Absorption, tissue distribution and metabolism of chlorpyrifos in channel catfish following waterborne exposure

Abstract

Abstract The pharmacokinetics, tissue distribution, and metabolism of waterborne chlorpyrifos were investigated in channel catfish (Ictalurus punctatus) fitted with arterial and urinary catheters. Pharmacokinetic analysis indicated rapid absorption of parent chlorpyrifos from water into blood and slower distribution to peripheral tissues. Total 14C residue concentrations were highest in fat and lowest in muscle. Parent chlorpyrifos comprised > 90% of the total 14C residues in the whole fish. 14C residues were excreted by renal and biliary routes as metabolites of chlorpyrifos; excretion of the parent chemical was negligible. Trichloropyridinol (TCP) was the major metabolite in blood (approximately 40% of total residues), whereas the glucuronide conjugate of TCP was the major metabolite in urine (60–90%) and bile (> 90%). The pharmacokinetics and metabolism of water-borne chlorpyrifos in the channel catfish were similar to the disposition of chlorpyrifos in other vertebrates.