Assessing Sources of Human Methylmercury Exposure Using Stable Mercury Isotopes

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• 作者：Miling Li ; Laura S. Sherman ; Joel D. Blum ; Philippe Grandjean ; Bjarni Mikkelsen ; P谩l Weihe ; Elsie M. Sunderland ; James P. Shine
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：August 5, 2014
• 年：2014
• 卷：48
• 期：15
• 页码：8800-8806
• 全文大小：347K
• ISSN：1520-5851

文摘

Seafood consumption is the primary route of methylmercury (MeHg) exposure for most populations. Inherent uncertainties in dietary survey data point to the need for an empirical tool to confirm exposure sources. We therefore explore the utility of Hg stable isotope ratios in human hair as a new method for discerning MeHg exposure sources. We characterized Hg isotope fractionation between humans and their diets using hair samples from Faroese whalers exposed to MeHg predominantly from pilot whales. We observed an increase of 1.75鈥?in 未²⁰²Hg values between pilot whale muscle tissue and Faroese whalers鈥?hair but no mass-independent fractionation. We found a similar offset in 未²⁰²Hg between consumed seafood and hair samples from Gulf of Mexico recreational anglers who are exposed to lower levels of MeHg from a variety of seafood sources. An isotope mixing model was used to estimate individual MeHg exposure sources and confirmed that both 螖¹⁹⁹Hg and 未²⁰²Hg values in human hair can help identify dietary MeHg sources. Variability in isotopic signatures among coastal fish consumers in the Gulf of Mexico likely reflects both differences in environmental sources of MeHg to coastal fish and uncertainty in dietary recall data. Additional data are needed to fully refine this approach for individuals with complex seafood consumption patterns.