data results: soil screening & … · version: 2.0 (march, 2008) author david m. kargbo, phd,...
TRANSCRIPT
SDMS DocID 2101262
Central Chemical Site Record of Decision - Operable Unit 1 September 17,2009
SSRG Tool for Soil Remediation Standards - protective of ground water
AR305183
SOIL SCREENING & REMEDIATION GOALS (8SRG) Tool
VADOSE ZONE PARAMETERS ENTRY FORMS Data entry for Scenario 1 ^
Vertical - Total lUlodeled Enter vertical Soil Type Hyd cond Exponential porosity
layer tfiickness Used Ks (m/y) Parameter, b nt (fraction)
Source Layer
Layer 1
Layer 2
Layer 3
Layer 4
0.8
0,5
0.5
0.5
0.2
Effective porosity
ne (fraction)
Moisture content
0w (fraction)
. Effective moisture content
0e (fraction)
Data entry for Scenario li
Dab
Add
Vertical ' Total Modeled Enter vertical Soil Type .Hyd cond Exponential porosity
layer thickness Used Ks (m/y) Parameter, b nt (fraction)
Source Layer 0,8 0,5
Layer 1 . 0.5
0.5
Effective porosity
. ne (fraction)
Moisture
content &M (fraction)
Effective
moisture content 0e (fraction)
1 1 1 1 1 1 1
1 1 1 1 1 1 .
Laver 2| 02 j j j | | | |
1 entry for Scenario III
Vertical Total Modeled Enter vertical Soil Type Hyd cond Exponential porosity
layer thickness Used Ks (m/y) Parameter, b nt (fraction)
Source Layer
0.8 0.5 0.5 0.5
• '
Effective porosity
ne (fraction)
Moisture content
0w (fraction)
Effective moisture content
0e (fraction)
1 I I 1 1 1 1
Layenl 02 j | 1 / 1 1 1 1
itional soil data entry Infiltration rate (m/yr)
0.24
Bulk density (kg/L)
1.5
Particle ' density (kg/L)
Frac. org carb (unitless)
2.65 0.004 1
on
'
AR305184
SOIL SCREENING & REMEDIATION GOALS (SSRG) Tool
Select Chemicals
(of interest)
4,4-DDT
2,4,5-T
2,4-D
2,4-DDD
2,4-DDE •
2,4-DDT
4,4-DDD 4,4-DDE Aldrin Alpha Chlordane Alpha-HCH (alpha-BHC) Atrazine Beta BHC Chlordane (technical) Delta BHC Dieldrin Diphenamid Endrin Endrin Ketone gamma chlordane gamma BHC(Lindane) Heptachlor Heptachor epoxide Naphthalene Toxaphene
Concentration in soil (Ct). (mg/kg)
Half Life
T„2 (Yrs)
Henry's Law Constant (H')
Dimensionless
Chemical . Solubility (8)
mg/L
Octanol-C Part Coeff Koc (L/Kg)
SELECT ORGANIC CHEMICALS AND ENTER PARAMETERS
130,000 0
0.1
0.0
2,300.0 120.0
39,000.0 10,000.0
920.0 3,100.0 2,000.0
3,100 2.300.0
240.0 120,000.0
750.0 670.0
1.7 0.9
98.0 2,000.0 1,700.0
840.0 83.0 85.0
140,000.0
* •
;
1.67E+01
9.00E-01 1.67E+01 1,67E+01 1.67E+01 1.67E+01
16.70 0.15 0.42
• 0.5 0.30 0.50 0.42
,0.09 2.37 1.76
14.00 . 14.00
0.42 0.29 0.12 0.12 0.05
14.00
'
^ •
0.0003
0.0000
0.0000
0.0007
0.0007
0.0000 0.0002 0.0009 0.0070 0.0352
4.35E-04 0.0000 0.0000 0.0020
. 0.0000 0.0006 0.0000 0.0003 0.0439 0.0532 0.0006 0.0447
^ 0.0004 0.0198 0.0002
003
278.00
680.00
0.14 0.14
0.09 0.09 0.12 0.18 0.06
2.00E+00 70.00
0.24 0.06 8.00 0.20
260.00 0.25 0.03 0.06 6.80 0.18 0.20
31.00 0.74
^
2630000.0
641.0
26.2
224000.0
155000.0
155000.0 1000000.0 4470000.0 2450000.0
120000.0 1.23E+03
619.0 1260.0
120000.0 1900.0
21400.0 204.0
12300.0 530000.0 120000.0
1070.0 1410000.0
83200.0 2000.0
257000.0
MCL or PRG (mg/L)
^
2.00E-04
3.70E-01
7.00E-02
2.80E-04
2.00E-04
2.OOE-04 2.80E-04 2.00E-04 4.00E-06 1.90E-04 1.10E-05 2.90E-04 3.70E-05 1.90E-04 1.10E-05 4.20E-06 1.10E+00 2.00E-03 2.00E-03 1.90E-04 6.10E-05 1.50E-05 7.40E-06 1.40E-04 6.10E-05
/
AR305185
SOIL SCREENING & REMEDIATION GOALS (SSRG) Tool
Chemical
(of interest)
Concentration in soil (Ct)
(mg/kg)
Half Life Ti,2 •
(Yrs)
Henry's Law Constant (H')
Dimensionless
Chemical Metal Solubility (S) . Distr Coeff
mg/L Kd(LyKg)
MCL or PRG (mg/L)
SELECTINORGANIC CHEMICALS AND ENTER PARAMETERS |
Arsenic Manganese Thallium •
407.0 1,020.0
4.1
)
• '
. •
39.0 65.0 71.0
,
1.00E-02 8.80E-01 2.00E-03
^
AR305186
Aquifer Mixing Zone Depth and DAF Parameters
Variable L K
da
i
©w
Pb .
Pp
foe
Value 183 316
76
0,02
0.30
1.50
2.65
0.004
Unit m
m/yr
' m
m/m
Unitless
kg/L
kg/L
Unitless
Descript ion
Source length parallel to groundwater flow Aquifer saturated horizontal hydraulic conductivity
Aquifer thickness
Horizontal hydraulic gradient in aquifer
Water-filled Porosity
Bulk Density
Particle density in aquifer
Fraction of organic carbon in aquifer
Calculated parameters
0
©a
d(calc) DAF
d(in DAF)
0.43
0.13
26.0 4.7
26.0
Unitless
Unitless
m unitless
m
Aquifer porosity
Air-filled Porosity • •
Calculated MixingiZone Depth
bilution,Attenuation Factor Mixing Zone Used in DAF Calculations
AR305187
P r o j e c t N a m e :
P r o j e c t L o c a t i o n :
P r o j e c t O f f i c e r :
D a t e :
Chemicals
(of interest) 4,4-DDT
2,4,5-T
2,4-D
2,4-DDD
2,4-DDE
2,4-DDT
4,4-DDD
4,4-DDE
Aldrin
Alpha Chlordane
Alpha-HCH (alpha-BHC)
Atrazine
Beta BHC
Chlordane (technical)
Delta BHC
Dieldrin
Diphenamid
Endrin
Endrin Ketone
gamma chlordane
gamma BHC(Lindane)
Heptachlor
Heptachor epoxide
Naphthalene
Toxaphene
* NE = Not evaluated
Central Chemica l
Hagers town, M D
Mitch Cron
9/17/2009
Measured
soi l
concen (Ct)
(mg/kg)
1.30E+05
5.50E-02
3.60E-02
2.30Et03
1.20E+02
3.90E+04
1.00E+04
9.20E-^02
3.10E+03
2.00E+03
3.10E-^03
230E+03
2.40E+02
1.20E+05
7.50E+02
6.70E+02
1.70E+00
8.60E-01
9.80E+01
2.00E+03
1.70E+03
840E+02
8.30E-^01
8.50E+01
1.40E+05
Kd(VZ)
U K g
1 05E+04
2.56E+00
1.05E-01
8.96E+02
6.20E+02
6.20E+02
4.00E+03
1.79E+04
9.80E+03
4.80E+02
4.92E+00
2.48E+00
5.04E+00 .
4.80E+02
7.60E+00. .
8.56E+01
8.16E-01
4.92E+01
2.12E-^03
4.80E+02
4.28E+00
5.64E+03
3.33E+02
8.00E+00
1.03E+03
SOIL SCREENINe & REMEDIATION OOAU (S5R0) Tool Vers ion: 2.0 (March, 2008)
Author David M. Kargbo, PhD, USEPA Region III
SSL and SSRG RESULTS FOR ORGANIC CONTAMINANTS
Scenarios
Kd(GW)
U K g
1.05E+04
2.56E+00
1.05E-01
8.96E+02
6.20E+02
6.20E+02
4.00E+03
• 1.79E+04
9.80E+03
4.80E+02
4.92E+00
2.48E-fO0
5.04E+00
-4.80E+02
7.60E+00
8.56E+01
8.16E-01
4.92E+01
2.12E+03
4.80E+02
4.28E+00
5.64E+03
3.33E-^02
8.00E+00
1.03E+03
^
Retardation
(R) 9.42E+04
2.40E+01
1.94E+00
803E+03
5.55E+03
555E+03
358E+04
1.60E+05
8.78E+04
430E+03
4.51E-^01
2.32E+01
4.61E+01
4.30E-1-03
6.91E+01
7.68E+02
8.31E+00
442E+02
. 1.90E+04
4 30E+03
3.93E+01
5.05E+04
2.98E+03
7.27E+01
9.21 E+03
-
Mean Travel
T ime Thru
k/ertical Laye
Tt (years)
1.32E+04
3.34E+00
2.71 E-01
1.12E+03
7.75E+02'
7.75E+02
5.00E+03
224E+04
1.23E+04
6.0aE+02
6.29E+00
3.23E+00
6.44E+00
6.00E+02
9.64E+00
1.07E+02
1.16E+00
6.16E+01
2.65E+03
6 OOE+02
5.49E+00
7.05E+03
4.16E+C2
1.01E+C1
1.29E-^03
Cgw f rom Ct
(w i thout
degrad)
mg/L
2.61 E+00
420E-03
2.49E-02
5.41 E-01
4.08E-02
1 33E+01
5.27E-01
1.08E-02
6.67E-02
8.78E-01
1.28E+02
1.81E+02
9.66E+00
. 5.27E+01 ,
2.03E+01
1.65E+00
3.53E-01
3.67E-03
9.75E-03
8 78E-01
8.00E+01
314E-02
526E-02
2.19E+00
2.87E+01
Cgw f rom Ct
(with
degrad)
mg/L
0
2.02E-02
0
0
0
0
0
0
0
2.09E-02
1.03E-01
1.28E-03
0
0
0
2.23E-01
1.74E-04
0
0
1 61E-04
0
0
0
0
MCL
1 or .
