Ecological Risk Ecological Risk Asssessment Asssessment Part I – The Basics Part I – The Basics
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