in the vicinity have documented that the metavolcanic rocks in the region are likely to contain NOA, while the slate is unlikely to contain NOA.

3.4.5 Groundwater

We encountered seepage in B3 at a depth of approximately 2½ feet, during our investigation on March 14, 2018. We assume nearby ponding water to likely be the source of the seepage. During a geotechnical investigation on February 16, 2018, for a proposed bridge approximately one mile west-southwest of the Site, we encountered seepage in a boring at a depth of approximately 14 feet (elevation 340 feet). Each of these observations likely reflects transient wet-season soil moisture and not permanent groundwater.


We reviewed available depth-to-groundwater data on the California Department of Water Resources Groundwater Information Center Interactive Map Application (GICIMA) (https://gis.water.ca.gov/app/gicima/#bookmark_DepthBelowGroundSurface). Information available on the GICIMA website indicates depth to groundwater in the site vicinity is greater than 190 feet (Spring, 2018). Based on the geologic conditions at the Site, we expect that perched groundwater/seepage may develop at variable depths generally at the contacts between fill and formational materials (bedrock), especially during winter and spring. Seepage can also occur within formational material based on the degree of weathering, fracturing, and bedding. Depth to groundwater can also vary significantly due to localized pumping, irrigation practices, and seasonal fluctuations. Therefore, it is possible that future groundwater may be higher or lower than the levels observed during our investigation. We did not measure groundwater flow direction; however, our experience in the vicinity indicates that groundwater flow direction is variable and dependent on rock fractures and topography. Surface water follows local topography and flows southwest towards Alder Creek. Groundwater flow direction likely also mimics downslope topography flowing generally toward the west-southwest. Depth to groundwater and groundwater flow direction beneath the Aerojet General facility approximately 3 miles west of the Site are frequently monitored through a vast array of onsite and offsite groundwater monitoring wells. Groundwater flow direction there is toward the northwest, west, and southwest (Geosytec, 2019). The nearest documented contaminant impacts in groundwater related to the Aerojet General facility are approximately 3.5 miles west (downgradient) of the Site, so are not a threat to impact groundwater beneath the Site.

3.5 Land Uses, Sensitive Receptors, Ecosystems, and Cultural Resources

3.5.1 Land Uses

The Site was undeveloped and used solely for livestock grazing until grading for construction began in 2017. We identified no evidence of hazardous substances or petroleum products use, storage, or release onto the Site. Land uses surrounding the Site are/will be low-density, single-family residential, recreational (parks), and open space. North of the Site, beyond Mangini Parkway are single-family residences. West of the Site is vacant land, which will be developed into a community park. Land to the south and east of the Site is currently undeveloped or in the process of being developed with single-family residences.

3.5.2 Sensitive Receptors

There are currently no sensitive receptors on the Site, however, as described in the Mitigated Negative


Declaration, Mangini Ranch Elementary School (MND) which is described in Section 10.2.2, the Site will be developed as an elementary school that will accommodate approximately 663 elementary school-age children, 30 teachers and administrative staff, and maintenance staff. The nearest offsite receptors will be residents occupying the single-family residences north, south, and east of the Site.

3.5.3 Ecosystems

Section 4.6 of the MND describes the site vegetation as being “annual grassland characterized by a dense cover of nonnative annual grasses interspersed with numerous species of nonnative annual forbs and native wildflowers.” Various vegetation species observed on the Site are listed. The MND states that there are no known sensitive biological areas or sensitive habitat on the Site.

3.5.4 Cultural Resources

Section 4.7 of the MND describes the prehistorical and historical settings of the Site and states that there are no structures considered to be historic resources or landmarks on the Site. Section 4.7.3, Cultural Resources Environmental Checklist and Discussion, lists all impacts as either “less than significant” or that there would be no impact from the project and makes the following statements regarding cultural resources on the Site:

“The subject site is not listed on a local, the State or National Register which lists properties or sites or historic significance.”

“There are no known archeological sites on the site and the site is currently disturbed and developed.”

“There are no known geological or paleontological resources in the vicinity of the site.”

“Although it is not anticipated that any human remains would be on site (i.e. the area of the site is not a known burial ground) in order to ensure impacts are less than significant, the District shall implement Mitigation Measure Cul-1.”

Mitigation Measure Cul-1 states: “If, during construction, human remains are uncovered, work shall

be halted or diverted in the immediate area while a qualified archaeologist, coroner, and or Native

American representative evaluates the find and makes recommendations pursuant to California

Environmental Quality Act (CEQA) Guidelines Section 15064.5(e). This language shall be included in

construction documents for the project.”

3.6 Climate

The local meteorology of the project area is represented by measurements recorded at the Folsom Dam station. The climate of the Site and surrounding region is characterized by hot, dry summers and cool, rainy winters. The average winter temperature is 49 degrees Fahrenheit (°F). During the summer, daily


temperatures range from 50°F to over 100°F. January temperatures range from an average minimum of 37.9°F to an average maximum of 53.7°F. July temperatures range from an average minimum of 60.3°F to an average maximum of 94.5°F (Western Regional Climate Center, 2010). Most precipitation in the area derives from storms that move in from the west or northwest from the Pacific Ocean during the winter months. More than half the total annual precipitation falls during the winter rainy season (November–February). The average annual precipitation is approximately 24 inches (Western Regional Climate Center, 2009). Dense low-level fog can occur between these winter storms. The predominant wind direction and speed is from the southeast-southwest at approximately 7 to 8 mph (https://www.windfinder.com/windstatistics/sacramento_mather_airport).

3.7 Previous Site Actions

Previous site actions have included:

Phase I Environmental Site Assessments (ESA) in 2007 and 2012 of the larger Mangini Property, which included the Site;

a “Limited Phase II Soil Investigation” of the Mangini property in 2007;

a NOA assessment of five proposed school sites in the larger Folsom Plan Area, which included the Site in 2013;

a geotechnical engineering study for Mangini Ranch, including the Site, in July 2014;

a NOA assessment of “Mangini Phase I School Site” in August 2014;

a supplemental geotechnical study for the Site in July 2017;

rough grading of the Site to a pad elevation of approximately 431 to 432 feet above MSL in 2017;

a geologic hazards evaluation and geotechnical investigation of the Site in July 2018; and

remedial grading of the Site to cover NOA-containing Gopher Ridge Volcanics in August 2018.

Following are summaries of the findings and results of these assessments, investigations, and site grading activities as presented in their respective reports and in chronological order. Copies of prior reports described below are in Appendix B.

3.7.1 Phase I ESA - 2007

Phase I Site Assessment for Mangini Property, APNs 072-0060-038 and 072-0060-069, NWC of White

Rock Road and Old Placerville Road, Folsom, Sacramento County, California, prepared by Youngdahl Consulting Group, Inc. (YCG) and dated March 20, 2007. This report describes YCG’s evaluation of two parcels (APNs 072-0060-038 and 072-0060-069) that included the Site and other surrounding land west and east of Scott Road. The current site parcel was formerly part of APN 072-0060-038.


The two parcels were undeveloped grazing land with livestock-related structure foundations, a well, a stone building, and former gold exploration features. Scott Road bisected the two parcels and unimproved ranch roads and Alder Creek extended across the property. Surrounding properties were similar livestock grazing land and rural residential properties. YCG’s interview with the former site owner, Al Mangini, indicated that he owned the property from 1975 to 2002 and used it for cattle grazing. Prior to 1975, Mr. Mangini indicated the land was used for gold exploration, cattle grazing, and dairy farming. Mr. Mangini sold the property to the developer Angelo Tsakopoulos in 2002, but the seasonal cattle grazing use continued. YCG noted remnants of past mining activities that included multiple open mine shafts, multiple exploration pits, waste rock piles, and the footprint and sidewalls of an old mining structure (residence). Four open, vertical mine shafts were noted in the northwestern portion of the parcel west of Scott Road. Waste rock piles and hummocky land (overgrown waste rock piles) were noted near the open mine shafts, along the banks of Alder Creek, and in areas with exploration pits. The remains of an historic house was located northwest of Scott Road and an abandoned well was near White Rock Road. YCG concluded that the potential adverse impacts from past mining operations were a recognized environmental condition (REC) for that property. None of the identified features were on the Site.

3.7.2 Limited Phase II Soil Investigation - 2007

Limited Phase II Soil Investigation for Mercury and Arsenic, Mangini Property, NWC of White Rock

Road and Old Placerville Road, Folsom, Sacramento County, California, prepared by YCG and dated May 2007. YCG conducted a limited investigation of soil on the Mangini Property for mercury and arsenic based on the findings of their Phase I ESA. Areas/features of concern were identified as the waste rock piles from four vertical mine shafts. None of the four areas investigated were on the Site or parcels adjacent to the Site. YCG also collected 30 soil samples within drainages that had been disturbed by mining and composited the samples into four composite soil samples prior to analysis.

YCG reported that mercury concentrations in the soil samples ranged from less than the reporting limit of 0.010 milligrams per kilogram (mg/kg) to 1.75 mg/kg and that none exceeded the California Human Health Screening Level (CHHSL) for mercury of 18 mg/kg for soil in a residential setting. Arsenic was detected at concentrations up to 98.1 mg/kg, which exceeded the CHHSL for arsenic in residential soil. However, YCG performed a statistical analysis of the arsenic concentrations and concluded that the arsenic in soil was likely representative of naturally occurring background conditions, and not the result of mining activities.

The CHHSLs that YCG references in their report are no longer used in favor of DTSC’s Human and Ecological Risk Office (HERO) Note 3 soil screening levels (Note 3 SLs, updated June 2018) or the USEPA’s Regional Screening Levels (RSLs, updated November 2018) if there is not a Note 3 SL for a COPC. The Note 3 SL for mercury in residential soil is 1.0 mg/kg and the RSL is 11 mg/kg. Only one of YCG’s soil samples had a mercury concentration that exceeded the Note 3 SL and none exceeded the RSL. The Note 3 SL for arsenic in residential soil is 0.11 mg/kg and the RSL is 0.68 mg/kg. All of YCG’s samples had reported arsenic concentrations exceeding the Note 3 SL and all but two exceeded


the RSL. However, as noted above the arsenic concentrations appear to be naturally occurring background levels for the area. See Section 4.4.4.1 for further discussion of site-specific arsenic studies.

3.7.3 Phase I ESA - 2012

Phase I Site Assessment for Mangini Property, APNs 072-0060-038 and 072-0060-069, NWC of White

Rock Road and Old Placerville Road, Folsom, Sacramento County, California, prepared by YCG and dated September 27, 2012. This report updated YCG’s Phase I ESA conducted in 2007. The Mangini property and surrounding properties had remained undeveloped and unchanged since 2007. YCG did not identify RECs; however, they noted a potential REC from existing gold exploration features that were identified away from the Site and adjacent properties.

3.7.4 NOA Assessment - 2013

Folsom Plan Area Schools, Folsom, California, Naturally Occurring Asbestos Assessment, prepared by YCG and dated September 10, 2013. YCG evaluated the potential presence of NOA on five previously-proposed school sites within approximately one mile west, north, and northeast of the Site. YCG excavated 5-foot-deep test pits on the properties and collected soil samples for NOA analysis. The five proposed school sites were within metavolcanic and/or metasedimentary rock some of which was suspected to contain NOA. YCG’s NOA assessment concluded that “low levels” (less than 1%) of NOA were identified in most of the metavolcanic rock samples. NOA was not identified in the metasedimentary rock samples.

3.7.5 Geotechnical Engineering Study – July 2014

Geotechnical Engineering Study for Mangini Ranch, Phase I, prepared by YCG and dated July 31, 2014. YCG evaluated the surface and subsurface soil conditions for the Mangini Property (including the Site) for purposes of providing geotechnical information and design criteria for future improvements. The study was performed for geotechnical purposes and not to evaluate potential environmental contamination. Thirty three test pits were excavated and soils logged. YCG reported that soils on the Site and in the surrounding vicinity consist of sandy silt from the surface to approximately 1.5 feet underlain by medium stiff clay from approximately 1.5 feet to 4 feet. Weathered bedrock was encountered beneath the clay to the total depth explored of 11 feet. Occasional perched groundwater was encountered on less weathered bedrock. No staining or odors were identified in the YCG test pit logs.

3.7.6 NOA Assessment – August 2014

Mangini Phase I School Site, Folsom, California, preparted by YCG and dated August 28, 2014. The property YCG evaluated was the future park site immediately adjacent to the west of the current school site. YCG reviewed available geologic literature, observed site geologic conditions, excavated eight exploratory test pits, and collected soil/rock samples for asbestos analysis. Slate bedrock was encountered in each test pit and asbestos was not detected in any of the eight samples analyzed. YCG’s conclusion from this assessment was that this property would not need mitigation for NOA as a school site.


3.7.7 Rough Grading Plans

Rough Grading Plans (Sheets 22 and 27), Mangini Ranch – Phase 1, prepared by MacKay & Somps, dated March 2017. The grading plans depict the existing topography and grading details for the project with the proposed Mangini Elementary School site depicted on Lot 19 and a large Park Site, Lot 20, to the west of the Site. The depicted topography of the Site shows higher elevations on the northeastern and northwestern portions of the Site.

3.7.8 Supplemental Geotechnical Study

Transfer of Geotechnical Responsibility and Supplemental Geotechnical Recommendations, Proposed

Mangini Ranch Elementary School, Folsom, California, prepared by Geocon, dated August 3, 2017. On July 21, 2017, we observed soil in seven test pits (TPB through TPH, Figure 3) excavated by the grading contractor (Goodfellow Top Grade Construction). We observed that soil and rock in the northeastern portion of the school site is underlain by metavolcanic Gopher Ridge Volcanics and the remainder of the Site by Salt Springs Slate. We provided supplemental geotechnical recommendations intended to supplement/supersede (as appropriate) the recommendations contained in YCG’s geotechnical report consisting of the following:

All fill material placed on the Site should be derived from the Salt Springs Slate and not from metavolcanics such as the Gopher Ridge Volcanics.

All fill material for the school site and placed within 5 feet of finished grade and within 10 feet of slope faces (slope zones) should consist of predominately 6-inch minus material with sufficient gravel/sand/fines portions to result in a broadly graded material.

Fill material placed greater than 5 feet below finished grade and outside of slope zones may consist of “soil-rock” fill with a maximum rock size of 2 feet in maximum dimension in a matrix of compacted “soil” fill.

The area of metavolcanic rock/soil at the Site should be overexcavated to a depth of at least 5 feet below finished grade, covered with a marker/warning barrier material (e.g., black or orange nylon mesh or construction fencing), and then backfilled to grade with engineered fill derived from the Salt Springs Slate.

Overexcavated metavolcanic rock/soil from the Site should not be reused elsewhere on the Site.

In addition to the undercut recommended to remove NOA from the northeastern portion of the Site, to reduce potential for differential settlement of planned structures, other cut portions of the Site should be undercut at least 3 feet below finished grade and replaced with engineered fill derived from the Salt Springs Slate.

3.7.9 Geologic Hazards Evaluation and Geotechnical Investigation

Geologic Hazards Evaluation and Geotechnical Investigation, Mangini Ranch Elementary School, White

Rock Road and Placerville Road, Folsom, California, prepared by Geocon, dated July 31, 2018. We performed a geologic hazards evaluation and geotechnical investigation for the Site (post-placement of Salt Springs Slate fill) in accordance with the current CGS guidelines to evaluate the subsurface


conditions at the Site and provide conclusions and recommendations relative to the geotechnical aspects of designing and constructing the project. Our scope of work included observing soil/rock in 19 test pits excavated on and immediately adjacent to the Site by the grading contractor and advancing five exploratory borings on the Site to depths ranging from approximately 5 to 15½ feet using hollow-stem auger drilling equipment. We confirmed that the northeastern portion of the Site is underlain by metavolcanic Gopher Ridge Volcanics, the remainder of the Site is underlain by Salt Springs Slate, and that the Site had been capped by approximately 3 to 20 feet of engineered fill material derived from Salt Springs Slate from the adjacent future park site. The engineered fill is at least 5 feet thick over the portion of the Site underlain by metavolcanic rock, and a layer of orange geotextile fabric was present between the fill and the metavolcanic rock serving as a warning barrier. Approximate lateral extents of the geologic units and fill we identified are shown on the Site/Development Plan, Figure 2. We concluded that no soil or geologic conditions were encountered during our investigation that would preclude development of the Site as planned, provided the recommendations contained in our report were incorporated into the design and construction of the project.

3.7.10 Summary

Prior assessments, studies, and investigations of the Site and surrounding properties found that the Site and surrounding properties have been undeveloped until the recent grading/fill placement on the Mangini Ranch Elementary School site and adjoining park area in 2017 and 2018. No releases1 of hazardous materials or petroleum products or evidence of RECs were identified at the Site with the exception that metavolcanic bedrock considered likely to contain NOA underlies the northeastern portion of the Site. We recommended in our July 2017 Transfer of Geotechnical Responsibility and

Supplemental Geotechnical Recommendations letter (Section 3.7.8) that the metavolcanic rock be overexcavated to a depth of at least 5 feet below finished grade, covered with a marker/warning barrier material (e.g., black or orange nylon mesh or construction fencing), and then backfilled to grade with engineered fill derived from the Salt Springs Slate. In our July 2018 Geologic Hazards Evaluation and

Geotechnical Investigation report, we observed that that recommendation had been substantially completed.

1 "Release" refers to an unauthorized release of a petroleum product or hazardous substance to the

environment - i.e. the ground surface, soil, soil vapor, groundwater, or surface water on a property.


