Risk assessment of methylmercury from fish consumption in Oahu, Hawaii using hair as a biomarker of exposure

Few studies address methylmercury exposure among healthy adults. Recent studies establish that men are susceptible to cardiotoxicity from methylmercury exposure, as well as known risks to the pregnant woman. This study assessed methylmercury exposure from fish consumption among 110 adults living in Oahu, Hawaii. Hair samples were obtained and questionnaires were administered for methylmercury exposure assessment to 110 adults (57 men, 53 women) throughout Oahu during December 2010 to January 2011. Hair samples were analyzed for total mercury with a direct mercury analyzer. Men > 46 years had a median of 2.00 ug/g compared to younger men with a median 0.97 ug/g (p < 0.05); the median hazard index (HI) value among men was 1.61, which was above the safety criteria of 1.0. Hair concentrations from older women had a median of 1.22 ug/g of mercury compared to 0.57 ug/g for younger women. Among women, the average HI value was 0.92; however, 38% of women of childbearing age had an HI > 1.0, indicating that both men and women were at risk. Final regression model supported that gender, age, length of residency, and fish consumption frequency were significant factors in increased hair mercury levels. Proper guidelines for safe fish consumption should include consuming < 1/4 pound of fish per meal at a frequency of < 1 day/week, and to consume fish meat and discard other organs. Following safe fish consumption practices allow residents to reap health benefits without excessive toxicant exposure.