Major Detoxification Pathways for Pentachlorophenol in Goldfish

Abstract

A study has been made to demonstrate the contribution of the branchial, renal, and biliary routes to the PCP excretion in goldfish, Carassius auratus, and also to determine the importance of the sulfate and glucuronide conjugations as the detoxification mechanisms for PCP in the fish.
The amounts of PCP excreted from the branchial, renal, and biliary routes corresponded to approximately 52, 24, and 22% of the total amount of PCP (approx. 5μmol) excreted by the fish (av. 68g) for 24h after 24-h exposure to 0.1ppm PCP. The excretion of PCP from the body surface was negligibly small compared with that from the above three routes.
Approximately 30% of the PCP excreted from the gills was in a free-form, whereas almost all the PCP excreted in both of the bile and urine was in a conjugated-form. The total amount of the sulfate conjugate excreted in the surrounding water and the urine was ca. 3μmol, while that of the glucuronide in the bile was ca. 1μmol.
However, a considerable amount of the PCP-glucuronide in the bile was hydrolyzed by the intestinal mucus of fish. This indicates that the glucuronide conjugation is not so important as compared with the sulfate conjugation to eliminate PCP from the fish body, because the PCP released from the glucuronide in the intestine must be reabsorbed there.