PRG
(mg/L)
200E-04
370E-01
7.00E-02
280E-04
2.00E-04
2.OOE-04
2.80E-04
2.00E-04
400E-06
1 90E-04
1 10E-05
2.90E-04
3.70E-05
1.90E-04
1.10E-05
420E-06
1.10E+00
200E-03
200E-03
1.90E-04
6.10E-05
1.50E-05
7.40E-06
1.40E-04
6.10E-05
Cgw based on
MCL, MCLG,
mg/L 9.49E-04
1 75E+00-
332E-01
1.33E-03
9.49E-04 .
9.49E-04
1 33E-03
9.49E-04
1.90E-05
9.01 E-04
5.22E-05
1.38E-03
1.75E-04
9.01 E-04
5.22E-05
1.99E-05
522E-^00
949E-03
9.49E-03
9 01 E-04
2.89E-04
7.11E-05
3.51 E-05
6.64E-04
• 2 89E-04
mg/kg 9.98E+00
4.85E+00
1.01 E-01
1.19E+00
5.88E-01
588E-01
5.31 E+00
1.70E+01
1 86E-01
4.33E-01
2.67E-04
3.68E-03
9.19E-04
4.33E-01
4.07E-04
1.71 E-03
5.30E+00
469E-01
2 01E+01
4.33E-01
1.30E-03
4.01 E-01
1.17E-02
545E-03
2.97E-01
' 'Further Action
;|i; (based on SSL)?
YES
NO
NO
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
NO
YES '
YES
YES
YES
YES
YES
YES
YES
SSRG' mg/Kg 9.98E+06
1.25E-01
1.19E+06
588E+05
5.88E+05
5.31E+06
1.70E+07
1.86E+05
433E+05
1.63E+00
6.47E+00
6.91E+00
433E+05
4.07E+02
1.71E+03
8.37E+00
9.91E+00
2.01 E+07
4.33E+05
6.45E+02
4.01E+05
1.17E+04
5.45E+03
2.97E+05
•Further Action
(based on SSRG)?
NO
NO
NO
NO
NO
NO
NO
NO
NO
YES
YES
YES •
NO
YES
NO
NO
NO
NO
NO
YES
NO
NO
NO
NO
AR305188
'r
Project Name: Project Locat ion: Project Off icer: ' Date:
Chemicals
(of interest) Arsenic Manganese Thallium'
,
~"
* NE = Not evalua
—
Central Chemical Hagerstown, MD Mitch Cron 9/17/2009
Measured
soil
concen (Ct)
(mg/lcg) 4.07E+02 1.02E+03 4.10E+00
; ted. Also n(
Kd(VZ)
L/Kg 3.90E+01 6.50E+01 7.10E+01
-
'
Dt evaluat
MIL $eitt£Nltl6 & l^m^lAmN 6AALS ( i iM) Yool Version: 2.0 (March, 2008)
Author: David M. Kargbo, PhD, USEPA Region III
Scenario 3
Kd(GW)
L/Kg 3.90E+01
, 6.50E+01 7.10E+01 •
,
• - - N
3d are SSRC
Retardation
(R) 3.50E+02 5.83E+02 6.37E+02
\
3 and Furthe
Mean Travel
Time Thru
Vertical Layer
Tt (years) 4.89E+01 8.14E+01 8.89E+01
-
-if Action base
Cgw from Ct
(without
degrad)
mg/L 2.19E+00 3.30E+00 1.21 E-02
d on SSRG
MCL
or
PRG
(mg/L) 1 .OOE-02 8;80E-01 2.00E-03
. , •'
",
Cgw based on
MCL, MCLG,
mg/L 4.74E-02 4.17E+00 9.49E-03
"
-•' ,•
SSL mg/Kg. 1.86E+00 2.72E+02 6.75E-01 "N
V
-
' • -
: >FurtK€(r Action
(based on SSL)? ;
YES YES
I YES
•
\
,.
AR305189
SOIL SCREENING & REMEDIATION
GOALS (SSRG) Tool Version 2.0
January, 2009
USER'S GUIDE &
TUTORIAL
by ^ David M. Kargbo, PhD
USEPA Region 3 Philadelphia, PA
AR305190
DISCLAIMER
The Soil Screening & Remediation Goals (SSRG) T,pol software, Version 2.0, and this User's , Guide & Tutorial (herein collectively referred to as "SSRG Tool") have been subjected to USEPA's peer and administrative review and have been approved for publication as a USEPA document. However, the SSRG Tool is made available on an as-is basis without guarantee or warranty of any kind, express of implied. Neither the United States Government (including the USEPA), nor the author or reviewers accept any liability resulting from the use of the SSRG Tool. In addition, any interpretation of the predictions of the SSRG Tool is the sole responsibility of the user. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
AR305191
ACKNOWLEDGEMENT
The SSRG Tool was reviewed by a distinguished group of technical experts. The author wishes to acknowledge the USEPA Region III Technical Support Staff for their comments and suggestions with special thanks to Ms. Bernice Pasquini, Ms. Nancy Rios, Mr. Bruce Rundell, . Ms. Mindi Snoparsky, Ms. Linda Watson, and Ms. Jennifer Hubbard. A thorough review was also performed by Mr. Rob Earle and Dr. Noman Ahsanuzzaman of Shaw Environmental, a contractor to the U.S. EPA Ground Water Technical Support Center (G WTSC) and the Center for Subsurface Modeling Support (CSMoS) in Ada, OK with special thanks to Dr. David Burden, GWTSC Director, for coordinating the review process. Finally, special thanks go to the author's Fate of Pollutants graduate class members (spring 2008) at Temple University's College of Engineering. These students utilized the SSRG Tool software for extensive project exercises and in the process, contributed significantly in improving the quality of the software.
AR305192
Conten t s
1.0 What's New in the SSRG Tool, Version 2.0 Software? 8
2.0 SSRG Tool Basics : '. ; ....8
3.0 SSRG Tool Modules.. :.. 10
3.1 Pore Water Velocity (PWV) Module 10
3.2 Model Equations for the PWV Module ..12
3.3 DAF/MZ Module : :... 13
3.4 Model Equations for the MZ/DAF Module 14
3.5 Results Module '. 15
3.6 Model Equations for the Results Module ..' 17
5.0 SSRG Tutorial , 20
5.1 The Problem 20
5.2 Data Requirements for SSRG Tool 20
5.3 SSL and SSRG Modeling Steps 21
AR305193
Figures
Fig. 1: Vadose Zone Parameters Entry Forms .....'. 10
Fig. 2: Schematic representation of contamination scenarios in SSRG modeling tool 11
Fig. 3A: Site specific data entry for scenario 2 '.. 12
Fig. 3B: Default parameters as a function of the selected layer soil type 12
Fig. 4: Groundwater parameters 14
Fig. T-1: Excel security warning : 21,
Fig. T-2: Vadose Zone Parameters Entry Forms .., .....; 22
Fig. T-3: Schematic of SCENARIO 1 contamination with only the source layer contaminated . 23
Fig. T-4: Data entry for Scenario 1 23
Fig. T-5: Schematic of SCENARIO 2 contamination with the surface layer and the layer beneath the surface layer representing the Source layer 24
Fig. T-6: Data entry for Scenario 2 24
Fig. T-7: Schematic of SCENARIO 3 contamination with surface layer and the layers beneath the surface layei* (except the layer above the groundwater) representing the Source layer 25
Fig. T-8: Data entry for Scenario 3 25
Fig. T-9: Additional soil data entry ; 25
Fig. T-10: Groundwater Parameters Entry Forms 26
Fig. T-11: Chemical Parameters Entry Form 27
Fig. T-12: Scenarios 1-3 vadose zone parameters and calculated pore water velocities 28
Fig. T-13: A clear entry screen following the clicking of the "Clear & Select oil Type" button. 29
Fig. T-14: Data cells filled with default parameters, calculated Vs based on default parameters.29
AR305194
Tables
Table 1: SSL and SSRG results for organic chemicals ; 16
Table 2: Summary Interpretation of Results - SSL versus SSRG 17
Table 3: Summary Interpretation of Results - Required action (or inaction) based on site contamination levels of each chemical (in parenthesis) and SSL & SSRG?. 17
Table T-1: SSL and SSRG results for organic chemicals 31
AR305195
Acronyms and Symbols
Acronyms DAF: Dilution Attenuation Factor MCL: Maximum contaminant level M2: Mixing Zone i PWV: Pore Water Velocity Module RBC: Risk Based Concentrations RGOs: Remedial Goal Objectives SSRG: Soil Screening & Remediation Goals SSL: Soil Screening Level TAL: Target Analyte List TCL: Target Compound List USEPA: U.S. Environmental Protection Agency
Symbols b: d C, Cgw: da;
loc:
Cw
H': i: I K: Kd: Ks:
Koc: L: Lv:
ne: nt R: S: TYi-. I mean:
Vs Pb PP
Ks exponential parameter (unitless) Mixing zone depth (m)
Total soil concentration (mg/Kg) Concentration in groundwater at hypothetical well at edge of source area (lag/L) Aquifer thickness (m) ^ Fraction of soil organic carbon (unitless) Maximum allowable concentration in groundwater (|ig/L) Henry's Law Constant (unitless) Horizontal hydraulic gradient (m/m) Vertical infiltration rate through vadose zoneXm/yr) Saturated horizontal hydraulic conductivity (m/yr) Distribution Coefficient (L/Kg) , Vertical hydraulic conductivity (m/yr) Organic carbon partition coefficient (L/Kg) Source length parallel to groundwater flow (m) Distance from the bottom of source layer to the water table (m) Effective porosity (unitless) Total porosity (unitless) Retardation coefficient (unitless) Aqueous solubility limit (mg/L) Degradation half-life (yr) Mean travel time to the top of the aquifer (yr) Vertical pore water velocity through the specified soil layer (m/yr) Bulk density (kg/L) . Particle density (kg/L) Volumetric moisture content (Vwater/Vioiai) Effective moisture content (Vwater/Vtoiai) Source Zone air-filled soil porosity (Vair/Vtotal)-
AR305196
1.0 W h a t ' s New in the S S R G Tool , Version 2.0 Sof tware?
The Soil Screening & Remediation Goals (SSRG) Tool and its User's Guide and Tutorial are collectively referred to as the "SSRG Tool". The SSRG Tool Version 2.0 is a significant improvement over previous versions of the SSRG Tool (Kargbo, 2006). Improvements include:
i. The ability for users to enter their own data, ii. ' Users can now toggle between the default database in the program or use their own
data on: vadose zone parameters; and chemical parameters, iii. Customized printing is available on a single click for: a) vadose zone parameters; b)
groundwater parameters; c) organic chemical parameters; d) inorganic chemical parameters; and e) soil screening levels (SSLs) and/or SSRG results for all chemicals of interest,
iv. Decision on whether further action is warranted based on a comparison of measured soil concentration and SSL and/or SSRG
2.0 SSRG Tool Basics
This User's Guide is developed to verify calculations performed by the SSRG Tool, Version 2.0, an executable MS Excel© workbook. It is a one-dimensional, steady-state, vadose zone contaminant fate and transport model. The model was designed to meet several objectives:
i. Calculate site-specific soil screening levels (SSLs) and/or remedial goal objectives (RGOs).
ii. Provide a user friendly tool that enables the user to either select from reasonable literature input parameters based on site soil types or directly input site specific parameters. .
iii. Provide more realistic estimates of contaminant migration to groundwater and resulting environmental risks posed by such migration. '
iv. Enable a user to select modeling scenario that may be similar to.his/her site conditions.
