Mercury cycling in Berry's Creek (Hackensack Meadowlands) and the Delaware River estuary (New Jersey)

Mercury speciation and transformations were evaluated in a highly contaminated, point-source impacted tidal creek (Berry's Creek, New Jersey Meadowlands) and throughout the tidal range of the Delaware River estuary. Mercury was analyzed as particulate mercury (PHg), dissolved mercury (DHg), total mercury (PHg plus DHg), monomethylmercury (MeHg), and particulate MeHg in each system. To estimate volatilization fluxes of elemental mercury (Hg0) from these estuaries, dissolved Hg0 in surface waters and, in the atmosphere were also measured. Mercury methylation and demethylation rates were quantified in surface waters and sediments of Berry's Creek and sediments of a tidal tributary to the Delaware River.; THg contents in Berry's Creek were up to three orders of magnitude higher and MeHg concentrations were one to two orders of magnitude higher than those found in other urban estuaries, including the Delaware River estuary. MeHg concentrations in Berry's Creek varied over a narrower range than THg concentrations indicating that factors other than gross contamination control steady-state MeHg levels in this contaminated system.; Surprisingly, dissolved Hg0 concentrations and estimated daytime volatilization fluxes of Hg0 were similar for Berry's Creek, the Delaware River estuary and other estuaries. Estimated daytime volatilization fluxes of Hg0 were approximately equal to average daily direct atmospheric deposition inputs at Berry's Creek and slightly higher than direct atmospheric fluxes to the Delaware River estuary.; Methylation and demethylation assays in sediments of Berry's Creek showed an increase in potential methylation rates with distance downstream from the point source, demethylation rates showed the reverse trend. Results indicate that in Berry's Creek, despite the high Hg contamination, McHg and Hg0 pools are kept at relatively low levels by geochemical and biological factors.; THg contents were obtained in dated sediment cores from Woodbury and Oldmans Creek (tributaries to the Delaware River). THg analysis indicates that mercury emissions and possible local and regional discharges peaked prior to 1970. Methylation and demethylation rates were assessed in sediment cores from Woodbury Creek. Assays revealed that methylation takes place in the top 15 cm of sediment. However, although demethylation was generally dominant, accumulation of MeHg occurs at all depths; suggesting reduced availability of MeHg to demethylators.