The Vineland Chemical Company (Vineland, NJ) manufactured arsenical pesticides for more than 50 years; it is now a Superfund site located alongside the Blackwater Branch, a tributary of the Maurice River, which in turn leads to Union Lake. Arsenic contamination exists in sediments throughout this 11-km stretch of waterway. Arsenic releases from sediments are often observed under reducing conditions; these processes have been shown to release arsenic to other lakes during seasonal (summer) anoxia and were hypothesized as a major source of arsenic to bottom waters of Union Lake. Significant arsenic release to bottom waters during seasonal anoxia was not observed in Union Lake; bottom water arsenic concentrations reached ~30 ppb at most, representing a small fraction of dissolved arsenic in the lake. During seasonal anoxia in Union Lake, manganese concentrations increased to high levels (~13 ppm) prior to increases in arsenic and iron concentrations in bottom water. Therefore, it was hypothesized that manganese serves as a redox buffer preventing and/or delaying large arsenic releases. Incubations of sediment and lake water were performed; those incubations with added manganese had later and more limited arsenic releases, supporting this hypothesis. Arsenic releases from contaminated sediment to lake water may be more important in lakes with greater concentrations of organic matter, with more labile organic matter, with lower concentrations of reactive manganese, and/or that remain anoxic more continuously than Union Lake.

Arsenic release from contaminated sediments is limited by manganese redox buffering in Union Lake, New Jersey

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.