4.0 PEA

As stated in Section 2.1, we performed the PEA as a confirmation assessment of the engineered fill derived from Salt Springs Slate excavated from the future park area immediately west of the Site and placed on the Site in 2017 for the potential presence of NOA. We performed the PEA in general accordance with the following guidance documents:

1. ASTM Designation E1527-13 Standard Practice for Environmental Site Assessments: Phase I Environmental Site Assessment Process.

2. DTSC’s Preliminary Environmental Assessment Guidance Manual, dated January 1994, Interim Final revised October 2015.

3. DTSC’s Interim Guidance, Naturally Occurring Asbestos (NOA) at School Sites, revised September 2004.

4. Interstate Technology Regulatory Council’s Technical and Regulatory Guidance – Incremental Sampling, dated February 2012.

4.1 Soil Sampling Rationale

We collected soil samples from the surface of the engineered fill material that had been placed on the Site to assess the potential presence of NOA. As described in Section 3.7.4, YCG had performed a preliminary characterization of the proposed (unexcavated) fill material borrow area for NOA (which Geocon observed on behalf of the District) in 2013 and asbestos was not detected (<0.0005 weight%) in any of the eight samples (YCG, 2013). Geocon representatives, on behalf of the District, observed the excavation, placement, and compaction of the fill material on the Site from August through October 2017. Because the process of excavation, loading, dumping, and placement/spreading of the fill on the Site appeared to thoroughly homogenize the fill, we collected only surface samples from the fill as we were confident they would be representative of the fill as a whole. We collected soil samples for asbestos analysis using two methods - incremental sampling methodology (ISM) and discrete sampling. We used an ISM sampling approach during three separate sampling events (Figures 4 through 6) to collect soil samples from the fill throughout the Site. We performed discrete sampling in selected locations in the northern and eastern edge areas of the Site (Figure 5), and compositing of discrete samples (with follow-up via ISM) after the remedial grading and last placement of fill on the northern and eastern edge areas of the Site was completed in August 2018 (Figure 6). Descriptions of ISM and discrete soil sampling methodologies and procedures are described in the following sections.

4.1.1 ISM Soil Sampling Methodology

ISM is a structured composite sampling and processing protocol intended to produce samples that, when analyzed, result in reduced data variability and uncertainty and which provide a reasonably unbiased, high-confidence estimate of mean COPC concentrations in a targeted area. The area to be


assessed is first divided into “decision units” (DUs). The size and locations of DUs can be determined based on several factors including: 1) the size of the area being investigated, 2) suspected or known nature and extent of COPCs from previous assessment/investigation, and 3) professional judgement. In cases where COPCs are expected to be somewhat evenly distributed or widespread across an area of interest, not every DU in that area may need to be sampled. A representative number of DUs can be randomly selected and sampled and the COPC concentrations for those DUs assumed to be representative of COPC concentrations in the area as a whole. The Site is approximately 8 acres, therefore we initially divided the Site into eight DUs (DU1 through DU8, Figure 4) of approximately one acre each. Due to the relatively homogenous nature of the fill, we then randomly selected DU2, DU4, and DU5 for ISM sampling. Next, we divided each DU to be sampled into 30 “sampling units” (SUs). We randomly selected three “increment” sampling locations (locations 1, 2, and 3, Figure 4) within each SU, the positions of which were kept the same in each SU. We then collected three increment soil samples from each SU. We combined the increment samples from the same location in each SU to create three, 30-increment “replicate” samples representing soil in that DU (“replicate 1”, “replicate 2”, and “replicate 3”). After the sampling was completed and the samples submitted to the laboratory, the laboratory further processed and subsampled the submitted replicate samples according to specific ISM laboratory protocols prior to analysis. A detailed description of ISM sampling procedures is in Section 4.2.2 and details of our iterative sampling approach over several “sampling events” using a combination of ISM, discrete sampling, and simple compositing of discrete samples to target specific areas of the Site, is in Section 4.4.2.

4.1.2 Discrete Sampling

We collected discrete soil samples MSS1 through MSS8 from the northern and eastern edge areas of the Site (Figure 5). We also collected discrete soil samples MSS9A/B/C through MSS14A/B/C (Figure 6) following the final round of engineered fill placement in August 2018. Samples MSS9A/B/C through MSS14A/B/C were composited by the laboratory into 3-part composite samples for analysis. As indicated on the Site Conceptual Exposure Model (SCEM, Figure 7), “affected soil” is the only source associated with NOA that could potentially impact receptors. Therefore, no other sampling of other environmental media (e.g., groundwater, surface water, soil vapor, etc.) was performed.

4.2 Soil Sampling Procedures

We collected ISM and discrete soil samples manually using stainless steel implements. No mechanically-powered sampling equipment (e.g., drill rig) or electronic screening devices (e.g., photo-ionization detector) was used. Field equipment included:


Cold Regions Research and Energy Laboratory multi-increment sampling tool (CMIST) for ISM sampling;

Stainless steel trowel for discrete soil sampling;

Decontamination equipment;

o 5-gallon buckets (three),

o Brushes (three),

o Non-phosphate detergent (one quart), and

o Purified water (approximately 10 gallons).

5-gallon replicate sample buckets (three);

Resealable plastic bags;

Level D personal protective equipment;

Cellular phone;

Digital camera;

Sample container labels and custody seals;

Sample chain-of-custody (COC) forms;

Permanent black-ink pens and markers; and

Support truck.

4.2.1 Field Screening

Field screening included observation of soil obtained during sampling for preliminary indications of chemical impacts (i.e., presence of non-soil debris, soil discoloration, odor). Observations were made by experienced field personnel and documented in field notes. There were no visible indications of possible chemical impacts observed in any of the samples.

4.2.2 ISM Soil Sampling Procedures

Following are descriptions of the ISM soil sample location and collection procedures we used for each DU:

We delineated DU1 through DU8 and the 30 SUs in DU2, DU4, and DU5 (Figure 4) using a measuring wheel and various site features (i.e., light posts, roadways, trees, fence lines, etc.).

We randomly selected three increment sampling locations within each SU then estimated the same locations in each SU as sampling progressed from one SU to the next.

We collected the increment samples using CMISTs. A CMIST is designed to collect a consistent volume of soil (the size of the coring bit is adjustable) to create replicate samples of a pre-determined volume – in this case approximately one kilogram. In some locations hard, gravelly conditions necessitated loosening of soil with a geologic hammer/pick prior to obtaining an increment sample with the CMIST.


In each DU we used three CMISTs to collect all three increment samples simultaneously. Each of the three increments were placed in their respective clean 2-gallon resealable bag placed in a 5-gallon bucket marked with the corresponding number (“replicate 1,” “replicate 2,” and “replicate 3”). Then the three CMISTs (each labeled with its respective increment/replicate number) and bags/buckets were moved to the adjacent SU to collect all three increment samples from the same relative positions and place them into their corresponding bag/bucket. This was continued until all 30 increments of all three replicates for that DU were collected.

When all 30 sample increments for each of the three replicate samples for a DU had been collected into the resealable bag in the respective buckets, the bags were each labeled with an ID corresponding to the DU and replicate (i.e., DU1-1 = soil sample from decision unit 1, replicate 1) and placed in a cooler for transport to the analytical laboratory.

The three CMISTs (and other tools, when applicable) were then decontaminated with a water and AlconoxTM solution and rinsed with clean deionized water for use in the next DU.

The next DU was sampled by repeating the same ISM process outlined above.

4.2.3 Discrete Soil Sampling Procedures

We collected discrete samples using a clean geologic hammer to loosen soil for collection and stainless-steel trowel or hand-auger from 0 to 6 inches below the ground surface. The area of and around the location to be sampled was cleared of surface debris and vegetation prior to sampling. The discrete samples were placed directly into individual resealable plastic bags, securely sealed, appropriately labeled, and placed in coolers for delivery by courier to the laboratory under standard COC protocol. The samples were analyzed on varied turnaround times. To prevent potential sample cross-contamination, sampling personnel wore appropriate disposable gloves, which were changed between samples.

4.2.4 Decontamination Procedures

All reusable equipment that came in direct contact with soil, including the CMISTs, geologic hammer, stainless steel hand-trowels, and hand-auger were initially decontaminated and then decontaminated before collection of samples using a three-bucket wash-and-rinse procedure as follows:

Approximately 3 gallons of de-ionized water were put into each of three 5-gallon buckets. An appropriate amount of non-phosphate detergent (e.g., “Liquinox” or “Alconox”) was put into the first bucket to create a detergent solution.

Brushed the entire surface of the equipment in the detergent solution.

Double-rinsed the equipment in the remaining buckets.

Allowed the equipment to air-dry, if time permitted.


4.2.5 Disposal of Residual Materials

Investigation-derived waste (IDW) generated during the PEA included decontamination water, personal protective equipment (e.g., disposable gloves), plastic bags, and miscellaneous paper/plastic trash. Waste decontamination water totaled approximately 6 to 8 gallons and was likely not materially impacted by COPCs due to dilution (if at all). It was poured on to a weed-covered portion in the northern slope area of the Site. Other IDW was put into a plastic bag and placed in a municipal refuse dumpster.

4.2.6 Sample Documentation and Shipment

Field personnel were responsible for documenting and appropriately communicating information obtained in the field to our Project Manager. Any problems or inconsistencies regarding sample documentation procedures were resolved immediately by our Project Manager based on consultation with field personnel. Sample documentation and shipping procedures included:

Maintenance of field notes to record where, when, how, and from whom pertinent project information was obtained.

Photographs to document site conditions and representative field activities.

Sample COC forms were completed as sampling activities progressed to record sample numbers, the sample collection date and times, and requested analyses.

Samples from each sampling event were brought from the field to Geocon’s office in Rancho Cordova, where the Project Manager reviewed the samples and COCs prior to shipping the samples to the laboratory via FedEx.

4.3 Laboratory Analysis

This section summarizes the laboratory analyses and results for the soil samples collected for the PEA. As stated in Sections 2.1, NOA associated with metavolcanic rock and associated soil is the primary COPC at the Site and therefore the focus of the majority of the laboratory analyses performed. Arsenic and mercury were added to the analysis program as COPCs at the request of the DTSC.

4.3.1 Analytical Laboratory

All samples were submitted to EMSL’s Cinnaminson, New Jersey laboratory for analysis. EMSL is accredited by the California State Water Resources Control Board’s (SWRCB) Environmental Laboratory Accreditation Program and the National Environmental Laboratory Accreditation Program. For ISM samples, EMSL performed ISM sample processing in accordance with their Quality Assurance Project Plan (QAPP) and standard operating procedures (SOPs). In summary, ISM sample processing consisted of the following steps:


Disaggregated the 1-kilogram sample by hand; if larger aggregates remain, they were broken down with a mortar and pestle (the sample was not pulverized in a ball mill);

The sample was then placed on an aluminum foil-lined tray, put in a fume hood, and air-dried for a minimum of 24 hours;

Once dry, the sample was sieved through a 2-millimeter (mm) sieve to remove any unwanted debris (leaves, roots, etc.), then all sieved-fractions were reincorporated into one homogenized sample;

The sample was then spread on to another aluminum-foil lined sheet and molded into a two-dimensional slab cake. The sample layer had a depth of less than one-half inch to allow for sampling throughout the entire depth of the sample layer;

The slab cake was then gridded into 30 units;

Approximately equal subsamples from each grid division were collected using a flat-ended spoon made of some inert material; and

The subsamples were combined into one aliquot for each analysis required.

Following the ISM processing steps outlined above, the prepared sample was then analyzed by the California Air Resources Board (CARB) Method 435 milling preparation or the ASTM D7521 sieving preparation for asbestos. The laboratory documented analytical data in written reports that include sample results and copies of COCs. In addition, per our request, they provided count sheets and photomicrographs for positive samples, and reported not only regulated asbestos structures, but also other non-regulated asbestiform minerals and elongate/non-asbestiform minerals. The laboratory reports are in Appendix C. Activities and responsibilities associated with laboratory data review, data management, and assessment oversight processes are summarized in EMSL’s QAPP.

4.3.2 Analyses

4.3.2.1 Asbestos

Samples were analyzed for asbestos using the following methods:

Transmission electron microscopy (TEM), USEPA Method 600/R-93/116 with CARB Method 435 (milling) preparation and analytical sensitivity of 0.0005 weight (wt) %;

ASTM D7521 sieves the sample (no milling) into three size fractions: coarse (>2-mm), medium (<2-mm and >106-µm), and fine (<106-µm) and has a method analytical sensitivity of 0.25 wt%. Each fraction is analyzed separately by stereomicroscopy and polarized light microscopy (PLM) using calibrated visual area estimation and identification consistent with USEPA 600/R-93/116; and

The fine fraction (<106 um) from the ASTM D7521 sieve preparation (no milling) was analyzed by EPA Method 600/R-93/116 by TEM, and analytical sensitivity of 0.001 wt%.


TEM analysis for NOA via EPA Method 600/R-93/116 with the CARB Method 435 milling preparation is the analytical method preferred and recommended by DTSC for school site evaluations (DTSC, 2004). We used this method as the initial step for all samples analyzed for this PEA. However, the milling preparation of samples is a matter of much debate among those involved in the field of NOA-related assessments, as the grinding of amphibole minerals such as actinolite can lead to the creation of elongate cleavage fragments that fit the counting criteria for asbestos structures (e.g., Langer et al., 1991; Thompson et al., 2011). In other words, the milling preparation of a sample may result in the creation of asbestos-like structures that were not present in the unmilled sample. The milling preparation serves, among other purposes, to break down coarser-grained sample material and generate more fines (potentially including asbestos fibers, if present) as may occur during earthwork/grading activities. As a supplemental characterization step in this study, and to aid in determining whether the milling preparation was creating asbestos-like structures (false positives), we had EMSL analyze unmilled portions of some site samples using USEPA Method 600/R-93/116 (PLM and TEM) with the ASTM D7521 sieving preparation method. This provided us with the opportunity to compare analytical results for milled and sieved (unmilled) preparations of the same sample.

4.3.2.2 Arsenic and Mercury

EMSL also analyzed selected samples at our direction for arsenic by USEPA Method 6010B and mercury by EPA Method 7471B. At DTSC’s direction, selected samples that had been analyzed for arsenic were subsequently analyzed for bioaccessible arsenic by the California Arsenic Bioaccessibility (CAB) method. The CAB analyses were performed by Prima Environmental, Inc. (Prima) of El Dorado Hills, California. Prima worked with the USGS, DTSC, and university researchers to develop the CAB method.

4.4 Findings

4.4.1 Field Observations

Our field observations were that, aside from changing seasons and weather conditions, the condition of the Site remained generally consistent during the period of the PEA. The Site was vacant and had been hydroseeded during fall 2017 following the initial grading and placement of clean fill. Weather conditions varied significantly during sampling activities, ranging from cool, cloudy springtime weather in the low 60s (degrees Fahrenheit) to hot summer temperatures on the order of 100 degrees Fahrenheit. We observed that the engineered fill placed across the Site is primarily gray to grayish-brown clayey sand with gravel and cobbles. The coarse fraction is predominantly slate, though some clasts of quartz, graywacke sandstone, siltstone, tuff, and andesitic rock were also observed. Photographs of the Site are provided following the figures and tables.


During Spring 2018, following receipt of the laboratory analysis results for the initial ISM samples from the Site, we observed visually obvious metavolcanic (NOA-containing) soil on portions of the northern and eastern edge areas of the Site, which had eroded and/or been tracked from the adjacent slopes onto the surface of the engineered clean fill during the preceding Winter wet season. No obvious indications of other chemical impacts (e.g. soil discoloration and odor) were observed or noted during sampling activities.

4.4.2 Laboratory Analysis Results - Asbestos

Laboratory analysis results are tabulated in Table 1, depicted on Figures 4 through 6, and summarized below. It should be noted that results of the ASTM D7521 preparation method (wt%) reflect the weight percent relative to the fine fraction (passing 106 micron sieve) of the sample only. As such, they are not directly comparable to results associated with the CARB 435 milling preparation, but serve primarily as a check on the presence/absence of asbestos structures.

April 13, 2018 Sampling Event – DU2, DU4, and DU5

Asbestos (actinolite) was detected in the milled preparations of ISM replicate samples from DU4 at concentrations ranging from <0.0005 to 0.0498 wt%. Asbestos was also detected in milled preparations of two of the DU2 replicates (DU2-1NOA at 0.0358 wt% and DU2-2NOA at 0.0017 wt%) and one of the DU5 replicates (DU5-3NOA). However, asbestos was not detected in the sieved preparations of DU2-1NOA or DU5-3NOA at an analytical sensitivity of 0.001 wt% (Figure 4). We noted the presence of visually obvious metavolcanics in the northern and eastern edge areas that had eroded and/or had been tracked from the adjacent embankments onto the clean fill and likely accounted for the confirmed presence of asbestos in the DU4 replicates. Based on these laboratory analysis results and our field observations, we reconfigured the DUs and conducted discrete sampling in the northern and eastern edge areas and ISM sampling of the other DUs. As shown on Figure 5, we reconfigured DU1 and DU3 by excluding the northern edge area portions from these DUs and we also excluded a wider portion of the eastern edge area from DU8. We subsequently widened DU6 and DU7 to cover the area of the former DU6, DU7, and narrower DU8. The north-northeast/south-southwest orientation of the boundary between the new DU6 and DU7 followed an observed pattern in the fill.

