The Distribution and Contaminant Burdens of Adults of the Burrowing Mayfly, Hexagenia, in Lake Erie

摘要: Hexagenia populations, eradicated in the 1950s by anoxia, are recovering western basin of Lake Erie. Water from Detroit River, which provides largest contaminant load into lake, flows west-to-east through center basin. We hypothesized that body burdens would reflect a gradient decreasing contamination west to east across basin, and central axis toward shorelines. In summer 1994, we used light traps or made use lakeside dock lights collect subimagos (females males) imagos (females) for 2 h at sunset three locations on River 22 throughout Imagos were found but only other areas Mayflies analyzed 59 organochlorine compounds including 42 congeners PCBs electron-capture detector gas chromatography. Results using principal component analysis reduce autocorrelations among contaminants. There was 1:1 correspondence PCB concentrations between subimago imago stages, indicating no change moults. The highest adults Monroe, Michigan (an Area Concern) reflects local sources contaminated sediments. high mayfly Middle Sister East islands lower near both northern southern shorelines confirmed as effective efficient monitors organochlorines.