NEWMOA Site Specific Cleanup Goals€¦ · Biological relevance 3. Unambiguous operational...

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Developing Site‐specific Clean‐up GoalsIncluding procedures for determining assessment &measurement endpoints

NEWMOA Ecological Risk Assessment WorkshopWestford MA & Danielson CT

September 13‐14, 2011

Presenter: Rex Bergamini, MESGreat Ecology & Environments, Inc.

Talk Overview

• Assessment Endpoints

• Measurement Endpoints

• Case Study: Middlesex Project

• Developing Remedial Goals

• Take Home Message

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Endpoints

• Concept of Assessment and Measurement Endpoints

– first described by Suter (1989, 1990)

– adopted by USEPA ERA guidance (USEPA 1992)

– definitions and use expanded upon (USEPA 1998)

• Assessment Endpoints: environmental values to be protected

• Measurement endpoints: measurable responses of a stressor used to estimate the effects of exposure on the Assessment Endpoint

Assessment Endpoints

• Definition: “Explicit expression of the actual environmental values that are to be protected” (USEPA 1992, 1997, 1998).

• a quantitative or quantifiable expression of the ecological property, entity or value considered to be at risk and to be protected

– Examples: most sensitive species in aquatic community; piscivorus mammals; plant aboveground biomass

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Criteria for Assessment Endpoints

• Five Criteria for Assessment Endpoints (Suter, 1993)

1. Societal relevance

2. Biological relevance

3. Unambiguous operational definition

4. Predictive & measurable

5. Hazard susceptibility

• should satisfy all criteria


1. Societal relevance: assessment endpoint valued by society and by decision makers

• relevance depends upon societal values of specific plant and animal species– public generally does not value

microbes or invertebrates as appropriate assessment endpoints

– public values species relevant to direct human interests (e.g., fish, birds and mammals)

• Example: Wetland protection provides ecosystem goods (nursery stock for fisheries)

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2. Biological relevance• significance of a biological property is relevant if it affects a

higher level of biological hierarchy

• bottom‐up effects

– physiological changes may affect survival, reproduction

– reproductive effects may affect population size or structure

– population effects may affect community structure

– community effects may affect ecosystem integrity

• conversely, top‐down effects (trophic cascades)

– changes in keystone species can adversely affect community structure


3. Unambiguous

• avoid “health”, “integrity”, “goods and services” “ambiguous endpoints result in ambiguous assessments” (Suter 1993)

• assessment endpoint definitions include both an entity (endpoint species) and a quantifiable property of the entity (endpoint process)

• Example of an entity: piscivorus raptors (e.g., Osprey)

• Example of a quantifiable property: mortality, fecundity, abundance

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4. Predictive and measurable

• able to predict and able to measure outcome

5. Susceptible to the Hazard

• the potential for and response to exposure

• susceptibility may be unknown for predictive assessments

• techniques for detecting potentially susceptible endpoints

Procedure for Determining Assessment Endpoints

• Consider current and future land use

• Identify biological and ecological resources of value

• Identify and/or develop site management goals and objectives prior to Assessment Endpoints selection

• Identify Assessment Endpoints at the individual, population or community level of biological organization

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• Individual Level

– Individual‐specific parameters

– Use when health consequences to individuals may result in profound ecological effects

• Threatened and Endangered (T&E) species

• Changes in top predator activity

• Loss of keystone or foundation species


• Population Level

– factors that affect relative abundance or densities of a single species within a specific area

– Use when demographic (i.e., BIDE) consequences to populations may result in profound ecological effects

• Survival and reproduction of a prey base (e.g., shrews, mice, voles)

• Survival and reproduction of a predator species (e.g., herons, raptors, fox)

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• Community Level

– factors that affect the biological diversity (species abundance or composition) within a habitat

• Estuarine communities

• Wetland communities

• Old growth forest

• Sensitive habitat communities (e.g., Coastal Riparian Woodland)

Importance of Assessment Endpoints

– provide risk assessors and managers with scaffolding for determining answers to specific questions

• ambiguous endpoints result in ambiguous assessments

– provide risk assessors and managers with information necessary to develop Measurement Endpoints