July 3, 2018 Sampling Event – DU1, DU3, DU6, DU7, and MSS1-0 through MSS8-0

Asbestos was not detected in milled preparations of any of the ISM replicate samples from DU1, DU3, DU6, or DU7, or in discrete samples MSS3-0 through MSS8-0 at an analytical sensitivity of 0.0005 wt%. Asbestos (actinolite) was detected in the milled preparations of discrete samples MSS1-0 and MSS2-0 at 0.1089 wt% and 0.3162 wt%, respectively. Asbestos was also detected in the sieved (unmilled) preparations of those two samples, confirming the asbestos detections in the milled samples (Figure 5). These results confirmed that fill in the pad area did not contain asbestos at concentrations equal to or exceeding 0.01 wt%, but that asbestos was present in the northern edge area adjacent to the Mangini


Parkway embankment fill at concentrations exceeding 0.01 wt%. Visually obvious surficial metavolcanic soil was also observed on the eastern edge area. Therefore, we performed remedial grading consisting of removal of 6 to 18 inches of fill from the northern and eastern edge areas in an effort to remove the surficial metalvolcanic soil from that area. In the northwestern edge area, visually obvious metavolcanic soils were present (mixed with the slate fill) to a greater depth than other edge areas, so remedial grading in that area extended to a depth of 18 inches.

August 10, 2018 Sampling Event – MSS1B and MSS2B

Discrete samples MSS1B and MSS2B were subsequently collected from the northwestern edge area following the remedial grading (removal) of surficial metalvolcanics from that area in July 2018. Asbestos was not detected in the milled preparation of discrete sample MSS1B at an analytical sensitivity of 0.0005 wt%. Asbestos (actinolite, ferro-hornblende, and magnesio-hornblende) was detected in the milled preparation of discrete sample MSS2B at a concentration of 0.2715 wt%. Based on the asbestos concentration reported for MSS2B, additional fill material was removed from the northwestern edge area down to native slate bedrock at depths of approximately 2½ to 3 feet and placed as deep fill at the future park site. Following this second remedial grading/removal, additional engineered fill consisting of Salt Springs Slate was placed on the school site pad to raise the entire pad approximately 1 to 2 feet to final rough-grade elevations and filling the remedial grading areas. Cross-sections A-A’ (Figure 8) and B-B’ (Figure 9) show the clean fill cover placed on the Site in 2017 and in August 2018.

September 7, 2018 Sampling Event – MSS9-ABC through MSS14-ABC

Confirmation samples consisting of composited 3-part discrete samples MSS9-ABC through MSS14-ABC were collected from the additional fill material placed on the Site. Asbestos was not detected in milled preparations of any of the composite samples at an analytical sensitivity of 0.0005 wt%. Sieved preparations of MSS9-ABC, MSS10-ABC, and MSS12-ABC were also analyzed for asbestos with an analytical sensitivity of 0.0005 wt%. Asbestos (actinolite) was detected in the sieved preparation of MSS10-ABC at a concentration of 0.1086 wt%, but was not detected (<0.0005 wt%) in the sieved preparations of MSS9-ABC and MSS12-ABC (Figure 6). With the exception of MSS10-ABC, these results generally confirmed the absence of asbestos across the Site following placement of the additional clean fill cover in August 2018. Due to the mixed results for sample MSS10-ABC, we followed up with ISM sampling of DU10, as described below, to obtain a more representative characterization.

October 12, 2018 – DU10-1 through DU10-3

Asbestos (actinolite) was detected in the milled preparations of replicate samples from DU10 at concentrations ranging from <0.001wt% to 0.283 wt%, but asbestos was not detected in any of the sieved preparations of the DU10 replicates at an analytical sensitivity of 0.001 wt% (Figure 6). These results indicate that the asbestos detections in the milled preparations were a result of the milling process and are therefore false positives.


4.4.3 NOA Summary

Confirmation assessment of the school site pad included collection of 40 surficial (ISM composite, 3-part composite, and discrete) soil samples of the engineered fill material and analysis for NOA via EPA Method 600/R-93/116 (TEM) with the CARB Method 435 milling preparation. Asbestos was not detected in 30 of those samples at an analytical sensitivity of 0.0005 wt%. Asbestos was detected at greater than 0.1 wt% in four of the samples (ranging from 0.1089 to 0.3162 wt%). Three of those samples (MSS1-0, MSS2-0, and MSS1B) were associated with the northwestern edge area soil that subsequently underwent remedial grading/removal from the Site. The fourth sample with asbestos content reported as greater than 0.1 wt% was ISM replicate DU10-1. Analytical results for the three DU10 replicates were 0.283 wt%, <0.001 wt%, and 0.018 wt% with CARB 435 milling preparation of the samples. However, analytical results for the same three DU10 replicates with the ASTM D7521 sieve-based preparation were all <0.001 wt%, suggesting that structures counted as asbestos in DU10-1 (and DU10-3) were a product of the milling preparation and are therefore false positives. The cumulative body of analysis data for the engineered fill used in the school site pad indicates that it does not contain NOA at levels greater than 0.01 wt%. Based on current project plans, school construction activities on the school site pad are not anticipated to disturb or expose NOA-containing material or expose students, teachers and administrative staff, school maintenance workers, third-party workers, or visitors to NOA. The laboratory reported the presence of rutile (titanium dioxide) fibers on all samples associated with this project. In follow-up correspondence with the laboratory, they reported that they come across rutile regularly in soil samples.

4.4.4 Laboratory Analysis Results – Arsenic and Mercury

4.4.4.1 Arsenic

As shown on Table 2, arsenic was detected in all ten soil samples (MSS9-ABC through MSS14-ABC, DU1-1, DU3-2, DU6-3, and DU7-2) analyzed at concentrations ranging from 19 to 52 mg/kg. These concentrations exceed the DTSC Note 3 SLs (DTSC, 2018) for arsenic in a residential or commercial/industrial setting of 0.11 and 0.36 mg/kg, respectively. However, arsenic is a natural mineralogic component of soil and its naturally occurring or “background” concentrations soils can range from <0.10 to 97 mg/kg (Bradford, et al, 1996; Shacklette and Boerngen, 1984) and higher in some areas depending on the mineralogy of the soil’s parent material. As an example, it is not uncommon for naturally occurring arsenic concentrations in mineralized zones (i.e., in arsenopyrite associated with quartz veins) within the California Motherlode to exceed 100 mg/kg. Because of its natural presence in soil at concentrations that typically exceed health risk-based screening levels, arsenic concentrations in soil are typically compared to naturally occurring background arsenic concentrations and not health risk-based screening levels.


As described in Section 3.7.2, in YCG’s Limited Phase II Soil Investigation of the larger Mangini Ranch property, arsenic was detected at concentrations up to 90.5 mg/kg. YCG performed a statistical analysis of the arsenic concentrations and concluded that the arsenic in soil was likely representative of naturally occurring background conditions, and not the result of mining activities. There was no evidence of mining or other anthropogenic sources of arsenic on the Site and the arsenic concentrations detected in our ten samples are within the range of concentrations YCG reported for the site vicinity. The arsenic concentrations detected in the site samples are therefore considered to be within the range of naturally occurring background for the Site and its vicinity. Five engineered fill samples (MSS9-ABC through MSS12-ABC and MSS14-ABC, associated with DU9 through DU12 and DU14, respectively) that were analyzed for arsenic were subsequently selected for analysis of bioaccessible arsenic. Bioaccessible arsenic concentrations in the samples ranged from 3.2 to 6.6 mg/kg and the associated arsenic relative bioavailability (RBA) ranged from 13 to 22%. The CAB analysis results are summarized in Table 2. The laboratory report for the CAB analyses is in Appendix C.

4.4.4.2 Mercury

Mercury concentrations in the ten site samples ranged from <0.045 to 0.16 mg/kg (Table 2). None of these reported concentrations exceed the HERO Note 3 SLs for mercury in residential or commercial/industrial soil of 1.0 and 4.4 mg/kg, respectively. Mercury is also a naturally occurring mineral and the concentrations detected are within the range of naturally occurring concentrations for mercury (Bradford, et al, 1996; Shacklette and Boerngen, 1984).

4.5 Conclusions and Recommendations

The analysis data for the engineered fill used in the school site pad indicates that it does not contain NOA at levels greater than 0.01 wt% by TEM. Based on current project plans, school construction activities on the school site pad are not anticipated to disturb or expose NOA-containing material or expose students, teachers and administrative staff, school maintenance workers, third-party workers, or visitors to NOA. The arsenic concentrations detected in the site samples are considered to be within the range of naturally occurring background for the Site and its vicinity. Arsenic RBA ranged from 13 to 22% in samples of the engineered fill from the Site (Table 2), lower than the assumed default RBA of 60%. Therefore, no further action is warranted with regard to arsenic at the Site. The mercury concentrations detected in site soil samples do not exceed the HERO Note 3 SLs for mercury in residential or commercial/industrial soil and are within the range of naturally occurring concentrations for mercury. Therefore, no further action is warranted with regard to mercury at the Site.


Conclusions of the PEA are summarized below:

NOA is the only COPC associated with the Site.

An area of approximately 1.2 acres in the northeastern portion of the school site pad, approximately 15 percent of the site, is underlain by metavolcanic rock (Gopher Ridge Volcanics), which is considered likely to contain NOA.

Approximately 85 percent of the school site pad is underlain by slate (Salt Springs Slate) which is considered and demonstrated unlikely to contain NOA.

Material placed as engineered fill for the school site pad consists of Salt Springs Slate and associated soil. The results of laboratory analyses of the engineered fill for NOA content demonstrate that it meets DTSC’s criteria as clean fill.

The portion of the school site pad underlain by metavolcanic rock has been capped by at least 5 feet of non-NOA-containing engineered fill, with an orange geotextile warning barrier placed between the underlying metavolcanic rock and the fill material.

The project is being planned such that construction excavations within the school site pad including utilities and foundations will not extend into metavolcanic rock beneath the engineered fill material.

The embankments adjacent to the northern and eastern site boundaries (northern and eastern slope areas) consist of a mix of metavolcanic and metasedimentary materials which have not been characterized for NOA content in conjunction with this PEA, but are assumed likely to contain low levels of NOA (<1%) based on the findings of various NOA assessments performed in the area by Geocon and others (e.g., YCG, 2013 and 2014).

Construction excavations within the northern and eastern slope areas for retaining walls, utilities, and/or other features, are likely to disturb NOA-containing soil. Therefore, mitigation measures should be implemented during construction to minimize the potential for receptors, including school students and staff, school maintenance workers, third-party workers, and site visitors to be exposed to NOA.

Based on the findings of this PEA, we recommend that a RAW be prepared that specifies NOA mitigation measures to be implemented during construction in the northern and eastern slope areas of the Site. Project plans already provide for complete capping of the northern and eastern slope areas by a combination of concrete ramp and stairway, retaining walls, and landscaping with 12 inches of clean imported topsoil, as well as fencing at the top of the slopes. An additional recommended mitigation measure is installation of a 3D geotextile material beneath the topsoil layer on the northern and eastern slopes. These mitigation measures are described in Section 9.2.2.2 as the selected removal action alternative for the Site - capping w engineering and institutional controls. The engineering controls comprise a cap over NOA-containing rock and soil with a warning barrier, a layer of clean fill, school hardscape and landscaping. The institutional control consist of long-term monitoring/inspection and maintenance of the cover in accordance with the OMP.


5.0 HUMAN HEALTH SCREENING EVALUATION

As described in DTSC’s guidance for evaluating NOA at school sites (DTSC, 2004) and discussions with DTSC, traditional health risk screening is not utilized for school sites where NOA has been identified because of the difficulty in modeling and predicting health risk from inhalation of airborne asbestos generated by disturbance of NOA-containing rock or soil. Following are summaries of the COPCs at the Site and the receptors that could be exposed to NOA. Also provided is a discussion of the uncertainty regarding the PEA sampling and laboratory analyses and how the sampling was performed to reduce uncertainty.

5.1 Chemicals of Potential Concern

As described in Section 3.7, previous investigation of the Site and surrounding Mangini Ranch property determined that NOA is the only COPC for the Site. The potential presence of arsenic and mercury in soil on the Site was also assessed at the request of DTSC, but those metals were found to be present at naturally occurring background concentrations and therefore are not considered COPCs for the Site. We also confirmed at the request of DTSC that contaminants at the Aerojet Superfund site approximately 3 miles west and downgradient of the Site are not COPCs for the Site.

5.2 Receptors and Exposure Pathways

The planned school development of the Site determines that the receptors that could be exposed to NOA will be students, teachers and administrative staff, school maintenance workers, third-party maintenance workers (i.e., utilities and construction workers), and site visitors. As shown in our SCEM (Figure 7), the only potential exposure route for receptors at the Site is via inhalation of particulates in air. Asbestos fibers can be inhaled deep into the lungs, where they may be retained indefinitely. Asbestos fibers can cause health effects including respiratory disease (asbestosis), lung cancer, and mesothelioma. Mesothelioma is a rare cancer, caused almost exclusively by exposure to asbestos (DTSC, 2004). The clean engineered fill placed over the Site will substantially reduce or eliminate the inhalation exposure pathway for site receptors thereby reducing their risk to acceptable levels. In addition to the clean fill placed on the Site, the proposed surface improvements consisting of buildings, paved areas, and landscape areas will provide an additional level of protection. The Operations and Maintenance Plan (OMP) described in Section 13.0 provides guidelines and procedures to ensure that the cover remains viable and effective and protective of site receptors’ health.

5.3 Uncertainty Analysis

This section provides a discussion of uncertainty with respect to the sampling and analyses performed for the PEA to characterize NOA on the Site.


5.3.1 Sampling Uncertainty

As described in Sections 3 and 4, NOA-containing formational material and associated soil was present in the northeastern portion of the Site and has already been excavated to a minimum of 5 feet below the rough pad grade and removed from the Site. The NOA-containing material was covered with an orange warning barrier and the entire Site covered with clean fill excavated from non-NOA-containing soil on the adjacent future park site to the west of the Site prior to performing the PEA. Therefore, the PEA sampling approach for the Site was to perform a “confirmation” assessment of asbestos in the fill and, in consideration of the relatively homogeneous nature of the fill material, consisted primarily of ISM with the specific intent to reduce uncertainty. Some discrete sampling and simple 3-part composite sampling were also used to target specific areas of the Site based on the results of the initial ISM sampling and analysis and as further confirmation sampling of remedial grading performed on the Site in August 2018. As described in Section 4.4.2, sampling was conducted through five separate events with each event specifically designed to build upon the findings of the preceding event. The initial sampling event in April 2018 assessed three representative DUs with the intent that the results would be representative of relatively homogeneous fill across the entire Site. The second sampling event in July 2018 targeted soil in the northern and eastern edge areas of the Site where NOA-containing metalvolcanic material was observed and, as a precautionary measure, also included the other DUs on the Site not previously sampled. The third sampling event in August 2018 further assessed a specific area in the northwestern edge area of the Site following remedial grading (targeted removal of NOA-containing material) in that area. The fourth sampling event in September 2018 reassessed soil throughout the Site after remedial grading and placement of an additional layer of clean fill over the entire Site. The fifth and final sampling event in October 2018 was performed to further assess DU10.

5.3.2 Laboratory Methods and Detection Limits

The laboratory methods and detection limits provided by EMSL for asbestos shown on Tables 1 and 2 and in the laboratory reports in Appendix C were consistent for all analyses and met the requirements of the PEA for asbestos. They are not a source of uncertainty for health risk evaluation for the Site.

5.4 Conclusions

The sampling approach and methods and laboratory methods and detection limits used for the PEA were specifically chosen to reduce uncertainty in the PEA findings and the health risk associated with NOA on the Site. The ISM sampling and analysis approach and the iterative nature of the sampling events, with each event based on the findings of the previous, have reduced uncertainty such that findings of the PEA can be relied upon for their intended purpose.


6.0 ECOLOGICAL SCREENING EVALUATION

As described in Section 3.5.3, the MND describes the Site as being in an area of annual grassland characterized by a dense cover of nonnative annual grasses interspersed with numerous species of nonnative annual forbs and native wildflowers. There are no trees, seasonal wetlands, freshwater seeps, swales, riparian woodland and scrub, or perennial drainages on the Site. The MND further states that there are no known sensitive biological areas or sensitive habitat on the Site.

Additionally, the Site has been graded and fill placed to rough pad elevation for the school development and to mitigate exposure to NOA.

Lastly, NOA as a COPC, is a naturally occurring hazard. Therefore, its presence in the environment is not an introduced or exacerbated threat to ecological receptors.


7.0 CONCEPTUAL SITE MODEL

Figure 7 is a SCEM diagram for the Site. The diagram depicts:

Primary source media and release mechanisms; Secondary source media and transport mechanisms; Exposure media and routes; and Potential receptors.

Each of the model components are described below.

7.1 Primary Source Media

The primary source media at the Site is NOA-containing rock and associated soil beneath the northeastern portion of the Site (Gopher Ridge Volcanics). The NOA-containing material has been overexcavated to a minimum depth of 5 feet below the final pad elevation in the northeastern portion of the Site in 2017 and covered with an orange warning barrier and clean fill imported from the non-NOA-containing Salt Springs Slate on the future park site adjacent to the west of the Site. Additional remedial grading (targeted removal of soil in areas where asbestos was detected and covering with additional clean fill) was performed in August 2018. NOA is not expected to be present in other media (groundwater, surface water, soil vapor, or air).

7.2 Primary Release Mechanism

The primary release mechanism is disturbance of NOA-containing rock or soil and dispersal of asbestos particulates into air. The presence of the clean fill cover over the NOA-containing rock and soil minimizes the potential for this release mechanism to occur.

