Lake trout toxaphene

Toxaphene elimination rates vary between species. In rats, the half-time persistence of toxaphene (time to 50% excretion = Tb 1/2) was 1 to 3 days (USEPA 1980a). If the trend persisted, virtually all toxaphene would be eliminated in five half-lives. Elevated blood toxaphene levels in a human subject who had eaten catfish fillets containing 52 mg of toxaphene/kg dropped 67% in 11 days. By 14 days after the initial measurement, toxaphene blood levels were below analytical detection limits (USEPA 1980a). Persistence seems to be longer in some fishes. Lake trout (Salvelinus namaycush) given a single intraperitoneal injection of 7 mg toxaphene/kg BW had a Tb 1/2 of 322 days for white suckers (Catostomus commersoni), this value was 524 days (Delorme et al. 1993). 

Delorme, P.D., D.C.G. Muir, W.L. Lockhart, K.H. Mills, and F.J. Ward. 1993. Depuration of toxaphene in lake trout and white suckers in a natural ecosystem following a single i.p. dose. Chemosphere 27 1965-1973. 

Fig. 4 Concentrations of organochlorine pesticides in lake trout and walleye (Lake Erie only) collected in 1988 and 1998. For mirex and toxaphene, 1991 concentrations are presented instead of 1988 values. From [32,33]...

Glassmeyer et al. [49,132] found that toxaphene concentrations in lake trout and rainbow smelt were ranked Lake Superior > Michigan > Huron > Ontario in samples collected in 1992. Whittle et al. [81] and Swackhamer [133] also found highest toxaphene concentrations in Lake Superior lake trout and lowest concentrations in lake trout from Lake Erie collected in 1998 and 1999-2000, respectively. Whittle et al. [81] used GC-ECD for quantifying toxaphene and selected chlorobornanes while Glassmeyer et al. [49,132] and Swack-... 

Toxaphene concentrations are also higher in Lake Superior and Lake Huron lake trout than in this species from inland lakes in northwestern and central Ontario [81,134]. Lake trout from Lake Nipigon had the highest mean (wet weight) concentrations, followed by Lake Simcoe (north of Toronto) and Sandy Beach Lake (west of Thunder Bay) (Table 11). 

Stapleton et al. [138] found that burbot (Lota lota) from Grand Traverse Bay had higher levels of toxaphene than lake trout, followed by salmon > sculpin > lake whitefish (Prosopium cylindraceum). Mean concentrations of toxaphene in lake trout from GTB were within the range (means of 350-810 ng/g wet wt) observed by Glassmeyer et al. [49] for three sampling locations in Lake Michigan. 

In Lake Siskiwit both piscivores (northern pike) and planktivores (lake whitefish (Coregonus clupeaformis), pigmy whitefish (Prosopium coulter)) had very similar total toxaphene concentrations to lake trout, while yellow perch (Percopsis omiscomaycus) had much higher concentrations of toxaphene than lake trout (Table 11) [74]. Indeed one sample of yellow perch had 1050 ng/g ww total toxaphene. 

Glassmeyer et al. [49,132] found that toxaphene concentrations in lake trout and rainbow smelt declined significantly (p < 0.05) in all lakes except Lake Superior. Results from their study, which compared samples from western Lake Superior between 1977 and 1992, are combined with data from Swack-hamer [133] and Muir et al. [74] in Fig. 12 to give a 24-year perspective on temporal trends of total toxaphene. No decline in toxaphene concentrations is evident over this time period. This agrees with water concentrations, which were estimated to be 1200 ng/L in 1977, based on concentrations in lake trout [49], and measured at 1120 ng/L in 1996 and 720 ng/L in 2002 (Table 9), representing a decline of 1-2% per year. 

The results show that toxaphene concentrations are similar in lake trout from Lakes Michigan and Superior and have not declined significantly since the 1980s. For the period 1982 to 1992, Glassmeyer et al. [49] found declines of 6 and 8% per year in Lakes Huron and Ontario, respectively, corresponding to... 

