MODEL OF ORGANIC-CHEMICAL UPTAKE AND CLEARANCE BY FISH FROM FOOD AND WATER

A comprehensive model is presented that describes the bioaccumulation of organic chemicals by fish from food and water, using size- and species-dependent parameters describing transport and transformation “resistances” and parameters for metabolic conversion and bioavailability. Uptake of a nonmetabolizing chemical from water tends to result in the chemical adopting a fugacity in the fish approaching that in the water, as expressed by a bioconcentration factor. Uptake from food may result in a fish fugacity that is higher than the food or water fugacity, corresponding to biomagnification. This is postulated to be due to food digestion causing a fugacity increase in the gastrointestinal tract. This biomagnification phenomenon is most significant for very hydrophobic, slowly clearing, nonmetabolizing chemicals. The model also describes food chain biomagnification, the dependence of fish concentration on rates of metabolism and growth, and the effect of reduced bioavailability. © 1990, American Chemical Society. All rights reserved.