fgd gypsum – putting environmental issues in context · lisa jn bradley, ph.d., dabt vice...

Lisa JN Bradley, Ph.D., DABTVice President and Senior Toxicologist

FGD Gypsum – Putting Environmental Issues in Context

Gypsum AssociationBaltimore, MD March 13, 2014

Overview

• Why do we need to discuss environmental issues?• Short history of coal ash regulatory, judicial, and

legislative activities• ENGO activity• EPA’s Beneficical Use Risk Assessment/Critiques• Toxicity and Risk Assessment• FGD• Mercury• Conceptual Site Models• Soil to Groundwater Risk – Leaching – LEAF

• Remember - It’s All About the Context!

• Lisa JN Bradley, PhD, DABT

• PhD in Toxicology from the Massachusetts Institute of Technology (MIT)

• Diplomate of the American Board of Toxicology

• Vice President

• 20 years of experience as toxicologist and risk assessor

• ACAA Executive Committee Member –Sec/Treas-Elect

USEPA Study Reaffirms FGD Gypsum in Wallboard

• U.S. Environmental Protection Agency on February 7, 2014, released an exhaustive study re-affirming the Agency’s support for two major uses of coal ash – fly ash in concrete and FGD gypsum in wallboard:– “…environmental releases of constituents of potential concern

(COPCs) from CCR fly ash concrete and FGD gypsum wallboard during use by the consumer are comparable to or lower than those from analogous non-CCR products, or are at or below relevant regulatory and health-based benchmarks for human and ecological receptors… EPA supports the beneficial use of coal fly ash in concrete and FGD gypsum in wallboard. The Agency believes that these beneficial uses provide significant opportunities to advance Sustainable Materials Management (SMM).”

– http://www.epa.gov/wastes/conserve/imr/ccps/pdfs/ccr_bu_eval.pdf

Why Do We Need to Discuss These Issues?

• Inside EPA, Posted: March 11, 2014

• Challenging Safety Finding, Advocates Fault EPA's Coal Ash Reuse Review

• “Environmentalists are questioning the quality and scope of EPA's recently released method for assessing the risks posed by encapsulated uses of coal combustion residuals (CCR), as well as the agency's accompanying document that found that reuse of coal ash in concrete and wallboard is safe, calling the process a "kangaroo court of science.”

Coal Ash Regulatory History

• 1980 Bevill Amendment to Resource Conservation and Recovery Acto Instructed EPA to "conduct a detailed and comprehensive

study and submit a report" to Congress on the "adverse effects on human health and the environment, if any, of the disposal and utilization” of coal ash

• 1988 and 1999 EPA Reports to Congresso Recommended coal ash should not be regulated as

hazardous waste

• 1993 EPA Regulatory Determinationo Found regulation as a hazardous waste “unwarranted”

• 2000 EPA Final Regulatory Determinationo Concluded coal ash materials “do not warrant regulation

[as hazardous waste] ” and that “the regulatory infrastructure is generally in place at the state level to ensure adequate management of these wastes”

With regulatory certainty in place, coal ash recycling rate increases almost 50% over next eight years

Year Percent2001 26%*2002 68%2003 70%2004 76%2005 77%2006 79%2007 76%2008 60%

FGD GypsumBeneficial Use

Rates

* All FGD ProductsData from the American Coal Ash Associationwww.acaa-usa.org

Since 2008….• December 2008 – Disposal unit at Kingston power plant

fails, reigniting EPA interest in Subtitle C (“hazardous waste”) regulation for direct federal enforcement

• 2009 – Discussions with EPA, OMB and other agencies seeking to prevent Subtitle C proposal that would damage recycling – a Subtitle D (“non-hazardous”) regulatory option is added

• 2010 – Response to Draft Proposed Rule, including public hearings

• 2011 – Congressional hearings, introduction of HR 1391, response to first EPA NODA

• 2012 – HR 2273, S 3512, Transportation Bill, “Fiscal Cliff” Bill, ENGO and ash marketers sue EPA for a deadline to the rulemaking (sue & settle), EPA Beneficial Use Risk Evaluation Methodology