7.3 Secondary Source Media

The secondary source media is “affected soil” such as fill that contains NOA as is the case in the northern edge area of the Site where the embankment of Mangini Parkway adjacent to the Site is composed of fill that contains some metavolcanics with NOA.

7.4 Transport Mechanism

The transport mechanism for NOA is disturbance that causes asbestos to become airborne.

7.5 Exposure Media and Routes

The exposure media for the Site is air that contains airborne asbestos particulates. The exposure route is inhalation of asbestos particulates. Other exposure media do not exist and other exposure routes are not considered complete.


7.6 Potential Receptors

The Site has been graded and filled for development of an elementary school. The only current receptors would be offsite residents or onsite workers; however, there is not a current transport mechanism or exposure route for those receptors as the NOA-containing material on the Site has been covered with clean fill. Future receptors will be students, school staff and administrators, school maintenance workers, third-party workers, and visitors. Following school development on the existing clean fill cover, and under routine inspection and maintenance of the cover in accordance with the OMP, there will be no transport mechanism or exposure route for future school-related receptors.


8.0 NATURE, SOURCE, AND EXTENT OF CONTAMINANTS

In summary, NOA is the only COPC on the Site and its source and extent has been defined. NOA is present in the Gopher Ridge Volcanics formation and associated soil beneath the northeastern portion of the Site, but has been covered by clean fill and will be further covered by the school development. Maintenance of that cover in accordance with the OMP will ensure that NOA is not a threat to the health of students, staff, and school maintenance workers.


9.0 ENGINEERING EVALUATION/COST ANALYSIS

This EE/CA was prepared as required under section 300.415(b)(4)(i) of the NCP for all non-time critical removal actions and in accordance with the EPA Guidance on Conducting Non-time Critical

Removal Actions Under CERCLA (EPA, 1993). This EE/CA evaluates removal action alternatives for long-term effectiveness and permanence, implementability, and cost. An EE/CA requires evaluation of at least three alternatives. As NOA is the only COPC that poses a risk to future site receptors, removal actions were chosen to specifically mitigate exposure to NOA.

9.1 Removal Action Scope and Objectives

The removal action implemented at the Site was placement of clean fill as a cover over NOA in the northeastern portion of the Site as part of construction grading to reach the rough-pad elevation of approximately 431 to 432 feet above MSL for construction of the school. Although NOA is only present beneath the northeastern portion of the Site, clean fill was placed over the entire Site to accommodate future construction of the school. The objective of the removal action was to cover the primary source of NOA, thereby mitigating future disturbance of NOA, transport of asbestos particulates in air, and the inhalation pathway.

9.2 Identification and Evaluation of Removal Action Alternatives

Three removal action alternatives are identified and evaluated including:

Alternative 1 – No Action

Alternative 2 – Capping of NOA-containing soil; and

Alternative 3 – Removal

9.2.1 EE/CA Alternative Evaluation Criteria

Each alternative listed above is evaluated against the following three criteria:

Long-term effectiveness and permanence

o Performance and reliability to eliminate or reduce the risk associated with exposure to NOA at the Site;

o Overall protection of public health and the environment (threshold factor);

o Compliance with ARARs presented in Section 10.0 (threshold factor);

o Long- and short-term effectiveness (balancing factor);

o Reduction of toxicity, mobility, or volume through treatment (balancing factor); and

o Ability to meet the RAOs described in Section 1.1.


Implementability

o Of the alternative with respect to site conditions, equipment availability, resource availability, utility requirements, monitoring/inspection, and operations and maintenance (O&M) in accordance with the OMP;

o Ability of the alternative to meet applicable federal, state, and local regulations and permitting requirements; and

o Ability of the alternative to meet the project schedule and facility operations requirements.

Cost - the relative cost of each alternative based on estimated capital cost for construction or initial implementation and ongoing (O&M) costs.

9.2.2 Description of Removal Action Alternatives

9.2.2.1 No Action

Under the no-action alternative, NOA-containing rock and soil at the Site would remain uncovered and exposed to be disturbed and potentially become airborne in particulates. Once airborne, asbestos particulates could be inhaled by receptors at the Site.

9.2.2.2 Capping with Engineering and Institutional Controls

This alternative consists of covering (“capping”) the NOA-containing rock and soil with a warning barrier, a layer of clean fill, school hardscape and landscaping, and long-term monitoring/inspection and maintenance of the cover in accordance with the OMP. The design and placement of the cover and development of the school itself are engineering controls. The OMP and its requirements for monitoring/inspection, maintenance, and repair are institutional controls.

9.2.2.3 Removal

This alternative consists of the physical removal (i.e., excavation, handling, transportation, and offsite disposal) of NOA-containing rock and soil from the Site.

9.2.3 Evaluation of Removal Action Alternatives

9.2.3.1 Long-term Effectiveness and Permanence

Alternative 1 – No Action: although, in effect, no action could be permanent as an alternative, it would offer no effectiveness in meeting the RAOs in either the short or long-term.

Alternative 2 – Capping of NOA-containing soil: this alternative can have long-term effectiveness and permanence as long as the cap is maintained in accordance with the OMP.

Alternative 3 – Removal: this alternative would be effective in the long-term and would be permanent if it could feasibly be implemented. However, as described under the next two criteria, complete removal of NOA-containing rock and soil from the Site is neither physically nor financially feasible.


9.2.3.2 Implementability

Alternative 1 – No Action: this alternative is readily implementable, but the Site would not be suitable for use as a school if no action is taken.

Alternative 2 – Capping of NOA-containing soil: this alternative is readily implementable physically and financially.

Alternative 3 – Removal: complete removal of NOA-containing rock and soil from the Site is neither physically nor financially implementable.

9.2.3.3 Cost

Alternative 1 – No Action: there is no cost associated with this alternative, but the Site could not be developed as a school if no action is taken.

Alternative 2 – Capping of NOA-containing soil: costs for this alternative include engineering, construction, materials, regulatory, and consulting (reporting) as follows:

Activity Estimated Cost

DTSC School Cleanup Agreement $26,346 Preparation of PEA/RAW $15,000 Project Management and Coordination $10,000 Imported Fill Material Evaluation $5,000 NOA-containing rock/soil overexcavation $25,000 Capping - Material A $390,000 Capping – Installation B $80,000 Construction Monitoring and Reporting $30,000 O&M Plan $5,000 Implementation of O&M Plan (1st year) $10,000 Long-term O&M C $600,000

Total Cost Estimate: $1,196,346 A. Import Fill Material = 130,000 cubic yards (cy) @ $3 per cy. B. Cap Installation = 8 acres @ $10,000 per ac C. 30-year period

Alternative 3 – Removal: costs for complete removal of NOA-containing rock and soil from the Site are not readily estimated without assuming some depth of excavation for removal. Alternative 2 included limited removal of NOA-containing rock and soil to a depth of 5 feet below finished pad grade for the school. The depth of NOA-containing rock beneath the Site could be hundreds or thousands of feet, so actual “removal” would have to assume some realistic limitation to the depth of excavation. Assuming an excavation depth of only 10 feet (twice the depth of the limited removal under Alternative 2) would at least double the cost of Alternative 3 making it financially infeasible. Full removal would be orders of magnitude greater in cost.


9.2.4 Removal Action Alternative Selection

Based on the evaluation of the three alternatives against the criteria of long-term effectiveness and permanence, implementability, and cost, Alternative 1 is not selected because it will not meet the RAO of being protective of human health and therefore the school would not be able to be constructed. Although Alternative 3 would meet some of the RAOs for the Site and the school development project by providing long-term protection of human health and permanence, the cost of this alternative makes it not financially feasible. Therefore, the Alternative 2 – Capping of NOA-containing soil is selected. This alternative includes long-term monitoring/inspection and maintenance in accordance with the OMP and will be the most effective in meeting the RAOs for the Site and project.


10.0 APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS

Applicable requirements are those cleanup standards, standards of control, and other substantive environmental protection requirements, criteria, or limitations promulgated under Federal or State law that specifically apply to cleanup at a site. The process for determining applicable standards is set forth in Section 121(d) of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). In part, CERCLA states that the more stringent of State or Federal requirements will apply to cleanup sites. Typically, California requirements are more stringent than Federal requirements.

Relevant and appropriate requirements are those cleanup standards, standards of control, and other substantive environmental protection requirements, criteria, or limitations promulgated under Federal or State law that, while not applicable, address problems or circumstances similar to those found where the proposed removal action will be performed, and are well suited to the conditions of the cleanup site. Requirements that are determined to not be legally applicable are evaluated to determine whether they are relevant and appropriate. A requirement must be both relevant and appropriate to be an ARAR. Criteria for determining relevance and appropriateness are listed in Part 40, CFR Section 300.400(g)(2).

According to CERCLA ARAR guidance (USEPA, 1988), requirements may be “applicable” or “relevant and appropriate,” but not both. ARARs are identified on a site-specific basis, using a two-part analysis to determine first if a requirement is applicable, and then, if not applicable, whether it is both relevant and appropriate. Based on CERCLA ARAR guidance, an ARAR qualifies as a State ARAR if it meets the following requirements:

It is a State law;

It is an environmental, or facility-siting law;

It is promulgated, and thus generally applicable and legally enforceable;

It is substantive rather than procedural or administrative;

It is more stringent than the Federal requirement;

It is identified in a timely manner; and

It is consistently applied.

ARARs typically are separated into three categories: 1) Chemical-specific; 2) Action-specific; and 3) Location-specific. Following are descriptions of each ARAR category.

Chemical-specific ARARs: usually health risk-based numerical values or methodologies which, when applied to site-specific conditions, result in the establishment of numerical values. These values establish the acceptable amount or concentration of a COPC that may be found in, or discharged to, the ambient environment.


Action-specific ARARs: usually technology- or activity-based requirements or limitations on actions taken with respect to hazardous wastes.

Location-specific ARARs: restrictions placed on the concentration of hazardous substances or the conduct of activities solely because they occur in special locations.

The potential ARARs for NOA and the selected remedy are described below. While federal and state non-promulgated standards, policies, or guidance documents, and legal requirements are not ARARs, the NCP states that these criteria are also to be considered when evaluating and selecting remedial actions necessary to protect human health and the environment.

10.1 Chemical-Specific ARARS

10.1.1 Screening Levels

DTSC’s screening level for NOA in soil at school sites is 0.01 wt% asbestos as measured by TEM.

10.1.2 Air Quality Management

The CARB and the USEPA have adopted ambient (outdoor) air quality standards. These legal limits on ambient air pollution are designed to protect public health. California Health and Safety Code Section 39606 provides the authority for the Sacramento Metropolitan Air Quality Management District (SMAQMD) to regulate ambient air pollution in the region of the Site. California Health and Safety Code Section 39666(d) provides for controlling emissions of airborne asbestos. Dust control activities and nuisance dust emissions are described and regulated under this authority by the SMAQMD. An Asbestos Dust Mitigation Plan (ADMP) and permit is required where NOA concentrations in soil exceed 0.25 wt% in any of the sample data. For the Site, the maximum detected concentration of NOA in soil was 0.3162 wt%. A copy of the ADMP is in Appendix D. Air monitoring for “visible dust” will be conducted for earthwork activity for school construction to document the effectiveness of dust control measures (water spray) and to evaluate the potential off-site migration of asbestos containing dust. The air monitoring program will consist of the collection of air samples for both site worker personnel, and for the site perimeter (or fence line) to evaluate the effectiveness of dust control measures during grading activities. Air sample collection will be conducted under the supervision of a California Certified Asbestos Consultant (CAC). A copy of the air monitoring plan for the Site is in Appendix E of the ADMP (Appendix D). Trigger and action levels for asbestos and total dust (PM10) are summarized in the following table. Trigger levels are used as indicators that current dust control measures need to be increased. Action levels indicate that dust control measures are not working and grading activities need to stop until improvements in dust mitigation are implemented.


Constituent of Concern

Monitoring Location

Trigger Level (by TEM Analysis)

Action Level (by TEM

Analysis)

Asbestos

Perimeter 0.005 s/cc 0.01 s/cc Work Zone

(PEL - 8 hr TWA) 0.05 s/cc 0.1 s/cc

Work Zone (30 Minute Excursion)

0.5 s/cc 1 s/cc

Total Dust (PM10) Perimeter “visible dust” 0.05 mg/m3 (a)

Notes: TEM – transmission electron microscopy PEL - Permissible Exposure Limit (8-hour, time-weighted average (TWA)) s/cc – structures per cubic-centimeter PM10 – Particulate Matter less than 10 microns in diameter mg/m3 – milligrams per cubic-meter (a) – California Ambient Air Quality Standard (24-hour average for PM10) The results of air monitoring will be summarized in a data spreadsheet identifying the worker and activity, perimeter and activity, sample location, and the results of asbestos structures and fibers. The spreadsheet will be updated as laboratory results are obtained and will be forward weekly to the District, DTSC, and the SMAQMD. Whenever action levels are exceeded, increased dust control measures will be taken immediately, and the DTSC project manager notified. If all dust control measures are shown to be ineffective when weather conditions are normal, then all work activities will cease and not resume until effective engineering control measures are implemented and conditions are determined to be acceptable to proceed.

10.1.3 Health and Safety Plan

All contractors will be responsible for operating in accordance with the most current requirements of Title 8, California Code of Regulations, Section 5192 (8 CCR 5192) and Title 29, Code of Federal Regulations, Section 1910.120 (29 CFR 1910.120), Standards for Hazardous Waste Operations and Emergency

Response (HAZWOPER). Onsite personnel are responsible for operating in accordance with all applicable regulations of the Occupational Safety and Health Administration (OSHA) outlined in 8 CCR General Industry and Construction Safety Orders and 29 CFR 1910 and 29 CFR 1926, Construction Industry Standards, as well as other applicable federal, state and local laws and regulations. All personnel shall operate in compliance with all California (Cal-)OSHA requirements. A site-specific health and safety plan (HSP) has been prepared for the Site in accordance with current health and safety standards as specified by the federal and Cal-OSHAs. A copy of the HSP is in Appendix E.


The provisions of the HSP are mandatory for all personnel of the District and its contractors who are at the Site. The District’s contractor and its subcontractors doing fieldwork in association with this RAW will either adopt and abide by the HSP, or shall develop their own safety plans which, at a minimum, meet the requirements of the HSP. All onsite personnel shall read and sign the HSP prior to initiating activity at the Site.

10.2 Action-Specific ARARs

10.2.1 Hazardous Waste Management

Under the California Health and Safety Code asbestos is not a designated Federal Hazardous Waste and the DTSC has classified friable and finely powdered wastes with more that 1% asbestos as hazardous waste. Asbestos concentrations identified at the Site do not meet either of these criteria. Although asbestos levels in soil at the Site may not be classified as hazardous waste; asbestos, including NOA, is classified as a hazardous substance under the Hazardous Substance Account Act (HSAA), Chapter 6.8 of the California Health and Safety Code (H&SC), and CERCLA (United States Code: Title 42, Chapter 103). DTSC, under HSAA authority, and/or the USEPA under CERCLA authority may require response actions when construction activities release NOA to the environment, including air, water, or soil. Under HSAA and other authorities, DTSC may issue orders to responsible parties requiring the investigation and cleanup of hazardous substance release sites. Responsible parties may include property owners and those that manage (handle, move, dispose, release, etc.) hazardous substances. DTSC and the USEPA both follow the NCP when response actions are required. DTSC also regulates the management of hazardous waste under the Hazardous Waste Control Act (HWCA) (H&SC Chapter 6.5) and is the delegated State agency for the Resource Conservation and Recovery Act (RCRA) program. Wastes containing asbestos are in some circumstances considered hazardous wastes under HWCA, such as when they originate from industrial waste streams or are discarded asbestos containing products. However, NOA in earthen materials such as soil or waste rock that are removed, unearthed, or otherwise displaced as a result of excavating or recovering an ore or a mineral is exempt as a hazardous waste. Therefore, the HCWA does not apply to the movement of earthen materials during land development and construction activities.

10.2.2 California Environmental Quality Act and Mitigated Negative Declaration

CEQA is a statute that requires State and local agencies to identify the significant environmental impacts of their actions and to avoid or mitigate those impacts, if feasible. In response to the passage of the National Environmental Policy Act in 1969, the California Legislature passed the CEQA in 1970 as a system of checks and balances for land use development and management decisions in California. CEQA was subsequently codified into the Public Resources Code (division 13, section 21000 et seq.). The Resources Agency adopts and certifies certain regulations (known as CEQA Guidelines) to explain and interpret the


CEQA law. These regulations were codified into the California Code of Regulations (CCR), title 14, chapter 3, section 15000 et seq. A CEQA Initial Study (IS) is a public document used by the decision-making lead agency to determine whether a project may have a significant effect on the environment. If the lead agency finds substantial evidence that any aspect of the project, either individually or cumulatively, may have a significant effect on the environment, regardless of whether the overall effect of the project is adverse or beneficial, the lead agency is required to prepare an environmental document. If the agency finds no substantial evidence that the project or any of its aspects may cause a significant effect on the environment, a Negative Declaration shall be prepared. If in the course of analysis, the agency recognizes that the project may have a significant impact on the environment, but that by incorporating specific mitigation measures the impact will be reduced to a less-than-significant effect, an MND shall be prepared. If the agency determines that even with the incorporation of mitigation measures the project will still result in significant and unavoidable impacts, then an Environmental Impact Report (EIR) shall be prepared to analyze the project at hand. The District prepared an IS/MND. The IS/MND describes the project and its potential impacts on the environment and provides mitigation measures to reduce any significant impacts that may result from the project to a level that is less than significant by the adoption and implementation of specified mitigation measures. The IS/MND also acknowledged the presence of NOA and identified mitigation measures to address potential impacts of NOA. The public comment period for the IS/MND was February 14, 2019 through March 16, 2019, and no comments were received that required the IS/MND to be revised. The District’s Board of Education on April 11, 2019, adopted Resolution No. 04-11-19-36: Approving the Mitigated Negative Declaration for the Mangini Ranch Elementary School Project. The District filed the Notice of Determination with the California Office of Planning and Research/State Clearinghouse on April 12, 2019 (State Clearinghouse Number: 2019029072). A copy of the MND is in Appendix F. The MND’s Mandatory Findings of Significance are shown in the following table:

Potential Environmental Impacts Findings of Significance

Does the project have the potential to degrade the quality of the environment, substantially reduce the habitat of a fish or wildlife species, cause a fish or wildlife population to drop below self- sustaining levels, threaten to eliminate a plant or animal community, reduce the number or restrict the range of a rare or endangered plant or animal or eliminate important examples of the major periods of California history or prehistory?

