Effects of Aroclor® 1248 and 1260 on the Fathead Minnow (Pimephales promelas)

Abstract

Fathead minnows were exposed to Aroclor® 1248 and 1260 in flow-through bioassays to determine the acute (30-d) and chronic (240-d life cycle) effects on the larvae and adults, as well as the bioconcentration of the mixtures of PCBs in the fish. Newly hatched larvae (< 8 h old) were the most sensitive; the calculated 30-d LC50 was 4.7 μg/L for Aroclor 1248 and 3.3 μg/L for Aroclor 1260. Reproduction in fathead minnows occurred at concentrations as high as 3 μg/L for Aroclor 1248 and 2.1 μg/L for Aroclor 1260, concentrations that significantly affected larval survival. The 20% reduction in the standing crop in the second-generation fish at concentrations as low as 0.4 μg/L was due to the death of the larvae soon after hatching. The bioconcentration factor for PCBs was independent of the PCB concentration in the water; in adult females at 25 °C it was ~ 1.2 × 105 for Aroclor 1248 and 2.7 × 105 for Aroclor 1260. Females accumulated about twice as much PCBs as the males because of the greater amount of lipid in the female. Exposed fish placed in untreated Lake Superior water eliminated < 18% of the body burden after 60 d. Key words: PCBs, bioassay, bioconcentration, chronic toxicity, embryo-larval, depuration