PARENT SESSION
MA4 - Biotransformation / Metabolism / Degradation
Chair: Zepp, Richard¹, ¹ U.S. EPA, Athens, GA
8:00 AM to 12:00 PM - Monday, 18 November 2002
Room Ballroom F

(195) Toxicokinetics and biotransformation of p-nitrophenol in red abalone (Haliotis rufescens).

TenBrook, Patti^*,1, Kendall, Shellie¹, Viant, Mark¹, Tjeerdema, Ronald¹, ¹ University of California, Davis, CA, USA

ABSTRACT- Red abalone (Haliotis rufescens) were exposed to 3.6 mM (0.5 ppm) ¹⁴C-labelled p-nitrophenol (PNP) for 24 h, then were allowed to depurate in clean seawater for another 24 h. Absorption, conditional uptake clearance and elimination rate constants were 0.12 + 0.04 h^-1, 3.2 + 1.1 mL g^-1 h^-1 and 0.05 + 0.02 h^-1, respectively. The sigmoidal shape of the PNP uptake curve suggests a biphasic process. A whole-organism total concentration factor (TCF) of 2.37 + 0.07 was determined from equilibrium tissue and water concentrations, with the highest concentration of PNP plus metabolites found in gill tissue (11.8 + 0.2 nmol g^-1, wet weight) . Digestive gland, foot muscle and remaining body tissues accumulated 8.8 + 0.9, 7.7 + 0.6 and 7.5 + 0.6 nmol g^-1 radiolabelled residues, respectively. Abalone depurated 87% of absorbed PNP within 24 h, of which 87.5 + 3.1% was unmetabolized parent compound, 13.1 + 3.1% was p-nitrophenylsulfate, 0.32 + 0.09% was p-nitroanisole, and 0.14 + 0.07% was p-acetamidophenol.

Key words: p-nitrophenol, abalone, toxicokinetics, biotransformation