With implementation of mitigation measures proposed in the relevant sections of this Initial Study, these potential impacts would be reduced to a level that is considered less than significant.


Does the project have impacts that are individually limited, but cumulatively considerable? ("Cumulatively considerable" means that the incremental effects of a project are considerable when viewed in connection with the effects of past projects, the effects of other current projects, and the effects of probable future projects)?

Implementation of the Proposed Project, in conjunction with other approved or pending projects in the region, has the potential to result in cumulatively considerable impacts to the physical environment. However, with implementation of mitigation measures proposed in the relevant subsections of this Initial Study, these potential impacts would be reduced to a level that is considered less than significant.

Does the project have environmental effects which will cause substantial adverse effects on human beings, either directly or indirectly?

Direct and indirect impacts to human beings would be less than significant with the implementation of mitigation measures listed in this Initial Study.

In addition, the MND summarizes the following mitigation measures to avoid significant effects that are directly related to the response action described in this RAW. AQ-1 All ground disturbing site preparation and construction activities, and all maintenance and operation activities shall adhere to all measures included in the PEA/RAW for the Mangini Ranch Elementary School site. The PEA/RAW outlines specific mitigation measures to reduce possible releases of NOA, the training of workers on the Site, and the methods of inspection to ensure compliance. This measure shall be included in the construction plans and specifications.

Timing/Implementation: To be incorporated as part of Project building design and during construction and operation of the Proposed Project.

Enforcement/Monitoring: the District

DTSC AQ-2 Reduce construction-period dust during construction period by the following procedures to be adhered to by the construction contractor(s) in accordance with Air District Rule 403: Basic Construction Emission Control Practices:

1) Water all exposed surfaces two times daily. Exposed surfaces include, but are not limited to soil piles, graded areas, unpaved parking areas, staging areas, and access roads.

2) Cover or maintain at least 2 feet of free board space on haul trucks transporting soil, sand, or other loose material on the site. Any haul trucks that would be traveling along freeways or major roadways should be covered.

3) Use wet-power vacuum street sweepers to remove any visible track-out mud or dirt onto adjacent public roads at least once per day. Use of dry-power sweeping is prohibited.

4) Limit vehicle speeds on unpaved roads to 15 miles per hour (mph).

5) All roadways, driveways, sidewalks, parking lots to be paved should be completed as soon as possible. In addition, building pads should be laid as soon as possible after grading unless seeding or soil binders are used.

6) Minimize idling time either by shutting equipment off when not in use or reducing the time of idling to 5 minutes (required by California Code of Regulations, Title 13, sections 2449(d)(3) and 2485). Provide clear signage that posts this requirement for workers at the entrances to the Site.


HAZ-1 All ground disturbing site preparation and construction activities, and all maintenance and operation activities shall adhere to all measures included in the PEA/RAW for Mangini Ranch Elementary School site. The PEA/RAW outlines specific mitigation measures to reduce possible releases of NOA, the training of workers on site, and the methods of inspection to ensure compliance. This measure shall be included in the construction plans and specifications.

Timing/Implementation: To be incorporated as part of Project building design and during construction and operation of the Proposed Project.

Enforcement/Monitoring: Folsom Cordova Unified School District

Department of Toxic Substances Control

The SMAQMD reviewed the draft MND and submitted a letter requesting that the District include applicable air quality mitigations measures from the Folsom Plan Area Specific Plan. Those mitigation measures are already incorporated in the construction documents. The SMAQMD also requested that the SMAQMD’s Basic and Enhanced Construction Emissions Control Practices, as adopted by the City of Folsom for the Folsom Plan Area be followed during the construction process. These recommended air quality mitigation measures will be incorporated as a requirement of the project. The letter provides information related to an Asbestos Dust Mitigation Plan on file at SMAQMD for the current site owners. DTSC is a Responsible Agency under CEQA. A Responsible Agency is defined in CEQA Guidelines (14 CCR § 15381) as a public agency which proposes to carry out or approve a project for which the lead agency is preparing, or has prepared, an Environmental Impact Report or Negative Declaration. While DTSC is a Responsible Agency under CEQA for the overall construction project. DTSC as the lead agency, which approves or determines the need to carry out a response for which a mitigated negative declaration was adopted, will file a Notice of Determination with the Office of Planning and Research (Section 21108 and Guidelines Section 15075(c)).

10.2.3 Stormwater Discharge

The SWRCB, as part of the National Pollutant Discharge Elimination System (NPDES), has adopted a statewide NPDES General Permit for Stormwater Discharges Associated with Construction Activity (General Permit) to address discharges of storm water runoff from construction projects that encompass one acre or more in total acreage of soil disturbances. Construction activities subject to the General Permit include demolition, clearing, grading, excavation, soil stockpiling, material storing, on-site staging, off-site staging, and other land disturbance activities (SWRCB Order No.2009-0009-DWQ [as amended by Order No. 2010-0014-DWQ], NPDES, General Permit No.CAS000002). To obtain coverage under the General Permit, dischargers are required to electronically submit the Permit Registration Documents, which includes a Notice of Intent, Storm Water Pollution Prevention Plan (SWPPP), and SWPPP Compliance Checklist, and mail the appropriate permit fee to the SWRCB. The SWPPP is required to specify best management practices (BMPs) to prevent all


construction pollutants from contacting storm water and with the intent of keeping all products of erosion from moving offsite into receiving waters. The discharger is required to obtain coverage under the General Permit prior to commencement of construction activities. When construction is complete or ownership has been transferred, the discharger is required to file a Notice of Termination with the appropriate California Regional Water Quality Control Board certifying that all State and local requirements have been met in accordance with the General Permit. As the area of disturbance is approximately 8 acres, an SWPPP was (and will be) required for this project. An SWPPP was prepared prior to the start of grading onsite. The SWPPP describes BMPs that were implemented to reduce or eliminate sediment and other pollutants from entering existing storm water drains located in adjacent streets. BMPs that were implemented at the Site during grading, and will again be implemented during school construction, include:

Control of runoff from stockpiled soil by covering each pile with plastic sheeting and surrounding the stockpile with silt fencing and/or filter roll barriers;

Temporary perimeter controls with silt fencing and/or filter roll barriers;

Protection of storm drain inlets with filter fabric and sand/gravel bag barriers;

Stabilized construction entrance/exit with truck tracking controls; and

Post construction erosion control measures (i.e., landscape and/or hardscape ground cover).

A site-specific SWPPP will be prepared for the school construction project. The SWPPP will be made available to DTSC prior to implementation of the RAW. Once available, the SWPPP will be added to the RAW as Appendix G.

10.2.4 Endangered Species Act

The MND states that there are no known sensitive biological areas or sensitive habitat on the Site. The MND describes the site vegetation as being “annual grassland characterized by a dense cover of nonnative annual grasses interspersed with numerous species of nonnative annual forbs and native wildflowers.” Various vegetation species observed on the Site are listed. There were and are no trees on the Site.

10.2.5 Quality Assurance Project Plan

Quality assurance/quality control measures that will be used during project execution are documented in our QAPP in Appendix H. The QAPP will ensure that project field and laboratory analysis data collected meet project data quality objectives (DQOs) and RAOs to support decisions for utilization of the Site as an elementary school.


10.3 Location-Specific ARARs

10.3.1 Public Participation

DTSC has developed a public participation strategy to determine the level of public interest in the proposed response action for the Site and ensure that the local community is informed of the proposed response action. Through a community survey, community interviews and/or other public participation activities, DTSC will provide the community with opportunities to be involved in DTSC's decision-making process for the Site. Based on expressed community interest or other factors, DTSC will hold a public comment period to accept comments on the proposed response action and, if appropriate (e.g., when there is high interest in the Site), a public meeting(s) to brief interested parties locally about the proposed response action during the public comment period, before approving the RAW. In general, DTSC will hold a 30-day public comment period. A responsiveness summary, including DTSC's response to all public comments received, will be added to the Final RAW as an appendix and be placed in the information repositories for public viewing.

10.3.1.1 Community Assessment

A community assessment will be conducted through a baseline community survey and/or interviews of nearby community members (including contiguous property owners, residents, business owners, elected/local officials, DTSC mandatory mail list recipients and other affected/interested parties). Pending the results of community feedback regarding the RAW, the compiled community concerns will be addressed in a Community Profile Report (Section 10.3.1.2) and a Community Update (fact sheet, Section 10.3.1.3) for the Site. Depending on community interest, as reflected in the community assessment, a public meeting may be planned in conjunction with a 30-day comment period for the RAW. The length of the comment period will be modified and the decision to have a public meeting will be made as appropriate.

10.3.1.2 Community Profile Report

DTSC will prepare a Community Profile Report (CPR). The CPR is based on information from a variety of sources including file review, site visits, demographic data, community interest/concerns (including interest from elected or local officials) expressed during the public comment period and any public hearing held by the District for the Site; similar or relevant community interest/concerns communicated during previous public participation activities for other DTSC projects within the surrounding community; and the likely or existing level of community interest/concerns identified for the Site through the community survey or interviews. A copy of the CPR will be made available in each of the information repositories established for the project (Section 10.3.1.4).


10.3.1.3 Community Update

A Community Update (Fact Sheet) will be prepared to provide information about the Site and the proposed response action, including information concerning Site history, chemicals of potential concern investigated and discovered, levels of contaminants found, possible health effects from contaminant exposures, proposed response action alternatives, precautions to minimize worker exposure, controls to reduce dust, public participation activities, and contact information. This Community Update will be circulated to a project mailing list that includes residents and businesses within a half of a mile of the Site, elected officials, special interest groups and DTSC's priority mailing list. A copy of the DTSC Community Update will also be placed in the identified information repositories (Section 10.3.1.4).

10.3.1.4 Public Participation Activities

A public notice in the languages appropriate to the community will be published in local newspapers and posted at the Site. This notice will inform the community of the proposed resonse action at the Site as well as the availability of the Administrative Record file for public inspection during office hours at the Central Information Repository (in the DTSC regional office listed below) and a temporarily established Information Repository (Folsom Public Library and District office) listed below. Copies of documents pertinent to this PEA/RAW (e.g., reports of previous site assessments and investigations, this PEA/RAW, and related DTSC determination letters for the Site) will be placed in the following information repositories:

Folsom Cordova Unified School District, Education Services Center - 1965 Birkmont Drive, Rancho Cordova, CA 95742

o Contact: Geri Wickham, 916-294-9000

o Hours: Mon – Fri, 7:30 am to 4:30 pm

DTSC, Regional Records Office - 8800 Cal Center Drive, Sacramento, CA 95826-3200

o Contact: File Room, 916-255-3758

o Hours: Mon – Thurs, 9:00 am to 5:00 pm (by appointment only)

Folsom Public Library - Georgia Murray Building, 411 Stafford Street, Folsom, CA 95630

o Contact: Public Counter, 916-461-6130

o Hours: Tues-Wed, 10:00 am to 8:00 pm; Thur – Sun: 10:00 am to 5:00 pm

DTSC - Envirostor, www.envirostor.dtsc.ca.gov/public. At the webpage click on the Site/Facility Search tool. In the City entry type "Folsom". In the Site/Facility Name entry type "Proposed Mangini Ranch Elementary School". This will take you to the Project File homepage, here you will be able to access related documents

10.3.1.5 District Public Outreach Activities

As stated in Section 10.2.2, the District prepared an IS/MND for the school project. The IS/MND describes the project and its potential impacts on the environment and provides mitigation measures to


reduce any significant impacts that may result from the project to a level that is less than significant by the adoption and implementation of specified mitigation measures. The public comment period for the IS/MND was February 14, 2019 through March 16, 2019, and no comments were received that required the IS/MND to be revised. At the District’s Board of Education meeting agenda on April 11, 2019, District staff will be recommending adoption of Resolution No. 04-11-19-36: Approving the Mitigated

Negative Declaration for the Mangini Ranch Elementary School Project.

10.4 Other ARARs

All necessary permits (State, County, and City) and approvals identified in this RAW will be obtained prior to any removal activities. Upon approval from DTSC, removal activities will be performed by a California-certified contractor with oversight from a California-licensed Professional Geologist (PG) and/or Professional Engineer (PE).

According to Education Code section 17213.2 (e), if a previously unidentified environmental concern is discovered at any time during the removal action and/or school construction process, the District shall cease all construction activities at the Site, notify DTSC, and take the necessary response actions as required by DTSC.


11.0 MITIGATION MEASURES/ENGINEERING CONTROLS

This section describes the mitigation measures/engineering controls that have been or will be implemented to meet the RAOs. The mitigation measures presented in this section represent typical construction (hardscapes) and landscapes associated with school site development. A minimum 6-inch-thick cap is required for all cap components in the area of potentially NOA-containing soil. Anticipated cap components are presented in Table 3.

11.1 Hardscape and Structures

As shown on Table 3, hardscape cap components include slab on-grade building foundations, hard courts, paved sidewalks, retaining walls, and parking and driveway areas. These hardscape components typically were previously planned for the school before the discovery of NOA. They will be a minimum of 6 inches in thickness and will provide a barrier to NOA-containing soil. Where hardscape and structures (except the handicap access ramp and stairway on the eastern embankment – Figure 3) will overlie NOA-containing soil, a warning barrier consisting of a geotextile membrane or 3-dimensional geotextile fabric will be placed over the NOA-containing soil to provide workers performing O&M activities a visual marker of the base of the clean fill and underlying NOA-containing soil. In most areas the warning barrier will be overlain by the 5-foot-thick clean fill layer and any base materials required for the hardscape or structure. The ramp and stairway on the eastern embankment will overlie an 8-inch-thick clean cover, but no warning barrier. The effect that the presence of NOA-containing soil has on these components is the implementation of additional health and safety and O&M requirements during maintenance and repair.

11.2 Landscape

The only high-activity landscape areas situated over NOA-containing soil are two apparatus areas in the northeastern portion of the Site (Figure 3). The apparatus areas will have a 15-inch-thick bark cover over the 5-foot-thick clean fill cap over the geotextile warning barrier. Low-activity landscape areas over NOA-containing soil are the northern embankment and portions of the eastern embankment. NOA-containing soil in these areas will be covered with a geotextile membrane or 3-dimensional geotextile fabric and 12 to 18 inches of clean fill material. Embankment protection is discussed further in Section 11.4. Depending on final site design the minimum 6-inch-thick cap for some low-activity areas (i.e., the northern embankment) may not be a requirement. For example, if the northern embankment is fenced so that there is no access to the school’s students, teachers, administrative staff, and visitors (only maintenance worker access) and vegetated to retain soil, then a cap may not be required. Other engineering controls described in Section 11.4 should be implemented to prevent run-on of NOA-containing soil to the flat, all-access areas of the school. These locations and requirements will be confirmed in consultation with DTSC.


11.3 Import Fill Material

Any proposed import fill material would be tested in accordance with the DTSC Information Advisory

for Clean Imported Fill (DTSC, 2001). When imported fill sources are identified, each will be evaluated according to the source. Sampling will be according to DTSC requirements as listed in this advisory. Fill material samples would be collected from the borrow area and analyzed before the fill is transported to the school Site. Sources of imported fill material will be sampled and analyzed for NOA initially using PLM. If all PLM results indicated ‘non-detect’, then 25% of the samples will be analyzed by TEM. If any of the samples indicate NOA detections by PLM, then all of the samples will be analyzed using TEM methods. The results will be evaluated using DTSC’s draft NOA Tiered Approach. Additionally, other potential COCs identified for the source material will be included in the suite of analyses.

11.4 Embankment Protection

The cut slope embankment on the eastern side of the Site and the fill slope embankment on the northern side of the Site will be covered variously by structures (retaining walls, concrete ramp and stairway) and by landscaping in 12 to 18 inches of clean fill. As described in Section 11.2, if access to the northern embankment is limited to workers only by fencing and vegetated to retain soil, then a minimum 6-inch-thick cap may not be required. A geotextile membrane or 3-dimensional geotextile fabric beneath the clean fill soil is planned to aid in soil retention on the embankments and to act as a warning barrier over NOA-containing soil for workers. Exclusionary fencing at the top of the embankments is also recommended. Lined brow ditches or other engineering controls should be used where deemed necessary by the Project Civil Engineer so uncontrolled concentrated flow of water over the surface of the embankment will be prevented so the embankment is protected against erosion into, and run-on of, NOA-containing soil onto the flat, all-access portions of the school.


