WP7 Environmental Effects of Active Pharmaceutical Ingredients (APIs)
201 Oregon Ballroom
1:20 PM - 4:40 PM, Wednesday
() Differences in the biochemical- through population-level responses of two minnow species exposed to a potent estrogen mimic.
Kidd, K.1, 2, Palace, V.1, Blanchfield, P.1, Mills, K.1, Wautier, K.1, Lazorchak, J.3, Lattier, D.3, 1 Freshwater Institute, Winnipeg, MB, Canada2 University of New Brunswick, Saint John, NB, Canada3 US EPA, Cincinnati, OH, Canada
ABSTRACT- We conducted a whole-lake study at the Experimental Lakes Area in northwestern Ontario from 1999 to 2004 to examine the effect of environmentally-relevant concentrations of 17
-ethynylestradiol (EE2) on fish populations. Surface waters of Lake 260 were maintained at EE2 concentrations of 5-6 ng/L through weekly additions during the summers of 2001 to 2003. In the spring and fall of each year, populations of fathead minnow (Pimephales promelas) and pearl dace (Semotilus margarita) were monitored and individuals were collected to examine biochemical- through organism-level parameters in both the study and reference lakes. In these lakes, fathead minnow mature at age 1+, live for up to 4 years, spawn in June through August and have considerable mortality after they spawn. In contrast, pearl dace mature at age 2+, live for at least 9 years, and spawn in the spring just after ice-off. In this experiment, males and females of both species showed induced vitellogenin production (up to 9000 X) when compared to reference lake fish. Although both species showed impaired testis development, there were differences in the timing and magnitude of these responses. For example, intersex developed in males of both species but was observed in fathead minnow a year after it developed in pearl dace. Year-class failures have been observed for the fathead minnow after the second and third season of EE2 additions, but this has not yet occurred for the pearl dace. To date, population-level impacts for the fathead minnow appear to be more pronounced than for the pearl dace. These differences in organism- through population-level responses are likely influenced by the timing of spawning, fish size, habitat utilization, and differences in post-spawning mortality.
Key words: endocrine disrupter, ethynylestradiol, fathead minnow, estrogen