The distribution of mercury (Hg) and sites of greatest Hg methylation are poorly understood in Catskill Mountain watersheds. Although concentrations of Hg in the water column are low, high concentrations of Hg in smallmouth bass and walleye have led to consumption advisories in most large New York City reservoirs in the Catskill Mountains. Mercury in natural waters can exist in many forms, including gaseous elemental mercury (Hg0), dissolved and particulate inorganic forms (Hg(II)), and dissolved and particulate methylmercury (MeHg). Most Hg in living organisms is MeHg, a highly neurotoxic form that bioaccumulates in aquatic food webs. The production of MeHg by methylation of inorganic Hg in the environment is a key process affecting the quantity of MeHg accumulated in fish. Small quantities of MeHg in the diet can adversely affect wildlife and humans, which are exposed to MeHg almost entirely through the consumption of fish.
This study was completed in 2002, but atmospheric mercury deposition monitoring at the Frost Valley YMCA Biscuit Brook National Atmospheric deposition station has continued and is planned for the foreseeable future. This has been the site of chemical deposition monitoring since 1983 and therefore is an excellent site to locate a Hg deposition collector because the long period of rainfall and atmospheric chemistry record will aid in the interpretation of Hg deposition data.
The Neversink watershed is a high relief, forested ecosystem that supplies part of New York City's drinking water supply. This watershed is in the general vicinity of some of the highest suspected atmospheric Hg deposition zones in the coterminous US, and as such the Hg problem here is likely not limited to the current supply of Hg in the watershed. Three water and sediment sampling surveys were conducted within the Neversink Reservoir watershed. The surveys were conducted during (1) dry, low water conditions, (2) during the period of increasing soil moisture in the fall, and (3) one month after fall rainstorms. Twenty sites were sampled. The data from this project is being compared to data from Hg research being conducted in the Adirondack Mountains of New York to identify differences in the way Hg is cycled in these different environments. As such, the data collected during this study will contribute to a regional understanding of mercury cycling.
Project Location
by County
Sullivan County, NY, Ulster County, NY