V. Utilize the SSRG tool as a detailed waste-unit specific model for contaminant fate and transport analysis,
vi. Perform vadose zone contaminant fate and transport analysis in a manner that is consistent with the contaminant migration protocol of the USEPA Soil Screening Guidance (USEPA 1996) and its supplement (USEPA 2001).
vii. Evaluate the effectiveness of remedial alternatives by allowing the user to modify key input parameters (e.g., infiltration rates, hydraulic parameters, etc) that infiuence contaminant transport time and concentration.
AR305197
The model estimates:
i. The mean travel time in the vadose zone for any analyte on the Region III RBC table, the USEPA target analyte list (TAL), and the USEPA target compound list (TCL) to arrive at the base of the vadose zone;
ii. The maximum groundwater concentration at a receptor location on the edge of the waste unit; and
iii. The maximum contaminant.concentrations in soil that will not exceed the maximum contaminant level (i.e.. Tap Water level in the RBC table) in groundwater using either the SSL approach and/or the SSRG approach.
,.\
The model would require only minimal data input with common, easily measured geotechnical - parameters. For example, SSRG tool successfully avoids solving complex equations such as the Richards, Phillips, or Green-Ampt infiltration equations, and avoids requiring exotic or esoteric experimental input parameters such as bubble pressure, disconnectedness index, suction front head, saturated suction, Green-Ampt wetting front suction, or sorptivity. This is based partly on the author's many years of teaching and researching the subject matter and incorporating computational expediencies into the program code. The result is a robust analytical tool that incorporates vadose zone processes for the purpose of screening sites and providing reasonable SSRGs. -
2.1 Model Assumptions:
There are several assumptions worth noting. These include: - ,
Dispersion is not incorporated into the vadose zone transport estimate, only equilibrium partitioning. -Dispersive mixing is assumed in the saturated zone (similar to the current SSL guidance). Transport time in the vadose zone is determined by Darcy's Law and represents mean flow. ^
iv. To simplify leaching estimate's, a homogeneously distributed source of contaminants is conservatively assumed in the source layer.
V. Reversible linear soil-water distribution of contaminants at equilibrium is represented ' in the source zone by the distribution coefficient (Kd) and Henry's Law Constant
(H'), which is calculated according to USEPA soil screening guidance (USEPA 1996; USEPA 2001) for organic contaminants and a value for mercury,
vi. The organic compound distribution coefficients used in the model are estimated from the organic carbon partition coefficient (K„c) described by USEPA (USEPA 1996; USEPA 2001).
vii. Vadose zone soil organic carbon fraction (foe) is different from groundwater organic carbon fraction,
viii. . The sources of the default Koc (and other chemical specific parameter) values.used in the calculations include Region III RBC table and other USEPA documents,
ix. First order decay of organic analytes is incorporated into the calculations utilizing published environmental half-lives for biological reactions. '
AR305198
3.0 SSRG Tool Modules
The SSRG Tool is a combination of independent analytical modules (PWV; DAF/MZ; Results) whose outputs are linked to logic arguments and numerical outputs of all the other modules. These modules are summarized below. ' . - • • - '
3.1 Pore Wafer Velocity (PWV) Module
The pore water velocity module (PWV) calculates, soil moisture content, effective moisture content, vertical pore-water velocity, and travel times in the vadose zone under the contaminant source and through a multi-layer soil column (Fig. 1).
Data entry for Scenario 1
Modeled layer
Sotirce La/e i
I j y e n
L>y«r S
| j y t r 3
I j y e r 4
Entsr Veracal
thct/ess
r
Sol Type UsEd
.VenfcjIHid cond
Ks.(nr.Vi Expcfienlial
PafaTie:er.b Tctal ptMOS ty nt (ffactcnj
EITeclirt pwosilv
ne(!raction)
;
(.ioislure eortem
a * (fracton:
Effective moi5lue content
Qe Ifrartai)
Data entry for Scenario 1
>Jodeted lave-
Source Layer
L i y e r 1
Enter Vertcal
IhtK/ess
-
Sol TvM ' U'.Ed
VerkalH-^d cond
Ks.fir.'vi Exponential Tctal poios !v
nt (ftachcn)
Effecive pcrtMttv
ne iffsclicn)
Uotsture content
3'A (fraction
Effecttve inorstu-e content
Qe (frarto)
l . l 1 1 1 1
l . l 1 1 ' 1 1 1 . . 1 • '.
L.y.r i l 1 1 1 1 , 1 1 1
Data entry for Scenario 3
Wodalcd laye-
Source La/e i
Enlsr Vertfca!
thickrea • Swl 1>1M
Uwd
Vertcal Hyd cond
KMrrM E<pcneib£l Pcra-n&tr. b
Total aorosity ' nl(fraclcnc
Effective porosity .
ne (Tactjo-i) 'f/oidutfe content
Qv (ffacton)
Efecjve mccture content
Qe (fra;l)cn}
/•
I I 1 1 1 1 U y . r l l 1 1 1 1 1 • 1 ' 1
Additional soil data entry
liifiltralion
.r.3to {iriiVr''
Bulk donstY(kq,'L)
Particle
dcrsilv 'kq/L)
-rac. orq carton funitloGC)
Fig. 1: Vadose Zone Parameters Entry Forms
The user-defined hydrogeological characteristics for the PWV module include:
i. Infiltration rate (I), ii. Bulk density (Pb),
iii. Particle density (Pp), iv. Layer thickness, and V. Layer soil type.
10
AR305199
Hydrogeological parameters that are functions of the selected soil type are automatica;lly displayed when the soil type is selected; These include:
i. Vertical hydraulic conductivity (Ks), ii. Ks exponential parameter(b),
iii. Total porosity (nt), and iv. Effective porosity (ne).
The code in the PWV module then uses the above parameters to calculate: the moisture content (0w); the effective moisture content (6e), and the vertical ppre water velocity (Vs) through the specific soil layer. ' ,
One of the strengths of the SSRG Tool software is the ability for the user to select one or multiple scenarios that may apply to the user's site. Like in previous versions, the current version allows users to choose one of three scenarios depending on the nature of contamination under the source. In Scenario 1, only the source.layer is contaminated. In Scenario 2, some of the layers (but not all) under the source are known to be contaminated. Scenario 3 is similar to the thought process in the current SSLs guidance. Here the source is directly over the aquifer.
Scenar io 1 Scenar io 2
r:- ^ d
r / ( . iv j - i L M - i
•1 . AiCrAo' . f ' -v iwic . .>, f
Fig 2: Schematic representation of contamination scenarios in SSRG modeling tool
Hydrogeologic parameter data entry is a unique feature of the SSRG model. Thcuser has the option of entering his/her own site specific data (Fig. 3 A) in USER-fNPUT worksheet or use SSRG's default hydrogeological characteristics (Ks, b, nt, and ne) in SCEN-INPUT worksheet. These default parameters are functions of the selected soil type and are automatically displayed with the calculated vadose zone parameters (6w, 6e,Vs) when the soil type is selected (Fig. 3B).
Ll
AR305200
Data entry for Scenario 2
Vtxif.teitl.ivei
Source Layer
I j y t r 1
• » i
O.S
f i ' : i . ;
S-Jir I'/Vt-
t.'fpj
Virtical H-«i
. a n d L^pcwntut 'ctalsofc-iiiy nl ifr.ic.licn|
pCftSif, nft f:rii{.t<;nj
WDshre . cunlen!
Cv> itra-Jliin)
=?feclivt} moisluT corJenl
(Jf firsitoi)
• 1 Sand
Sa r * L^aiii.
*(ii: J
m
i^
.V
0.44
o.^t.
yu>
1 <lilJ2
D.isy
• '5.25}
I.I.I56
02W 1
U v . r 2 | n j Hai t i . W J e 0,1S . CtC<' . . O.^w <^9K. 1
Fig. 3A; Site specific data entry for scenario 2
Data entry for Scenario 2
UDdslsd
Sourcs Layer
Entar • . •Bl iC3l
"tisanma
_ 06
0.5
Eiilsr Soil
Si:y
Soro
Soil Typs ir»Mi
varttcal
cona EjtponOTtu)
Paraiii«:8r, b
Tota pcroiiiy
ntifractionl
Ef(ocB-.> poroai})'
ns ifrictjom
Moisltira contsflt
ewffractioni
Sard cOW it!£ ' ,1 OCjV' j ^ o i r s ' '
Effftctr/»
qa rtractjoni
Ci5eulatM Vsniul port
W3»fv»)«a;y VB lm8;»t^^9a^
! -.££ -'' t
Layer 1
0 5
0.;.
Lmr; 53rO/
ux-n LcaiT: -S5 ' '. as 0 « 5 " c i i r ' i - 3: :o ' 113S
Laver 2 0 5 LO-iri LKrr, 15' 5 35 OiSS OiSi C i&5 S 267 0K5
Fig. 38: Default parameters as a function of the selected layer soil type.
Selection of the soil type to represent multiple contaminated layers is also unique in SSRG. For example, in Scenario 2 above (Fig. 3B), the contaminated layer (Sand) under the source layer is now considered as part of the source layer. However, to err on the side of health, the most permeable of the two soil layers (i.e., silty clay sand versus sand) is automatically selected for the user and used in the computations. In this case, sand is selected. A similar logic is used for Scenario 3 (see Tutorial at the end of this User's Guide for a complete example).
It should be noted also that the current SSRG version uses as point of compliance the water under the defined source. Scenarios 4-6 in the next version will compute contaminant transport in the aquifer to any defined point of compliance and calculate the applicable SSLs and SSRGs.
3.2 Model Equations for the PWV Module
The endpoint for the PWV module is the derivation of the mean travel time (Tmean) for each chemical in vadose zone. It is the mean retarded contaminant travel time in the vadose zone and is calculated by dividing the distance from the bottom of the contamination in the Source Layer to the top of the water table surface by the mean retarded pore water velocity using the following equatioris 1-5:
12
AR305201
Equation
Equation name
Equation #
Mean Travel Time
1
v = '
Soil-pore water velocity
2
n,
Effective moisture content
3
Volumetric moisture content
4
Retardation. coefficient
5
where
I uean
Lv V, R I e.v
lit
nt
b • K v
p?
