For 15 years, Minnesota has played a central role in research on endocrine disrupting compounds in the environment. Here are some of the research projects that have studied the compounds, their presence in surface waters and their impacts on fish:
- Teams of scientists led by Larry Barber from the U.S. Geological Survey lab in Boulder, Col., and Kathy Lee, a USGS hydrologist in Mounds View, sampled and analyzed water and sediment from the full length of the Mississippi River in Minnesota in several studies. They found EDCs in multiple places.
- Scientists, including Leroy Folmar of the U.S. Environmental Protection Agency, Lee and Heiko Schoenfuss of St. Cloud State University, conducted a succession of studies, capturing and examining fish from eight species at 70 sites in Minnesota streams. They found vitellogenin, an egg-making protein, in males from more than 40 percent of the sites. They found immature egg cells-a further step toward feminization-in male smallmouth bass at five sites along the Mississippi.
- Paige Novak, a University of Minnesota civil engineering professor, led researchers who measured the presence of estrogen-like compounds in water before and after treatment by wastewater treatment plants in Duluth and St. Paul. They concluded those plants, especially the St. Paul plant, did a good job of removing EDCs. But even removing 90 percent, as the St. Paul plant did, is not good enough, at least where fish are concerned. The effluent from both treatment plants still had EDC concentrations that other research had shown could alter sex characteristics in fish.
- Novak and a graduate student, Mark Lundgren, recently tested discharges from 19 industries in Minnesota and Iowa-including an ethanol plant, a biodiesel plant, a soy milk factory, a dairy and a barbecue meat processing plant-and found high levels of vegetable-and soy-based phytoestrogens. The research found concentrations up to 250 times higher than levels that other studies found had feminized fish.
- Schoenfuss and a graduate student, Megan McGee Painter, videotaped larval fathead minnows, raised in water tainted with anti-depressants in concentrations similar to those recorded downstream from treatment plants. They found the minnows were 60 percent slower than control minnows from untainted water in reacting and swimming away from a stimulus mimicking the approach of a predator fish.