A reconnaissance study was conducted of 22 streams tributary to Green Bay to determine whether any of the streams contribute toxic substances to the bay. This effort was part of a comprehensive investigation of Green Bay funded by the U.S. Environmental Protection Agency, Great Lakes National Program Office.
The U.S. Geological Survey sampled the bottom sediments and water columns of 11 streams tributary to western Green Bay for polychlorinated biphenyls, lead, and cadmium. Four of these streams also were sampled for dieldrin, a pesticide previously used in the watershed. An additional 11 streams tributary to eastern Green Bay were sampled for dieldrin in the bottom sediment and storm runoff. Samples were collected from July 1987 through April 1988.
Neither dieldrin nor cadmium was detected in any of the sampled tributaries. Detectable concentrations of polychlorinated biphenyls and lead were found at only three sites. Polychorinated biphenyls (0.10 microgram per gram) and lead (10 milligrams per kilogram) were found in the bottom sediment of Duck Creek, a western-shore tributary near the city of Green Bay. Lead (10 milligrams per kilogram) also was found in the bottom sediment of the Suamico River near the mouth, about 5 miles north of Duck Creek. Lead (4 micrograms per liter) was detected in a spring-runoff sample from the Fishdam River, a tributary from upper Michigan.