• 2013 – HR 2218 passes House, second NODA, Federal court orders deadline

Coal Ash “Haz Waste” Proposal Waning…

• From April 19, 2013, EPA announcement concerning proposed “Effluent Limitation Guidelines” for coal-fueled power plants:– “Although a final risk assessment for the CCR rule has not yet been

completed, reliance on the data and analyses discussed above may have the potential to lower the CCR rule risk assessment results by as much as an order of magnitude. If this proves to be the case, EPA’s current thinking is that, the revised risks, coupled with the ELG requirements that the Agency may promulgate, and the increased Federal oversight such requirements could achieve, could provide strong support for a conclusion that regulation of CCR disposal under RCRA Subtitle D (non-hazardous) would be adequate.”

• ELG proceeding under Clean Water Act has a consent decree deadline of May 22, 2014

• EPA announced intent to “align” the ELG and CCR rulemakings

Deadline Set to Complete Coal Ash Rule

• From January 30, 2014, federal court consent decree between EPA and environmental groups and coal ash marketers who sued to force conclusion of EPA’s four-year-old rulemaking:– “The EPA Administrator shall, by December 19,

2014, sign for publication in the Federal Register a notice taking final action regarding EPA’s proposed revision of RCRA subtitle D regulations pertaining to coal combustion residuals.”

Where Does This Leave Legislation?

• Subtitle D (“non-hazardous”) regulation via either:– EPA action resulting in citizen lawsuit enforcement– Congressional action resulting in state enforcement

• ENGOs continue to oppose Congressional option• HR 2218 as passed House of Representatives in 2013 does not have

necessary 60 votes in Senate – White House Statement of Adminstrative Policy opposed, but did not threaten to veto the bill

• Senator Max Baucus (D-MT) – whose staff previously led effort to craft amendments necessary to attract sufficient Democrat support – has accepted position as Ambassador to China

• Senate bill leaders are now John Hoeven (R-ND) and Joe Manchin (D-WV)

• Future in Senate depends on developing a compromise over regulatory treatment of legacy disposal sites

9

What is Happening Now?

• February 2, 2014, spill of approx. 80,000 tons of coal ash from Duke Energy’s Eden power plant into the Dan River (North Carolina and Virginia)

• ENGOs renewing calls for Subtitle C regulation saying incident proves states are too cozy with utilities they regulate

• As noted earlier, some ENGOs are questioning the validitiy of USEPA Beneficial Use Risk Assessment

• Drumbeat of toxic coal ash and arsenic, lead, mercury, chromium….

How Did We Get Here?• TVA Kingston• USEPA’s proposed rule-making• Environmental group publications• See PADEP rebuttal:• http://www.uswag.org/pdf/2011/CCRNODA/NODAComme

nts/PADEPReviewofEIPCCWReports.pdf

Kingston Spill – Then and Now

SOURCE: Tennessee Valley Authorityhttp://www.tva.gov/kingston/before_after_06-13-2012/index.htm

Before After

Public Employees for Environmental Responsibility - PEER

SOURCE: http://www.peer.org/campaigns/public-health/coal-combustion-waste/coal-ash-is-everywhere.html

PEER Advocacy

SOURCE: http://www.peer.org/campaigns/public-health/coal-combustion-waste/epa-coal-partnership.html

Why did EPA do the Beneficial Use Risk Evaluation?• The Coal Combustion Products Partnership (C²P²) program is a cooperative effort

between EPA and the DOE, the FHWA, and the USDA-ARS to promote the beneficial use of coal combustion products (CCPs) and the environmental benefits that result from their use.

