Chemical and physical controls on mercury source signatures in stream fish from the northeastern United States

Environmental Science & Technology
By: , and 

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Abstract

Streams in the northeastern U.S. receive mercury (Hg) in varying proportions from atmospheric deposition and legacy point sources, making it difficult to attribute shifts in fish concentrations directly back to changes in Hg source management. Mercury stable isotope tracers were utilized to relate sources of Hg to co-located fish and bed sediments from 23 streams across a forested to urban-industrial land-use gradient within this region. Mass-dependent isotopes (δ202Hg) in prey and game fish at forested sites were depleted (medians -0.95 and -0.83 ‰, respectively) in comparison to fish from urban-industrial settings (medians -0.26 and -0.38 ‰, respectively); the forested site group also had higher prey fish Hg concentrations. The separation of Hg isotope signatures in fish was strongly related to in-stream and watershed land-use indicator variables. Fish isotopes were strongly correlated with bed sediment isotopes, but the comparison of isotopic composition between fish and sediment was variable due to differing ecosystem-specific drivers controlling the extent of MeHg formation. The multivariable approach of analyzing watershed characteristics and stream chemistry reveals that the Hg isotope composition in fish is linked to current and historic Hg sources in the northeastern U.S. and can be used to trace bioaccumulated Hg.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Chemical and physical controls on mercury source signatures in stream fish from the northeastern United States
Series title Environmental Science & Technology
DOI 10.1021/acs.est.9b03394
Edition Online First
Year Published 2019
Language English
Publisher American Chemical Society
Contributing office(s) Upper Midwest Water Science Center, New York Water Science Center, Wisconsin Water Science Center, Texas Water Science Center, New England Water Science Center
Country United States