Arsenic Cycling in Union Lake, NJ

Extensive arsenic contamination at the Vineland Chemical Company Superfund site (>10,000 µg/L or >130 µmole/L in groundwater) has spread downstream to the Blackwater Branch, Maurice River, and Union Lake. Sediments in these waterways are heavily contaminated with arsenic. Union Lake has been shown to stratify and become anoxic during summer months, permitting arsenic release from sediments. Sediment cores were taken in this lake and porewaters were analyzed for dissolved metal concentrations, as well as arsenic speciation. Lake water samples were taken at deep, intermediate, and shallow depths over two summers, and were analyzed for both chemical and microbiological parameters. Continuous monitoring data of temperature and dissolved oxygen in the lake over this time period are also available. These data in conjunction with previous studies examining particulate transport in and out of the lake demonstrate the ways in which this lake is both a source of and sink for arsenic.