Organochlorines in Lake Superior's Food Web

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• 作者：John R. Kucklick and and Joel E. Baker
• 刊名：Environmental Science & Technology
• 出版年：1998
• 出版时间：May 1, 1998
• 年：1998
• 卷：32
• 期：9
• 页码：1192 - 1198
• 全文大小：137K
• 年卷期：v.32,no.9(May 1, 1998)
• ISSN：1520-5851

文摘

Lake Superior's food web was analyzed in 1994 forhydrophobic organochlorine contaminants (OCs) includingtoxaphene, chlordane and metabolites, hexachlorocyclohexanes, hexachlorobenzene, dieldrin, and polychlorinatedbiphenyl congeners. Toxaphene was the dominant organochlorine contaminant in the Lake Superior food web, withconcentrations 2-15 times higher than total PCBs.Amongthe biota studied, wet weight toxaphene levels werehighest in bloaters (Coregonus hoyi) at 1100 ± 270ng/g(mean ± 1 standard deviation) and lowest in Mysisrelicta(32 ± 804 ng/g). Total PCB concentrations rangedmorethan a factor of 20 on a wet weight basis but less than afactor of 6 on a lipid weight basis. The lipid contentofthe organisms explains 81% of the variability in wetweightt-PCB, with trophic position exerting a smaller influence.Using path analysis and regression techniques, themaininfluence of trophic position on t-PCBs was shown tobe due to the concurrent increase in lipid content withtrophic position. The relative distributions oforganochlorinesamong trophic levels were very similar, despite the 3orders of magnitude range in OC hydrophobicity.Unlikeour work in Lake Baikal, the accumulation of OCs in theLake Superior food web was not significantly (p <0.05)related to the log octanol/water (K_ow) partitioncoefficient,suggesting either that organochlorines in this food webequilibrate with surrounding dissolved OCs rapidlyrelativeto dietary uptake or that the OC assimilation efficiencyof predators does not vary with log K_ow.Based on OCconcentrations in benthic amphipods, we conclude thatsettling particles are an important source of OCs to deepwater organisms in Lake Superior.