Toxicokinetics and biotransformation of p-nitrophenol in white sturgeon (Acipenser transmontanus)

White sturgeon (Acipencer transmontanus) were exposed to 7.2 μM (1.0 ppm) 14C-labeled p-nitrophenol (PNP) in brackish water for 24 h and then allowed to depurate in clean brackish water for another 24 h. Absorption, conditional uptake clearance, and conditional elimination rate constants were 0.08±0.04 h−1, 8.1±3.6 mL g−1 h−1, and 0.46±0.21 h−1, respectively. A whole-organism total concentration factor of 18.7±2.6 was determined from equilibrium tissue and water concentrations. Sturgeon depurated 89.4% of absorbed PNP within 24 h, of which 53.0±8.3% was unmetabolized parent compound, 9.6±3.6% was p-nitrophenyl-β-D-glucuronide, and 39.1±8.3% was p-nitrophenylsulfate.