Concentrations and loads of polychlorinated biphenyls in major tributaries entering Green Bay, Lake Michigan, 1989-90

The U.S. Geological Survey collected water samples from the five major tributaries to Green Bay, Lake Michigan, to determine the load of total polychlorinated biphenyls (RGB's) entering the bay. These samples were collected from January 1989 through early May 1990 from the Escanaba, Menominee, Peshtigo, Oconto, and Fox Rivers. Sampling sites were located near the mouth of each river and also just upstream of De Pere dam on the Fox River. Water samples were collected for analysis of total, dissolved, and particulate concentrations of PCB's at the nanogram-per-liter level. Loads of PCB's entering Green Bay were computed using a total-integration method. The methods used to collect water samples and compute the loads of total PCB's entering the bay are described in this report. Graphs showing total PCB's concentrations and loads are presented for each site, along with the corresponding data tables. These data indicate that the amount of total PCB's entering the bay from the Fox River is greater than from all other major tributaries combined.