Investigation on endocrine disruption of the larval lampricide 3-trifluoromethyl-4-nitrophenol: Short-term reproduction assay with fathead minnow (Pimephales promelas).

: 3-trifluoromethyl-4-nitrophenol (TFM) has been used for over 60 years to control the invasive parasitic sea lamprey (Petromyzon marinus) in the Great Lakes basin. In the early 1990s, researchers reported that TFM induced vitellogenin in fish and that TFM was an agonist for the rainbow trout estrogen receptor. To support continued registration of TFM for sea lamprey control, regulatory agencies required further testing to evaluate potential endocrine disruption effects. Fathead minnow (Pimephales promelas) were exposed to TFM at measured concentrations of 0.0659, 0.181, 0.594, 1.79, and 5.11 mg active ingredient (a.i.)/L for 21 days. No-observable- and lowest-observable-effect concentrations (NOEC and LOEC, respectively) were determined to be 1.79 mg/L or greater for each endpoint. Male survival in the highest treatment group was reduced relative to the controls. Percent egg fertility was reduced in the highest treatment group, resulting in an estimated NOEC of 1.79 mg/L. While no effect on gonadal-somatic index (GSI) was observed for males, female GSI was increased in the 5.11 mg/L treatment. Vitellogenin production was not altered relative to the controls for all TFM treatment groups. However, female testosterone was elevated in the 5.11 mg/L treatment. The results suggest that prolonged exposure to TFM at concentrations exceeding 1.79 mg/L has the potential to disrupt endocrine function. Biologically relevant effects in this study were found at the highest exposure concentration following a 21-day exposure. However, the duration of exposure in this study is not consistent with typical treatment durations (12-h) for sea lamprey control. This article is protected by copyright. All rights reserved.