Effect of pH on the toxicity and accumulation of pentachlorophenol in goldfish.

Abstract

A study has been made of the effect of pH on the toxicity and accumulation of pentachloro-phenol (PCP) in goldfish, Carassius auratus. The toxicity of PCP to the fish abruptly decreased with an increase of the pH of PCP-media, as shown in the 24-h LC50 values increase from 0.052 ppm at pH 5.5 to 16 ppm at pH 10. The accumulation of PCP by the fish also decreased with the increase of the pH of the media. The bioconcentration of PCP by the fish also decreased with the increase of the pH of the media. The bioconcentration ratios at 1-h exposure to 0.1 ppm PCP-media at pH 5.5, 6, 7, 8, 9 and 10 were 131, 120, 56, 24, 12 and 2, respectively. On the other hand, the concentration of PCP found in all the dead fish in the media ranged from 82 to 115 μg/g body weight independent of the variation of the pH and PCP concentration of the media. From these results, it was demonstrated that the accumulation of PCP by the fish decreased with an increase of the pH of PCP-media, and consequently the PCP concentration in the fish body did not readily reach to the lethal level (about 100 μg/g body weight) at the high pH, resulting in the reduction of the toxicity of PCP to the fish.