Kd
mean navel time to the top of the aquifer (yrs) distance from the bottom of source layer to the water tnble (meter) pore- water velocir)' in the vadose zone (ineter/yeai) unsaturated retardation coefficient (unitless) verticil intiltiation rate through vadose zone (merer/year) vohinietric nioistiue content (\ vater/V',oii) (fraction) effective moisnire content (fiaction) , effective porosity (fraction) total pnmsiry (frnclion) soil-specific exponential parameter limitless) saturated'K parameter (raeier/year) soil hulk density (kg/T.) distribution coefficient of tlie chemical (Lk")
3.3 DAF/MZ Module
The dilution attenuation factor (DAF) and mixing zone (MZ) module calculates DAF and MZ values using analytical equations consistent with the USEPA soil screening guidance.
13
AR305202
GROUNDWATER PARAMETERS
Aquifer Mixing Zone Depth and DAF Parameters
Variable '
L K
Da ^
1 . '
0W
• Bb
3D
foo
Calculated parameters
0
•©a
d(calc)
DAF d(in DAF)
Value
122 334
183
0.025
0.30
•1.50
• 2.65
0.013
Unit m
m/yr
m i
IM/MI
Unitless
kq/L
kg/L
UniUess
Description Source lenath parallel to qroundwater tlov/ Aquifer saturated horizontal hydraulic conductivity
• Aquifer thickness
hoiizuiilal liyUiaulic giadieiit in aguitei
Water-filled Porosity
Bulk Density ' '
Particle density, in aqurer
Fraction of organic carbon in aauifer
0.43
0.13
16.5 5.5
16.5
Unitless
Unitless
m
unitless m
Aquifer poiosity
Air-filled Porosity
Calculated Mixinq Zone Depth
Cilution Attenuation Factor
Mixinq Zone Used in DAF.Calculations
Fig. 4: Groundwater parameters
3.4 Model Equations for the MZ/DAF Module i
34.1 Mixing Zone Depth (MZ) Equation 6 is used in the code to estimate mixing zone depth (d). This is the same equation used in the USEPA Soil Screening Guidance (USEPA 1996; 2001).
\0..5 r/ = (0,0112-Z7^r/,.(l-f"-^^':^''-')
where
K = saturated horizontal hydraulic conductivity in the aquifer (m/year) i = horizontal hydraulic gradient (m/m) I = vertical infiltration rate through vadose zone (m/year)
' da = aquifer thickness (m) L = length of source parallel to groundwater flow (m)
Built into the code is the logic that if the calculated mixing zone depth is greater than the actual measured aquifer depth, the mixing zone depth defaults to the aquifer depth.
14
AR305203
3.4.2 Dilution Attenuation Factor (DAF) Like the MZ calculation, the equation for the dilution attenuation factor (Equation 7) is the same equation used in the USEPA Soil Screening Guidance,
^ • L -. : . . . • . . . . . . . . : . . 7
where
K, i, d, I, L are as previously defined.
3.5 Results Module
The result module is the most sophisticated component of the model. It evaluates five fijndamental logic criteria including: ' /
i. Computation of the retardation coefficient of each chemical based on the chemical's properties and the weighted vertical seepage velocity through the vadose zone,
ii. Comparison of the calculated groundwater concentration to the action limit, iii. Comparison of the retarded, mean travel time of a contaminant to reach the aquifer to
the user-defined transport evaluation time.; iv. Comparison of the measured soil concentration and the calculated SSL and/or SSRG
to determine whether further action is need at the site. -V. Comparison of the unit source total contaminant concentrations to the mass limited
soil screening limit (MLSSL).
Logic (v) is in development. An example Results Screen comparing Scenarios 1, 2, and 3 is provided as Table 1. For additional details on the data input and generation of these results, please refer to the Tutorial at the end of this User's Guide.
AR305204
Table 1: SSL and SSRG results for organic chemicals
1
Project rJame: S
Project Location
Project Officer: .J
Date:
Scenario 1
Chemical* Ic f ln t i res t )
i . | .Ci(r ,k;K>*are
EtTyiberzere
% i ( ! n t
hc i totMt^v iene
vn>i d l o f i * :
k y 5 h i w . e «
sRG Evaluation of ABC
Nowhere Towship
ofn Ltoe
3/18i20C8
MGKured to l l
M T O n l C i l K<I(V5
i a E . 0 2 7 f«E-5 l
OSCE'O; Sf.^r-C'l
6 5 ^ - O J 3 T i i - m
4 . 0 C E ^ ! I .J iS-CI
4.JJt*'.r.' ; ; . lo rHL i
SJiiE-C? 2 42E3 I
4 i : E . O : 2.ISS f i j
Soil Screening & Remediation Goals (SSRC
Version: 2 (Marcli. 2(I0S) Author Dff;id M. Karqto. FtiD.
. USEPA Region III .
s Site soils
S S L a n d S
man L'Xg
7 .ȣ4 ) l
• i .S3r-OI
4 ? 2 E - »
• ; i E - ) l
• n ' . t - j l l •
2 . t 2 : < i l
JICE.»
SRG RESU
Rebrd3«on
6,°8E-00
' 6 J 3 E - M
3.75E-01
? ? f E - S l
l . ' b t - l - ;
2.S?E-00
i . ' S E . ; :
•
LTSrORO
T I f M T h m
VerUoal b y v
T t i y e j K )
9.e5E.C0
S i i : > m
. S . l K ' C l
l.:9E.(2
:;.44"H1
J.!5E>(0 •
;.44=.(1
RCANIC CONTAMINANTS
Cgw t o r n Ct
|v«1*oul Cgwfron-.Ct
degrad) tv^ith degi^d}
11161 W L
•:.71E-0-
18<E-32 .
2.J!E-0
7.IJ;E-M
• J 2 ' t - U '
; 3 ; E - 3 ;
3 ; - E . C ' '
! .C1E.«
3 i 3 E ^ »
c •
i;
1 ! 1= -W
j . - 7 E a j
c •
J) Tool
. M C L o r P R O
Ino 'L )
4 40E.Oi
KOE-Ol •
7C0E.0:
• ! COE-5'
iL'JCAJJ
2 COE 0^
5 (0E-D !
» U C l ,
MCLO. iTtd'L
2.43E.C4
5S2E<:r
3 « 7 E - « i
5 . ! 2 E J : 1
^ . ' 0 t 4 J i
I.10EC2
";.'GE-C2
SSL • i i iBKg
2 M E «
5 0 7 E J : I
I .5 ;E-OI
•;89E-00
cb2=.\.'z
5 98EM
• i : 2 = - : 2
• F u r f w ' -' ' A c t o n 3
I S a s J d o n -
•'.• 'SSU? ' • '
YES
•ES
• YES
VES
u y
Y:.5
YES
1
JP;:" f 5SR0
m » K l ! '
4.36E-01
; .59E-03
I.S-.E-07
5.65E-06
l . « . : - H )
3 44E-02
£ . 6 I E 0 4
. Furtw . A c t o n
( iHsedc
SSRQ)
YES
m NO
NO
i t j
• i t ?
no
Sceuni io
C h e m i o l i lof I n t H X t )
i |.OicWoroetia.-ie
•..2-
DkJikiroelh'/ lene
(t fansl
Et^->^I>en2ene•
Sfc-rene
I T rc - i lwo f lhy tene
Vinvl 'Z 'or:6e
1 NafMater?
2
r4e3«iiredso<l
conoeh (Ct)
( n * t ( l l
l . ( f3E-02
9 .50E-02
5 5 4 E . 0 2
4 OOE-02
• 4 .33E-02
5.46E-02
4.33E-C'2
Kd(V2 l
L X o
7 66E-0I
6 33E-01
4 7 2 E - J : O
101E-Q1
2 -.SE-X)
2 42S.01
2:,SE-00
Kd lOW L K d
7.66E.0I
S63E .01
4.72E-D0
1.CIE-01
2 . I 6 E - 0 0
2.42E.OI
2.I6E-30
Retardation
IRI
5 .35E.00
4 8 8 E . 0 0
2 . 7 8 E . 0 I
5 . 84E .0 I
I .33E.OI
• 2 .37E.0C
1 .33E.0 I
Mean Tmvel
t l m e r h m
Venioal U y e i
T l l y e ^ l
6 .75E-00
8 I 5 E - 0 0
• 3 . 5 1 E - 0 i
7 .35E-0 i
• . .67E.0)
2.99E-Otl
l . ;7E-3i
Cflwfroni CI
(V«ft(»llt
de j rad l
1 .7 iE-OI
. I.88E.'0S
2 .39E.01
7.03E.OO
3.27E-C1
l . 83E '02
.3 2 7 E . 0 I
Cow from Ct
(with degrad)
.n»'L
'3 .47E-03
4.25E-0I
0
0 .
3 2 2 E . 0 0
4 . 5 c E J 2
0
•
rdCLor '
PRO
( m f l l l
4.4OE.05
1 OOE-OI
7..30E.01
l.'3C=-01
5 00E4D3
2 OOE-03
£..3eE-03
Cgw •
based on
MCL,
MCLO.
m»-L
2.43E-CM
5.52E-01
3 87E-C0
5.52E.01
2.76E-02
i . lOE.05
2.76E.02
SSL 1 m s ' K f l y
2.58E-04
5C7E-01
l . 9 i E . i ) l
5.69E-00
6.e2E.02
5.68E.03
8.S2E-02
' ' 1
•Further
AoOon
(based en
6SL)? «..
VE.5
YES
YE.S
YE.5
YES
YES
VES
ssRa, * - m g H s ' 1
1 27E-013
2.23E-C2
1.91E-C7
5 . 6 9 E . M
6 72E-01
2 . 4 0 E . 0 I
S . W E - W
. F u r l h J r , ,
Act ion
(baeedon
SSRI2I7
YES
YES
NO
, NO
YES
YES
NO
I (
.Sceuniio
lof inteieU)
1 r. l -DicfJoroetr iane
; 2.
Dichk)-oelh;^ene
i saas i
Elr i '^benzene
1 Sr j iene
1 T tKT ikywJ iv lene
Vinyl cr ior.de
1 Naphtf ialene
i
(Jeatured.o l l
concen (Ct)
(m t r t o l
I.OOE-02
S 5 0 E - i ) 2
S 5 4 E - 0 2
4.OOE-02
4 .33E.02
b 4 b E - 0 2
4 3 3 E - 3 2
Kd(VZ)
LK„ 1
7.56E4:>1,
9 . a j E - 0 l
4 .72E-00
1.0)E-01
2.I4E.O0
2.42E.CI
2 l6£.0a
KdlOVV) ,
UKo
7.65E-0)
6 .S3E4; i
4.72E-D0
l O I E - 0 1
2.ieE.»D
242E.C1
1 216E-00
Retardation
1 (Rl
5 92E.D0
5 . M E . O 0
3 . I3E .C1
6 5 3 E . 0 i
t 4 3 E . C i
2:w=.oo
I.45E-C1
Mean Travel
Time Thru
Vertioai Layer
Tt (years)
] 6 6 E - 0 0
t . o lE -O l )
a .77E-00
1.J4E-01
4 . 1 6 E - 0 0
7. !3E.C)
4 ISE-aO
Cf lwfrom Ct
(without
degrad)
m f l L
1.71E-0(
I.SSE.02
• 2.39E.01
7 03E-00
:27E-OI
1.835-0^2
3.27E.01
Cgw from Ct
(w l lhdegnd)
mgfL
2 i i E - C 0
J . 2 ! E - 0 I
0
0
l . 8 4 E - ; i
2 5 : E - 0 1
I.C5E-0S .•
MCLot
PRO
(msO.)
