ESTIMATED ANNUAL LOADS OF SELECTED ORGANIC CONTAMINANTS TO CHESAPEAKE BAY VIA A MAJOR TRIBUTARY

The aim of the Chesapeake Bay Fall Line Toxics Monitoring Program has been to determine the annual loads for selected organonitrogen, organophosphorus, and organochlorine pesticides, polychlorinated biphenyls, and polynuclear aromatic hydrocarbons to Chesapeake Bay derived from above the fall line of the Susquehanna River, the bay's largest tributary. Load results are presented in this report for 15 samples collected from March 1992 through February 1993. Annual load estimates were obtained using 14 methods, grouped according to whether they are of averaging, ratio, or regression type to ensure convergence to an approximate mean load value for each contaminant. The results indicated a high degree of uniformity across the methods with most yielding relative deviations 1.5 or less when normalized to the mean load derived from all 14 load estimation methods.