The LA Times reports the state Department of Environmental Protection has begun sampling waterways in response to a recent study by the U.S. Geologic Survey which found intersex fish in three Pennsylvania river basins.
Male fish carrying eggs were found in the Delaware, Susquehanna and Ohio River systems.
The USGS said the findings show that exposure to chemicals that disrupt endocrine or hormone systems – such as estrogen – may be more widespread than researchers previously thought.
Amanda Witman, a DEP spokeswoman, said the agency is testing two tributaries of the Susquehanna River: Juniata River and Swatara Creek.
The USGS research said that two fish species, smallmouth bass and white sucker, were exhibiting intersex characteristics due to exposure to endocrine-disrupting chemicals — hormones and hormone-mimicking chemicals that caused the male fish to produce eggs.
“The sources of estrogenic chemicals are most likely complex mixtures from both agricultural sources, such as animal wastes, pesticides and herbicides, and human sources from wastewater treatment plant effluent and other sewage discharges,” said Vicki Blazer, a fish biologist and lead author of the USGS study.
Estrogenic chemicals disrupt the endocrine system, which regulates the release of hormones such as estrogen and testosterone. This interferes with the fish’s ability to reproduce.
Some of the compounds and contaminants found were new, and researchers had to develop new laboratory test procedures to measure them, Witman said.
“The results will provide a much better understanding of the kinds, distribution and concentrations of these compounds,” she said.
As StateImpact Pennsylvania has reported, wastewater treatment plants are not designed to remove certain compounds such as pharmaceuticals. Researchers say that while these compounds are not entering our drinking water in full or “therapeutic” doses, there is more work to be done on whether they pose long-term risks to humans and aquatic life.