The influence of legacy contamination on the transport and bioaccumulation of mercury within the Mobile River Basin

Journal of Hazardous Materials
By: , and 

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Abstract

Past industrial use and subsequent release of mercury (Hg) into the environment have resulted in severe cases of legacy contamination that still influence contemporary Hg levels in biota. While the bioaccumulation of legacy Hg is commonly assessed via concentration measurements within fish tissue, this practice becomes difficult in regions of high productivity and methylmercury (MeHg) production, like the Mobile River Basin, Alabama in the southeastern United States. This study applied Hg stable isotope tracers to distinguish legacy Hg from regional deposition sources in sediments, waters, and fish within the Mobile River. Sediments and waters displayed differences in δ202Hg between industrial and background sites, which corresponded to drastic differences in Hg concentration. Sites that were affected by legacy Hg, as defined by δ202Hg, produced largemouth bass with lower MeHg content (59–70%) than those captured in the main rivers (>85%). Direct measurements of Hg isotopes and mathematical estimates of MeHg isotope pools in fish displayed similar distinctions between legacy and watershed sources as observed in other matrices. These results indicate that legacy Hg can accumulate directly into fish tissue as the inorganic species and may also be available for methylation within contaminated zones decades after the initial release.


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Publication type Article
Publication Subtype Journal Article
Title The influence of legacy contamination on the transport and bioaccumulation of mercury within the Mobile River Basin
Series title Journal of Hazardous Materials
DOI 10.1016/j.jhazmat.2020.124097
Volume 404
Year Published 2021
Language English
Publisher Elsevier
Contributing office(s) Upper Midwest Water Science Center
Description 124097, 10 p.
Country United States
State Alabama
Other Geospatial Mobile River Basin
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