Cranberry Lake

ATMOSPHERIC AND WATERSHED INPUTS OF MERCURY TO CRANBERRY LAKE, ST. LAWRENCE COUNTY, NEW YORK... 

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. 

Results to date indicate that levels of mercury in atmospheric fallout at Cranberry Lake are low rainfall and snowpack levels are usually less than 25 ng Hg/1 of liquid sample. The Cranberry Lake watershed contributes more mercury to the lake than it receives from the atmosphere, as stream inputs to the lake exceed... 

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 Additional sampling conducted between 1972 and 1975 (Harris, unpublished data) for predator species such as smallmouth...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.

Figure 2. Cranberry Lake stream and precipitation, sediment and snowpack sampling locations.

Between October, 1972 and July, 1974, 1 1 Harris of the New York State Department of Environmental Conservation (NYSDEC) conducted a study of atmospheric fallout at Cranberry Lake (NYSDEC, 1978). This study gave an atmospheric deposition rate of 44 yg, Hg/m -yr, with over eight percent of the mercury associated with particulate material >0.45 ym. Curiously, one sample location at a nagnetite sintering operation about 20 km to the northwest of Cranberry Lake had an atmospheric deposition rate of 280 yg/m -yr. This sintering operation was terminated in 1975. 

In 1978, a study was initiated at Cranberry lake with several objectives, including ... 

There are three possible causes of the high mercury values in fish which may be relevant to the Cranberry Lake situation, including ... 

Cranberry Lake is located in the northwest portion of the Adirondack Forest Preserve (Figure 1). The lake was enlarged to its present 28 lState controlled the area is sparcely populated and there are no industrial discharges into the lake watershed. 

St. lawrence County, located about 70 Km from the Cranberry Lake watershed (Brown, 1970). 

Even though no known sulfide ore mineralization is known to exist within the Cranberry Lake watershed, this possible source of the abnornally high concentration of mercury identified in Cranberry Lake smallmouth bass cannot be completely discounted until more extensive studies are conducted. 

Sampling stations were established in July, 1978 at six Cranberry Lake watershed sites (Figure 2). Rain and stream water samples were collected ard analyzed for the following chemical parameters pH, alkeilinity, sulfate, Ca, Na, Mg, total nitrate and total mercury. 

Figure 3. Cranberry Lake watershed including locations of sampled tributaries ...

Table I. Cranberry Lake Watershed Collecting Stations Sanpled During Period July 29, 1978 to NDvember 16, 1978...

Cranberry Lake Total vatershed East Creek Sucker Brook Chair Rock Six Mile Creek Oswegatchie River Wanakena... 

In addition to watershed precipitation and stream samples. Cranberry Lake water, snowpack and sediment core samples were collected (See Figure 2 for locations). Open lake water samples were collected with a two liter PVC Kanmerer wato sampler samples were collected at one meter intervals from the surface to lake bottom. 

Cranberry Lake Canopy Rain 8/28/78 to 11/16/78 Sanples Collected ... 

Table IV. Cranberry Lake Watershed Stream Water Quality Data for Period 7/21/78 to 11/16/78...

Table IV summarizes Cranberry Lake watershed stream data for the preiod July 21 to November 16, 1978. During this period alkalinity (CaC03) concentrations ranged fran <1.0 to 14.5 mg/1 with an average value of about 5.1 mg/1. Calcium concentrations of collected stream samples were significantly above open and canopy precipitation concentrations and ranged from 0.06 to 1.8 mg/1 with an average concentration of about 1.3 mg/1. Ifeignesium concentrations ranged from 0.43 to 0.83 mg/1 mean concentration of about 0.6 mg/1 which was approximately equal to the mean magnesium concentration of canopy precipitation v ues.

Are these mercury values for Cranberry Lake streams high or low They a2 e similar to levels reported for Lake Windemere (12 -29 ng/1) by Gardner (1978) and the unpublished work of Harris (1971). on the Oswegatchie River (17 - 72 ng/1) but sonewhat lower than Onondaga Lake, near Syracuse, New York contaminated by chlor-alkali plant residues. Buller s synoptic survey (1972) of mercury in surface waters of the Adirondack Mountain region yielded no samples above 500 ng/1 total mercury and 100 ng/1 soluble mercury. 

Snowpack samples were collected from three sites within the Cranberry Lake watershed during the period December 1, 1978 to Lferch 10, 1979 (see Figure 2 for sampling locations). Table V summarizes the snow chanical data. Calcium concentrations ranged from < 0.1 to 7.1 mg/1 and averaged about 0.85 mg/1 which was comparable to canopy and open precipitation concentrations. Lfagnesium concentrations cilso closely paralleled canopy and open precipitation (rain) concentrations and averaged about 0.3 mg/1. Mercury concentrations in all collected snow samples were <25 mg/1. 

Open water samples were collected form Cranberry Lake during the period Septerriber 20 to November 16, 1978 from the lake surface to depths of nine meters. These data are summarized in Table VI. 

Table V. Cranberry Lake Snow Samples Collected During Period 12/1/78 to 3/10/79...

Table VI. Summary of Cranberry Lake Water Quality Data Collected September 20, 1978 to November 16, 1978 for All Depths...

Seven 4.45 cm diameter core samples and four bottom grab samples were collected from within the Cranberry Lake watershed. Core lengths which varied from 28 to 44 cm were vertically sectioned at observed lithologic changes and analyzed for total mercury concentrations utilizing flameless atomic absorption spectrophotometry following Environmental Protection Agency (1977) procedures. Table VII summarizes the mercury concentrations of all collected core samples. The four bulk bottom sediments were all collected from the same location and varied in mercury content from < 0.08 - 0.10 mg/kg. 

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. 

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