12.0 REMOVAL ACTION IMPLEMENTATION

The PEA confirmed the presence of NOA in soil beneath the northeastern portion of the Site at concentrations exceeding DTSC’s screening level for school sites of 0.01 wt% by TEM (Section 10.1.1). An EE/CA for the removal is included in Section 9.0. The most effective removal action alternative has been determined to be the capping of NOA-containing soils with engineering and institutional controls. The removal action is not anticipated to disturb NOA-containing soil. Removal activities will be performed by a California-licensed contractor, with supervision of a California-licensed PG and/or PE. Removal activities will be performed in accordance with applicable Federal, State, and local laws, regulations, ordinances, and requirements. Field operations shall follow the suggested operational guidelines to prevent cross-media transfer of contaminants, as specified in Best Management Practices (BMP) for Soils Treatment Technologies (USEPA,1997).

12.1 Site Preparation and Security Measures

The contractors implementing the removal action will provide additional barriers, as needed, to enclose the contaminated soil work area. Access to the Site will be controlled by gates which can be locked during inactive hours. Appropriate signage will be used to mark the hazard and exclusion zone. The contractors will be responsible for preparing the Notice of Intent and SWPPP prior to the start of soil-disturbing construction activities. Such activities include site grading, excavation/trenching for utilities installation, and excavation and drilling for foundation construction.

12.1.1 Pre-Construction Planning and Notification

Prior to the beginning of construction, a pre-job meeting will be held with representatives of the contractors, subcontractors, District personnel, Division of State Architect inspectors, consultants, and regulatory agencies working on or involved with the project. The purpose of this meeting will be to review the project plans, discuss special health and safety requirements, and the procedures/protocols that will need to be implemented during construction activities.

12.1.2 Security Measures

Appropriate barriers and dust/privacy fencing will be installed prior to beginning the excavation process to ensure that all work areas are secure and safe. To ensure trespassers or unauthorized personnel are not allowed near work areas, security measures will include, but are not limited to:

Posting notices directing visitors to the manager of the Site.

Maintaining a visitor’s log. Visitors shall have prior approval from the Site Manager to enter the Site. Visitors shall not be permitted to enter the Site without first receiving Site-specific health and safety information from the designated Site Safety Coordinator.


Installing barrier fencing to restrict access to sensitive areas such as exclusion zones.

Providing adequate site security to ensure unauthorized personnel have no access to work areas and/or impacted materials.

Before leaving the Site, all personnel must sign out in the visitor’s log.

Maintaining a safe and secure work area, including areas where equipment is stored or placed, at the close of each workday.

Equipping all site access gates with locking devices that will be locked during non-operation activities.

Limiting access to the Site to authorized personnel only.

Persons requesting site access will be required to demonstrate a valid purpose for access and if access to work areas and/or impacted materials is planned, provide appropriate documentation to demonstrate they have received proper training required by the site-specific HSP (Appendix E).

12.1.3 Contaminant Control

To prevent offsite receptor’s potential exposure to NOA-containing, the following measures will be implemented during the course of earthwork activities:

The removal action will be conducted when the RAW is approved by DTSC.

The District will take necessary steps to minimize the impact to the community. Because air monitoring procedures will be implemented during NOA-intrusive earthwork, the covering of windows and doors at the nearby residences and/or commercial businesses is not warranted or anticipated.

12.1.4 Cultural Resources Consideration

As described in Section 3.5.4, the Site is not in an area of cultural resources significance. However, prior to excavation, all contractors and subcontractors will be informed of the potential for discovering important paleontological, prehistorical, or historical resources below the ground surface and the legal consequences for damaging or destroying such resources. In the event that any prehistoric or historic cultural resources are discovered during earthwork, all work within the immediate area of the resources shall be halted and the District will consult with a qualified archaeologist or paleontologist to assess the significance of the find and make recommendations for further action.

12.1.5 Biological Resources Consideration

The US Fish and Wildlife Service (2018) has not identified the Site as located within a wetland or riparian area. Potential exposures to ecological receptors are not expected at the Site as there are no known sensitive biological areas or sensitive habitat on the Site. Additionally, because the Site has been historically used for livestock grazing and is proposed for development as a school, no wildlife


habitat will be maintained, no assessment of potential exposure to sensitive ecological receptors is necessary, and an ecological screening evaluation was not conducted for the Site.

12.1.6 Noise Control

Noise-generating construction operations will be limited to the hours of 7am to 7pm, Monday through Friday and 8:00 AM to 5:00PM Saturday and Sunday. There shall be no start-up of machines or equipment before 6:30am, and there shall be no cleaning or servicing of machines or equipment past 7:30pm. Construction equipment will be properly maintained and equipped with noise reduction intake and exhaust mufflers and engine shrouds, in accordance with manufacturers’ recommendations. Equipment engine shrouds will be closed during equipment operation. When not in use, motorized construction equipment will not be left idling. Trucks waiting in the on-site staging area to be loaded with soil for off-site transport or within the on-site staging area to be unloaded from off-site import will not sit idling for more than five minutes. If this is the case, the driver will immediately shut down the engine until it is ready to be loaded.

12.1.7 Permits and Plans

As described in Section 10.2.3, an NPDES General Permit for storm water discharges associated with construction activity, and the necessary grading permits or approvals will be obtained prior to the implementation of the RA. For the NPDES General Permit, an SWPPP will be prepared and electronically submitted to the SWRCB.

12.1.8 Field Oversight and Documentation

The District will designate a “competent person” to observe construction activities (i.e., earthwork, including grading) during the implementation of the RAW. A competent person is one who is/has:

Capable of distinguishing the potentially NOA-containing soil at the Site from the clean fill material that serves/will serve as the cap on applicable portions of the Site.

Capable of identifying existing and predictable conditions in the surroundings or working conditions which are unsanitary, hazardous, or dangerous to employees;

Capable of recommending the appropriate control strategies for NOA exposure; and

Authority to recommend prompt corrective measures to eliminate such hazards.

The competent person may be a PG, PE, or a trained technician working under the direct supervision of the PG or PE for the school construction project.

12.2 Earthwork Activities

Earthwork specifications including locations and planned depths of soil disturbance will be provided by the District. Earthwork activities that could disturb NOA-containing soil at the Site, will include:


Rough grading (completed);

Trenching for underground utilities (water, electrical, sewer, storm drains, etc.);

Excavations for building pads and footings (fences, bollards, lighting pole bases, etc.); and

Some landscaping and hardscape (paved) play areas (playfields, planting areas, bio-swales, open-space areas, playcourts, other paved outdoor areas, etc.).

Planned earthwork activities will be compared to pre-construction site conditions, to determine and document the thickness of the cap components based on final site design.

12.2.1 Soil Segregation Operations

When performing NOA intrusive work, clean fill comprising the cap and the underlying NOA-containing soil (if encountered) shall be segregated and properly identified at all times throughout the duration of the work to ensure that the material used to replace the cap does not contain NOA. If the orange warning barrier is not encountered during soil intrusive construction activities, then the contractor may assume they are working in clean cover material or in an area where NOA-containing soil is not present. If accidental mixing of the segregated materials occurs, then additional clean fill material will have to be imported to the Site to replace the cap. The source and quality of potential import materials, if not from the adjacent park site fill source, need to be approved by DTSC. If there is confusion regarding the identity of the NOA-containing and NOA-free soil, and the materials remain segregated, then sampling and laboratory testing for the presence of asbestos can be performed to determine which material came from the cap (NOA-free) and which is NOA-containing.

12.2.2 NOA-Containing Soil Stockpiling

If temporary stockpiling of NOA-containing soil is necessary, then the material will be kept adequately wetted or covered with plastic sheeting, which will be secured in place. Additionally, stockpiles should be bermed to prevent run-on and runoff. The excavated soil will be placed on heavy plastic sheeting, or other impermeable surface (concrete foundation, roll-off bin, etc.), to avoid contaminating the underlying soil or landscape features, if present. These control measures will be inspected daily whenever NOA-containing soil is stockpile at the Site.

12.2.3 Disposal of NOA-Containing Soil

Excess NOA-containing soil, if generated from NOA-intrusive work in the northern and eastern slope areas, may be reused below the cap in those areas, if possible. If placement below the cap is not possible, excess NOA-containing soil generated during NOA intrusive work may be disposed of offsite at an appropriately permitted waste disposal facility. Disposal or re-use of NOA-containing soil at another facility other than a previously DTSC-approved permitted waste disposal facility will not be permitted.


Samples of the material will be collected and analyzed to characterize the waste. In addition to analysis for asbestos by CARB 435, additional analyses may be requested by the disposal facility. Laboratory analysis results will be provided to the waste disposal facility for acceptance prior to off-site transportation and disposal.

12.2.4 Import Fill Material

If additional clean fill must be imported to the Site, it will be done in consultation with the DTSC project manager after the source of import fill has been identified and following the recommended sampling schedule in DTSC's Information Advisory, Clean Imported Fill Material (DTSC, 2001). If the fill source is located within a 10-mile radius of or in a downgradient drainage area of a known or suspected NOA-containing geological unit, asbestos should be included as a target compound in accordance with the draft DTSC NOA Tiered Approach to assess potential NOA fill source material. All samples should be analyzed by PLM with 25% of the samples analyzed by TEM if all PLM results are non-detect, and all samples analyzed by TEM if any detections by PLM are identified. If the TEM analyses indicate NOA concentrations greater than 0.01 wt%, then the source material will be rejected. DTSC recommends that the following counting rules be used when quantifying the NOA content in the soil:

All asbestiform amphibole minerals should be counted including ferroactinolite;

Fibers with an aspect ratio of greater than 3:1 should be counted;

Fibers that a length greater than 0.5 um should be counted; and

A detection limit of 0.005 wt% should be used for the TEM analysis.

For quality assurance/quality control purposes, 10% of the soil samples collected from the import material will be randomly selected for duplicate analysis by a second laboratory. The laboratories will be coordinated so that the primary lab sends the sample to the secondary lab after completion of the CARB 435 preparation. The following action levels will be used:

CARB 435 PLM Asbestos Screening Level: 0.25 wt% (dry weight) - the CARB 435 PLM Method may be used to analyze the soil samples for screening a potential source of import fill. If asbestos is detected at the screening level of 0.25 wt% by or greater, the potential source of fill should be rejected. If not detected at the screening level, 25% of the collected samples should be analyzed using the EPA Bulk TEM Method.

TEM Action Level: 0.01 wt% - DTSC recommends that the draft NOA Tiered Approach be used to assess potential fill sources. An interim action level of 0.01 wt% for asbestos (using EPA Bulk TEM Method) is appropriate to determine if a source of import fill is acceptable.


12.2.5 Documentation of Construction Activities

Earthwork activities will be monitored by a “competent person” working under the direct supervision of a PG or PE. The “competent person” will document where NOA containing soil is encountered, removed, and reused. Locations and depths of clean fill material and native clay soil (NOA containing soil) encountered during earthwork activities will be recorded, documented and mapped. This documentation will be used to confirm that final site design meets the minimum requirements of the design system components across the Site. Photographic documentation will be used where appropriate.

12.3 Air Monitoring

This section details the air monitoring strategy and methodologies that will be used at the Site during earthwork activities. The strategy and methodologies are designed to achieve the following:

Identify and measure air contaminants generated during the earthwork activities to assign the appropriate personal protective equipment and safety systems specified for those activities.

Provide feedback to site operations personnel regarding potential hazards from exposure to hazardous air contaminants generated through earthwork activities.

Identify and measure air contaminants at points outside of the earthwork activity zones. Air monitoring will be conducted during work activities to measure potential exposure of sensitive receptors to site chemical constituents, as a result of earthwork activities.

12.3.1 Meteorological Monitoring

Ambient weather conditions including temperature, relative humidity, wind speed, and wind direction, will be monitored onsite during earthwork activities by a qualified environmental consultant using a portable weather meter and wind sock. The meteorological equipment will be checked and recorded every hour during earthwork activities.

12.3.2 Dust Monitoring

Dust monitoring will be performed when NOA-containing soils are being disturbed. During earthwork operations dust levels will be monitored at the following four locations:

One upwind location;

One exclusion zone location;

Two downwind locations.

Dust monitoring locations will change daily in accordance with excavation location and wind direction. Dust levels will be monitored using particulate meters (Thermo Scientific PDR 1500 or equivalent). The particulate meters will be operated in data logging mode and used to measure and record real-time airborne dust concentrations. The locations of the meters will be determined each day by the Site Safety Manager or designated personnel, and will be based on the daily prevailing wind direction. The particulate meters will be checked approximately every 15 to 20 minutes during the course of earthwork


activities. Each time the meters are checked, the difference between the average upwind dust concentration, and the average downwind dust concentrations, will be compared to the CARB ambient air quality standard of 0.05 mg/m3 for total dust (24-hour average for PM10). This standard has been selected as the fence line action level, and is protective of public health.

Dust control measures as described in Section 12.4 will be implemented when total dust levels are within 50% of the Cal-OSHA PEL for total dust. Therefore, the site action level within the area of earthwork activities will be 5 mg/m3. Dust monitoring action levels to be implemented are presented in the following table.

Chemical of Concern CAL/OSHA PEL Exclusion Zone

Action Level (50% of PEL)

Fence Line Action Level (a)

Total Dust 10 mg/m3 5 mg/m3 0.05 mg/m3 Notes: PEL - Permissible Exposure Limit (8-hour, time-weighted average (TWA)). (a) – California ambient air quality standard (24 hour average for PM10).

12.3.3 Perimeter and Personal Air Monitoring

Perimeter and personal air sampling will be conducted. The air sampling plan will consist of the collection of air samples for both site worker personnel, and for the site perimeter (or fence line), to evaluate the effectiveness of dust control measures during grading activities. The site perimeter sampling will focus on the upwind and downwind fence lines. Air sample collection will be conducted under the supervision of a California CAC and/or a Certified Industrial Hygienist (CIH). A copy of the air sampling plan is presented in Appendix B of the ADMP in Appendix D of the RAW.

12.4 Dust Control Plan

The District’s contractor will implement appropriate procedures to control the generation of airborne dust during earthwork activities. Procedures will include, but not be limited to:

The site air monitoring professional will monitor dust levels, and will have the authority to stop-work in the event that onsite activities generate dust levels in excess of the California ambient air quality standards for particulate matter (0.05 mg/m3). Additionally, dust control measures will be taken if visible dust emissions are observed from the point-of-origin. Generation of dust during the earthwork will be minimized as necessary with the use of water as a dust suppressant. Water will be available via a water truck or a metered discharge from a fire hydrant located proximate to the Site. The District’s contractor will control dust generation by spraying water prior to daily work activities, during excavation/loading activities (as necessary to maintain concentrations less than action levels), and at truck staging locations. Watering equipment will be continuously available to provide proper dust control.


The air monitoring professional will monitor onsite meteorological instrumentation and/or coordinate with offsite meteorological professionals to identify conditions that require cessation of work. If wind speeds become elevated, initially, the increased application of water suppressant (water) will be employed. If an uncontrollable condition occurs (e.g. exceeding action levels for NOA), removal activities will cease, stockpiled soil(s) will be covered, and the excavation areas will be covered, if necessary. Work activities will not resume until conditions are stabilized or mitigation and/or effective engineering control measures are implemented and conditions are found acceptable to proceed.

Air monitoring personnel will measure airborne dust levels, using real-time, data-logging particulate monitors (Thermo Scientific PDR 1500 or equivalent). These instruments will be calibrated daily and monitoring information posted daily, and discussed with site workers. The monitors will be visually read every 20 minutes. In consultation with DTSC, the frequency may be changed based on site conditions and newly available data. Additionally, the particulate meters will be set to log dust levels over 5 minute periods.

During the course of earthwork, dust levels will be monitored at one location upwind of the exclusion zone; one location within the exclusion zone; and two locations downwind and outside the work zone, with one located closest to the nearest residences.

Dust control measures will be increased in the event particulate concentrations exceed 0.05 mg/m3 and/or if visible dust emissions are observed from the point-of-origin.

Perimeter fencing will be equipped with wind/dust/privacy screens for added off-site dust control.

12.5 Transportation Plan for Off-Site Disposal

Excess NOA-containing soil generated during NOA intrusive work (if any) will be disposed of off-Site at an appropriately permitted landfill facility. Samples of the material will be collected and analyzed for asbestos by CARB Test Method 435 by PLM. The analytical results will be forwarded to the appropriately licensed landfill facility for approval prior to transportation. Soil containing greater than 1% asbestos will be characterized as hazardous waste. It is anticipated that soils excavated from the Site will be managed (handled, transported and disposed of) as a non-hazardous waste. In addition to any other specific landfill requirements, the disposal of soil to a permitted landfill will likely require the material to be chemically analyzed for CAM17 Metals by EPA Method 6010/7000 series. If detected concentrations of metals do not exceed the California total threshold limit concentration (TTLC), then the soil will be disposed of as a non-hazardous waste. If detected metals concentrations exceed their respective TTLCs, then the soil will be classified as a hazardous waste. The soil sample is then analyzed by the California Waste Extraction Test (WET) for comparison to the soluble threshold limit concentration (STLC) or by the toxicity characteristic leaching procedure (TCLP) for comparison to Federal hazardous waste toxicity criteria, depending on the acceptance criteria of the landfill facility. If detected metals concentrations exceed the TCLP, then the soil will be classified as a RCRA-hazardous waste.


