Mercury Exposure Level For Residents And Mercury Stable Isotope Tracer In Zhoushan,China

Highly mercury contaminated fish may cause health risk to humans.Mercury absorbed by human mainly concentrates in the brain and other tissues,affecting the development of central nervous system.To assess level of human mercury exposure in Zhoushan area,the total mercury and methyl mercury concentrations in seafood and human hair samples were analyzed.Using mercury stable isotopes to assess the sources of human total mercury exposure.A series of experimental results are analyzed and summarized:?1?The results showed that the average concentration of total mercury in aquatic production from Zhoushan was 43.9 ?g·kg^-1and the average concentration of methyl mercury was 22.8 ?g·kg^-1,methyl mercury accounted for 63.4% of total mercury,and there was no sample exceeded the corresponding maximum level established by the Chinese government,which is 500?g·kg^-1 for methyl mercury.The mercury concentrations of aquatic production in Zhoushan were comparable with other areas in China,similar to Guangdong and Hainan,while higher than Hunan and Beijing.There were significant differences of total mercury concentrations between different species in the seafood,mercury concentrations in mollusks were significant higher than shrimp and fish.Fish THg concentrations were correlated with the body length.?2?The average concentration of total mercury in hair collected from residents was 1.77 mg·kg^-1and the average concentration of methyl mercury was 0.88 mg·kg^-1.Methyl mercury accounted for 59.2% of total mercury.Hair total mercury concentrations had the trend of increasing with the age of study population and male showed significant higher hair total mercury concentrations than female.There were 60.3% of populations with hair total mercury concentrations higher than 1 mg·kg^-1 set by USEPA,which suggested that local residents have health risk of mercury exposure.?3?The isotopic compositions of mercury in seafood and hair samples collected form Zhoushan are similar to those reported in previous studies.Negative ?²⁰²Hg and positive ?¹⁹⁹Hg were observed in seafood samples.The mass independent fractionation in seafood subject to the photoreduction of Hg²⁺.The results of isotopic compositions of mercury in hair samples showed positive ?²⁰²Hg and positive ?¹⁹⁹Hg and the mass independent fractionation in hair subject to the photoreduction of Hg²⁺.Comparing the two samples collected,seafood has the same ?¹⁹⁹Hg to hair,which indicted that seafood consumption is the primary route of mercury exposure for residents in Zhoushan.