Factors influencing blood mercury levels of inhabitants living near fishing areas

Methylmercury (MeHg), a well-known neuro-toxicant, is usually emitted by industrial and other man-made activities; it is ingested with seafood and shellfish, and accumulates in the human body. The aim of this study was to compare the differences in blood levels of total mercury (T-Hg) and MeHg in residents of 4 coastal sites and 4 inland sites around Taiwan. Meanwhile, the potential question is warranted to find out the association between dietary intake and MeHg accumulation. We found that coastal residents had significantly higher mean blood T-Hg levels (mean: 16.1 μg/L, range: 0.9-184.9 μg/L) than inland residents (mean: 11.8 μg/L, range: 0.8-146.6 μg/L). The same was for blood MeHg levels: coastal residents (mean: 16.5 μg/L, range: 0.9-184.9 μg/L), inland residents (mean: 11.8 μg/L, range: 2.1-133.4 μg/L). These elevated levels were positively associated with seafood and shellfish consumption. However, the nature of their residential area may also be an important factor, because the highest T-Hg and MeHg levels were found in residents of a relatively non-industrialized area. To protect vulnerable population-especially children and pregnant women-it is important to know whether locally caught or raised and consumed fish has any source of Hg and MeHg pollution.