Ecological Risk Assessment

Ecological Risk Assessment 

ESM 223 

Ecological Risk 

Assessment 

Process to evaluate likelihood of adverse 

ecological effects as result of exposure to 

one or more stressors 

Function of ERA 

document whether actual or potential 

ecological risk exists at a site 

screen contaminants present at a site for 

those that pose an ecological risk 

generate information to evaluate options 

How is ERA regulated 

USEPA’s Responsibilities 

Part of RCRA and CERCLA 

set standards, take action 

Strengthened by SARA 

cleanup levels and remedial alternatives 

National Contingency Plan (NCP) 

implementation of CERCLA & SARA regulations 

remediation goals based on applicable or relevant and 

appropriate requirements (ARAR) 

Directed by regulatory and resource agencies 

USEPA 

Dept of Toxic Substances Control 

Regional Water Quality Board 

Section 404 of Clean Water Act 

Federal Water Quality Control Act 

Clean Air Act 

Toxic Substances Control Act 

Federal Insecticide, Fungicide and Rodenticide Act 

Endangered Species Act 

Section 662(a) and 2903 of Fish & Wildlife Conservation 

Act 

Coastal Zone Management Act 

Section 2171 of Wild and Scenic Rivers Act 

Migratory Bird Treaty Act 

Steps in ERA Process 

Screening Level Risk Assessment 

Problem Formulation 

assessment endpoints 

conceptual model(s) 

analysis plan 

Analysis 

Ecological Exposure and Effects 

Risk Characterization 

Estimation and description 

Risk Management 

Decision making 

Simplified risk assessments 

Make rapid decisions early in the 

process 

Divide sites into 

Sites that present significant immediate 

ecological risk and require early remedial 

action 

Sites with no ecological risk, requiring no 

further action 

Sites that require further study

Screening ERA 

Tools in an ERA 

For the screening level 

Assessment endpoints must be explicit 

Measurable endpoints must be a measurable 

ecological characteristic - related to 

assessment endpoint 

Determine whether exposure is or may be 

above the levels where adverse ecological 

effects might be expected 

Establish exposure pathways of concern 

Environmental Chemistry 

Determine contaminant fate and transport 

Literature-based ecotoxicological data 

NOAEL 

LOAEL 

Ecotox information sources 

AQUIRE Database 

PHYTOTOX Database 

Integrated Risk Information System (IRIS) 

Hazardous Substances Databank 

US FWS Contaminant Hazard Review 

ATSDR Toxicological Profiles 

Registry of Toxic Effects of Chemical 

Substances (RTECS) 

Screening Criteria 

Water 

USEPA Ambient Water Quality Criteria 

Water Quality Objectives (CRWQCB, 1986) 

Sediments 

Sediments Effects Range Data from NOOA (Long & Morgan, 

1991) 

Sediment Quality Objectives (CRWQCB, 1986) 

Washington State Marine Sediments Criteria (WDOE, 1991) 

Soils 

Quebec Soil Clean-up Criteria (QME, 1988) 

Dutch Soil Clean-up Act (Beyer, 1990) 

Criteria for Contaminated Soil/Sediment Cleanup (Fitchko, 1989) 

ERA Example 

NAWS at Point Mugu 

Effects of sediment contamination on 

organisms near the base 

Copper and PCBs are the main concern in this 

region 

Copper can be acutely or chronically toxic to 

various organisms 

PCBs bioaccumulate and bioconcentrate, 

producing reproductive impairment

Fox River Case Study 

Fox River Human Health and Ecological 

Risk Assessment 

Executive Summary 

Table of Contents 

Geographical Setting 

Details of ERA 


Highlights of Executive Summary 

Populations considered 

Recreational anglers 

Subsistence anglers 

Hunters 

Drinking water users 

Local residents 

Recreational water users 

Construction workers




Fish contain PCBs 

Anglers can have Cancer Risks (CR) up to 1.5 

x 10 -3 

Hazard Index up to 56 

Based on Fish Tissue data from 1990 (study 

conducted in 1999) 


Potential population exposed 

Up to 47,000 recreational anglers 

About 2-5,000 subsistence anglers 

Cancer risk about the same in the four 

reaches considered 

Highest risk from carp, followed by perch, 

walleye and white bass 



Risk to hunters ~ 10 -4 (PCB contaminated 

waterfowl) 

Risk to people drinking contaminated water 

~10-6 in most contaminated stretch – mostly 

from arsenic in water 

May require further sampling to determine if 

arsenic continues to be a concern 

This water is not directly used a drinking source 


Sources 

Fox River Case Study



Pollutant loading has decreased by 85% 

since 1970s 

Although PCBs not discharged directly, still 

estimated loading of 3-5 kg/year from 

landfills and other sources (very low 

concentrations) 

Non-point sources: eroded particles and 

contaminated sediments from small creeks 


Transport Processes 

Atmospheric transport: contributes 2-16 kg 

PCB/yr to Green Bay in snow and rain plus 

some dry deposition 

Sediment transport: primary mechanism for 

moving PCBs through the watershed and river 

Fox River contributes > 90% of PCB loading to 

Green Bay 

Concentrations in water ~50-100 ng/L 


Sediment concentrations (from 532 

samples!) range from 2 to 222 x 10 3 

µg/kg 

In Sediment Deposits A, C and POG, total 

PCB loading exceeds 50 x 10 3 µg/kg 

Reflect specific point sources discharging 

PCBs in this region 


PCBs in fish tissue have been as high as 

26 x 10 3 µg/kg tissue in carp (in 1976) 

Have generally dropped about an order of 

magnitude in more recent samples 

Tissues also contain dioxins, furans, 

pesticides (DDT, DDE, Dieldrin), mercury, 

lead and arsenic … 

See Figures 2.1 to 2.20 in report 


Where does the data come to do the risk 

assessment


Human Health Risk Analysis 




Ecological Risk Analysis

Ecological Risk Assessment

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