• 2010 EPA Office of Inspector General report concludes EPA should evaluate risks before endorsing beneficial use

• EPA closed down the C²P² website• Agency subsequently commits to development of risk “evaluation” methodologies

by:– April 2012 – Methodology for encapsulated uses– Fall 2012 – Large scale structural fill guidance for rulemaking– 2nd Quarter 2014 – Methodology for unencapsulated uses

• June 2012, EPA opened discussions with stakeholders on the methodology for encapsulated use

• February 7, 2014, EPA releases the methodology and the risk evaluation for fly ash in concrete and FGD gypsum in wallboard

Methodology 5-Step Process • Step 1: Literature Review

– Eliminates from further evaluation releases and exposures of constituents of potential concern (COPCs) that have been sufficiently addressed by the literature

• Step 2: Comparison of Available Data– Eliminates from further evaluation releases of COPCs that are comparable to or below those from analogous non-CCR products

• Step 3: Exposure Review– Eliminates from further evaluation releases of COPCs with no complete exposure pathways

• Step 4: Screening Assessment– Eliminates from further evaluation exposures of COPCs at or below conservative screening benchmarks

• Step 5: Risk Assessment– Eliminates from further evaluation exposures of COPCs with calculated risks at or below relevant regulatory and health-based benchmarks

NOTE – Steps do not need to be followed sequentiallyNOTE – Used to evaluate consumer use of the product, not the life cycle

Methodology Flow Chart – Steps 1 - 3

Methodology Flow Chart – Steps 3 - 5

Beneficial Use Risk Assessment for FGD Gypsum – Step 1

• STEP 1• (USEPA 1998) Identified types of releases to the environment from

wallboard:– Generation of dust– Emanation to air– Leaching to ground and surface water– Decay of naturally occuring radionuclides

• (USEPA 1999) Polycyclic aromatic hydrocarbons (PAHs) and dioxins are at or below detection limits in CCRs and in leachate, and are not volatile, thus PAHs and dioxins eliminated from further evaluation

• (Yost, et al. 2010) Wallboard used in indoors and not exposed to most environmental media, thus potential releases limited to emanation to indoor air and radioactive decay

• (CPSC 2010) Eliminated reactive sulfur gases from consideration

• (Long et al. 2012) Risk assessemnt of FGD and mined gypsum wallboards in a residential and school setting; EPA concluded that because n=3 for each material, the population was too small to adequately characterize the building products. Thus retained mercury as a COPC for emanation to air.

• (Various Rad Studies) Studies compared radiation from FGD and mined gypsums – because the radionuclide content will not change during manufacture, these studies were used as surrogates for the final wallboard. EPA concluded that FDG activities are within the range of mined gypsum, thus radionuclides were eliminated from further consideration.

• Thus one COPC, mercury, and one pathway, emanation to air, was retained for further analysis in Step 2.


• STEP 2 - Because the low FGD gypsum wallboard emanation rate is greater than the highest mined gypsum wallboard emanation rate, mercury emanation retained

• STEP 3 - Potential exposure pathways evaluated and found to be potentially complete

Beneficial Use Risk Assessment for FGD Gypsum – Steps 2&3

• STEP 4• Model indoor air concentration of mercury due to emanation from wallboard,

using default assumptions and an equilibrium assumption• Probabilistic evaluation


Probabilistic Risk Assessment

• Per USEPA’s Guiding Principles for Monte Carlo Analysis (USEPA, 1997, pp 1-3), information describing each input and output distribution is required. Both graphical and statistical descriptions (including minimum, maximum, and percentiles) of all probability density functions (PDFs) in the analysis are required for both input parameters and output results.

USEPA. 1997. Guiding Principles for Monte Carlo Analysis. EPA/630/R-97/001. March 1997.

Inside EPA Article continued…

• For wallboard, EPA relied on a study performed by wallboard producer Georgia Pacific and Exponent consultants, rather than performing its own assessment of dust as an exposure pathway. EPA described the findings of the Yost et al. study on wallboard, published in 2010, and stated that "[b]ased on these findings, the current evaluation limited the selection of COPCs to those with the potential to be released through emanation to indoor air or radioactive decay."

• A second environmentalist calls EPA's explanation "threadbare," arguing the agency does not "explain why it would consider one study, rather than multiple ones, preferably not funded by industry, to be sufficient to discount this major potential exposure pathway," dust.

• The decision led to questions during the webinar about EPA's definition of the consumer use phase of the product's lifecycle, since dust is often generated during renovation or demolition. OSWER's Jason Mills, replied that EPA considers the consumer use to be "as long as the structure is in use," which for wallboard would be when it is in place and not disturbed.

