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Public Health Practice and Risk Assessment … Limitations and Opportunities.

Public Health Practice and Risk Assessment … Limitations and Opportunities. . Tom Sinks, PhD National Center for Environmental Health - and - Agency for Toxic Substances and Disease Registries Centers for Disease Control and Prevention.

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Public Health Practice and Risk Assessment … Limitations and Opportunities.

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  1. Public Health Practice and Risk Assessment … Limitations and Opportunities. Tom Sinks, PhD National Center for Environmental Health - and - Agency for Toxic Substances and Disease Registries Centers for Disease Control and Prevention

  2. Public health practice blends “evidence-based” and “uncertainty-based” decision making. When faced with uncertainty, risk assessment is useful for decision making. The greater the uncertainty the less likely we are to be effective. Opportunities exist to improve hazard and exposure data; by doing so we will improve the accuracy of risk assessment and the effectiveness of public health practice. What I’m going to say …

  3. Review our mission. Describe our activities involving risk assessment. Illustrate challenges for risk assessment in applied public health programs. Highlight opportunities from applied public health for risk assessors. How I’m going to say it …

  4. The consolidation of NCEH and ATSDR(circa May 2004)

  5. Prevent asthma and childhood Pb poisoning Measure chemicals and nutritional biomarkers in people’s blood and urine. Investigate disease outbreaks and exposures Improve local/state environmental services Provide laboratory quality assurance programs Link environmental and health data Prepare and respond to urgent threats and disasters. Protect your health on cruise ships Provide public health for refugees and displaced people At NCEH/ATSDR We don’t regulate your environment … We... N C E H

  6. And we … • Identify public health hazards at sites (NPL, Federal facilities, and petitions). • Publish Toxicological Profiles, Health Assessments, and Consultations. • Provide environmental health education at sites and for clinician education. • Establish and maintain registries of people exposed to hazardous substances (NER, tremolite asbestos, WTC). • Respond to emergencies from chemical releases. • Conduct surveillance on chemical emergencies and releases. • Fund Great Lakes and Minority Health research A T S D R

  7. Ensure Widespread Adoption Develop and Test Prevention Strategies Identify Risk and Protective Factors Define the Problem APublic Health Approachto Prevention New information

  8. A PUBLIC HEALTH APPROACH TO PREVENTION Identify Risk Factors Etiologic research Translation research Develop and Test Prevention Strategies Define the Problem Ensure Widespread Adoption Cleveland Municipal Stadium

  9. Risk Management The Risk-Assessment Approach to Prevention Risk Characterization Exposure Assessment Hazard Identification New Information

  10. Public Health Practice and Risk Assessment Have a Common Goal … health Cleveland Municipal Stadium

  11. NCEH/ATSDR and risk assessment • Provide data on hazards, exposures, and dose-response. • Use standard risk assessment techniques to establish Minimal Risk Limits (MRLs) and safe exposure values for Chemical Demilitarization. • Establish public health guidelines and programs (i.e. Pb Poisoning, emergency response, and health assessments)

  12. Estimate the extent of exposure in the population or among the population at risk. Quantify relationship between exposure and hazard (dose-response) Exposure Assessment in Risk Assessment

  13. In Risk Assessments, useful studies require quantitative exposure information for comparison across all studies.

  14. Exposure Assessment to Validate Risk Assessment Assumptions.

  15. Childhood blood levels declined with leaded gasoline consumption from 1976 – 1981.

  16. Changes in blood lead levels in U.S. children; 1976-1999 NHANES data 18 16 14 12 G. mean blood lead levels (ug/dL) 10 8 6 4 2.7 2.0 2 0 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 Year Decline in childhood blood levels after banning leaded gas.