4.40E4;5
l . f O E J j l
7.tOEJ:'1
100E .OI
5.00E4J3
2.t«E.i33
5 .WE.03
Cgw
based on
I t C L
MCLO
m s L
2.43S-04
5 5 2 £ . 0 -
3 . 9 7 E - M
5.52E.01
2 7^E.02
) 1 0 = 0 2
2 76E-02
mm LA SSL , ^ • . ' ' r i ^ ' ' t ^ : ' '
2.58E.04
5.07E-3I
I . 9 IE .C1
5 nSE-OC
6 6 2 E - 0 2
S.SdE-OJ
6.62E..92
:-;Further,.-
I A c t » n g
(based e n ^
w a S L ) ? * *
YES
VES
YES
YES
YES
YES
YES
SsSROg'
2 . 0 9 E J : 3
2 2 6 E - 0 0
I . 9 I E - 0 7
5 6 9 E - 0 6
1 . t9E4 ; i
4.34E4;2
e.«E-(M
4A is t ion .
( iMMdaiS
• SSROI?.-
YES
VE.S
NO •
M :
YES
YES
NO 1
Based on the above results, Tables 2 and 3 provide a summary interpretation of the results with respect to SSL & SSRG.
16
AR305205
Table 2: SurVimary Interpretation of Results (SSL versus SSRG) with initial contaminant soil concentration in parenthesis
Scenario 1 Scenario 2
Scenario 3
TCE (433 mg/Kg)
SSL 6.62i;-02
6.62F,-()2
6.62F,-02
SSRG I.96E-00 6.72 E-01
1.I8E-0I
Vinyl Chloride (546 mg/Kg)
SSI., . 5.9X11-03.
5.98r.-03
5,98i:-03
SSRG 3.44E+02
2.40E+01 4.34E-02
t-l,2-DCE (950 mg/Kg)
SSI. . 5.07E-01
.5.07E-01
5.07E-0I
SSRG 2.69E+03
2.23E+02
2.26E+00
Ethylbenzene (654 mg/Kg)
SSI. 1.91 El 01
1.91E+01
1.9IE+0r
SSRG 1.91 E+07
1.91 E+07
1.91 E+07
Table 3: Summary Interpretation of Results - Required action (or inaction) based on comparison of site contamination levels of each chemical (in parenthesis) and calculated SSL & SSRG
Scenario 1
Scenario 2
Scenarios
TCE (433 mg/Kg)
SSL YES
YES
YES
SSRG YES
YES
YES
Vinyl Chloride (546 mg/Kg)
SSL YES
YES
YES
SSRG YES
YES
YES
t-l,2-DCE (950 mg/Kg)
SSL YES
YOS '
YES
SSRG NO
YES
YES
Ethylbenzene (654 mg/Kg)
SSL YES
YES
YES
SSRG NO
NO
NO
For chemicals that decay, remediation goals (or SSLs) become more stringent as the source gets closer and closer to groundwater.
3.6 Model Equations for the Results Module
3.6.1 Derivation of Groundwater Concentrations The equations used in the SSRG model are all a form of a linear isotherm (with exponent =1) based on the Freundlich equation and used in USEPA in Soil Screening Guidance (USEPA 1996; 2001). The basic equilibrium partitioning equation for predicting groundwater concentration, given a measured or assumed soil concentration (CO for mercury (Hg) and organic chernicals that volatilize but do not degrade, is Equation 8:
C C;-[lQOOtig^mg] ,
^/(DAF)
where
DAF = Dilution Attenuation Factor (unitless) Ci = total soil concentration (mg/kg) Cgw = concen. in groundwater at hypothetical well at edge of source area (|J,g/L) Kd = distribution coefficient (L/kg) H = Henry's Law Constant for volatile organics/mercury (unitless) 6w = source zone water-filled soil porosity (Vwaier/Vtotai) Oa = source zone air-filled soil porosity (VairA'ioiai) pp = soil bulk density (kg/L)
17
AR305206
The groundwater concentration equation for metals, other than Hg is Equation 9, while Equation 10 is the groundwater concentration equation for organic chemicals:
A'. 0.
c gl f . /
Pl i ) -
fc .e -°*°-*'"-««' i ::5-) (Z).-lF)-[lOOOua/iug]
A'. + Pi
where
T'/: is the chemical's half life and the rest of the parameters are as previously defined.,
3.6.2 Derivation of the soil screening levels and decay adjusted soil screening levels The code currently calculates two types of SSLs for each ianalyte; the SSL based on the USEPA guidance, and a decay adjusted SSL that is influenced by time of travel of the chemical in the vadose zone and the.chertiical's half life. Equation 11 is the SSL equation for any metal analyte, excluding Hg:
MCL • DAF • A , + ^
SSL,, , = Pii }•
A-OmT^,,,^T,,,) [lOOOug.'ing]
.11 where
The parameters are as previously defined, The degradation half-life (TVz) is assumed to be infinite for metals, and The MCL parameter is either the MCL or the PRG value in the USEPA Region III RBC table (which can be accessed from the USEPA website).
For mercury, the SSLr/: is calculated using Equation 12 while for an organic analyte Equation 13 (which includes first-order degradation) is the applicable equation:
MCL • DAF • j A" +
• ^ • ^ n 2 =
{e.,-H-oJ
Pa :.-^.mT,,
-.'[lOOOug/mg]
,12
.SSZ-i , = MCL • DAF • < K j + ^ + ^ ' ^" Pii
& ,1-0.(593 r,^^v
-/[lOOOug/ma] .13
AR305207
4.0 References
1. Kargbo, D.M. 2006.'Soil Screening and Remediatioii Goals (SSRG) Tool. USEPA, . Philadelphia, PA.
2. U.S. EPA. 1996. Soil Screening Guidance: User's^Guide. USEPA, OSWER, Washington D.C.Publication 9355.4-23; EPA540/R-96/018
3. U.S. EPA. 1996. Soil Screening Guidance Technical Background Document. USEPA, OSWER, Washington D.C., Publication 9355.4-17A; EPA/540/R-95/128
4. U.S. EPA. 2001. Supplemental Guidance for Development of Soil Screening Levels for Superfund. USEPA, OSWER, Washington D.C., Publication OSWER 9355.4-24
19 -
AR305208
5.0 S S R G Tu to r i a l ,
5.1 The Problem
Company ABC hired a consultant (Super Screen, Inc) to develop a Remedial Investigation/ Feasibility Study (RI/FS) for the Superfund site, NoWhere, that has resulted in the contamination of soils at the NoWhere site within ABC's property. Initial screening using the USEPA soil screening guidance documents (USEPA, 1996; USEPA, 2001) previously resulted in very conservative soil screening levels (SSLs). The screening results indicate that if site remediation is to be based on the calculated SSLs, it will require the removal or in-situ remediation of the entire 100-acre site to a depth of at least 20 feet at a cost of $81 million. SoilScreen met with regulators to determine a reasonable approach that will be cost effective and protect human health and the environment. The use of the recently developed Soil Screening & Remediation Goals (SSRG) software that incorporates both site specific geotechnical and chemical data to generate SSLs and SSRGs was suggested.
5.2 Data Requirements for SSRG Tool
Following extensive discussions with SoilScreen's in-house technical staff and meetings with environmental regulators, SoilScreen decided to generate the following data.
5.2.1 Vadose zone parameters • . • . Surface and subsurface soils are contaminated and there are 5 different soil layers (including a surface layer) identified in the RI between the surface arid groundwater. SoilScreen decided to generate the following parameters for each layer between the surface and groundwater, as required by the SSRG software:
i. Soil type of each soil layer; ii. Layer thickness (I, m);
iii. Vertical hydraulic conductivity (Ks, m/y); iv. Exponential parameter (b) V. Total porosity (nt, unitless); • ' '
vi. Effective porosity (ne, unitless); vii. Moisture content (9w, unitless);
viii. Effective moisture content (6e, unitless); ix. Infiltration rate (I, m/y); x. Soil bulk density on a weighted average basis (Pb, kg/L);
xi. Particle density on a weighted average basis (Pp, kg/L); and , xii. Fraction of organic carbon in soils on a weighted average basis (foe,' unitless).
5.2.2 Groundwater Parameters All of the required groundwater parameters have already been generated by SoilScreen during the RI stage and were used in generating the SSLs. These include:
20
AR305209
i. Source length parallel to groundwater flow (L, m/y); ii. Aquifer saturated horizontal hydraulic conductivity (K, m/y);
iii. Aquifer thickness (da, m); iv. Horizontal hydraulic gradient in aquifer (i,.m/m); v. Water-filled Porosity (Gw, unitless);
vi. Aquifer bulk density (Pb, kg/L); vii. Aquifer particle density (Pp. kg/L); and .
viii. Fraction of organic carbon in aquifer (foe, unitless)
,5.2.3 Chemical Parameters ' SoilScreen decided to research the literature for the latest data generated on chemical fate parameters for each of the chemicals of interest. For each chemical, SoilScreen generated the following:
i. Half life for each organic chemical (Ti/2, y) ii. Henry's Law constant (H', unitless)
iii. Octanol-carbon partition coefficient for organic chemicals (Koc, L/Kg) iv. Distribution coefficient for metals (Kd, L/Kg) V. Chemical solubility (S, mg/L)
vi. MCL or PRG (mg/L)
In addition. Soil Screen compiled the concentration of each chemical at the site at various depths.
5.3 SSL and SSRG Modeling Steps
5.3.1 Step 1 - Install and open SSRG software
ACTION: SoilScreen copied the MS Excel program (SSRG Tool, Ver 2.0) to its hard drive and opened the software. When asked whether to enable macros or not (Fig. T-1), the company selected "Enable macros" as required by the SSRG software.
|«i-^sya;to^¥^'^-'-'""''""---s:--"• •• • - - ^ '' • • tS '^ Hi-- . ~
rr-^^'>*«!rW^Wi>«-rf)i.-3*iii*(vBriia>iiiS'r;r-sij.r.;.:.*'P!»
;.! __ •;^^'.^i..«*f-..
Fig. T-1: Excel security warning
COMMENT: The SSRG software contains four worksheets: USER-INPUT; SCEN-INPUT; SCEN-0RGAN1CS_RESULTS; and SCEN-METALS RESULTS worksheets.
