^aAssuming body weight of 70 kg for the general population and 60 kg for women of childbearing age.

^bData from EPA 1997a.

^cUnweighted average across ethnic groups.

^dData from Stern et al. 1996.

^eWomen 15-45 years old.

^fWomen 18-40 years old.

Survey (NHANES IV) might provide information on regional fish consumption. NHANES IV is also designed to provide information on MeHg exposure in U.S. populations.

Consumption of animals or poultry fed fish meal might increase the exposure to MeHg, but data are not available. The use of organic Hg compounds as preservatives in vaccines and medical preparations is also a source of exposure and is of particular importance in young children who might be more sensitive to those mercurials than adults. As many as 219 such products are in use (FDA 1999). Thimerosal (TM) (sodium ethylmercurithiosalicylate) and phenylmercuric acetate (PMA) are the most frequently used compounds, at concentrations of 0.01% and 0.0002%, respectively. The FDA estimates that 75-80 kg of Hg compounds are used annually by the manufacturers of those vaccines and medical preparations. The risks associated with thimerosal use in vaccines have been discussed in an interim report to clinicians (American Academy of Pediatrics 1999).

Small amounts of MeHg can be formed in the gut by intestinal bacte-

Front Matter (R1-R20)

Executive Summary (1-12)

Introduction (13-30)

Chemistry, Exposure, Toxicokinetics, and Toxicodynamics (31-71)

Biological Variability (72-104)

Dose Estimation (105-146)

Health Effects of Methylmercury (147-249)

Comparison of Studies for Use in Risk Assessment (250-270)

Dose-Response Assessment (271-303)

Risk Characterization and Public Health Implications (304-332)

Appendix to Chapter 7 (333-336)

Glossary (337-344)