HPLC DETERMINATION OF PLASMA THIOCYANATE CONCENTRATIONS IN FISH BLOOD- APPLICATION TO LABORATORY PHARMACOKINETIC AND FIELD-MONITORING STUDIES

The pharmacokinetics of thiocyanate (SCN-) in the blood plasma of 35-g rainbow trout (Oncorhynchus mykiss) were followed during a 20-day exp osure to 39.8 mg SCN- liter(-1) and the subsequent 16-day depuration p eriod. SCN- concentrations were determined by reverse-phase HPLC. Kine tic constants were estimated using a one-compartment first-order kinet ic model fitted to the data by the computer programs BIOFAC and SYSTAT . The respective BIOFAC and SYSTAT estimates for the uptake rate const ant (k(1), 0.55 and 0.49 day(-1)), the depuration rate constant (k(2), 0.34 and 0.29 day(-1)), and the bioconcentration factor (BCF, 1.61 an d 1.66) were similar for both methods of calculation. Field studies we re conducted to determine the impact of SCN- on white sucker (Catostom us commersoni) populations in waters receiving SCN--bearing effluents. The assessment was based on SCN- concentrations in water and fish pla sma, and the thyroid histology of the fish. Although SCN- was detected in the water at one site, no SCN- was detected in fish plasma and non e of the thyroid pathology characteristic of chronic SCN- exposure was present. The results suggest that SCN- was not a hazard to the white sucker populations studied. (C) 1995 Academic Press, Inc.