21
AR305210
5.3.2 Step 2-Enter data into USER-INPUT worksheet data entry forms
ACTION: SoilScreen opened the USER-INPUT worksheet and entered the site specific data it had collected'with respect to the vadose zone parameters, groundwater parameters, and the fate parameters for each chemical of interest.
COMMENT: The USER-INPUT worksheet has three (3) input areas:
a) The Vadose Zone Parameters Entry Forms; b) The Groundwater Parameters Entry Forms; and c) > The Chemical Parameters Entry Form.
• I , . . , . • _ .
Vadose Zone Parameters Entry Forms: There are three possible scenarios of contamination pattern in SSRG and users are required to select a scenario (or scenarios) that best match their site. SoilScreen concluded that any of the three scenarios could apply to their site and decided to utilize all three scenarios. Sample data collected by SoilScreen will be entered into the blank USER-INPUT worksheet provided in Fig. T-2.
VADOSE ZONE PARAMETERS ENTRY FORMS Data entry tor Scenario I
Msiclod loi'ci
. Source Laver
Leyert
L « y « t }
Uyw 3
L i ^ < f 4
Fnt«
thiiJmcia
-,
So;!T>w •
'
V^ral H>rf CCrfvd
Ksirr.S')
.
Exoort«ntal, PafOtrKlo 0
Total DWOfrV nti(;x«!crtf
Fftrt-.T!
DOWtV . content 0 * J(ftKJ)Mlj
. .COT MM
Onto en t ry tor Scenar io 2
u x i i k i teiH
Source Uyer
Lay i f i
•Emet Veratj; VjilT«>e
Used
Vertcal H>d cooJ.
Ksirrh) Exponents! Parsrrw'.a. b
Total pOfKit/ n' I fraction;
Eftclve pcresit .
ne iiarjxn)
tAsstue toBtent ,
Qv if[Bction)
EPerHi-e rroiflure coilent
1. 1 1 1 1 1 1 1 1 1 I I
' Lmr i i 1 1 1 1 1 1 1 (
Data ent ry for Scenar io 3
Mj i f cW Itfjei
Source Layer
Enter VefSc*
1
L i t ;
V;rbC0l H,xJ .;ond
< > ; i i M - Pdi(iitd<:t.b ToW porcsih •|l[ti*,'.lUl;
Ef*:clvc
0 * (bcnliiJii;.
t f k d r . t
Oe!li<ii;w.!
' •
1 1 1 _ 1 _.._ 1 . J 1
Liven 1 I • i 1 1 1 I 1 1
• Additional soti data einry inf i l l r-at iori
rate (rn'vr;
Bulk
3enoiiv{:(q'Lj
Pdrti'Je
density (kq/L)
FrQC. o ra c a r t w n
• iuniu«s}
' Fig. T-2: Vadose Zone Parameters Entry Forms
In the SW area of the site, only the surface soil (Source Layer), estimated to be a Silty Clay soil from field observations, is contaminated to a depth of 2 ft (0.6 m). Depth to groundwater from the soil surface is 8.ft (2.4 m). Based on soil boring data subsequently
22
AR305211
gathered by SoilScreen, soil layers encountered below the contaminated surface layer . were not contaminated. They include:
i. Sand layer (Layer I), 2 ft (0.6 m) thick; ii. Loam soil layer (Layer 2), 2 ft (0.6 m) thick and below the Sand layer;
iii. Sandy Loam layer (Layer 3), 1 ft (0.3 m) thick and beneath the Loam layer; and
iv. Loam soil layer (Layer 4), 1 ft (0.3 m),and below the Sandy Loam layer.
This warrants the use of SCENARIO 1 (Fig. T-3) in modeling site SSRGs. SoilScreen entered the vadose zone data for Scenario 1 in the appropriate data entry form (Fig. T-4).
.'^^Mlka:
i
"« % - \ Source Layer
n n ' ' VadcKe Zone Layer 1
h. K. Vadose Zone Layer 2
Vadose Zone Layer i
Vadoie Zone Liiyer A
r a r ' . " ' ' . , ™.%,. ,'f
All layer fAaterial Pfopefties: p^ f
Fig. T-3: Schematic of SCENARIO 1 contamination v 'ith only the source layer contaminated
Data emi7 tor Scenarl
Modeled layer
" Source Leyer
Layer 1
Layer 2
Layer 3
Layer 4
Q l Ente
Vmcal , lhir,kness
06
06
0.9
03
0.3
•Soil Tvoe Used
Silty C!3y •-
Sord
Loam
Sand\' Loam
Loam
VentMlHyd , c:nd
Ks iirJj) ,;
32 .
5000
800
790
800
Ewxinential ^Aromeief, b
9.9
i.2
5
3
6
Tola! ocfosiry nt (faction:.
0.48
0J4
0.45
0 45
0 45
EffMVS porcsitv
ne {'Vocicn;
0.42O
0.405
0.40O,
0.402
0 400
Mctslure content
Qft/lreclion)
0.3*1
0.180
0.2X
0.233
0 2,30
Eftecif/e moisture con'jnl
• Oe (fiacbc«)
0.340
•0156
0.210
0.210
0210
Fig. T-4: Data entry for Scenario 1.
In the central area of the site, contamination has migrated below the Source layer and contaminated the Sand layer as well. While traces of groundwater contamination are
23
AR305212
evident, the soil layers beneath the contaminated Sand layer are essentially clean. This warrants the use of SCENARIO 2 in modeling SSRG (Fig. T-5). SoilScreen entered the vadose zone data for Scenario 2 in the appropriate data entry form (Fig. T-6).
Fig. T-5: Schematic of SCENARIO 2 contamination with the surface layer and the layer beneath the surface layei" representing the Source layer.
Data entry for Scenario 2
Modeled layer
• Source Layer
Layer 1
• Enter Vertical
Itiidtness
06 .
06
06 03
Sal Type Used
Vertical Hyd cond
Ks |n-.V) Exponential
Pj.'B.'neter, b Total pc*osity nt ffra^on)
Eflectp/e pcrosity
ne ffeacrjcr)
Moisture contanl
0 * (^actic^J
EIlecti>.fe moisture cailent
Ot (fr3Cfit-.nl
, Sand 5000 4,2 0 44 C.405 0.180 0,155
•
Sandy Loam 790 9 0.46 0,402 0 233 • 0 210 •
Layer 2 0,3 loam 600 6 0 45 C400 • 0,2K 0,210
Fig. T-6: Data entry for Scenario 2.
In this scenario, the Source Layer is equivalent to the Source Layer (Silty Clay) plus Layer 1 (Sand) of SCENARIO 1. SoilScreen decided to use the Sand layer and its measured vadose zone parameters as the soil type and parameters represented in the model for SSRG calculations since the Sand layer is the more conservative of the two with respect to its ability to transmit fluids vertically to groundwater. Actual vertical pore water velocity may be less than represented by the Sand layer. Similarly, the Loam and Sandy Loam layers beneath the Source layer are grouped as one, layer (Layer 1) and the more conservative Sandy Loam is used to represent Vadose Zone layer I in SCENARIO 2.
Finally, at the NE corner of the site, almost all the soil layers are contaminated with significant contaminant concentrations in ground water. This warrants the use of SCENARIO 3 in modeling SSRG (Fig. T-7) and SoilScreen entered the vadose zone data for Scenario 3 in the appropriate data entry form (Fig. T-8).
24
AR305213
• ' - • * — - > .
i ( , 'JOufCeCi^»*i
kdcc* Z o n i i j y a r l
Aqi*';:i Li?£'
A\l i~i^ Vftffirlt^i>''"Tf' 1
Fig. T-7: Schematic of SCENARIO 3 contamination with the surface layer and the layers beneath the, surface layer (except the layer, above the groundwater) representing the Source layer. •"
Data entry for Scenario 3
Modeled tavw
Source Layer
Enter Vertical
thictness
0,5
0.5
0,6
0.3
• SolTytK Used
Veilical H/i cond
Ks!ni.'v! E^cnent.'al i'arameler. b
Tolal poroaty nt il-acliati
Elleclire POfOSllV
ne ilractwn) Vtistuie content
Qwjlraclioni
Elfeclive rrclslu.'e content
Qcitracnoni
Sand 500C' 4,2 044 I O405 , 0160 0,155
•
Layer 1 | 0,3 Loam 800 0 45 0 40O 0 230 3 210 •
Fig. T-8: Data entry for Scenario 3.
Like in Scenario 2, the most conservative layer of all the contaminated layers (Sand) is used to represent the Source Layer in Scenario 3 (Fig. T-8). The layer next to ^ groundwater (Loam) then becomes Layer 1 in SCENARIO 3.
It should be noted that this scenario closely mirrors the scenario represented in the USEPA Soil Screening Guidance.
Additional vadose zone parameters are entered as weighted averages in Fig. T-9.
Additional soil data entry Infjltiatlon rate (m/yr)
0.25
• Bulk •
density (kq./L)
• 1 . 5
Particle density (kq/L)
2.65
Frac org carbon (unitless)
0.013
Fig. T-9: Additional soil data entry
25
AR305214
It is anticipated that the majority of soil contamination patterns at most contaminated sites will be represented by one or more of the three scenarios in SSRG software.
Groundwater Parameters Entry Form: In this form (Fig. T-10), SoilScreen will enter the same parameters that were used to determine the dilution factor (DF) in the SSL determination. There are a couple of things to note here. First, it is commonly recognized that the foe in groundwater is different and lower than the foe in soils. SSRG allows the user to input foe values for the vadose zone and groundwater separately. Consequently, the partition coefficient for each chemical in soils will be different than that in groundwater. Second, SSRG will prevent users from violating certain basic physical principles. For example, the sum of the water filled porosity and air filled porosity cannot be greater than'the aquifer porosity. When this happens, SSRG prompts users to check their data input. . i
GROUNDWATER PARAMETERS • '
Aquifer Mixing Zone Dapth and DAF Parametsrs
Variable
L
k Da
1
0 ,
9b ,
So
l«
Calculated parameters
0
0= d(calcl
• DAF
• dlit iDAF]
Value
122 334
183.
