Every spring, Dr. Carl Isaacson, a professor of environmental studies at Bemidji State University, sends his students out to collect perch from waters across Minnesota.
Then, they study an egg yolk protein found in the perchs’ livers, called vitellogenin, which may provide evidence of endocrine disruption in the state’s aquatic species.
Over the past few years, studies of Minnesota’s waters have found a variety of unregulated chemicals — such as pharmaceuticals, fragrances, fire retardants, detergents and insecticides — which are widespread in the state’s lakes and rivers.
When male fish are exposed to EACs, they can start to develop female attributes, such as increased vitellogenin concentrations; in more extreme instances, male fish have also been found to produce eggs in their testes.
And while these chemicals have been linked to health problems such as infertility and different types of cancer, “it’s too soon to say whether feminized fish are indicative of health effects for humans too,” an article by National Geographic said.