Ecological Risk Ecological Risk AsssessmentAsssessment

Part I – The BasicsPart I – The Basics

IntroductionIntroduction

Subject normally taught at end of Subject normally taught at end of course, after exposure to background course, after exposure to background materialmaterial

Teach it now to Teach it now to Help class understand why some topics Help class understand why some topics

are being coveredare being covered Allow everyone to start thinking about Allow everyone to start thinking about

risk assessment proposalsrisk assessment proposals

Definition and UsesDefinition and Uses

Environmental Risk assessment – the Environmental Risk assessment – the probabilityprobability of an effect occurring on of an effect occurring on an ecological systeman ecological system

ERA’s are designed to provide ERA’s are designed to provide information oninformation on Risk? (Risk = hazard X exposure)Risk? (Risk = hazard X exposure) Magnitude?Magnitude? Ecological significance?Ecological significance?

Uses of an ERAUses of an ERA

Protect environmental and/or Protect environmental and/or humanshumans

Guide risk managers in making Guide risk managers in making decisions regarding exposuredecisions regarding exposure

Compare costs to benefits (ex. Compare costs to benefits (ex. Stream bed gravel mining)Stream bed gravel mining)

Determine how risks can be reduced Determine how risks can be reduced or eliminatedor eliminated

Components of an ERAComponents of an ERA

Since risk is hazard x Since risk is hazard x exposure, to exposure, to perform ERA one perform ERA one must develop an must develop an

1.1. Estimation of Estimation of hazard due to a hazard due to a stressor (often stressor (often based on LCbased on LC5050, , chronic test, chronic test, ecosystem level ecosystem level test, case study if test, case study if available)available)

2.2. Estimation of Estimation of exposure due to a exposure due to a stressor (stressor stressor (stressor poses no risk unless poses no risk unless there is exposure)there is exposure)

Components of an ERAComponents of an ERA

StressorStressor – any substance, – any substance, circumstance or energy field that circumstance or energy field that causes a negative impact on a causes a negative impact on a biological systembiological systemchemicalchemicalradiationradiationtemperaturetemperatureturbidityturbidityhazehazeanother organismanother organismetc.etc.

Hazard – potential of a stressor to Hazard – potential of a stressor to cause a particular effect upon a cause a particular effect upon a biological systembiological system

Exposure – measure of the Exposure – measure of the concentrations or persistence of concentrations or persistence of a stressor within a defined a stressor within a defined systemsystem

Framework for Framework for Environmental Environmental

Risk AssessmentRisk Assessment

-Previously risk assessment seen only as hazard assessment and fate but not easily separated in ecological systems (when release chemical starts to change ecosystem while ecosystem is changing chemicals)

Environmental risks in the Environmental risks in the seasea

Hazard Assessment vs. Hazard Assessment vs. Ecological Risk AssessmentEcological Risk Assessment

CharacteristicCharacteristic Hazard Hazard assessmentassessment

Risk Risk AssessmentAssessment

Probabilistic resultProbabilistic result NoNo YesYes

Scales of ResultsScales of Results Dichotomous (it is Dichotomous (it is or it ain’t)or it ain’t)

ContinuousContinuous

Basis for regulationBasis for regulation Scientific judgmentScientific judgment Risk managementRisk management

Assessment Assessment endpointsendpoints

Not explicitNot explicit ExplicitExplicit

Expression of Expression of contam.contam.

ConcentrationConcentration ExposureExposure

Tiered assessmentTiered assessment NecessaryNecessary UnnecessaryUnnecessary

Decision criteriaDecision criteria JudgmentJudgment Formal criteriaFormal criteria

Use of modelsUse of models Deterministic fateDeterministic fate Probabilistic Probabilistic exposure and fateexposure and fate

Not all segments of society are interested in all Not all segments of society are interested in all parts of an environmental risk assessmentparts of an environmental risk assessment

Not all States require risk assessment of activity affecting the Not all States require risk assessment of activity affecting the environmentenvironment

Example: removal/repair/installation of underground storage Example: removal/repair/installation of underground storage tanks (UST)tanks (UST)

current framework developed by the EPA in 1992

See Figure 12.2, p. 363

Just understand basic concept, will go into details in ERA II (October)

Biggest challenge today: identifying activities Biggest challenge today: identifying activities that are obviously causing high riskthat are obviously causing high risk

Deformed frog Reduction in human sperm count

Class Proposals for Risk Class Proposals for Risk AssessmentAssessment

A. List of chemicals will be given A. List of chemicals will be given use published data to use published data to perform a hazard evaluationperform a hazard evaluation

B. List of chemicalsB. List of chemicals1. Other chemical name(s)1. Other chemical name(s)2. Common names(s)2. Common names(s)3. Chemical Abstract Service (CAS) #3. Chemical Abstract Service (CAS) #4. Human toxicity4. Human toxicity5 Human health effects5 Human health effects6. Ecological effects (if available or predictable)6. Ecological effects (if available or predictable)

C. RankingC. RankingD. Site evaluationD. Site evaluationE. Sampling needsE. Sampling needs