CHLOROBORNANES IN WATER, SEDIMENT AND FISH FROM TOXAPHENE TREATED ANDUNTREATED LAKES IN WESTERN CANADA

Concentrations of toxaphene (CHB) and -exo,3-endo,5-exo,6-endo,8,9,10- heptachlorobornane (B7-1001; Hp-Sed), a major toxaphene component know n to be present in the sediment of toxaphene treated lakes, were deter mined in water, sediment, and fish from 13 lakes to examine the relati onship between chlorobornane levels in fish and environmental variable s. The lakes were situated in either the boreal plain, montane, or sub alpine ecozones in western Canada. Five of the lakes had been treated with toxaphene between 1958 and 1962. Mean concentration of CHB tall c hlorobornane congeners) in fish from the lakes ranged from 1.9 to 303 mu g/kg with the maximum concentration occurring in lake trout from Bo w Lake, an oligotrophic glacial fed lake with no record of toxaphene u sage. CHB and in particular B7-1001 levels, were higher in water, sedi ment, and fish from treated relative to matched untreated lakes select ed as ''control'' sites. CHB concentrations in sediment were not relat ed to the levels measured in fish; however, levels of atmospheric CHBA tm (CHBAtm = CHB - [B7-1001]) in fish, from both treated and untreated lakes combined, were inversely related to indicators of lake producti vity (p < 0.05, dissolved phosphorus r = -0.64, percent organic conten t of lake sediment r = -0.84, and midsummer water temperature r = -0.6 8). These relationships suggest that the process and pathway of CHBAtm accumulation in fish is mediated by limnological and perhaps physiolo gical factors in addition to exposure levels. B7-1001 concentrations i n fish were not related to indicators of lake productivity or the char acteristics of fish from the lakes (weight, age, lipid content), but w ere related to B7-1001 concentration in sediments (r = 0.74, p < 0.05) .