Mercury in human hair and fish: Is there a Hong Kong male subfertility connection?

Hair is a useful indicator of a person's exposure to mercury. For this reason, hair samples from 94 fertile and 117 subfertile Hong gong residents were compared over four separate age groups. A typical 30 year old Hong gong male had a hair mercury concentration of approximately 3.3 mg/kg mercury while a 60 year old Hong gong subfertile male had a hair mercury concentration of about 7.5 mg/kg, Most of this mercury comes from seafood consumption. Individuals consuming four or more meals of fish per week had a hair mercury of 4.07 mg/kg dry weight of hair while those consuming fish less frequently had significantly lower levels (2.56 mg/kg), Hong gong residents that consumed no fish had only 1.21 mg/kg hair mercury. The relative risks of males with moderate and high levels of mercery in their hair were significant (p = 0.062), Age corrected estimates of risk indicated that compared with men with low levels of mercury in their hair, men with higher levels were twice as likely to be subfertile (relative risk, 1.95) and there was a dose-response trend that was highly significant (p < 0.0005), In light of these risks we concluded that the maximum permitted mercury level in food sold in Hong gong should be lowered from 0.5 mg/kg wet weight to a level to be determined hy risk analysis. In Japan, where fish mercury levels and fish consumption rates are lower than those in Hong gong, the maximum amount of mercury permitted in food for human consumption is 0.3 mg/kg wet weight, (C) 1999 Elsevier Science Ltd. All rights reserved.