• "In the beneficial use of [CCR] materials, [consumer use] was the critical aspect we wanted to consider" because regulated disposal sites are already adequately controlled and address the end-of-life phase of the product's lifecycle, Kinch added. "With wallboard . . . if there is new construction scrap, basically recycling of that material goes to new wallboard construction, [creating] an internal loop," he said.

Risk Assessment Interlude

• What is toxicology?

• What is risk assessemnt?

• What is in coal ash and FGD gypsum?

• How can we use risk assessemnt to understand if there is a risk?

Toxicology

• The study of poisons

• Dose-Response

“All substances are poisons; there is nonewhich is not a poison. The right dose differentiates a poison from a remedy.”

Paracelsus, 1500s

Risk Assessment

Risk = Exposure x

Toxicity

Hazard Identification

Exposure Assessment Toxicity Assessment

Risk Characterization

If there is no exposure,

there is no risk

Source: USEPA. 1989. Risk Assessment Guidance for Superfund: Volume I. Human Health Evaluation Manual (Part A). Interim Final. Office of Emergency and Remedial Response. U.S. Environmental Protection Agency, Washington, D.C. EPA 540/1-89/002.

USEPA Regional Screening Level (RSL) Table

• Environmental Media:– Residential Soil– Industrial Soil– Residential Air– Industrial Air– Tapwater– MCLs– Soil-to-Groundwater

SSLs• Soil RSLs address:

– Incidental Ingestion– Dermal Contact– Inhalation

• Target Risk Levels:– Noncancer HI=1– Cancer Risk - 1 in 1

million– Provides guidance for

additional risk levels

RSLs: USEPA. May 2012. Values for residential soil. http://www.epa.gov/reg3hwmd/risk/human/rb-concentration_table/index.htm

As noted by USEPA, the screening levels (RSLs) are considered by the Agency to be protective for humans (including sensitive groups) over a

lifetime

USEPA Regional Screening Levels for Residential Soils

Carcinogenic by the oral route of exposure: As Carcinogenic by the inhalation route of exposure: As, Be, Cd, Co, Ni, Cr6 – RSL driven by oral route

Risks in Perspective

Conservatism in the Process

US Age at Death – 1930-2000US Cancer Rates – 1975-2007

American Cancer Society: The ACS addresses nutrition, physical inactivity and obesity, alcohol consumption, excessive sun exposure, prevention of certain chronic infections, and selected other environmental factors.

Fontham et al. 2009. American Cancer Society Perspectives on Environmental Factors and Cancer. CA Cancer J Clin 2009;59:343–351. http://cacancerjournal.org

Background cancer rate in the US – 1:2 for men and 1:3 for women

What are in CCPs?

SourceEPRI, 2010. Comparison of Coal Combustion Products to Other Common Materials – Chemical Characteristics. Report No. 1020556. Available for download at www.epri.com

Trace Elements

• What are trace elements?

– Sb – Antimony– As – Arsenic– Ba – Barium– Be – Beryllium– B – Boron – Cd – Cadmium– Cr – Chromium– Co – Cobalt– Cu – Copper– Pb – Lead– Li – Lithium– Mn – Manganese– Hg – Mercury– Mo – Molybdenum– Ni – Nickel– Se – Selenium– Sr – Strontium– Tl – Thallium– U – Uranium– V – Vanadium– Zn – Zinc

• Why are they called trace elements?

• They are present in concentrations of milligram per kilogram (mg/kg), equivalent to:

– One part per million (ppm):1 penny in a stack of $10,0001 second in 11.5 days1 inch in 15.8 miles

Comparison of FGD Gypsum to US Background Soil Levels

Source: EPRI, 2010. Comparison of Coal Combustion Products to Other Common Materials – Chemical Characteristics. Report No. 1020556. Available for download at www.epri.com. FGD n = 27.

