Endocrine-disrupting contaminants such as environmental estrogens have been found and studied in large lakes and streams and shown to exist at concentrations that have adverse effects on wildlife. However, very little is known about the sources and effects of environmental estrogens in small, shallow lakes. Preliminary data suggests that these compounds are present in shallow lakes and have an effect on the survival and reproduction of wildlife. Researchers at the University of St.
Moose, one of Minnesota's prized wildlife species, are dying at much higher rates in Minnesota than elsewhere in North America. Recently observed increases in mortality rates amongst some moose in northeastern Minnesota have led to concern that the population there may be entering a decline like that seen in the northwestern part of the state, where moose populations fell from over 4,000 to fewer than 100 in less than 20 years. Additionally the specific causes of increased mortality amongst individual moose remain under investigation.