0.025
0 30
-50
2.65
,0,0:3
Unit
in iT/yr
, ' n
nVin
Lnilles5
• kg?.
ka'-
Uniilesi
Desra-lptlon
Source lenqlh parallel b ]rounjwatef llav
Aqu.fei satuieted horzonlal hydraulic condujUviiy
Aquifer thickness
Horizontal tiydraulic qradient in aquifsr
Water-filled Poiosity' ' , ' ,
Bulk Density
Particle densi'.y in aquifer ' '
Fiadionoforganc;,-£rbon n aquifer
0.43
0.13
16.5
5.5 18.5
lii i l less
Unitless
n initless'
n
Aquifer porosity
Ai--filled Porosity
Calculated Mixinq Zone Depth
Diluiicn Altenustion Factor
Mixinq Zone l.lsed in DAF Calculations
Fig. T-10: Groundwater Parameters Entry Forms
Chemical Parameters Entry Form: SSRG has an in-built list of organic and inorganic chemicals with data on: half life; Henry's Law constant; octanol-carbon partition coefficient for organic chemicals; distribution coefficient for metals; chemical solubility; and health-based MCLs and PRG. A user will simply click on a cell under the column, "Select Chemical" to select a chemical of interest. In addition to fate and transport parameters for each chemical, users can also enter the measured concentration of each contaminant. It should be noted that contaminant concentration is not needed to calculate an SSL or SSRG for that chemical. However, the concentration of each chemical in the soil is used to generate the expected concentration of the same chemical in groundwater whether degradation is assumed or not. SoilScreen used the Chemical Parameters Entry Form to enter the chemicals of concern (COC) at the NoWhere site. These include: 1,1-
26
AR305215
dichloroethane; 1,2-dichloroethylene (trans); ethylbenzene; styrene; trichloroethylene; vinyl chloride; naphthalene; barium; cadmium; chromium VI; and mercury (Fig. T-11).
CHEMICAL PARAMETERS ENTRY FORM
S€l€Ct
cre-nicals
[ i f inte-ei:!
C6nc£c'r3:on
m-iiiic:^'
(ng-m
Hsf Lift
-« ;v^5j
Henri's La/;
ccn5;3r,:i:-n
D nsnsico'e:.-
Cte.^icai
SCiLJiilV 155
r<;.l
Octa-icl-C
Pan cceii
*3C iLiKCI
MCL
cr PRG
tn j .U
. ' , 1 SELECT ORGAHIC CHEMICALS AND EN 1 t K PARAMETERS
•>J-C'icflcro>ir5ne
',2-Dic.toro5lf.>!e,-« (trans)
Stvrsne
T.ncri(cro«Ti)'.6ne
vinyl cnoriH
to?r:n3ler5
•co.c
SJJ.C
654,0 iX'.O i'H.ii 54».,Ci 433.0
0^550
0.700 C.027 0.077
5.CC0 C.250 C.-32
1.0700
G..3a50 0 3230 C.J13D 0 4220 i.noo 0,4220
se.-i
52.5
563.0
775.0 166.0
ie.6 I6S.0
i . i C : « .
I.CCE-C-1
-.CCS-C'I
1.00EJ3t 5.00EJ)3
. 2.00E-C3 5.00E-C3
Chemioai
fof intsrest)
Concentration
in io i l fCt:
(mg^kfii
Ka . f l i f e
T,,-:
(Yrs)
He.trv's Law
Constant (H'l
: Dsnensionltss
Chemfca! Meial Sciubil^iy
• Sj Ois;rCceff
mg/L Kef L/Kg)
MCL
or PRG
. f rr.gr Ll
1 SELECT IMORGAMIC C H E M I C A L S A N D ENTER P A R A M E T E R S
Bar ium Cadmium Chronhiuni •.I Mercury
12,343.0 234.0
7,367.0 676.0 0.467
A].Q
75.0 19.0 E.2.0
2.6aE-01 ».&aE-03
5.50E+00 1.00E+00
Fig. T-11: Chemical Parameters Entry Form
5.3.3 Step 3 - Select and display data for use by SSRG in SCEN-INPUT worksheet
ACTION: SoilScreen opened the SCEN-INPUT Worksheet to find all the data entered in the USER-INPUT worksheet displayed in the appropriate cells
r of the SCEN-INPUT worksheet. The company is interested, in seeing how the default data compares with the site specific data.
COMMENTr'AII data entered in the USER-INPUT Worksheet gets displayed.in the SCEN-INPUT Worksheet (Fig. T-12). The data for each soil layer is used by SSRG to calculate a Vertical Pore Water Velocity (Vs, m/y) for that soil layer and is displayed in the last column.
27
AR305216
Ha<Hled En-Jif
V(>f«C4l i l t k i u *
Ertor S<:IITn» U*ad
Vertteit Iryrfeoic X* (m/f)
EipcntnTliI PirirmAff. b
Toi i l .pom.tty
r t (ft»ellont
Effective par««lty -
ne.fr.ctlon)
Moittuie eai tsr t
Ow (fr«Uo-i)
Eir«Cl:Vt moltture cortont
OB .FncUoni
CtJeu ated V«rtl:al po-e w»tar vslaclty
V» (TMltrf/nJr)
Sourca LavBi ' -J.i
L a y . i 1
Layer 2
n i i
O i j
Laver 3 ,13
Layer 4 ?3
C l a / 32 " 1 9 0 48C 0 423 D390 0 340 - 0 7.13 ' ^ ~ '
. - S a n d
Loa fn
- 6 0 0 0 ^ ,
* , 9 C 0 ^ .
1 ' J i
, ' '< a
0 41C -
0 45C
>.O405
• 0 40D
, .D 180
* 'D230
0 155
0 210
/ f 1 5 M .
1.223 r.'> Ji
! > « n d /
L o a m T'^O - 9 o isr 0 402 J 233 0 210 ' , 1 2J1 •
L o a m sro 9 (i4sr 0400 3 230 0210 1 223
. Clear & IMPORT USER INPUT data Clear & Select SoilType
Ill0<l«l>ll K y r
S o u r c e L a y e r
Enui vmllci l
thlckn«st
• 0 ,6
0,3
Enttr Sdl
Tvp.
Soil Typ. Uisd
VSaiH'
Vertlctl Byd
C9K4
• • •MOO'^
Eifuvuntlal , Piram«t»f, b '
•f^SWW
ToUl pofasjty
rtlfmellMil
" • ' O:A4O''S
EBedive p s m i t y
n i t f r iet tw]
SOM'!^"
MolHuie eonliirt
Qw (fritt len)
• • • f tTso ' " '
efkcUn mNttumcemtwl
Qelfraetlofll
0 166' .;,
VBticalptre wt1*f vulMlty VstmtlM^ev)
i;iiii^72«5?
[jyai 1
o,a
0,3
Sandy '
Lui i i i -790 0,450 0.402 0.253 , 0210 0,913-
Layer 2 I 0,3 • l!cam I 0450 0.400 • 0 230 , . 0210 • i-"-'^:i:o7o^
Clear & IMPORT USER rjPUT data Clear* Select Soil Type
Modeled
• l<ycr
Sourca Layer
Emer
> ; r t cd
tti icKndu
0.6 0.6 0,6 n.'i
E r t e
Soil type
Type
JJKl
IfSiirGi'
Vtrtlca:-
Hyd cond
p^mn-::
Ejp«nentul
Psrameier b
'S'My.^
real
pereeity
nT|'ri;tion;
..••tidoai
EfeclKe
putiity
m
imaioii
aniiinsj^
UcUtuie
conlert
Q*|(ri«or|
>.¥o:i8ii;;^'-
mcietun cairsni
dc l t r i c l io i i l
• 0 ;5S
iTi lcu i te i l
V4rtc:J part
w i t r velocity
VsimcurJiciri
i i ? 7 . : .
Layer 1 I lj,3 ' LcarniM.^;i)iM^|lgI§S^4'-iO/isCK?^V' t).400^:'-Nl%i30'--':i'.- 0.21J.' ; i .o?o; .
Clears, IMPORT USER NPUT data Clear & Select Soli Type
Fig. T-12: Scenarios 1-3 vadose zone parameters and calculated pore water velocities.
One convenient feature of SSRG software is that the user can toggle between the data entered in USER-FNPUT Worksheet and the default data in the software's database. SoilScreen was interested in comparing the default data for the soil type of each soil layer. To display the default data in Scenario 1 for the soil layers encountered at the site, the SoilScreen modeler clicked the button "Clear & Select Soil Type" which displayed the following (Fig. T-13) empty data screen.
28
AR305217
DEF.aULT PARAMETERS FOR EACH SOIL TYPE
U c d i t d
Scurce Lr/er
Enter veic'c:!
tbicttnets
C.l
Lryert C.6
' Lj-,e,J C.5
U y e r : C :
L r , e r i c,:.
Enter Sori
Soil Tvw Used
f i ' '
:iyd a n d f t
i r i y ;
ExpotfntsI
\
portsrty n!
i , V ;
EFfe«vr poccMCy
ne
Hoislurt. conwrt
moistuiv eonlert
ae
*
Calsi lKH Vcrtio¥l ^9r«
WBtr ^locity
(mneiiyeaf)
1 1 1 ..• 1 . 1 • 1 1 . f ' • •
.. . - . • -•,.
• •• 1 1 1 - 1 ' 1 1 1
Fig. T-13: A clear entry screen following the clicking of the "Clear & Select oil Type" button •
Any site-specific data previously carried from the USER-INPUT Worksheet is temporarily rernoved for default data to be entered.
The following should be noted: -
i. The "DEFAULT PARAMETERS FOR EACH SOIL TYPE" statement is displayed on the top of the data eritry screen to indicate any selected soil type from the drop down list will display default values.
ii( The layer thickness values entered into the USER-INPUT Worksheet do not disappear but remain on the screen. Clicking "Clear & IMPORT USER-INPUT data" will replace any default data with user input data,
iii. No data can be entered into any cell in the SCEN-INPUT Worksheet except to toggle between the two datasets. )
The default parameters for the soil types entered in the USER-Input Worksheet are displayed in Fig. T-14:
DEFAULT PARAIWETERS FOR EACH SOIL TYPE •
Medeled
tiycr
Scurce -,. L*5er
v'. E;T>ler
vrrtcal
thiGlin«s
C.5
L^e r 1 C,5
Li'yer2 C.5
l i-rer S C ;
Liver 4 ^
Enter Seil Tror
Cle.
Sr.-:
I.CfT.
Se-tv LcB"-.
LCB!-.
Soil Type Usnl
=•,• S t . Cl.y
Verliiai rt,d » n d Ks
1mry^
2 i i i
Etponenlsal ?ar3ffle<^^,
, b
& \ K.: \ :
Total poretity
n: ifriKionr
.f vJTs':;
Effeccve pcfc-sic/
ne ilrsiioor'l
K.S,.i:;-';-
Moisture cont-ent
•frjslloni
: , !S4 '
Effective moi&LLrc content
Oe (Ir jKionj
' • * i } ^ e '
, CslEiitetiJ yenieal cwr^
• t n t t i velocit/
|mrtcr.'ifear}
' >.:Si:, •,•• U H • 6ow;-? V. iZ i ^ . fS B.,0407 .:. W 1 7 . . . . 3.171; • 0 - 8 ;. ••• i.4eT.-
.i-'.sn U - r , ;.'9- . - • v J ! 3 • • . - 3 J ; 4 : K £ •3.::f .• ,; ; g7 :•. J i J 5 .•
•iiem •55 ''. i i ' ' , v4S3 .>: '• D.J15S-' -3.:-i2' - -.•^i'ri'isc-^? 1,i;5 J i i i
'iv-em "•"•'i7 ^ '" •• 5 .SUV,:-. . •C.«J-.V • O J M f " : • : : ' '•• 0 :57 c.y ^ • , ^ 9 : 2 5 - .
