1. US Environmental Protection Agency, Mid-Continent Ecology Division; Grosse Ile; Michigan; USA
2. US Environmental Protection Agency, Mid-Continent Ecology Division; Duluth; Minnesota; USA
3. Environment Canada, Aquatic Contaminants Research Division; Burlington; Ontario; Canada
4. Canadian Rivers Institute and Department of Biology, University of New Brunswick; Saint John; New Brunswick; Canada
5. Computer Sciences; Grosse Ile; Michigan; USA