Toxaphene Effects on Growth and Bone Composition of Fathead Minnows, Pimephales promelas

Abstract

Fathead minnows (Pimephales promelas) were exposed to toxaphene (55–1230 ng/liter) in a flow-through diluter system for 150 days. Growth was not affected by toxaphene for up to 90 days of exposure, but within 150 days it was significantly reduced at all concentrations. Collagen content of the backbone was decreased (P < 0.05), amino acid composition was changed, and calcium concentration was increased. Results from this study suggest that toxaphene altered the development and quality of the backbone, and induced biochemical manifestations of the "broken-back" syndrome. Radiographic analyses of the fish support our hypothesis that toxaphene induced a weakened, fragile backbone.