Studies on Humans Exposed to Methyl Mercury Through Fish Consumption

Human subjects exposed to methyl mercury through consumption of fish were studied during and after varying degrees of exposure. Methyl mercury made up half or less of the blood cell total mercury in “normal” subjects. The proportion was higher in heavily exposed subjects. There was a relationship between exposure to methyl mercury by ingestion of fish and blood mercury levels, and between mercury levels in blood and hair. No symptoms and signs indicating methyl mercury poisoning were observed in subjects exposed at most to 0.8 mg of mercury as methyl mercury per day and having mercury levels of up to 1,200 ng/gm blood cells and 185,000 ng/gm hair. After the end of exposure, biologic half-life of mercury was 33 to 120 days in hair and 99 to 120 days in blood cells in five and two subjects, respectively.