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 reas on, hair samples from 94 fertile and 117 subfertile Hong gong residents wer e compared over four separate age groups. A typical 30 year old Hong gong m ale had a hair mercury concentration of approximately 3.3 mg/kg mercury whi le 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. I ndividuals 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 frequentl y had significantly lower levels (2.56 mg/kg), Hong gong residents that con sumed 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 twic e as likely to be subfertile (relative risk, 1.95) and there was a dose-res ponse trend that was highly significant (p < 0.0005), In light of these ris ks we concluded that the maximum permitted mercury level in food sold in Ho ng gong should be lowered from 0.5 mg/kg wet weight to a level to be determ ined hy risk analysis. In Japan, where fish mercury levels and fish consump tion 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.