Comparison of FGD Gypsum to Fertilizers


Comparison of FGD Gypsum to USEPA Soil Screening Levels


Dust Generation Evaluation

USEPA Fugitive Dust Report for CCR

• Report addressed fugitive dust emissions from a landfill using SCREEN3 model– Assumed a location with 0 precipitation– Did not correctly calculate PM10 (did TSP

instead)– Did not account for ash conditioning during

landfilling operations– Did not account for the sequential nature of

landfilling operations – assumed the entire area of the landfill was a continuing source

– The maximum modeled dust concentration was 13,390 ug/m3 – a condition that would have been experienced near the eruption of Mt. St. Helens

• Data from TVA indicate that there have been no air quality standards exceedances during the Kingston recovery project

USEPA. 2010. Inhalation of Fugitive Dust: A Screening Assessment of the Risks Posed by Coal Combustion Waste Landfills. May 2010.

Elements in Coal Ash

Source:Coal Ash Chronicles. http://www.coalashchronicles.com/about

Mercury is Present in Our Natural Environment

Source: USGS. National Geochemical Survey. http://mrdata.usgs.gov/geochem/doc/averages/countydata.htm

Mercury is Present in a Variety of Forms

• Mercury Sulfide = HgS– Mercury Ore - Cinnabar

• Elemental Mercury = Hg0

– No ingestion hazard, toxicity value based on inhalation– Thermometers, manometers– Dental amalgams may contain 43–54% elemental

mercury• Mercuric Chloride = HgCl2

– Basis of EPA oral toxicity value for mercury compounds– Used in photographic printing

• Methyl Mercury = CH3Hg– Basis of EPA oral toxicity value– Organic mercury created in the environment– Complex mercury cycling– Present in foodstuffs, fish

Exposure to Mercury in Our Environment

• Range of estimated daily absorbance of mercury from dental amalgams is 3–17 ug

• Estimated daily absorbance from all forms of mercury from fish and seafood is 2.31 g

• Estimated daily absorbance from other foods, air, and water is 0.3 g

• Compact fluorescent light bulbs (CFLs) currently contain approximately 5 mg (5,000 ug) mercury – (NEWMOA, 2008; see the EPA-funded report at

http://www.newmoa.org/prevention/mercury/imerc/factsheets/mercuryinproducts.pdf). The maximum amount of mercury detected in the various types of coal ash is 1.5 mg/kg (EPRI, 2010), though the normal range of mercury in coal ash is much lower than this.

Source: ATSDR. Toxicological Profile for Mercury. http://www.atsdr.cdc.gov/toxprofiles/tp.asp?id=115&tid=24

Constituents in the Human Body

Constituent

Total Mass In Human Body

(mg)

Concentration in Human Body

(mg/kg)EssentialNutrient?

Background Range in Soil

(mg/kg)Aluminum 60 0.857 15000-- 100000Antimony 2 0.029 BDL-- 1.3Arsenic 7 0.100 2-- 12Barium 22 0.314 200-- 1000Beryllium 0.036 0.001 BDL-- 2Boron 18 0.257 BDL-- 70Cadmium 50 0.714 BDL-- 0.5Chromium 14 0.200 Yes 15-- 100Cobalt 3 0.043 Yes BDL-- 15Copper 72 1.029 Yes 5-- 50Iron 4,200 60.000 Yes 7000-- 50000Lead 120 1.714 BDL-- 30Manganese 12 0.171 Yes 100-- 1000Mercury 6 0.086 0.02-- 0.19Molybdenum 5 0.071 Yes BDL-- BDLNickel 15 0.214 5-- 30Selenium 15 0.214 Yes BDL-- 0.8Silver 2 0.029 BDL-- BDLStrontium 320 4.571 20-- 500Thallium 0.5 0.007 0.2-- 0.7Uranium 0.1 0.001 NA-- NAVanadium 0.11 0.002 20-- 150Zinc 2,300 32.857 Yes 22-- 99

94% = Carbon, Hydrogen & Oxygen

Source: Emsley, J. 1999. The Elements. Oxford University Press.

