Stillwater reservoir

Cranberry Lake is a lar e (28.2 km ) reservoir located in the northwestern Adirondack Mountains in New York State. The area surrounding the lake is primarily wilderness with no major industry. In 1969, fish collected from Cranberry Lake and nearby Stillwater Reservoir as part of a Statewide sample collection program yielded anomalously elevated mercury levels when compared to similar sized and aged fish of the same species from other lakes in the State. This paper documents studies conducted by New York State over the last ten years concerning the (Cranberry Lake situation. 

Two northwest Adirondack Mountain reservoirs. Cranberry lake and Stillwater Reservoir (Figure 1) produced fish with high mercury levels despite the undeveloped nature of their watersheds. Additional sampling conducted between 1972 and 1975 (Harris, unpublished data) for predator species such as smallmouth... 

Figure 1. Cranberry Lake and Stillwater Reservoir locations in relation to the Adirondack Forest Preserve, New York.

The high levels of mercury found in the smallmouth bass of Cranberry Lake and Stillwater Reservoir cannot be so easily interpreted as those in the other lakes described, due in part to the sites remoteness and absence of anthropogenic mercury sources. 

Figure 9 is a bivariate plot which represents a canposite of various fish species from Cranberry Lake and Stillwater Reservoir. 

Table VIII summarizes the cumulative uptake rates for mercury in fish from Cranberry Lake and Stillwater Reservoir. Uptake rates were derived by dividing the mercury concentration by the age of the fish, resulting in mg/kg body weight-year. Whereas this method of calculating uptake rates is useful in determining trends of mercury accumulation in fish for a number of successive year classes, it does not reflect true instantaneous accumulation rates from year to year due to the nature of the calculation. It is apparent that average uptake rates for fish in both lakes increases as one proceeds fron lower to higher trophic levels. A lack of fish from a diverse number of age groups preeludes the use of uptake rates in defining year class composition for most fish speoies analyzed.

Smallmouth bass in Cranberry Lake indicate an upward trend in mercury uptake from age IV to age IX fish. The discrepancy observed in age III samllmouth bass is attributed to the mercury analysis of only one fish. SamllmDuth bass in Stillwater Reservoir display a slightly greater increase in mercury accumulation with age when compared to Cranberry Lake. More mercury may be available to the fish in Stillwater Reservoir via food composition or increased mercury availability in the environment. 

Table VIII. Mercury Cumulative Uptake Rates for Fish in Cranberry Lake and Stillwater Reservoir (in mg Hg/kg body weight per year)...

TOMLINSON One thing that I think is interesting is that Cranberry Lake is a humic lake, a brown lake. In Quebec and some of the Ontario lakes, it appears that when this brown color of the water is combined with a low pH, fish show higher levels of mercury than in clear lakes of similar pH. When Dr. Jernelov s co-worker s first reported the combination of elevated mercury in fish with low pH of water, it was noted that the lakes were brown in color. It could be very well that the mercury coming in via the rain is methylating more rapidly in these waters and the methylmercury becomes available to fish. So when you are checking these other lakes, you want to look at the color. The Stillwater Reservoir is quite clear, is it not ... 

Information from our fish management unit this year is that when they went to collect their 1979 samples from Cranberry and Stillwater Reservoir to determine mercury in smallmouth bass, they could not find any smallmouth bass in Stillwater Reservoir. It was not possible to secure any, althou this lake had been quite adequate in producing fish in the past years. We also found this year that the pH of Cranberry Lake, despite it s large size, was top to bottom pH 4.5 during snow-melt conditions, exactly the same as the influent water. 

Oxidant residuals in the form of total residual chlorine were first reported by the New York State Department of Environmental Conservation in rainfall and lake waters of the Western Adirondacks of New York State in 1976-77. Chlorine residuals analyzed by the orthotoline colorimetric procedure developed by Palin (1957) were detected in rainfall at Boonville and Stillwater, New York and in Echo Lake, Hinckley Reservoir and Stillwater Reservoir (Figure 2. Total residual chlorine in rainfall near Boonville, New York... 

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