Distribution and Elimination of 3-Trifluoromethyl-4-Nitrophenol (TFM) by Sea Lamprey (Petromyzon marinus) and Non-target, Rainbow Trout (Oncorhynchus mykiss) and Lake Sturgeon (Acipenser fulvescens)

The pesticide, 3-trifluoromethyl-4-nitrophenol (TFM), has been highly successful in the control of sea lamprey (Petromyzon marinus) populations in the Great Lakes. Treatments with TFM involve applying it to streams, where it targets larval sea lamprey which live burrowed in the stream substrate. While the toxic mechanism of TFM has been elucidated, and its effects on sea lamprey described, its effects on non-target fish species such as rainbow trout (Oncorhynchus mykiss) and lake sturgeon (Acipenser fulvescens) are not as well understood. The present work demonstrated that rainbow trout show a great capacity to detoxify the lampricide using glucuronidation, when exposed to TFM concentrations typically used in TFM applications, and with no adverse physiological effects. Larval sea lamprey, on the other hand, showed very little ability to detoxify TFM, and experienced pronounced reductions in glycogen concentration in the liver. In contrast to previous suggestions, lake sturgeon were able to biotransform TFM and generate TFM-glucuronide at levels that were similar to those observed in rainbow trout. However, they were exposed to a lower concentration of TFM, which does not rule out possible toxic effects of TFM at higher concentrations. In conclusion, this study has demonstrated that rainbow trout readily tolerate TFM at environmentally relevant concentrations, and that lake sturgeon are capable of TFM detoxification. This suggests that the greater sensitivity of lake sturgeon is a result of other factors such as body size, glycogen stores and/or possibly limitations in their capacity to use glucuronidation to detoxify TFM