Conceptual Site Model (CSM)

• Direct Contact with Coal Ash

• Leaching to Underlying Groundwater

Conceptual Site Model (CSM)Pathway1. Movement of

constituents out of the source material

2. Movement of constituents through the soil column

3. Movement of constituents into & through groundwater

4. Movement of constituents through groundwater –reactions *Receptors

5. Movement of constituents into down-gradient surface water *Receptors

Methods1. Comparison

to Screening Levels – or –Leach testing

2. SESOIL

3. MODFLOW –or direct measurement

4. MT3DMS –or direct measurement

5. Dilution (mixing zone) – or direct measurement

Direct Contact with Coal Ash

Leaching to Underlying Groundwater

12

34

5

CSM – Leaching – Screening Levels

• USEPA developed soil-to-groundwater (SGW) screening levels in their Soil Screening Level Guidance in 1996 – referred to as SSLs

• These SSLs are updated with the USEPA RSL table, but the list of SSLs has not been expanded

• Many state programs provide some form of SGW SSLs as Tier 1 standards or screening levels – and Tier 2 invariably allows for development of site-specific SGW SSLs

Leaching Testing – What is Leaching?

• Leaching in an environmental context is the process of constituent transfer from a solid material to a contacting liquid or aqueous phase. – The release of constituents is governed by a combination of chemical

processes and mass transfer mechanisms based on the chemical composition and physical properties of the solid material along with the pH, redox and composition (i.e., dissolved constituents) of the contacting liquid.

• In environmental applications, leaching represents the source term for release of potentially hazardous substances.

» From: Background Information for the Leaching Environmental Assessment Framework (LEAF) Test Methods, EPA/600/R-10/170, November 2010

• We all leach everyday!– Coffee– Tea– Bouquet garni

What Affects Leaching?• Condition or size of the

material to be leached– Coffee beans – we don’t make

coffee with these!– Ground coffee – the finer the

grind, the stronger the coffee

• The liquid to solid ratio– The more coffee you use per

cup, the stronger the coffee

• Method of mixing the liquid and the solid– Batch test – mix the liquid and

the solid, shake for a prescribed period of time – think French press coffee

– Column test – pour the liquid over the material in a column –one pass – think drip coffee maker

– Monolith test – soak a solid form in water – we don’t do this for coffee!

• The type (or pH) of liquid used for leaching – “Own/Self pH” – the pH when

material is extracted with DI water at liquid to solid ratio of 10 mL/g

General Leach Testing Methodology

Combine Solid Material with Liquid (Specific Volume and pH)

Mix (Shake, Percolate, Soak)

Separate Solid from Liquid

Analyze Liquid for Metals

Leach Testing MethodsTCLP – EPA Method 1311• Toxicity Characteristic Leaching

Procedure• Single batch test.• Leaching liquid is acetic acid at a pH of 4.93

– to mimic leachate created in an MSW landfill

• TCLP test results are required by federal regulations to determine whether a waste passes or fails the RCRA toxicity characteristic as defined at 40 CFR 261.24. So, whether a waste can be disposed in an Subtitle D / MSW landfill, or if it is characterized as hazardous and needs to be disposed in a Subtitle C landfill.

• Table 1 of 40 CFR 261.24 provides “Maximum Concentration of Contaminants for the Toxicity Characteristic”

SPLP – EPA Method 1312 • Synthetic Precipitation Leaching

Procedure• Single batch test.• Leaching liquid is a combination of nitric

acid and sulfuric acid at a pH of 4.2 East of Mississippi River or 5.0 West of the Mississippi River – to mimic rainfall

• No reguatory authority• More representative of environmental

conditions

• Leaching Environmental Assessment Framework – a collection of:

• Four leaching methods (next slide) • Data management tools• Leaching assesssment approaches

LEAF

Source: http://www.epa.gov/epawaste/hazard/testmethods/sw846/online/1_series.htm

LEAF – Leaching Methods

• 1313 – pH Range– Batch test over 9 fixed pH values (2 to 13), plus self pH – Particle size 0.3 mm, 2 mm, or 5 mm (increasing mass, time

and volume) [head of a pin, grain of sand to grain of salt]

• 1314 – Column– Column testing using DI water (self pH), effluent sampled at

fixed points over time– Particle size 0.3 mm, 2 mm, or 5 mm (increasing mass, time

and volume)

• 1315 – Monolith– Testing of a monolithic or compacted granular material

submerged into solution– Solution sampled at fixed points in time over several months

