The discovery of intersex fish -- male fish carrying eggs -- has spurred concerns that Pennsylvania waterways may be contaminated by endocrine-disrupting chemicals that cause hormonal imbalance in aquatic wildlife. The unusual finding was made by scientists at the U.S. Geological Survey (USGS), during a study of watersheds in the Northeast. Apart from Pennsylvania, similar intersex fish were also found in Ohio and Delaware.
As a result, Pennsylvania's Department of Environmental Protection (DEP) has started an investigation in an attempt to understand what caused the mutation and possibly to identify chemicals present in the water and their source. Amanda Witman, a spokeswoman for the state DEP, told the Los Angeles Times that the Juniata River and Swatara Creek, both tributaries of the Susquehanna River, were being sampled for chemicals.
Two species of fish were found to have intersex characteristics due to endocrine disruptors, the USGS revealed. These were smallmouth bass and white sucker. Researchers identified several intersex characteristics, including formation of eggs in male fish. Those are most likely caused by hormones and hormone-mimicking compounds present in watersheds, scientists claimed.
Vicki Blazer, lead author of the study, explained that the sources of estrogenic chemicals that most likely led to the phenomenon were a mixture of agricultural sources, including animal wastes, pesticides and herbicides, and human sources, such as wastewater treatment plant effluent and sewage discharges.