The PEA laboratory analysis results for soil suggest that the excavated soil is anticipated to be disposed of as a non-hazardous waste. The following waste facility has been identified to accept and store and/or treat non-hazardous soil generated from the removal activities:

Kiefer Landfill 12701 Kiefer Boulevard Sloughhouse, CA 95683

In the event that waste characterization identifies that the soil is required to be disposed of as a California hazardous waste, or as a RCRA hazardous waste, then the Transportation Plan will be revised to identify other appropriate waste facilities.

12.6 Decontamination

Equipment and trucks that come into contact with NOA-containing soil will be decontaminated to avoid cross-contamination. Disposable equipment intended for one-time use will not be decontaminated, but will be packaged for appropriate disposal. Decontamination will occur prior to and after each designated use of a truck or piece of equipment. Excavation and transportation equipment that handles NOA-containing soil will be decontaminated prior to use in uncontaminated areas and after the work is complete. Dry methods are the primary means of decontamination and consist of brushing and scraping to remove soil, debris, and dust. If dry methods are not effective, wet methods may be used such as steam cleaning and/or pressure washing. Washtubs with soap and water and rinse tubs will be provided for the cleaning of re-useable hand-held equipment. Wastewater from wet decontamination, if any, will be containerized and appropriately disposed.

12.7 Field Documentation

Earthwork and construction activities in proximity to NOA-containing material and the installation of engineering controls will be overseen by a qualified representative of Geocon in order to document and direct, on behalf of the District, the excavation, stockpiling and placement of both impacted (NOA) and non-NOA soil material. All earthwork activities will be monitored by the “competent person” working under the direct supervision of the Geotechnical Engineer of Record. The “competent person” will document where NOA-containing soil is removed and reused. This documentation will be used to confirm that final site design meets the requirements of the removal action across the Site. Photographic documentation shall be used where appropriate. The District’s contractor will be responsible for maintaining a field logbook during the course of their work. The field logbook will serve to document observations, personnel on-site, equipment arrival and departure times, and other vital project information.


12.8 Variance or Explanation of Significant Difference

After the RAW is approved and finalized, new information may be received or generated that could affect the implementation of the remedy selected in this RAW (Section 9.2.4), or could prompt the reassessment of that remedy. Appropriate actions should be taken to address the newly developed situations (which are deviated from or are not covered by the approved RAW). New information may include:

A change in scope, performance, or cost of the selected remedy; and

Advances in remediation science and technology which may impact the remedy selection.

Variances from the work plan will be discussed with DTSC prior to any action being taken except for emergencies (when an immediate response is required). The DTSC will be notified if an emergency response is implemented. The field variances will be documented in the Removal Action Completion Report (Section 14) prepared for the project. For the purposes of notification, DTSC must be notified by the responsible party by telephone call and/or email within 24 hours of discovery of new information.

12.8.1 Fundamental, Significant, or Minor Changes

Based on an evaluation, and depending on the extent or scope of modification being considered, one of the following three types of change may be classified, determined, and followed: minor changes, significant changes, or fundamental changes. Under CERCLA, 42 U.S.C. Section 9617(c), Section 117(c) requires that, if the removal action being undertaken at a Site differs significantly from the Record of Decision (ROD) (or in this case, the approved RAW) for that Site, the USEPA shall publish an explanation of significant differences (ESD) and the reasons such changes were made. An ESD, rather than EOD amendment, is appropriate where the adjustments being made to the ROD are significant, but not fundamentally alter the remedy with respect to scope, performance, or cost. For this project the approved RAW will be the ROD.

12.8.2 ESD Process

The Consultant will coordinate activities with the DTSC when an ESD is necessary. DTSC will determine the appropriate CEQA approach for changes to the Project.


13.0 OPERATION AND MAINTENANCE PLAN

The OMP in Appendix I presents the policies and procedures of the District for long-term operation, maintenance, and monitoring of engineering controls and management of soils containing elevated concentrations of NOA at the Site. The purpose of the OMP is to reduce or eliminate potential exposure pathways to humans to NOA in soil through the inhalation, dermal absorption, and ingestion exposure pathways. The selected remedial action for mitigating the presence of NOA in soil beneath the Site are engineering controls and institutional controls. Engineering controls include development of a cap with clean (non-NOA-containing) fill, paved areas, and building foundations. Institutional controls include administrative measures and the implementation of a long-term OMP. Any future construction performed within the Site following completion of the removal action will be managed under the OMP, to be approved by DTSC. The current OMP is a draft and will be finalized following completion of the school construction project. The OMP is finalized after construction is complete in order to incorporate as-built conditions into the scope of the plan.


14.0 REMOVAL ACTION COMPLETION REPORT

A Removal Action Completion Report (RACR) will be prepared and submitted to the DTSC upon completion of the removal action. The RACR will document compliance with this RAW, any deviations from the plan described herein, present the results of confirmation soil sampling and analysis, and document the capping of NOA-containing soil. The RACR shall contain the following information:

A summary of removal action implementation activities;

A description of field activities completed and justifications for any deviations from the RAW;

As-built drawings showing clean fill placement and final grade;

Copies of all permits;

Description of any excavations that encountered NOA-containing soil and documenting handling (segregation, stockpiling, covering) and replacement or offsite disposal;

NOA-containing soil disposal (if any) facility;

Photograph log during the implementation;

Clean fill borrow source and location;

Clean fill quantities and analytical data;

Conclusions and recommendations associated with the goals and objectives of the RAW; and

Identify any remaining areas of contamination and planned action or monitoring requirements.

The RACR should also contain the following on a compact disk attachment to the final report:

Field notes;

Laboratory reports; and

Copies of the disposal manifests.


15.0 PROJECT SCHEDULE

Enter into VCA Agreement ............................................................................ January 23, 2019

Submission of Draft RAW to DTSC ................................................................ March 11, 2019

DTSC review/comment and preparation of Final RAW .................................... April 24, 2019

Public notice of availability of RAW for public review .................................... April 25, 2019

30-day public comment period .......................................................... April 26 – May 25, 2019

DTSC issues responsiveness summary ............................................................... May 31, 2019

Final RAW approval ............................................................................................. June 7, 2019

Begin Construction ............................................................................................. Summer 2019

Complete Construction ............................................................................................... Fall 2020

Submit draft Removal Action Completion Report ....................................... Winter 2020/2021


16.0 LIMITATIONS

This PEA/RAW has been prepared solely for the District, in consideration of their requirements. Other parties may rely on the data and information presented in the PEA/RAW for informational purposes only. However, the owner and other parties who may rely on the findings and conclusions of the PEA/RAW should recognize that this PEA/RAW does not constitute a complete set of construction plans or specifications and should not be construed as such. The recommendations as presented in this PEA/RAW are predicated on the results of limited sampling and laboratory analyses performed. The information contained herein is only valid as of the date of the PEA/RAW and may require updating to reflect changes to conditions at the mine. Therefore, the PEA/RAW should only be deemed conclusive with respect to the information presented. No guarantee of the results of the study used to generate the PEA/RAW is implied within the intent of this PEA/RAW or any subsequent report, correspondence or consultation, either express or implied. The services performed were conducted in accordance with the local standard of care in the geographic region at the time the services were rendered.


17.0 REFERENCES

American Society for Testing and Materials, Designation E1527-13, Standard Practice for Environmental Site Assessments: Phase I Environmental Site Assessment Process.

Bradford, G.R., A.C. Chang, A.L. Page, D. Bakhtar, J.A. Frampton and H. Wright, 1996, Background Concentrations of Trace and Major Elements in California Soils, Kearney Foundation of Soil Science, University of California, Division of Agriculture and Natural Resources, March.

California Division of Mines and Geology (now the California Geological Society), 1981, Geologic Map of the Sacramento Quadrangle (Scale 1:250,000).

California Environmental Protection Agency, Department of Toxic Substances Control, Memorandum: Removal Action Workplans, September 23, 1998b.

California Environmental Protection Agency, Department of Toxic Substances Control, Preliminary Endangerment Assessment Guidance Manual. http://www.dtsc.ca.gov, 1994, (Second Printing, 1999).

California Environmental Protection Agency, Department of Toxic Substances Control, 2015c, Preliminary Endangerment Assessment Guidance Manual, October.

California Environmental Protection Agency, Department of Toxic Substances Control, 2016a, Human Health Risk Assessment Note Number 3: DTSC Recommended Methodology For Use Of U.S. EPA Regional Screening Levels (RSLs) In The Human Health Risk Assessment Process At Hazardous Waste Sites And Permitted Facilities, Human and Ecological Risk Office (HERO), updated June 2018, http://www.dtsc.ca.gov/AssessingRisk/upload/HHRA-Note-3.pdf.

California Environmental Protection Agency, Department of Toxic Substances Control, 2015, Update of the Schools NOA Guidance, Powerpoint presentation by M. Malinowski and B. Duke at the AEG Naturally Occurring Asbestos TWG Meeting, September 15.

California Environmental Protection Agency, Department of Toxic Substances Control, 2004, Interim Guidance, Naturally Occurring Asbestos (NOA) at School Sites, revised September.

California Geological Survey, 2006, Relative Likelihood for the Presence of Naturally Occurring Asbestos in Eastern Sacramento County, California, Special Report 192.

Geocon Consultants, Inc., 2017, Transfer of Geotechnical Responsibility and Supplemental Geotechnical Recommendations, Proposed Mangini Ranch Elementary School, Folsom, California, August 3.

Geocon Consultants, Inc., 2018, Geologic Hazards Evaluation and Geotechnical Investigation, Mangini Ranch Elementary School, White Rock Road and Placerville Road, Folsom, California, July 31.

Geosyntec, Site-Wide October 2018 Potentiometric and Fall 2018 Isoconcentration Contour Maps, Aerojet Superfund Site, 21 January 2019.

Groundwater Information Center Interactive Map Application (GICIMA), Depth to Groundwater, Spring 2018.

Interstate Technology Regulatory Council, 2012, Technical and Regulatory Guidance – Incremental Sampling, February.

Langer, A.M., R.P. Nolan, and J. Addison, 1991, Distinguishing between amphibole asbestos fibers and elongate cleavage fragments of their non-asbestos analogues, in: R.C. Brown et al., eds., Mechanisms in Fibre Carcinogenisis, Plenum Press, New York, p. 253-267.


MacKay & Somps, 2017, Rough Grading Plans (Sheets 22 and 27), Mangini Ranch – Phase 1, March.

Shacklette, H.T. and Boerngen, J.G., 1984, Element Concentrations in Soils and Other Surficial Materials of the Conterminous United States, U.S. Geological Survey Professional Paper 1270.

Thompson, B.D., M.E. Gunter, and M.A. Wilson, 2011, Amphibole asbestos soil contamination in the USA: A matter of definition, American Mineralogist, v. 96, p. 690-693.

United States Environmental Protection Agency, 1988, CERCLA Compliance with Other Laws Manual, Draft Guidance, 540/G-89/006, August.

United States Environmental Protection Agency, 1990, National Oil and Hazardous Substances Pollution Contingency Plan. Federal Register 55:8666.

United States Environmental Protection Agency, Office of Solid Waste and Emergency Response, 1993, Guidance on conducting non-time-critical removal actions under CERCLA, EPA/540-R-93-057; OSWER-9360.0-32.

United States Environmental Protection Agency, 1997, Best Management Practices (BMPs) for Soils Treatment Technologies, Suggested Operational Guidelines to Prevent Cross-Media Transfer of Contaminants During Cleanup Activities, EPA530-R-97-007.

United States Geological Survey, 2012, Clarksville, California, 7.5’ Quadrangle; Scale 1:24,000.

Western Regional Climate Center, Folsom Dam, California, 1981 – 2010, Temperature and Precipitation.

Youngdahl Consulting Group, Inc., 2007, Phase I Site Assessment for Mangini Property, APNs 072-0060-038 and 072-0060-069, NWC of White Rock Road and Old Placerville Road, Folsom, Sacramento County, California, March 20.

Youngdahl Consulting Group, Inc., 2007, Limited Phase II Soil Investigation for Mercury and Arsenic, Mangini Property, NWC of White Rock Road and Old Placerville Road, Folsom, Sacramento County, California, May.

Youngdahl Consulting Group, Inc., 2012, Phase I Site Assessment for Mangini Property, APNs 072-0060-038 and 072-0060-069, NWC of White Rock Road and Old Placerville Road, Folsom, Sacramento County, California, September 27.

Youngdahl Consulting Group, Inc., 2013, Folsom Plan Area Schools, Folsom, California, Naturally Occurring Asbestos Assessment, September 10.

Youngdahl Consulting Group, Inc., 2014, Geotechnical Engineering Study for Mangini Ranch, Phase I, July 31.

Youngdahl Consulting Group, Inc., 2014, Mangini Phase I School Site, Folsom, California, Naturally Occurring Asbestos Assessment, August 28.

N0 2000

Scale in Feet

Ref: USGS Clarksville, California, Folsom, California, Folsom SE, California and Buffalo Creek, California, 2018, 7.5-minute Topographic Quadrangles

PROJECTSITE

MANGINI PKWY

PLACERVILLE RD

MANGINI PKWY

SITE LATITUDE: 38.627128SITE LONGITUDE: -121.102414

PLACERVILLE RD

Proposed Mangini Ranch Elementary SchoolFolsom,

CaliforniaVICINITY MAP

April 2019 Figure 1S1376-03-02

P H O N E 9 1 6 . 8 5 2 . 9 11 8 – FA X 9 1 6 . 8 5 2 . 9 1 3 23 1 6 0 G O L D VA L L E Y D R – S U I T E 8 0 0 – R A N C H O C O R D O VA , C A 9 5 7 4 2

0 100

Scale in Feet

N Proposed Mangini Ranch Elementary SchoolFolsom,

CaliforniaSITE PLAN



LEGEND:

Approximate Test Pit Location (7/21/17)


TPB

Slate

Slat

eSl

ate

Slat

e

Slat

e

TPH

TPBTPG

TPE

TPD

Slate

Slat

e

Slat

eSl

ate

Slat

eSl

ate

Slat

e

Jss

Jss

Jss

Jss TPH

TPBTPG

TPE

TPD

School 2

School 3

School 4School 5

School 6

Park 25

Park 14

Park 13

Park 2

Park 30

TPA

School 2

School 3

School 4School 5

School 6

Park 25

Park 14

Park 13

Park 2

Park 30

QefmQefm

Slat

eSl

ate

TPFTPF

TPCTPC

????

Park 2Park 2

Engineered Fill of Mangini Parkway

Geologic Contact (dashed where approximate; dotted where covered)

Salt Springs Slate

Gopher Ridge Volcanics

Jss

Jgo

Qefm

??

??

JgoJgo

School 1School 1

??

Approximate Site Boundary

0 100

Scale in Feet

N


CaliforniaSITE / DEVELOPMENT PLAN

Jss

Jss

Qefs

Qefm

Qefs

Jgo

School 2

School 3

School 4School 5

School 6

Park 25

Park 14

Park 13

Park 2

Park 30

Jss

Jss

Qefs

Qefm

Qefs

Jgo



Engineered Fill of Mangini Parkway (potentially NOA-bearing)

Engineered Fill derived from Salt Springs Slate (non-NOA-bearing)

Qefs over Jgo bedrock

Salt Springs Slate (non-NOA-bearing) Naturally Occuring AsbestosRemoval Action WorkplanOperations and Maintenance Plan

NOA =RAW =OMP =

Gopher Ridge Volcanics (potentially NOA-bearing)

TPH

TPBTPG

TPE

TPD

TPHTPA

School 2

School 3

School 4School 5

School 6

TPBTPG

TPE

TPD

TPFTPF

B4

B3

LEGEND:


Approximate Boring Location (3/14/18)



Geologic Contact (dashed where approximate; dotted where covered)

Approximate Cross-Section Location

Area of RAW/OMP Applicabiliity

TPB

B5

B4

B3

Park 2

3' Undercut

????

??

??