  17. Listing of Hazardous Substances Preparation of Toxicological Profiles Initiation of Substance-Specific Research Division of Toxicology

  18. Purpose of serving as a guideline for assessing public health implications of dioxins in residential soils Includes dioxins, dibenzofurans, dioxin-like PCBs as total TEQs (EPA, 1989) Published in Toxicology and Industrial Health 13:759-768, 1997 ATSDR Interim Policy Guideline for Dioxins in Soil

  19. Based on Intermediate Minimal Risk Level (MRL) of 1 pg/kg/day for reproductive effects in rats Used to develop an Environmental Media Evaluation Guide value (EMEG) of 50 ppt (0.05 ppb) in residential soil 50 ppt Screening Level

  20. Based on analysis by Kimbrough et al., 1984 of Kociba et al., 1978 rat cancer study 1 ppb considered to be a “level of concern” and recommended as “a reasonable level to begin consideration of action to limit exposure” 1 ppb Action Level

  21. If total [soil] TEQ < 50 ppt: no further evaluation If > 50 ppt, but < 1000 ppt (1 ppb), then evaluate site-specific exposure factors (i.e. bioavailability, ingestion rates, pathway analysis, soil cover) If > 1000 ppt, then consider potential public health actions (e.g. surveillance, research, health studies, education, exposure investigation) Health Assessment Decision Process

  22. Division of Health Assessment and Consultation Evaluate releases of a hazardous substance into the environment and determine what actions are needed to reduce exposures. Health Consultations for Dioxin Contamination: City of Midland and the Tittabawassee River Floodplain

  23. Dioxin TEQ Soil Samples MichiganPhase I: December 2000 – July 2001

  24. Dioxin TEQ Soil Samples MichiganPhase 2: 5-9/ 2002

  25. Michigan standards on cleanup of dioxin stir fierce debate … Residents split on idea of a big dig. (Tim Martin / Associated Press) Michigan SENATE BILL No. 1276 … A bill to amend 1994 PA 451, entitled "Natural resources and environmental protection act,“ …(establishing cleanup criteria and approving remedial actions) … If the hazardous substance is a dioxin, the cleanup criteria shall be the action level provided (by) the agency for toxic substances and disease registry,…

  26. UM School of Public Health has been funded by Dow Chemical to conduct a dioxin exposure investigation Objective of the investigation are to identify the factors that contribute to the variability in serum dioxin levels Study populations (estimated 600-700 total participants): a. Residents of the floodplain b. Residents of the affected counties outside the floodplain c. Residents outside of Saginaw and Midland counties Each participant will have an exposure interview and serum sample taken House dust and soil samples to be taken from each residence University of Michigan Dioxin Exposure Investigation

  27. Accurate data on exposure and hazard. Differences between assumptions and reality. Evaluating risk management strategies. Expanding one chemical one hazard to multiple chemicals and multiple risks. Challengesfor Risk Assessment

  28. Enhancing exposure assessment and dose-response using biomonitoring. Risk/Risk analysis Future opportunities

  29. Exposure Assessment - National Report on Human Exposure to Environmental Chemicals Biomonitoring provides answers … Who is exposed? How exposed are they? If exposure causes disease? If exposure varies across populations? If interventions work? • 2003 Report: > 120 chemicals • www.cdc.gov/nceh/dls/report

  30. Bad Exposure information … Indicates there is no emergency when an emergency exists. Indicates there is an emergency even though there isn’t. Identifies the wrong priorities. Fails to identify cause and effect associations.

  31. Assessing People’s Exposure to Methyl Mercury from Fish Consumption • EPA – 1999 Report • 7% women and 19% children above EPA RfD - 5.8 ppb Hg in blood. • National Exposure Report • 8% of women above EPA RfD • Children’s levels are 1/3 those of women • No observations above the BMDL • Fish are a healthy source of nutrients and proteins.

  32. Public health practice blends “evidence-based” and “uncertainty-based” decision making. When faced with uncertainty, risk assessment is useful for decision making. The greater the uncertainty the less likely we are to be effective. Opportunities exist to improve hazard and exposure data; by doing so we will improve the accuracy of risk assessment and the effectiveness of public health practice. What I said …

  33. How environmental exposures lead to human illness. Emission Source Environmental Concentration Exposure Environment / Human Interface Dose Biological Effects Adverse Outcomes

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