Human Health Risk Assessment and Risk Management. Julie Wroble EPA Region 10 Toxicologist email@example.com. What is Risk Assessment. Scientific approach for evaluating potential for harm from hazardous substances and activities How harmful?
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Human Health Risk Assessment and Risk Management Julie Wroble EPA Region 10 Toxicologist firstname.lastname@example.org
What is Risk Assessment • Scientific approach for evaluating potential for harm from hazardous substances and activities • How harmful? • How important a priority (which chemicals most of concern, comparative risk)? • How clean is clean?
What Is Risk? RISK = TOXICITY x EXPOSURE
What Is Risk? RISK = TOXICITY x EXPOSURE TOXICITY = Chemical's ability to cause adverse effect EXPOSURE = Concentration + Route
BASELINE RISK ASSESSMENT 1. Data Collection and Evaluation What contaminants exist and are of potential concern? 2. Exposure Assessment How might a receptor be exposed on or off site? 3. Toxicity Assessment At what level of exposure are adverse effects likely to occur? 4. Risk Characterization What are the risks and uncertainties at this site?
Human Health Risk Assessment Data Collection and Evaluation Exposure Assessment Toxicity Assessment Risk Characterization
Checklist for Human Health • What human receptors are near your site? • Are residential properties close by? • Is site access restricted? • What contaminants are present? • Is there a threat or demonstrated release? • What media have been impacted? • What data are available?
Data Collection and Evaluation • Identify site-related contaminants of potential concern (COPCs) at the site • Collect data from areas where receptor exposures are potentially of concern • Compare findings to naturally-occurring (background) levels near site – typically done for inorganics only • Ensure quality control samples are not tainted by site activity?
Exposure Assessment • Identify and estimate concentrations of chemicals potentially affecting human health or ecological receptors • Characterize the site in terms of: • Physical characteristics • Soil characteristics, surface water location, groundwater (flow depth), meteorology • Exposed populations • Human activities and land use (recreation, residential/industrial/commercial) • Proximity to release • Potential future uses
Identify exposure pathways • Develop a conceptual site model • Determine amount of exposure for each pathway using monitoring data or fate and transport models • Analyze concentrations, frequency and duration of contaminant exposure to population groups • Consider characteristics of affected population groups - age of individuals, age, unique exposure considerations, other factors
External Loading Terms Historical and Current Historical and Current Historical and Current Atmospheric Deposition Historical and Current Stormwater Runoff Riverbank Erosion Industrial Discharge Overwater Releases Historical and Current Historical and Current Historical and Current Upstream Surface Water Upland Groundwater Plumes Advection through Contaminated Sediments Upstream Sediment Transport Historical and Current Historical and Current RM 11 RM 2 Navigation Channel Boundary
Toxicity Assessment • Compare dose of contaminant with incidence of adverse human health effect to ascertain relationship (by researchers) • Determine whether exposure to certain chemicals results in adverse health effects • Evaluate available toxicity information • Databases - IRIS • Identify data gaps • Investigate human health problems near the site
Risk Characterization • Combine information gathered in the Exposure Assessment and Toxicity Assessment • Quantify risks to human health from individual chemicals and exposure pathways • Sum risks for various exposure scenarios • Evaluate cancer risk, non-cancer hazard separately • Describe all assumptions, areas of uncertainty
Regulatory Basis For Ecological Risk Assessment CERCLA requires EPA to remediate uncontrolled hazardous waste sites in a way that protect both human health and the ENVIRONMENT. (42 USC Sec. 9604) National Contingency Plan requires that the baseline risk assessment characterize the current and potential threats to human health and the ENVIRONMENT. (40 CFR Part 300)
ECOLOGICAL RISK ASSESSMENT FRAMEWORK RA-RM Discussion (Planning) PROBLEM FORMULATION Data Acquisition: Verification And Monitoring ANALYSIS Ecological Effects Exposure RISK CHARACTERIZATION RA-DM Discussion Source: U.S. EPA 1992a Risk Management
CONTAMINANT EFFECTS ON ECOSYSTEMS • Reduction in population size • Change in community structure • Changes in ecosystem structure and function
Risk Assessment versus Risk Management • Risk assessment – unbiased scientific approach to assessing risk • Risk management – incorporates the results of risk assessment, factors in societal values, legal mandates, other considerations • Risk communication is a critical piece of each of these
RiskManagement The process of weighing policy alternatives and selecting the most appropriate regulatory action by integrating the results of risk assessment with engineering data in addition to social, economic, and political concerns to reach a decision.
Communicating Risk • Human response to risk is not always rational • Level of risk play little role in acceptability to public • Emotional response often makes it difficult to communicate risk • People apply personal values when evaluating risk
Factors Affecting Risk Perception • Voluntary vs. Involuntary • Familiar vs. Unfamiliar • Visibility of Threat • Catastrophic vs. Non-catastrophic • Natural vs. Man-made • Affects Adults vs. Children • Trusted vs. Untrusted Communicator • Equal vs. Unequal Benefits
Covello’s Cardinal Rules of Risk Communication • Accept and involve the public as a legitimate partner • Plan and carefully evaluate communication efforts • Identify audience, understand problems, pretest message • Listen to public’s specific concerns • Be honest, frank and open
Cardinal Rules Continued • Coordinate and collaborate with other credible sources • Meet needs of media • Speak clearly and with compassion