Comparative sublethal actions of 3-trifluoromethyl-4-nitrophenol in marinemolluscs, as measured by in vivo P-31 NMR

The sublethal actions of the piscicide, 3-trifluoromethyl-4-nitrophenol, we re characterized in two marine molluscs by ill vivo P-31 nuclear magnetic r esonance spectroscopy. This noninvasive technique is ideal for examination of cellular respiratory toxicity since inorganic phosphate, phosphoarginine , and adenosine 5 ' -triphosphate levels, and the arginine kinase rate cons tant, can be measured. These parameters were characterized in both red abal one (Haliotis rufescens) and owl limpets (Lottia gigantea) during 5-h expos ures, to 3 mg L-1 (14.5 muM) 3-trifluoromethyl-4-nitrophenol, followed by 5 -h recovery periods. In exposed abalone, phosphoarginine decreased by 50%, inorganic phosphate increased by 900%, and the arginine kinase rate constan t quadrupled-all compared to controls and consistent with an uncoupling of oxidative phosphorylation. Limpets were less severely impacted, showing no change in phosphoarginine, an increase of only 200% in inorganic phosphate, and an approximate doubling of the arginine kinase rate constant. Adenosin e 5 ' -triphosphate level's remained constant in all control and exposed mo lluscs. In addition, at the cessation of dosing, all biochemical parameters in abalone returned to preexposure levels within 3-4 h, consistent with ra pid depuration, whereas the limpet recovery data were inconclusive. We sugg est that the owl limpet's greater tolerance toward the pesticide could resu lt from an increased capability for anaerobic glycolysis, which is required to survive the periodic anoxia associated with residing higher in the inte rtidal zone. Thus, the natural histories of nontarget organisms should be c onsidered when the effects of pesticide exposure are determined. (C) 2001 A cademic Press.