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Measurement Endpoints

• Measurement endpoints = measurable responses of a stressor used to estimate the effects of exposure on the assessment endpoint

– quantitative summaries (e.g., mean, median, 95% UCL) of observations (e.g., biological surveys, toxicity tests) conducted to define effects of a hazard


• chosen to represent Assessment Endpoint and the sensitivity of the endpoint

• often require extrapolation to Assessment Endpoints

• should not be de facto adopted as Assessment Endpoints

• Specific sub‐definitions (USEPA 1998)– Measures of Exposure

– Measures of Effect

– Measures of Ecosystem and Receptor Characteristics

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• Measures of Exposure

– “Measures of stressor existence and movement in the environment and their contact or co‐occurrence with the Assessment Endpoint or its surrogate.”

– chemical‐specific values

– modeled or empirically‐derived to evaluate receptor exposure

– media specific (surface water, sediment, soil and/or food concentrations) or based on food intake per receptor body weight


• Measures of Effect

– “Measurable changes in an attribute of an Assessment Endpoint or its surrogate in response to a stressor to which it is exposed.”

– Primarily quantitative observations (media concentrations, toxicity tests using site‐specific media, etc)

– made at both study and reference sites for statistical comparative purposes

– appropriateness depends on number and types of lines of evidence needed to support risk‐management decisions

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• Measures of Ecosystem & Receptor Characteristics

– “Measures of ecosystem characteristics that influence the behavior, life history, and distribution of populations or individuals in a community that may be adversely affected by contaminant exposure.”

– Site‐specific information and potential for site to influence populations, communities and ecosystems.

– Utilize measures such as species abundance and diversity indices, community function (e.g., extirpations, changes in species compositions) and ecosystem function (e.g., biomass, carbon cycling)

Procedure for Determining Measurement Endpoints

1. Determine Assessment Endpoints first– eliminates assessment endpoints “for which no good measures of

effect or exposure are available”

2. Base on exposure routes of concern

3. Base on susceptible receptors ecologically relevant to site and Assessment Endpoints

4. Use criteria protective of the Assessment Endpoints for inferring risks

5. Representative of the Assessment Endpoints (i.e., inclusive of all risks to all species, populations or communities)

6. Should NOT be T&E species!

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Example of Assessment & Measurement Endpoints

Hazard/ Goal Assessment Endpoint

Indicators of Effects MeasurementEndpoints

Lead toxicity in soil / Sustain raptor population

Probability of >20% mortality in RaptorsAmerican kestrel abundance, breeding success

Direct soil toxicity to food‐chain organisms

Chemical concentrations in soil Earthworm toxicityCollembola toxicityEarthworm density per m2

Bioaccumulation in food chain organisms

Earthworm tissue toxicologySmall mammal tissue toxicology

Laboratory toxicity to prey species

Rat dietary LD50

Japanese Quail dietary LD50

Field toxicity to prey species

Number of prey carcasses per hectare by species

Laboratory toxicity to raptors

American kestrel dietary LD50

Avian field toxicity Number of dead or moribund raptors per hectare

Case Study: Middlesex (2011)• Project Location

– Middlesex NJ

• Site History– pesticide manufacturing

(northern portion)

– dredge spoils (southern portion) – heavy metals & radionuclides

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• Sensitive Ecological Receptors– Freshwater ponds

– Forested wetlands

– Freshwater wetlands

– Tidal wetlands

– Raritan River

Site Characterization• Comprehensive contaminant delineations

– vertically and laterally

• Comprehensive hydrologic modeling– characterized contaminant plume depth and flow

• Wetland & habitat delineations

• Biological studies– Vegetation, Invertebrate & Wildlife Surveys

• Suite of contaminants of concern generally localized– Lakes: metals, pesticides, cholorotoluene, VOCs and DNAPLs– Forested wetlands: metals (lead, vanadium)– Southern & Central wetlands: radionuclides (thorium), toxaphene

• Specific assessments of risk for Areas of Concern (AOCs)

