Human Health Risk Assessment. Marian Olsen U.S. EPA ERRD October 13, 2011

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1 Human Health Risk Assessment Marian Olsen U.S. EPA ERRD October 13, 2011

2 Presentation Overview Conceptual Site Model Defining Risk Assessment Conceptual Site Model Superfund Risk Assessment Process Data Evaluation / Hazard Identification Dose Response Exposure Assessment Risk Characterization Risk Assessment and Risk Management

3 Why Risk Assessment? EPA conducts risk assessment to characterize the risks of cancer and non-cancer health effects posed by the site. Risk Assessments provide a framework to understand the: Nature and magnitude of the risk Adversity of the risk Confidence or reliability in estimates Areas of uncertainty Evidence supporting the decision.

4 Conceptual Site Model Who is exposed? What is the exposure media (i.e., sediment, fish, surface water, etc.)? What activities bring them into contact with the River (i.e., fishing, wading, swimming, etc.)? What is the frequency and duration of the exposures (i.e., # of days and # of years)? What are the potential health effects from this exposure?

5 Conceptual Site Model Human and Ecological: Sources, Pathways, and Receptors

6 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?

7 BASELINE RISK ASSESSMENT Toxicity Assessment Data Collection Data Evaluation Risk Characterization Exposure Assessment

8 Toxicity Assessment Toxicity Studies Animal Studies/Human Studies of workers exposed to high levels of contaminants, etc. Weight of Evidence Cancer Non-cancer health effects Toxicity Values Cancer Slope Factor Inhalation Unit Risk Oral Reference dose Inhalation Reference Concentration

9 CANCER RISKS Cancer Slope Factor Risks expressed as risk per unit dose or concentration Increasing Effect Increasing Dose

10 Non-Cancer Hazard THRESHOLD Dose (mg/kg-day)

11 Sources of Toxicity Information Hierarchy of Toxicity Information Memo dated 12/2003 (OSWER Directive ) Integrated Risk Information System Provisional Peer Reviewed Toxicity Values Other Sources ATSDR CalEPA Health Effects Assessment Summary Tables NJDEP Superfund Technical Support Center

12 U.S. EPA Superfund Risk Assessment Exposure Risk Toxicity Evaluated under current (baseline) and future conditions Baseline conditions evaluated in the absence of institutional or other controls Goal is health protection under reasonable maximum exposures

13 EXPOSURE ESTIMATES Central Tendency Exposure OBSERVATIONS Reasonable Maximum Exposure 0 TOTAL EXPOSURE

14 EXPOSURE FACTORS Intake = C x IR x EF x ED BW x AT EXPOSURE FACTOR Concentration in Fish (C) Ingestion Rate (IR) Exposure Frequency (EF) Exposure Duration (ED) Bodyweight (BW) AT (averaging time) VALUE Sampling Results Meals/year 365 days/year, Years 70 kgs (adult) (depends on whether a carcinogen or a non-carcinogen)

15 Summary of Important Exposure Factors Exposure Factor Central Estimate Reasonable Maximum (RME) Fish Ingestion Consumption (grams/day) Exposure Duration (years) Contaminants Lost in Cooking (%) Exposure to Water/Sediment Adult/Child Recreation (Summer) Adolescent Recreation (Summer) Residence Duration (years) Part of 17 Mile Study Part of 17 Mile Study

16 OW Hierarchy of Fish Ingestion Rates Four preference hierarchy (OW Methodology for Water Quality Criteria) use of local data; use of data reflecting similar geography/ population groups; use of data from national surveys; and use of EPA s default intake rates. (From EPA Office of Water Methodology for Deriving Water Quality Criteria for the Protection of Human Health (2000))

17 Cooking Loss Reasonable Maximum Exposure No Cooking Loss Central Tendency Exposure Evaluation of literature based values Dioxins PCBs Other contaminants

18 Other Parameters Residence Time Bodyweight - defaults 70 kgs for adult (18 years and older) 15 kgs for child (1 to 6 years of age) Lifespan 70 years

19 BASELINE RISK ASSESSMENT Toxicity Assessment Data Collection Data Evaluation Risk Characterization Exposure Assessment

20 RISK CHARACTERIZATION STEPS 1. Review exposure and toxicity data 2. Quantify risks for individual and multiple chemicals 3. Combine risks across exposure pathways 4. Evaluate and present uncertainties 5. Summarize risk assessment results

21 EVALUATE UNCERTAINTY CATEGORIES OF UNCERTAINTY RISK ASSESSMENT SELECTION OF SUBSTANCES EXPOSURE ASSESSMENT TOXICITY VALUES MULTIPLE PATHWAY SUMMATION Source: U.S. EPA 1989, pages 8-17

22 Risk Assessment and Risk Management Risk Assessment Dose Response Assessment Statutory, legal considerations Politics Risk Management Hazard Identification Exposure Assessment Risk Characterization Available Technology Social Factors Risk Management Options Economics 22

23 Resources Risk Portal National Center for Environmental Assessment including the guidelines and Exposure Factors Handbook: IRIS: Staff paper on Principles and Practices: Office of the Science Advisor: Superfund Guidance: m

Outline: risk assessment. What kind of environmental risks do we commonly consider? 11/19/2013. Why do we need chemical risk assessment?

Outline: risk assessment. What kind of environmental risks do we commonly consider? 11/19/2013. Why do we need chemical risk assessment? Outline: Human health h and ecological l risk assessment Purpose of risk assessment Methodology for quantifying risk Case study: Children s exposure to As from CCA wood staircases Issues practical and