Toxicokinetics of trifluralin in rainbow trout

• Published in: Aquatic toxicology Vol. 26; no. 3; pp. 287 - 306
• Main Authors: Schultz, I.R., Hayton, W.L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.08.1993; Elsevier Science
• Subjects: Agnatha. Pisces; Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on vertebrates; Fish; Fundamental and applied biological sciences. Psychology; Metabolism; N-Dealkylation; Toxicokinetic model; Trifluralin; Fish; Trifluralin; N-Dealkylation; Toxicokinetic model; Metabolism; Nitro compound; Fresh water; Pesticides; Oncorhynchus mykiss; In vitro; Herbicide; Toxicokinetics; In vivo; Pollutant; Vertebrata; Pisces; Distribution; Intraarterial administration; Pharmacokinetics
• ISSN: 0166-445X; 1879-1514
• DOI: 10.1016/0166-445X(93)90035-Y

Rainbow trout weighing 80 g were statically exposed at 12°C to 2 ng/ml 14C-trifluralin (TF), a widely used herbicide. After various exposure times, TF was determined in exposure water, plasma, and carcass homogenate; the total amount of metabolites formed was also estimated. A two compartment toxicokinetic model, that included gill plasma flow and the plasma/water distribution coefficient as model parameters, was used to analyze these concentration-time profiles. The value of the uptake clearance (33.3 ml·h −1·g −1) approximated the ventilation volume of the gills, an indication that TF uptake was water flow limited. The apparent volume of distribution was 3,240 ml/g. The model predicted BCF and depuration half-life were 2280 and 144 h. Five trout weighing between 238 and 1339 g received 1 mg/kg TF via intraaortic injection. The plasma concentration-time profile was characterized up to 240 h and analyzed using a three compartment model. TF distributed rapidly and extensively to tissues; its elimination half-life was variable, ranging from 54 to 290 h in three of the fish. In two fish, the plasma concentration-time profile showed no detectable decline between 50 and 240 h. A free fraction in plasma for TF of 0.39% was determined by equilibrium dialysis. Pretreatment of hepatic microsomes with TF in vitro and exposure of fish to TF in vivo prior to microsome preparation did not affect N-depropylase activity.