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Site Characterization

• Endpoint Identification– Important Environmental Receptors

– Goal: Minimize loss of wetland habitats

– Assessment Endpoints• top predator abundance & breeding success

• different Assessment Endpoints for different AOCs

– Measurement Endpoints• toxic effects to prey species

– invertebrates

– avian and small mammal trophic guilds

– fishes

Exposure & Effects Characterization

For all wetlands:– Sediments

• Screening COPCs against NJDEP LEL & SEL criteria

• Pore water analyses

• Sediment Quality Triad

– Soils

• Screening COPCs against NJDEP Eco‐SSLs or Wildlife PRGs or developing sites‐specific Eco‐SSLs

• May look at Ambient Media Toxicity Testing or Body Burdens

– Freshwaters

• Screening COPCs against NJDEP Acute & Chronic criteria

• Body Burdens

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Remediation

Chlorinated pesticides, metals and radionuclides may pose severe potential risks to ecological receptors

– persistent, and/or

– high toxicity, and/or

– highly recalcitrant, and/or

– bioaccumulative

The million dollar question:• Do we need to remediate?

• If so, how do we remediate?

2‐chlorotoluene

4‐chlorotoluene

Toxaphene

Remedial Goals

• Remedial goals (EPA 1990a)– identify contaminants & media of concern– identify potential exposure pathways– specify site‐specific cleanup criteria

• Developed iteratively beginning with problem formulation and ending with site‐specific goals

• Preliminary Remediation Goals (PRGs)– Generic PRGs: generically derived starting point for developing cleanup targets– Site‐specific cleanup goals

• Derive initial, site‐specific remediation goals (i.e., cleanup levels) using data collected from the risk assessment; and

• Refine the calculated cleanup levels based on the magnitude and extent of observed risk and relevant regulatory compliance

• Remedial Goals = ultimate, site‐specific cleanup targets set by risk managers

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Data Needed to Develop PRGs

• Driven by site and chemical characteristics• Example for aquatic sites:

– exposure to wildlife receptors from incidental ingestion of surface water and sediment, or from consumption of contaminated fish and shellfish primary

• Data needs– CoC concentrations in sediment and pore water (particularly metals);– Organic carbon content and particle size of sediment;– Collocated sediment toxicity tests; and– Collocated tissue residues and lipid content of biota.

• Additional data needs– exposure parameters used for modeling CoC partitioning between sediment

and pore water– aquatic receptor bioaccumulation factors

PRG development approach

• A seven‐step process separated into two phases:

– Derivation phase (steps 1‐5)

• information from the risk assessments is used to determine the “Limiting” Contaminants of Concern (CoCs) and to calculate protective concentrations (PRGs).

– Implementation phase (steps 6‐7)

• site specific conditions and practicality of PRGs are considered in the analysis for supporting reduction of identified risks and Applicable or Relevant and Appropriate (ARAR) compliance.

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Aquatic PRG Derivation Approach

– Step 1. Benchmark consolidation & hazard calculation• Most sediment, water and tissue residue benchmarks have published values

• not all chemicals have benchmarks• requires conversion of a benchmark for one medium (e.g., sediment) into equivalent concentrations for another medium (e.g., water or tissue)

– generically called “no effect” concentrations– Not PRGs for the site: a step in the process towards deriving site‐specific PRGs

• use alternative water‐based contaminant criteria decision tree if no promulgated Water Quality Criteria values

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• Where Water Quality Criteria benchmarks are lacking, derive sediment‐based correlative benchmarks

– Translate Effects Range‐Low (ER‐L) bulk sediment concentrations into pore water equivalent using an equilibrium partitioning model

– assumed using ER‐L provides a level of protection similar to other water quality based benchmarks


• Benchmark Derivation based on equilibrium partitioning

– Equilibrium Partitioning Model (DiToro et al. 1991)» permits calculation of chemical concentration in pore water from sediment concentration (e.g., the ER‐L is converted into a water‐based value)

CPW = CSed /( foc * Koc)

where CPW = pore water concentration

CSed = sediment concentration

foc = fraction of organic carbon in dry sediment

Koc = organic carbon/water partitioning coefficient

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• Step 2. Review of site‐specific conditions and refinement of chemical exposure assumptions