Fig. T-14: Data cells filled with default parameters and calculated Vs based on the default parameters.
^ Differences in the user-input data and the default data resulted in differences in calculated Vs. This process caii be repeated for each Scenario. ,
29
AR305218
A similar concept applies to the chemical parameters where the user can toggle between the user input values and the default values in the SSRG database.
5.3.4 Step 4 - Display & print results
ACTION: SoilScreen opened the SCEN-ORGANIC_RESyLTS worksheet to review and print the results of their modeling exercises.
COMMENT: All calculated parameters including the SSL and SSRG results are displayed for the selected organic chemicals and metals. Calculated parameters include: |
i. Kd in the vadose zone (Kd(VZ), L/Kg) ii. Kd in groundwater (Kd(GW), L/Kg);.
iii. Chemical retardation (R); iv. Mean travel time through the vertical layer (Tt, years) V. Expected concentration in groundwater resulting from onsite
contamination and with or without degradation (mg/L) vi. SSL and SSRG (mg/Kg) .
vii. Further action warranted based on comparison of SSL or SSRG and the measured soil concentration of the chemical. • "' .
It should be noted that with metals, no SSRG are calculated since there is no degradation of the chemicals. Only SSLs are generated and will therefore not be featured in the tutorial. This is consistent with the USEPA guidance on SSLs. • '
Based on the parameters entered by SoilScreen in the USER-INPUT Worksheet, the results (Table T-1) show the following:
I
i. All SSL numbers are much lower than SSRG for each organic chemical . ii. Time of travel decreases as the contaminant source gets closer to groundwater, iii. Concentration in groundwater increases as the source layer gets closer to
. groundwater. . iv. While SSLs remain constant for each chemical irrespective of the scenario,
SSRG decreases as the source gets closer to groundwater. V. Based on the concentration of chemicals measured in soils, the SSLs indicate
that further action is needed for each chemical, vi. However, on the basis of SSRG, no further action is warranted for 1,2-
Dichloroethylene (trans), Ethylbenzene, Styrene, and Naphthalene for portions / of the site represented by Scenario 1. The chemicals 1,1-Dichloroethane,
Trichloroethylene, and Vinyl chloride require some further action. As contamination gets closer to ground water as in Scenarios 2 & 3, Styrene is added to the list of chemicals that require further action.
Each of these results can be printed by simply clicking the print button. .
30
AR305219
Table T-1: SSL and SSRG results for organic chemicals
Project Name: SSRG Evaluaac Project Location' Ncwtet^ l o Project Officer: John Ctoe Date i18,'2Da8
Scenario 1
Moacercdcoll Cbemcalt concen tCt'j |i>(lnUrMl) (mslrjl
I,14:'.;i-k:rc5th3ie ; IXE.02 l,2C-crtcffi£t^:/en« Itrani! 9 K t * ^ J .
ElhJb.;rMr? 6 51E-C2
•Slyienc J OOE'C?
T,ic*a»Ihv1«n* <o!E'02:
V. - r ) *Of i * i M i ' l i
Nart-i-tvi^v. j.i.'.F+i::- ••
•
not ABC WSllIB
KdlVO LKo
' 7 6iEOl
.b.BJt.^'
i.r;£-ci:i
l . j l r - i l
i.i?E-i:o
2,42E*
? if=.rf i
Soil Screening & Remediation Goals (SSRG) Tool
Vers ion : : (tyiarcti, 2008) Aulhot.Dai/idM.Kaigbo, PhD ,
USEPA Region III
s see soils
S S L a n d S
KdtOWl LKfl
7,6f,=j:i
r.bit.Vi
1 ? ; •£ -»
1 CIE-Ol
2 leEi i i
;-,4:E-CI
J l iF-ni
SRG RESU
Ret3nl:d4on
t«E-0O
t:,^h-y.i
176E-C1
7,SSE-0l
i,76E-:-i
• 2SE< l l
• Tff..'-
LTS FOR 0
rriean TiTlvtl
T ine Thru
Vertical Layer
Ttlveml
5,5s=-:<i
i i ^ - ^ i ; ,18:>01
I, :«E.02
2,J4E«:il
J i5E.OO
.; i4-Hii
RG/IWC c o ^
Cgwr ron Cl
(Mdiajt d«gr3d)
••71E-D1
• , « b - i ' Z
2 S E - 0 1
• 7 , ( 1 3 E - D :
. 3,27E-31
- , « 3 E - H
-177F--.1
TAMINAMTS
Cgwr rcn iC t
:wllhdegr.id)
, m g ( L
I,C1E.M
J ^ t V J
C
0
ll lE'OC
3 17E01
,-
MCL Of PRO Cnfl-L) .
• 41CE03
•:Xi:-.'I
7XE.31
:,KE.Dl
5 BE Do
2.KE 33
sS-F.I.- i
C j v ,
based
0.1 MCU
IKLtt. met
2 43.E.34
ot. ' t-Jl
3 87E«>;
5;:'E.)i
2 J5E-)2
1 lOE-K
7 7; F-12
.119 Kg
2 M E «
5Li/b^;i
1 3iE-31
5i9E-00
o62E-:2
'.•iitJ-.i
?.f 7F.r,y
1
•FdrtherS ,A^, -ntv
Ibowdsn . 55L|7.'
VES
rt.^
YE-S
'ES
• "ES
•-ES
VCR
'
1
; Furtbef
• . .Ao l ien
SJRS 'Onsedo r t
i T f K a 6SR0)?
J M E ' C l VE5
2,bt=-i.:) NO
t , 9 !E - t 7 .NO
; .HE-C6 • NO
l ,«E-r . l ] VEF
i,«4E-C2 YE.;
=.^;F-rj , NO
S c e i i R i i o
Chemical (el Interesll
i l-DicMcriKinane 1.2-Dichto-oettiyiene iliansi
Elnylbenzene
Srrreiw
Tt^cnlo.'M'hylene
Vtnvl c i orde
Naphthalene
2
coiwen (Ct) tnWkBl
1 l>3E.02
' 9,50E.02
6.aJE»02
4,l»E-02
4 , 3 J E - 0 2
5,45E-02
.4,33E-02
Kd(VZ) L'Kg
7 66E-01
8ME-01
4,72E-00
lOiE-Ol
2 li5E-W
• 2 45E-01
2 16E-i»
KdlGWi UKlI
7 6oE-CI
6,a3E.Cl
4,72E.O0
i.OlE-01
2,16E-OC
2,42E-lll
2,16E-'J0
Relanbtlm IRI
5,35E-0C
4,88E-0'j
2,7BE-01
5.ME-01
1.33E-01
2,37E-0';
•1,33E-01
Mejn Travel TrmeThru
Vertical Uyer Tl (years)
8,75E-(30
D,t5E-Kl
3 ,51E-0- -
r,35E-o-.
1.67E-3-
2,S!iE-M
l,67E-0:
Ct lwr rwn Ct
(wHhotit
degrad)
mft ' l .
l,7iE-CI
1 38E.C2
2 39E.01
7 03E.M
3 27E.C1
1 B3E.C2
3 27E-01
CBVjlromCt (with depad)
moL
3,47E-03
4,25E-01
0
0
3 22E-n(J
4E6E-02 •
0
M a e r PRG
(n«l.T.)
4,4CE-05
' 1,CCE-01
7,0CE-01
I,00E-Ci1
S.OOE-03
2 OOE-03
6,'3CE-03
C,« based on
MCL MCLG, mg.l
2 43E-04
5 52E.01
367E»00
5 52E.OI
2,76E.02
1, IDE-02
2,7eE.02
SSL
2 53E-*;
5.07E-01
1 91E-0I
5 63E-CC
6,6/E-Cl2
5,ME-M
6,62E-02
- - i ^
' F u l h e r ^
Action ;
(baeed o n ^
SiUl iKB
YES
VES
YES
YES
YES
YES
YES
SSRG
1.27E-0i ;
2 ,23E .02
1.91E.07
5 .e9E.06
6 72E.01
2 ,40E .C l
e S 2 E . 0 J
Further
Act ion
(based on
5 5 R C ) 1 -
VES
YES
NO
NO
YES
YES
NO-
Scenario
Chemicate
(of Interest;
' l-Dicl:lr.roetnane 12-Dichlo'oethylene (Udnsi
Errivltwnz(?ne ,
Sryrerw
T,":c".ioroe.:hv'lene •
Vinvl c?i:or-de
Naphlhalene
Measured soil
ooncm (Ct)
(mft'kgi
ymi'Oi
9 50E-02,
S i tE-02
4,lXIE-02
4,:'3E-02
5 45E-02
4,35E-02
Kd(VZ) L.Kg
7,SoE-0|-
6,83E-01
4,72E.30
1,0IE».3:
2,ieE-«i-2.42E-01
2.I6E-30
KdtOWl " LKg
7,5f,E.0l
6,B3E-01
4.72E-IW
1,(1IE-01
2,16E.OO
2 42E-01
2 16E-M
Retartlatjon IRI
5.92E-1JO
5 3 8 E ^
3 13E.0i
eseE.oi UPE. i l !
2.55E.00
t 45E.0i
Mean Travel TInwThnr
Verticil Layer Tl (years)
•„66E-03
-..SIE-OO
8 77E-D0
-, 84E-0:
4 l6E-a3
7,;SE.01
4,16E-M
, Cgw (rom Ct (without degrad) mffL i
1,7>E-C1 •
1,S8E.C2
2.39E.C1
7,03E-CO •
3 27E-C1
1 93E.C2.
3 27E.C1
Cgw from Ct (v/ith depadi
2,! IE-CO
i,21E-01
Cl
0
1 84E-01
2,51E-C1
• 105S-0B
M a e r PRO
(m»l)
4,40E-05
1,ClOE-01
7,00E.01
I00E-C1
5i )0E-O3
, 2 M E . 0 3 •
• ' j CinE-03
Cgw
based cn
M C L
M C L a
2 43E-34
5 52E-0'.
3 e7E-M.
5.52E-31
• 2.76E-32
1 lCE-02
2 76E-32
3SL moKa
2 58E-M
5.07E.O1
ig iE . iJ I
5,59E.OO
6 62E-a2
5 5eE-Ci3
e«E-Ci2
•Fu t thor '
Act ion.
[bosedon
8SL)7
YES
YES
YES
YES
VES
YES
. Y E S
SSRO' maKs
2.09E-(13
2.26E>M
IStE.07
6,6SE-05
1,18E-«1
4 34E-02
6 6 2 E . 0 4
F > ^ l . -ActioAt (based « v
35BO)?.«
YES
YES
NO
NO
YES
YES
NO
31
AR305220