Spatial and Seasonal Variability of Dissolved Methylmercury in Two Stream Basins in the Eastern United States

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• 作者：Paul M. Bradley ; Douglas A. Burns ; Karen Riva- Murray ; Mark E. Brigham ; Daniel T. Button ; Lia C. Chasar ; Mark Marvin-DiPasquale ; Mark A. Lowery ; Celeste A. Journey
• 刊名：Environmental Science & Technology
• 出版年：2011
• 出版时间：March 15, 2011
• 年：2011
• 卷：45
• 期：6
• 页码：2048-2055
• 全文大小：1082K
• 年卷期：v.45,no.6(March 15, 2011)
• ISSN：1520-5851

文摘

We assessed methylmercury (MeHg) concentrations across multiple ecological scales in the Edisto (South Carolina) and Upper Hudson (New York) River basins. Out-of-channel wetland/floodplain environments were primary sources of filtered MeHg (F-MeHg) to the stream habitat in both systems. Shallow, open-water areas in both basins exhibited low F-MeHg concentrations and decreasing F-MeHg mass flux. Downstream increases in out-of-channel wetlands/floodplains and the absence of impoundments result in high MeHg throughout the Edisto. Despite substantial wetlands coverage and elevated F-MeHg concentrations at the headwater margins, numerous impoundments on primary stream channels favor spatial variability and lower F-MeHg concentrations in the Upper Hudson. The results indicated that, even in geographically, climatically, and ecologically diverse streams, production in wetland/floodplain areas, hydrologic transport to the stream aquatic environment, and conservative/nonconservative attenuation processes in open water areas are fundamental controls on dissolved MeHg concentrations and, by extension, MeHg availability for potential biotic uptake.