Park 25

Park 14

Park 13

Park 2

Park 30

TPCTPC

Jss

Jgo

Qefm

Qefs

Qefs

A'

B'

A'

B'

A A'

AA

B1B1

School 1School 1

BB

B5B5

B2B2

0 80

Scale in Feet

M A N G I N I PA R K W AY


N

Folsom, CaliforniaApril 2018 Sampling Layout

and Analysis Results

DU1

DU2

DU3

DU4

DU5

DU6 DU7DU8

DU1

DU2

DU3

DU4

DU5

DU6 DU7DU8

Figure 4


Proposed Mangini Ranch Elementary School

April 2019S1376-03-02

13

2

13

2

13

2

13

2

1

3

2

1

3

2

1

3

2

1

3

2

LEGEND:


Sampling Unit (SU) Boundary

Decision Units (DU) Boundary

Replicate Sample Locations(Same for all SUs Sampled)

All Asbestos Results in Weight Percent (wt%)

Percent by weight relative to finefraction of sample after sieving

Less than the laboratory reporting limit

Not analyzed

< =

--- =

Sam

ple

ID

Dep

th

DU4-1NOADU4-2NOADU4-3NOA

0'-0.5'0'-0.5'0'-0.5'

Dat

e

4/13/184/13/184/13/18

0.00920.0498

< 0.0005

0.148*0.811*

---

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

DU4

Sam

ple

ID

Dep

th


0'-0.5'0'-0.5'0'-0.5'

Dat

e

4/13/184/13/184/13/18

0.03580.0017

< 0.0005

< 0.001*------

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

DU2

Sam

ple

ID

Dep

th


0'-0.5'0'-0.5'0'-0.5'

Dat

e

4/13/184/13/184/13/18

< 0.0005< 0.00050.0232

------

< 0.001*

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

DU5

*

Folsom, CaliforniaJuly and August 2018 Sampling Layout

and Analysis ResultsFigure 5



April 2019S1376-03-02

0 80

Scale in Feet



N

MSS1

MSS2

MSS3

MSS4

MSS5

MSS6

MSS7

MSS8

DU1DU2

DU3DU4

DU5DU6

DU7

MSS1

MSS2

MSS3

MSS4

MSS5

MSS6

MSS5

Fill SoilRemoval Area(August 2018)

Fill SoilRemoval Area(August 2018)

MSS7

MSS8

DU1DU2

DU3DU4

DU5DU6

DU7

13

2

13

2

LEGEND:




Discrete Soil Sample Location




Arsenic and Mercury Results inmilligrams per kilogram


Not analyzed

1

32

1

32

1

3

21

3

2

1

3

2

1

3

2

1

3

2

1

3

2 < =

--- =

Sam

ple

ID

Dep

th

DU1-1DU1-2DU1-3

0'-0.5'0'-0.5'0'-0.5'

Dat

e

7/3/187/3/187/3/18

Arse

nic

52------

Mer

cury

0.13------

< 0.0005< 0.0005< 0.0005

---------

AsbestosCA

RB

435

Prep

ASTM

D75

21Pr

ep

DU1

Sam

ple

ID

Dep

th

MSS1-0MSS1B

0'-0.5'1.5'-2'

Dat

e

7/3/188/10/18

0.1089< 0.0005

2.016*---

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

MSS1

Sam

ple

ID

Dep

th

MSS2-0MSS2B

0'-0.5'1.5'-2'

Dat

e

7/3/188/10/18

0.31620.2715

0.049*---

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

MSS2

Sam

ple

ID

Dep

th

MSS3-0 0'-0.5'

Dat

e

7/3/18 < 0.0005 ---

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

MSS3

Sam

ple

ID

Dep

th

MSS4-0 0'-0.5'

Dat

e

7/3/18 < 0.0005 ---

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

MSS4

*

Sam

ple

ID

Dep

th

DU3-1DU3-2DU3-3

0'-0.5'0'-0.5'0'-0.5'

Dat

e

7/3/187/3/187/3/18

< 0.0005< 0.0005< 0.0005

---------

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

DU3

Sam

ple

ID

Dep

th

DU6-1DU6-2DU6-3

0'-0.5'0'-0.5'0'-0.5'

Dat

e

7/3/187/3/187/3/18

< 0.0005< 0.0005< 0.0005

---------

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

DU6

Sam

ple

ID

Dep

th

DU7-1DU7-2DU7-3

0'-0.5'0'-0.5'0'-0.5'

Dep

th

7/3/187/3/187/3/18

< 0.0005< 0.0005< 0.0005

---------

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

DU7

Sam

ple

ID

Dep

th

MSS5-0 0'-0.5'

Dat

e

7/3/18 < 0.0005 ---

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

MSS5

Sam

ple

ID

Dep

th

MSS6-0 0'-0.5'

Dat

e

7/3/18 < 0.0005 ---

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

MSS6

Sam

ple

ID

Dep

th

MSS7-0 0'-0.5'

Dat

e

7/3/18 < 0.0005

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

MSS7

Sam

ple

ID

Dep

th

MSS8-0 0'-0.5'

Dat

e

7/3/18 < 0.0005

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

MSS8

---

---

Arse

nic

---39---

Mer

cury

---0.16---

Arse

nic

------31

Mer

cury

------

0.12

Arse

nic

---19---

Mer

cury

---0.15---

Folsom, CaliforniaSeptember and October 2018

Sampling Layout and Analysis ResultsFigure 6



April 2019S1376-03-02

0 80

Scale in Feet



N

A

A

C

C

C

B

B

B

A

A

C

C

C

B

B

B

DU9/MSS9-ABC

DU9/MSS9-ABC

AA

A

13

2

13

2

1

3

2

1

3

2

LEGEND:




Discrete Soil Sample Location




Arsenic and Mercury Results inmilligrams per kilogram


Not analyzed

A

C

B

A

C

B

A

C

B

A

C

BBB

A

C

A

C

DU12/MSS12-

ABC

DU10/MSS10-

ABC DU11/MSS11-

ABC

DU14/MSS14-

ABCDU13/

MSS13-ABC

DU12/MSS12-

ABC

DU10/MSS10-

ABC DU11/MSS11-

ABC

DU14/MSS14-

ABCDU13/

MSS13-ABC

< =

--- =

*

Sam

ple

ID

Dep

th

MSS9-ABC 0'-0.5'

Dat

e

9/7/18 < 0.0005

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

MSS9-ABC

< 0.0005*

Sam

ple

ID

Dep

th

MSS10-ABC 0'-0.5'

Dat

e

9/7/18 < 0.0005

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

MSS10-ABC

0.1086*

Sam

ple

ID

Dep

th

MSS11-ABC 0'-0.5'

Dat

e

9/7/18 < 0.0005

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

MSS11-ABC

---

Sam

ple

ID

Dep

th

MSS13-ABC 0'-0.5'

Dat

e

9/7/18 < 0.0005

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

MSS13-ABC

---

Sam

ple

ID

Dep

th

MSS14-ABC 0'-0.5'

Dat

e

9/7/18 < 0.0005

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

MSS14-ABC

---Sam

ple

ID

Dep

th

MSS12-ABC 0'-0.5'

Dat

e

9/7/18 < 0.0005

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

MSS12-ABC

< 0.0005*

Sam

ple

ID

Dep

th

DU10-1DU10-2DU10-3

0'-0.5'0'-0.5'0'-0.5'

Dat

e

10/12/1810/12/1810/12/18

0.283< 0.0010.018

< 0.001*< 0.001*< 0.001*

Asbestos

CAR

B 43

5Pr

ep

ASTM

D75

21Pr

ep

DU10

Arse

nic

19

Mer

cury

<0.047

Arse

nic

37

Mer

cury

0.068

Arse

nic

21

Mer

cury

0.067

Arse

nic

19

Mer

cury

<0.045 Arse

nic

22

Mer

cury

0.094

Arse

nic

20

Mer

cury

0.054

Folsom,California

Site Conceptual Exposure Model

Figure 7



April 2019S1376-03-02

PRIMARYSOURCES

SECONDARYSOURCES

TRANSPORTMECHANISMS

POTENTIALEXPOSURE

ROUTESPOTENTIALRECEPTORS

Students and StaffSite VisitorsConstruction Workers

Inhalation ofParticulates

AIRAffected

SoilAirborne

DustNOA-Containing Soil


CaliforniaCROSS-SECTION A – A'



0 60

20

0

HorizontalScale in Feet

Note: 3X Vertical ExaggerationVe

rtic

alSc

ale

in F

eet

430

440

ANorthwest

A'Southeast

420

410

Elev

atio

n in

Fee

t (M

SL)

430

440

420

410

Elev

atio

n in

Fee

t (M

SL)

TD=15.5'8" CanyonDrain

6" Canyon Drain

3212*

50/2"

50/6"

Refusal @ 6.5'

54

TD=5.1'

86

50/1"*Qefs

Jss

OGOG

TD=6'

TD=7'

TD=6'

Elev

atio

n in

Fee

t (M

SL)

TD=Total Depth (Ft.)

Boring/Test Pit Location

Geologic Contact

Blow Counts (California ModifiedSampler/*SPT Sampler)

32

B5

TD=15.5'8" CanyonDrain

6" Canyon Drain

3212*

50/2"

50/6"

Refusal @ 6.5'

54

B4 (P

roje

cted

75'

NW

)

TD=5.1'

Hard Courts

86

50/1"*

B3

B3

School BuildingPlay Fields

Qefs

Jss

80/8"72*

B5

80/8"72*

B5

Pick Up/Drop Off

TrafficLane

Engineered Fill Derived From Salt Springs Slate

Salt Springs Slate

Approximate Original Grade

Approximate Existing Grade

OG

EG

LEGEND:

EG

OGOG

OGOG EGEG

TD=6'

TPA

(Pro

j. 10

' SW

)TP

A(P

roj.

10' S

W)

TD=7'

SCH

4(P

roj.

35' S

W)

SCH

4(P

roj.

35' S

W)

TD=6'

TPC

(Pro

j. 30

' NE)

Qefs

Jss

Roadway –"L" Drive


CaliforniaCROSS-SECTION B – B'



0 60

20

0

HorizontalScale in Feet

Note: 3X Vertical ExaggerationVe

rtic

alSc

ale

in F

eet

School BuildingParking Lot Drop-OffPick-Up

Warning Barrier

430

440

450

BSouthwest

420

410

400

TD=15.5'

TD=10.5'

3212*

50/2"

50/6"

B2B5 B2

430

440

450

B'Northeast

420

410

400

Elev

atio

n in

Fee

t (M

SL)

Elev

atio

n in

Fee

t (M

SL)

Elev

atio

n in

Fee

t (M

SL)

Elev

atio

n in

Fee

t (M

SL)

HardcourtsHardcourts

EG

OG

EGOG

Ram

p/St

airs

Bus

Dro

p-O

ff

50/6"*85/11"*50/6"*85/11"*

86/11.5"69*86/11.5"69*

B5

72*72*72*

TD=Total Depth (Ft.)

Boring/Test Pit Location

Geologic Contact

Blow Counts (California ModifiedSampler/*SPT Sampler)

32

B5 Engineered Fill Derived From Salt Springs Slate

Salt Springs Slate

Gopher Ridge Volcanics

Approximate Original Grade

Approximate Existing Grade

OG

EG

LEGEND:

Qefs

Jss

Jgo

Qefs

Jss

Jgo

10" Canyon Drain(Proj. 25' SW)

TD=7'

TPF

(Pro

j. 40

' SE)

TPF

(Pro

j. 40

' SE)

TD=7'

TPB

(Pro

j. 50

' SE)

TD=6'

Roadway –"L" Drive

SCH

1 (P

roj.

45' S

E)SC

H1

(Pro

j. 45

' SE)

EG

Geocon Project No. S1376-03-02April 23, 2019Page 1 of 4

SAMPLE ID SAMPLEDESCRIPTION

ANALYTICALMETHOD

RESULT ASBESTOS TYPE

TEM - EPA 600/R-93/116(CARB 435 milling prep)

0.0358 wt% Actinolite

PLM - ASTM D7521(sieving prep; no milling)

ND None Detected

TEM - EPA 600/R-93/116(ASTM D7521 sieving prep; no milling)

<0.001 wt% None Detected

DU2-2NOA ISM TEM - EPA 600/R-93/116(CARB 435 milling prep)



<0.0005 wt% None Reported




ND None Detected


0.148 wt%* Actinolite




ND None Detected












ND None Detected


<0.001 wt%* None Detected

DU1-1 ISM TEM - EPA 600/R-93/116(CARB 435 milling prep)








DU4-2NOA ISM

DU5-3NOA ISM

7/3/2018 SAMPLING EVENT

DU2-1NOA ISM

DU4-1NOA ISM

FOLSOM, CALIFORNIA

TABLE 1SUMMARY OF LABORATORY ANALYSIS RESULTS - SOIL

PROPOSED MANGINI RANCH ELEMENTARY SCHOOL


ASBESTOS



ANALYTICALMETHOD


FOLSOM, CALIFORNIA


PROPOSED MANGINI RANCH ELEMENTARY SCHOOLASBESTOS

























MSS3-0 Discrete TEM - EPA 600/R-93/116w/milling prep












MSS1B Discrete TEM - EPA 600/R-93/116(CARB 435 milling prep)


MSS2B DiscreteTEM - EPA 600/R-93/116(CARB 435 milling prep) 0.2715 wt%

Actinolite, Ferro-hornblende, Magnesio-hornblende

MSS1-0 Discrete

MSS2-0 Discrete




ANALYTICALMETHOD


FOLSOM, CALIFORNIA






<0.0005 wt%* None reported


<0.0005 wt% Actinolite

TEM - EPA 600/R-93/116(ASTM D7521 sieving prep; no milling) 0.1086 wt%* Actinolite

MSS11-ABC 3-part composite TEM - EPA 600/R-93/116(CARB 435 milling prep)



<0.0005 wt% None reported


<0.0005 wt%* None reported








ND None Detected






ND None Detected






ND None Detected



DU10-3 ISM

DU10-2 ISM

DU10-1 ISM



MSS9-ABC 3-part composite





ANALYTICALMETHOD


FOLSOM, CALIFORNIA



Notes:TEM = Transmission Electron MicroscopyPLM = Polarized Light Microscopywt% = Percent by weightwt%* = Percent by weight relative to fine fraction of sample after sievingND = None detected< = Less than the laboratory reporting limitCARB = California Air Resources BoardShaded rows = Associated soil removed during edge area remedial grading during August 2018


Sample IDMercury(mg/kg)

Total in sub-250-micron fraction (mg/kg)

Bioaccessible(mg/kg)

RBA(%)

MSS9-ABC <0.047 19 30 4.7J 16J

MSS12-ABC <0.045 19 20 4.6J 22J

DU7-2 0.15 19 --- --- ---

MSS14-ABC 0.054 20 18 3.2J 18J

MSS11-ABC 0.067 21 22/22 4.9J/4.4J 21J/19J

MSS13-ABC 0.094 22 --- --- ---

DU6-3 0.12 31 --- --- ---

MSS10-ABC 0.068 37 52 6.6J 13J

DU3-2 0.16 39 --- --- ---

DU1-1 0.13 52 --- --- ---

Screening Levels (1)

Residential 1.0 0.11Commercial/Industrial 4.4 0.36

Notes:

mg/kg = milligrams per kilogram

< = Less than laboratory reporting limit--- = not analyzedRBA = arsenic relative bioavailability


ARSENIC AND MERCURYPROPOSED MANGINI RANCH ELEMENTARY SCHOOL

FOLSOM, CALIFORNIA

Arsenic

California Arsenic Bioaccessibility (CAB)Total

(mg/kg)

J Estimated Value. Analyte was detected in the extraction fluid below the reporting limit, but above the method detection limit. Calculations based on the concentration in the extraction fluid are therefore also estimates.

(1) Screening levels are the DTSC Human and Ecological Risk Office (HERO) Note 3 Screening Levels for Soil


Sample IDArsenic(mg/kg)

Mercury(mg/kg)

MSS9-ABC 19 <0.047

MSS12-ABC 19 <0.045

DU7-2 19 0.15

MSS14-ABC 20 0.054

MSS11-ABC 21 0.067

MSS13-ABC 22 0.094

DU6-3 31 0.12

MSS10-ABC 37 0.068

DU3-2 39 0.16

DU1-1 52 0.13

Screening Levels (1)

Residential 0.11 1.0Commercial/Industrial 0.36 4.4

Notes:

mg/kg = milligrams per kilogram

< = Less than laboratory reporting limit(1) Screening levels are the DTSC Human and Ecological Risk Office (HERO) Note 3 Screening Levels for Soil


ARSENIC AND MERCURYPROPOSED MANGINI RANCH ELEMENTARY SCHOOL

FOLSOM, CALIFORNIA

PHOTOS NO. 1 & 2


April 2019GEOCON Project No. S1376-03-02

Folsom,California


Photo No. 1 First day (8/9/17) of engineered fill (Salt Springs Slate) placement on the Site.

Photo No. 2 Placement of engineered fill (Salt Springs Slate) on central portion of the Site. Photo date 8/22/17.

PHOTOS NO. 3 & 4



Folsom,California


Photo No. 3 Overexcavation of NOA-bearing metavolcanic rock on northeastern portion of the Site. Photo date 8/21/17.

Photo No. 4 Warning barrier placement over NOA-bearing metavolcanic rock on northeastern portion of the Site. Photo date 10/6/17.

PHOTOS NO. 5 & 6



Folsom,California


Photo No. 5 Placement of engineered fill (Salt Springs Slate) over warning barrier on northeastern portion of the Site. Photo date 10/6/17.

Photo No. 6 Placement of engineered fill (Salt Springs Slate) over warning barrier on northeastern portion of the Site. Photo date 10/6/17.

PHOTOS NO. 7 & 8


Folsom,California


Photo No. 8 View to the west along the northern Site boundary. Photo date 5/16/18.

Photo No. 7 View to the southwest of the vacant Site following initial fill placement and hydroseeding. Photo date 5/16/18.


PHOTOS NO. 9 & 10

Photo No. 9 View to the north along the eastern Site boundary. Photo date 5/16/18.



Folsom,California


Photo No. 10 View to the east along the southern Site boundary. Photo date 5/16/18.

PHOTOS NO. 11 & 12

Photo No. 12 View to the east along the northern site boundary. Photo date 5/16/18.

Photo No. 11 View to the north along the western site boundary. Photo date 5/16/18.



Folsom,California


PHOTOS NO. 13 & 14

Photo No. 14 View to the east of topographically higher undeveloped land. Photo date 5/16/18.

Photo No. 13 View to the north of Mangini Parkway beyond which is land under construction for residential use. Photo date 5/16/18.



Folsom,California


PHOTOS NO. 15 & 16

Photo No. 16 Land being excavated for fill material west of the Site. Photo date 5/16/18.

Photo No. 15 View to the south of undeveloped land extending to White Rock Road south of the Site. Photo date 5/16/18.



Folsom,California


PHOTOS NO. 17 & 18

Photo No. 17 Stockpiled fill material on the adjacent property to the west of the Site. Photo date 5/16/18.



Folsom,California


Photo No. 18 Eastern and northern edge area remedial grading. Photo date 8/8/18.