Post‐Audit Study of Dieldrin Bloconcentration Model

Abstract

A post-audit study was made of a predictive water quality model. An analytical model using annually averaged parameters is in good agreement with recent data. The model uses an analytical loading function, first-order kinetics, and constant coefficients. The model is accurate in predicting both whole-body dieldrin residue and oil-normalized dieldrin residue in carp for an impoundment of the Iowa River. The oil-normalization of the field data reduce its variability of dieldrin in mg/kg oil and emphasize the importance of lipid bioconcentration of hydrophobic pollutants. Dieldrin has a low water solubility, and partitions to sediments. Carp were chosen as the worst case for pesticide accumulation because of their high fat content and bottom-feeding behavior. Dieldrin accumulation data for carp were available for the period 1968–1988. Dieldrin concentrations are expected to be 30 μg/kg in carp in 1990.