An Age Dependent Model Of PCB In A Lake Michigan Food Chain

Abstract

An age-dependent food chain model that considers species bioenergetics and toxicant exposure through water and food is developed. It is successfully applied to PCB contamination of the Lake Michigan lake trout food chain represented by phytoplankton, Mysis, alewife, and lake trout. The model indicates that for the top predator lake trout, PCB exposure through the food chain can account for greater than 99 percent of the observed body burden. A simple steady-state computation indicates that ratios of chemical concentration in predators to that in prey in feeding experiments may be as low as 0.2 and still result in significant food chain transfer. It is estimated that a criterion specifying that PCB concentrations of all ages of lake trout be at or below 5 ug/g (wet weight) in the edible portion would require that dissolved PCB concentrations be reduced to somewhere between 0.5 and 2.5 ug/R. The range reflects uncertainty in the PCB assimilation efficiency of the species and the dissolved PCB concentration. This report was submitted in fulfillment of Cooperative Agreement No. CR805916010 by Manhattan College under the sponsorship of the U.S. Environmental Protection Agency. This report covers the project period May 1, 1978 to September 30, 1981.