DEVELOPMENT OF A MASS-BALANCE MODEL OF THE FATE OF 17 CHEMICALS IN THE BAY OF QUINTE

A multi-segment water quality model based on the QWASI (Quantitative Water Air Sediment Interaction) fugacity/aquivalence approach is developed for the Bay of Quinte. The model of the bay consists of seven water column compartments, five sediment compartments, the atmosphere, and two compartments in Lake Ontario. Chemicals enter the bay from tributaries and runoff, industrial and municipal point sources, the atmosphere, and Lake Ontario. Over 50 rate expressions are used to describe the transport and transformation of chemicals through and between segments under steady-state conditions. A food chain model applicable to organic chemicals and consisting of six trophic levels is also described. The bay model was calibrated with concentration data for arsenic and pentachlorophenol and tested with copper and zinc data sets. Since varying amounts of information were available for the remaining chemicals, the bay and food chain models were used to ''back-calculate'' the loadings of to chemicals based on known in-bay water, sediment, or fish concentrations. For all chemicals (four inorganics and 13 organics), the model gives order-of-magnitude estimates of loadings, concentrations in water, sediment and biota, amounts, rates of movement, and estimates of persistence from which appropriate remedial measures are discussed.