– site‐specific factors may exist that modify the degree of chemical exposure to target receptors

– calculate under site‐specific conditions the highest degree of departure from the literature‐based benchmark that can allowed for a given chemical without an adverse effect being likely to occur

• called the “no effects concentration”


• Step 3. Retain analytes likely to substantially contribute to risk at the site

– identify and retain only analytes for which PRG implementation will lead to effective risk reduction at the site

– test‐specific no effects concentration (hazard‐normalized) either the 95% upper confidence limit or unity (test NOEQ = 1)

– maximum toxic hazard quotient and no effect quotient are compared for each analyte

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• Step 4. Compare protective concentrations with background

– In the long term usually not technically feasible to remediate a site to concentrations lower than regional background values (from reference locations)

– pathway‐specific PRG ≥ regional concentration estimate

– If availability of reference data is insufficient to calculate the 95% UCL (e.g., n < 3), maximum value is used

– Determine threshold effects value (greater of the no effect concentration and the background value)


• Step 5. Assess CoC exceedences of threshold effects values to identify “limiting” pathway‐specific CoCsfor PRG selection

– Calculate Hazard Quotients based on threshold effects value data by dividing the site media concentrations by the respective threshold effects values

– Inter‐compare data for each station to determine the CoCcausing maximum risk at each station

• designated as the “Limiting CoC” and is retained for further PRG development

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• Step 6. Determine PRGs for limiting CoCs

– methods and equations for calculating baseline PRGs depend on the exposure pathway

Aquatic exposure pathway Avian predator exposure pathway

PRGbase = Csed / HQTEV /N PRGbase = TOCsed * TEV/Lipidtiss HQTEV /BSAF)/n


• Step 7. Evaluate the practicality of the PRGs for effective risk reduction

• qualitative, risk‐based interpretation

• based on best professional judgment

• primarily a spatial analysis– location of PRG exceedences (e.g., HQPRG > 1) for each of the limiting

CoCs is reviewed with respect to the spatial distribution of observed risks at the site

• apparent risk reduction to remediated area is presented as recommended PRGs

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Summary

• Developing site‐specific remedial goals is an iterative process

• Begins with developing unambiguous Assessment Endpoints

• Incumbent on site‐specific exposure/effects assessment and risk characterization

• Must consider the ecological impact from remedial alternatives

• Should minimize impacts to ecologically sensitive areas to as great an extent as possible

Resources for More Information

Suter, GW II. 1989. Ecological Endpoints. In: Ecological Assessments of Hazardous Waste Sites: a Field and Laboratory Reference Document. (Warren‐Hicks W, Parkhurst BR, Baker SS Jr, eds.). EPA 600/3‐ 89/013, US Environmental Protection Agency, Washington DC.

Suter, GW II. 1990. Endpoints for Regional Ecological Risk Assessments. Environmental Management 14:19‐23.

USEPA. 1992. Framework for Ecological Risk Assessment. EPA/630/R‐92/001. Risk Assessment Forum, Washington DC.

USEPA. 1996. Eco Update: Ecological Significance and Selection of Candidate Assessment Endpoints. EPA/540/F‐95/037. Office of Solid Waste and Emergency Response, Washington DC.

USEPA. 1997. Interim Final, Ecological Risk Assessment Guidance for Superfund: Process for Designing and Conducting Ecological Risk Assessments. Office of Solid Waste and Emergency Response. EPA 540/R‐97/006. Office of Solid Waste and Emergency Response, Washington DC.

USEPA. 1998. Guidelines for Ecological Risk Assessment. EPA/630/R‐95/002F. Risk Assessment Forum, Washington DC.

USEPA. 1999. Issuance of Final Guidance: Ecological Risk Assessment and Risk Management Principles for Superfund Sites. OSWER Directive 9285.7‐28 P. Office of Emergency and Remedial Response, Washington DC.

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Contact Information

Rex Bergamini, MES, Senior EcologistGreat Ecology and Environments, Inc.

2231 Broadway, Suite 4New York, NY 10024

www.greatecologyandenvironments.com

212‐579‐6800 / MAIN

413‐244‐4335 / CELL

email: [email protected]

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