Assessing and Managing the Risks Associated With Eating Seafood

1. Assessing and Managing the Risks Associated With Eating Seafood Don Schaffner, Ph.D. Professor and Extension Specialist Rutgers - The State University of NJ Seafood: Assessing the Benefits and Risks

2. Overview • Understanding risk analysis, risk assessment and risk management • The steps in risk assessment • Special attention focusing on exposure and dose-response • Using Methyl Mercury (MeHg) as an example • Risk management • Continue with MeHg example • Show how FDA Foods Advisory Committee feedback was used to improve the risk message Seafood: Assessing the Benefits and Risks

3. Risk Analysis Components • (Quantitative) Risk Assessment • How big is the risk, what factors control the risk? • Scientific process • Risk Management • What can we do about the risk? • Political process • Risk Communication • How can we talk about the risk with affected individuals? • Social and psychological process Seafood: Assessing the Benefits and Risks

4. Risk Assessment • Hazard Identification • What agents, food(s) and people are involved? • Exposure Analysis • What is the chance of exposure? • What is the level of exposure • Dose-Response Analysis • What is the human health effect of the exposure? • Risk Characterization • Complete picture of the assessed risk Seafood: Assessing the Benefits and Risks

5. Hazard Identification • Agent: Developing neurological system is very sensitive to toxicity of methyl mercury • Food: Mercury is a naturally occurring and also released into the air through industrial pollution. Mercury can accumulate in streams and oceans. Bacteria transform mercury into methyl mercury. Fish absorb methyl mercury as they feed. Methyl mercury builds up more in some fish than others depending on what they eat. • People: Women (of child-bearing age, who are pregnant, who could become pregnant, who are nursing mothers) and young children Seafood: Assessing the Benefits and Risks

6. Dose-Response Analysis • Reference dose (RfD) is an estimate (with uncertainty spanning perhaps an order of magnitude) of a daily oral exposure to the human population (including sensitive subgroups) that is likely to be without appreciable risk of deleterious effects during a lifetime. Seafood: Assessing the Benefits and Risks

7. Background on MeHg RfD • EPA derived a MeHg RfD in 1995 based on a MeHg poisoning incident in Iraq. • Congress mandated (1997) that EPA fund a National Research Council study to determine if the RfD was scientifically justifiable • NRC panel found RfD to be scientifically justifiable (2000) but suggested EPA revisit the issue using new 3 new studies • The three new studies are the Seychelles Islands study, Faroe Islands study and the New Zealand study. Seafood: Assessing the Benefits and Risks

8. Data used for RfD • Seychelles Islands (-) • 779 mother-infant pairs, infants followed from birth to 5.5 years, standardized neuropsychological endpoints, maternal hair mercury concentrations. • Faroe Islands (+) • About 900 mother-infant pairs, Children tested w/ variety of tasks at 7 years of age, cord blood mercury and maternal hair mercury measured. • New Zealand (+) • 38 children of mothers with hair mercury levels during pregnancy greater than 6 ppm matched with children whose mothers had lower hair mercury concentrations, 237 children were assessed on a number of neuropsychological endpoints (similar to Seychelles study) at 6 years of age Seafood: Assessing the Benefits and Risks

9. RfD determination • There are several ways to determine a RfD, and one is to used a Benchmark Dose (BMD) • BMD calculations use a model to relate exposure to effect, but to use it we need to know • how low is “abnormal” • If exposed, chance of becoming abnormal • Add uncertainty factor • Intra-human variability • RfD was determined to be 0.1 ug/kg/day, which corresponds to 5.8 mg MeHg/L blood Seafood: Assessing the Benefits and Risks

10. Exposure assessment • What foods are responsible for the exposure? • What is the chance of a particular individual being exposed? • If exposed, what is the level of exposure? • If enough data are available, a computer model can be used to predict exposure, and to investigate interventions. Seafood: Assessing the Benefits and Risks

11. Exposure assessment model Seafood consumption Diet-blood ratio Blood-hair ratio MeHg by Species MeHg Exposure MeHg Blood Levels MeHg Hair Levels Species market share Seafood: Assessing the Benefits and Risks

12. Exposure scenarios • Divide fish into high, medium and low MeHg species • Run different computer simulations including: • No dietary exclusions at all • Consumption from the Medium and Low groups, but not High • Consumption from the Medium and Low groups, limiting the amount from the Medium group • Consumption Low group, no Medium or High Seafood: Assessing the Benefits and Risks

13. Exposure model summary • Model appears to predict the National Health and Nutrition Examination Survey (NHANES) data from the JAMA article • Model will be peer reviewed, and can be used to inform risk management decisions Seafood: Assessing the Benefits and Risks

14. Risk Management • The results of the exposure and dose-response assessments have given us a picture of the situation • Now we must weight competing issues • Fish is… • a good source of protein, provides important nutrients and is generally affordable • Fish may also contain substances that are harmful to health Seafood: Assessing the Benefits and Risks

15. About 8% of at-risk population above the RfD Objective: reduce this %, and still keep fish in the diet Risk Management Seafood: Assessing the Benefits and Risks

16. Improved risk message • As a results of feedback FDA received from it’s Foods Advisory Committee (FAC) • FDA and EPA should combine their two independent advisories • Tell people what “eat a variety of fish” mean? • People want to know about canned tuna… so tell them! • Unify commercial and recreational fish message • Create specific advice for children Seafood: Assessing the Benefits and Risks

17. Summary • The risk analysis process and it’s components • The step in risk assessment, included examples from exposure assessment and dose-response for methyl mercury • The nature of risk management and the approach used by FDA and EPA in creating their new (March 2004) advisory for methyl mercury in fish for women and children Seafood: Assessing the Benefits and Risks