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 W ater Air Sediment Interaction) fugacity/aquivalence approach is develo ped for the Bay of Quinte. The model of the bay consists of seven wate r column compartments, five sediment compartments, the atmosphere, and two compartments in Lake Ontario. Chemicals enter the bay from tribut aries and runoff, industrial and municipal point sources, the atmosphe re, and Lake Ontario. Over 50 rate expressions are used to describe th e transport and transformation of chemicals through and between segmen ts under steady-state conditions. A food chain model applicable to org anic 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 var ying amounts of information were available for the remaining chemicals , the bay and food chain models were used to ''back-calculate'' the lo adings of to chemicals based on known in-bay water, sediment, or fish concentrations. For all chemicals (four inorganics and 13 organics), t he model gives order-of-magnitude estimates of loadings, concentration s in water, sediment and biota, amounts, rates of movement, and estima tes of persistence from which appropriate remedial measures are discus sed.