Clay Lake, Ontario

FIGURE 3.1 Observed mercury concentrations in standardized 50-cm walleye from Clay Lake, Ontario (1970-1983) following reductions in mercury releases from an upstream chlor-aUcali facility. (Source Data from Parks and Hamilton 1987.)... 

It is noteworthy that muscle from two species of recreationally inportant fish spotted seatrout (Cynoscion nebulosus, red drum, Sciaenops ocellatus) collected from coastal bays in Texas considered minimally impacted by mercury exceeded the current recommended value in the U.S. of 0.3 mg total Hg/kg FW muscle. And walleye (Stizostedium vitreum vitreum) collected from Clay Lake, Ontario - a water body heavily contaminated by mercury wastes from a chloralkali plant between 1962 when discharges began and 1970 when the plant closed - contained 2.7 mg... 

Scott, D.P., "Mercury Concentration of White Muscle in Relation to Age, Growth and Condition in Four Species of Fishes from Clay Lake, Ontario." J. Fish. Can. 31 1723 (1971 ). 

Thomas, R. L., 1969. A note on the relationship of grain size, clay content, quartz and organic carbon in some Lake Erie and Lake Ontario sediments. J. Sed. Petrol. 42 66-84. 

It has been stated [413] that in Clay Lake, which lies within this water system, the mercury concentration is about twenty times as great as that found in relatively uncontaminated waters in the area. D Itri and D Itri [414] have reported that where mercury is a fresh-water contaminant, populations (such as the 0jibway Indians of Ontario) which depend on fish or shellfish as a major food source, carry clinically dangerous levels of mercury in the blood. 

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