Ecological Risk Assessment Definition Evaluates the likelihood that

Ecological Risk Assessment Definition - Evaluates the likelihood that adverse ecological effects may occur or are occurring as a result of exposure to one or more stressors.

Legislation and Ecological Risk Ü NEPA Ü FIFRA Ü TSCA Ü FWPCA Ü CERCLA

Levels of Organization Ü Genetic Ü Bioaccumulation Ü Cell Ü Bioconcentration Ü Tissue Ü Biomagnification Ü Species-Individual Ü Population Ü Community Ü Ecosystem

Process Ü Ü Ü Ü Screening-level problem formulation and ecological effects eval. Screening-level exposure estimate and risk calculation* Baseline risk assessment, assessment endpoint selection Study design and DQO process* Verification of field sampling design Site investigation and data analysis Risk characterization Risk management*

Problem Formulation Ü Qualitatively evaluate contaminant release, migration, and fate Ü Identify: Contaminants of concern Receptors Complete exposure pathways Known effects Ü Endpoint selection Ü Develop conceptual model

Characterization of Contaminants Ü Documentation of all releases Volume Duration Release Mechanism Ü Routes of migration

Characterization of Contamination Ü Evaluate physiochemical properties Solubility Bioaccumulation potential Ü Mechanisms of pathways Spatial aspects Temporal aspects

Environmental Receptors Ü Characterize receptors Relevant species (e. g. endangered) Life history Feeding habits Habitat preference

Complete Exposure Pathways Ü Source Ü Route of exposure Ingestion Inhalation Dermal absorption Ü Exposure point Concentrations

Ecological Effects Assessment Ü Literature Ü Toxicity testing Ü Field studies

Assessment Endpoints ÜA formal expression of the actual environmental value to be protected Reduction of key population Disruption of community structure Ü Long-term persistence, abundance, or production of populations of significant species or ecological relevant habitats

Examples of Assessment Endpoints Ü Population- brown trout in reservoir Extinction Abundance Ü Communities- aquatic food web Market sport value Recreational quality Ü Ecosystems-entire reservoir Productivity or function

Measurement Endpoints ÜA physical, chemical, biological, or ecological condition that can be quantified Ü Measured in the laboratory or field Ü Must be associated with an assessment endpoint Ü Creates a method to meet the assessment endpoint that is quantifiable

Examples of Measurement Endpoints Ü Individual Death Melanomas Abnormal behavior Ü Population Occurrence Abundance Percent affected

Examples of Measurement Endpoints Ü Community Number of species Species diversity Ü Ecosystem Productivity Nutrient cycling

Developing a Conceptual Site Model Ü Receptors Ü Contaminant sources Ü Routes of exposure Ü Primary and secondary pathways Ü Contamination media

Analysis Phase of ERA Ü Determination of Ecological Effects Ecological Response Analysis/Ecotox Assessment Stressor response profile Effects linked to assessment endpoints Ü Characterization of Ecological Exposure pathways Receptor characteristics Exposure concentrations

Contribution of Toxicity Tests in ERA Ü Bioavailability of stressors Ü Aggregate toxic effects for all stressors Ü Development of new toxicity information Ü Characterization of nature of toxic effect Ü Distribution of toxicity Ü Biomonitoring

Toxicity Tests used in ERAs Ü Freshwater Aquatic and Sediment Tests Daphnia, minnow, algae, amphipod or midge Ü Marine and Estuarine Tests Sheepshead minnow, silverside, mysid shrimp Ü Terrestrial Tests Earthworm, collembola, seed germination and root elongation, growth on rooted plants, FETAX (Frog embryo teratogenesis assay), avian toxicity tests

Toxicological Endpoints Ü NOAEL = No observable adverse effect level Ü LOAEL Ü LD 50, LC 50, EC or ED, effective conc or dose

Endpoints with Chronic testing Ü Growth Ü Reproduction Ü Nerve function impairment Ü Immobility or behavioral changes Ü Development of morphological abnormalities

In-situ Toxicity Tests Ü Expose test organisms on-site Ü Measures bioavailability Ü Organisms are exposed to natural stressors Ü Uncontrolled environment

Analysis Phase Characterization of Receptors Ü Life History Ü Feeding habits, Diet, and Food sources Ü Habitat Preferences Ü Energy Requirements, Physiological and Metabolic pathways Ü Pathway analysis and/or food chain

Ecological effects and exposure Ü Stressor Response Ü Characterize the Analysis receptors Ü Link effects, dose, or Ü Determine exposure toxicity value to routes and pathways endangered species Ü Measure or estimate exposure point conc.

Risk Characterization Ü Final step Ü Integration process Ü Estimation of risk- quantitative or qualitative Hazard quotient Probabilistic risk estimates Weight of evidence Ü Should include an Uncertainty Analysis

Hazard Quotient Method Ü Provides a point estimate and relates stressor concentrations with effects levels Ü Hazard Quotient (HQ) = EEC/ TEC Expected Exposure Conc. TEC Toxicological Endpoint Conc. (NOAEL or LD 50)

Hazard Quotient Method Ü Represents ratio of safe to unsafe exposure Ü If HQ exceeds unity, toxicity threshold is exceeded an adverse toxicological effects is expected Ü Multiple stressors can be summed for same pathways to determine an Hazard Index (HI) Ü Range of HQs or HIs