• 1316 – Liquid/Solid Ratio Range– Batch test over 5 fixed ratios of liquid solution to solid sample– Self pH– Particle size 0.3 mm, 2 mm, or 5 mm (increasing mass, time

and volume)Source: http://www.vanderbilt.edu/leaching/leaf/

pH Scale and LEAF pH Levels

If “own/self” pHIs within other pH targets

13

12

10.5

9

8

7

5.5

4

2

1

LEAF Results – pH (1313)

Source: U.S. EPA, Characterization of Coal Combustion Residues from Electric Utilities – Leaching and Characterization Data. EPA-600/R-09/151. Dec 2009. http://www.epa.gov/nrmrl/pubs/600r09151/600r09151.html

• Leaching from materials is pH dependent

• These pH tests require that the leachate maintain the stated pH, not just the initial solution – so acid or base must be added to maintain the pH throughout the test

• The circled values are the results for the material at is “own” or “self” pH –when the material is mixed with water

LEAF Summary

• LEAF provides new laboratory methods to assess the source term potential for leaching

• Methods allow testing over a range of conditions – ideally, conditions are chosen that are consistent with management scenario

• LEAF does not provide any method(s) to assess environmental impacts

• No “bright line” regulatory compliance level like TCLP; no pass-fail

• Without a clear “Assessment Framework” (the AF of LEAF), the test results can be taken out of context

NEED PHOTOHERE

ENGO Take on LEAF Results• Myth #1: Coal ash is like dirt.

• Fact: Coal ash is hazardous. According to the U.S. Environmental Protection Agency (EPA), a waste is “hazardous” if it leaches toxic chemicals, like arsenic or selenium, above a certain threshold when tested using the Toxicity Characteristic Leaching Procedure (TCLP). When EPA tests coal ash using a new, more accurate leach test, the resulting leachate can exceed hazardous waste thresholds. Claims that coal ash is not hazardous are based on the TCLP. Yet the EPA’s Science Advisory Board and the National Academy of Sciences have determined that the TCLP does not accurately predict the toxicity of coal ash. When tested with EPA’s new, more accurate test, coal ash leached arsenic at up to 18,000 parts per billion (ppb), which is 1,800 times the federal drinking water standard and over 3 times the hazardous waste threshold. The new test revealed selenium leached from one coal ash at up to 29,000 ppb, which is 580 times the drinking water standard and 29 times the hazardous waste threshold. This is not backyard soil, unless you live at a Superfund site.

Source: Earth Justice. http://earthjustice.org/sites/default/files/CoalAshMythFactSheetMar2011.pdf

LEAF Results for Arsenic

= 18,000 ug/L Source: U.S. EPA, Characterization of Coal Combustion Residues from Electric Utilities – Leaching and Characterization Data. EPA-600/R-09/151. Dec 2009. http://www.epa.gov/nrmrl/pubs/600r09151/600r09151.html

LEAF Results for Selenium

= 29,000 ug/L Source: U.S. EPA, Characterization of Coal Combustion Residues from Electric Utilities – Leaching and Characterization Data. EPA-600/R-09/151. Dec 2009. http://www.epa.gov/nrmrl/pubs/600r09151/600r09151.html

Leaching and Management Scenarios

Remember – Leaching testing only provides the source term for evaluating a management scenario –

it does NOT represent either the groundwater underlying a management scenario nor the

exposure point concentration

Summary

• Everything can be toxic• Risk is a function of exposure and toxicity• If there is no exposure, there is no risk• The constituents present in CCPs are present

in our natural environment• Conceptual site model for coal ash:

– Direct Contact – With few exceptions constituent concentrations in coal ash are below screening levels for residential soils, and are similar in concentration to background US soils

– Leaching – Leaching tests need to be interpreted as a source term within the context of an environmental management scenario

– Field Investigations – need to be guided by a realistic conceptual site model.

• Everything needs to be evaluated in context.

Lisa JN Bradley, Ph.D., DABT978-905-2131; [email protected]

fgd gypsum – putting environmental issues in context · lisa jn bradley, ph.d., dabt vice...

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