NY RESERVOIR HG Data

Project Objectives and Location:

Assessment of Mercury, PCB, and Organochlorine Pesticide Residues in indicator fish in the New York City Reservoir System, 2001 - 2002

Jefferey J. Loukmas, Lawrence C. Skinner, and Timothy Sinnott

Bureau of Habitat, Division of Fish, Wildlife, and Marine Resources

New York State Department of Environmental Conservation

Albany, NY 12233-4756

There are 19 reservoirs in the New York City water supply system and all support active fisheries. From 1998 - 1999 five reservoirs (Ashokan, Cannonsville, Neversink, Pepacton and Rondout reservoirs) were assessed to determine PCB, organochlorine pesticide, and mercury levels in popular recreational fish species. Elevated mercury concentrations (>1.0 µg/g) were documented in fish from all five reservoirs (NYSDEC, unpublished data), which prompted the New York State Department of Health to issue health advice to consumers of affected fish from these reservoirs. Health advice was issued for smallmouth bass in all five reservoirs and for walleye in Ashokan Reservoir.  PCB and organochlorine pesticide concentrations did not provide a cause for issuance of health advice.

Because all five NYC reservoirs that were tested contained at least one fish species containing elevated mercury concentrations, there is a likelihood that additional reservoirs may have similar conditions.  Other than for the five reservoirs noted above, there is a paucity of recent data on mercury and other chemical residues in fish from the remaining New York City reservoirs. Our objectives were: 1) to provide current information on the concentrations of mercury, PCB and organochlorine pesticides in representative samples of indicator fish species taken from the New York City reservoirs lacking recent analytical data; 2) in consultation with the New York State Department of Health, to provide appropriate health advice to consumers of fish taken from New York City reservoirs; 3) to provide a limited assessment of the relative health of fisheries as part of the aquatic and terrestrial ecosystem; and 4) to provide baseline data for future contaminant trend analysis.

We selected 16 New York City reservoirs for fish sampling. The three reservoirs (Ashokan, Rondout and Neversink) having adequate chemical residue information collected from 1998-1999 were excluded. We included Cannonsville and Pepacton reservoirs because only 1 species was previously sampled.

Six fish species were selected to represent those species with the greatest likelihood of containing elevated concentrations of mercury or the organic chemicals of interest, and/or are species with high public interest. The six fish species were smallmouth bass, walleye, brown trout, lake trout, yellow perch and largemouth bass.  However, not all of these species were present in each of the reservoirs, so we selected other available fish species as substitutes. White perch, common carp, chain pickerel, cisco, and white catfish were species used as substitutes in 2001. Legal edible sizes of fish were taken and the samples represented the range of legal edible sizes available to the angler. 

Fish were sampled from 6 reservoirs in 2001 and 10 reservoirs in 2002. The data provided represents all 2001 samples and samples from 2 reservoirs in 2002. The remaining 2002 data should be available in Spring 2003.