Fig. 12 Trends in concentrations of toxaphene (means 90% confidence intervals) in lake trout from Lakes Superior, Michigan (Charlevoix/Grand Traverse Bay area), Huron and Ontario. Results from Glassmeyer et al. [49] (1977-1993) are combined with more recent results from Stapleton et al. [138], Swackhamer et al. [133] and Muir et al. [74]...

Log bioaccumulation factor = concentration in lake trout (lipid weight) concentration in water. Toxaphene water concentrations from Swackhamer et al. [65] except for Muir et al. [74], PCB water concentrations from Pearson et al. [146] for Lake Michigan and Swackhamer [141] for Lake Superior... 

Fig. 14 Bioaccumulation factor (BAF) in Lake Superior lake trout versus octanol-water partition coefficient (.Kow) for 19 toxaphene congeners plus B9-715 and B10-1010 [74], Results for 6 congeners (P31, B8-1413, B9-1679, B9-1046, B9-715 and B10-1010) were estimated assuming water concentrations at the detection limit. The coefficient of variation r2 = 0.35 P< 0.01...

TMFs for toxaphene and selected congeners in Lakes Superior and for total toxaphene in Grand Traverse Bay of Lake Michigan are compared in Table 14. TMF values for toxaphene range from 1.07 to 1.40 in three separate studies and are within the range observed for lake trout food webs in northern lakes in Canada [147,148] and for Lake Baikal in Russia [150]. 

The elevated toxaphene levels in Lake Superior have social and economic impacts as well. The 2003 Guide to Eating Sport Fish published by the Ontario Ministry of Environment and Energy [158] indicates fish consumption advisories for Lake Superior lake trout due to toxaphene levels. As a result of the high toxaphene levels, the Ontario Ministry of Natural Resources has restricted sale with Ontario (but not the export) of large lake trout harvested from Lake Superior as of 1995. An assessment of toxaphene levels in Lake Superior fish fillets by Health Canada concluded that consumption of lake trout, salmon, longnose sucker and whitefish muscle from northwestern areas of the lake should be limited to one or two meals per month (55-135 g/week) based on a provisional tolerable daily intake of 0.2 pg/g body wt/day [159]. 

Glassmeyer, S.L., de Vault, D., Hites, R. (2000) Rates at which toxaphene concentration decrease in lake trout form the Great Lakes. Environ. Sci. Technol. 34, 1851-1856. 

The concentration ratios of the three main components in fish (B8-1413 (P-26), B9-1679 (P-50), and B9-1025 (P-62)) differed between species and sites. However, B9-1679 (P-50) was most abundant in more than 80% of more than 200 investigated samples. Delorme et al. estimated the half life of B8-1413 (P-26), B9-1679 (P-50), and technical toxaphene in lake trout (Salvelinus namaycush) and white suckers (Catastomus commersoni). The half life time of the toxaphene compounds in white suckers was about twice that of lake trout. Delorme et al. 

B9-1327, isolated by Anagnostopoulos et al. [71] and later assigned as Toxicant C, was four times more toxic in the Musca domestica test than technical toxaphene [71]. Chandurkar et al. found B9-1679 (P-50) to be four times more toxic to fish and as harmful to mosquito larvae as the technical mixture [80]. Furthermore, B8-806/B8-809 (P-42) was more potent than B9-1679 (P-50) [80]. Olson et al. found a difference in the toxicity of B7-515 (P-32) and B8-806/9 (P-42) for lake trout compared to technical toxaphene by studying behavioral parameters such as inferior swimming ability and delayed righting reflex [245]. 

P.D. Delorme. The effects of toxaphene, chlordane and 2,3,4,7,8-pentachlorodibenzofuran on lake trout and white sucker in an ecosystem experiment and the distribution and effects of 2,3,4,7,8-pentachlorodibenzo-furan on white suckers and broodstock rainbow trout in laboratory experiments. PhD Thesis, University of Manitoba, Winnipeg, Man., 1995. 

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