Intersex Fish Found in Pennsylvania Prompts Chemical Search

The discovery of intersex fish in three of Pennsylvania's rivers has prompted the state's Department of Environmental Protection (DEP) to conduct an extensive sampling of chemical contaminants, a department spokeswoman said.

Male fish carrying eggs were found in the Susquehanna, Delaware and Ohio river basins, a sign that the water may be tainted with chemicals, according to a US Geological Survey study released Monday.

The USGS research said that two fish species, smallmouth bass and white sucker, are exhibiting intersex characteristics due to exposure to endocrine-disrupting chemicals. These are hormones and hormone-mimicking chemicals that caused the male fish to produce eggs. The findings suggest that this type of hormone imbalance may be more widespread than previously thought.

"The number of fish affected and the severity was surprising," Vicki Blazer, a fish biologist and lead author of the USGS study, told the Los Angeles Times.

Blazer and colleagues collected fish from 16 sites in the Susquehanna, Delaware and Ohio river systems. Smallmouth bass were affected the most, with intersex characteristics being worse the closer they were to wastewater treatment plants, researchers said.

Red and white suckers were also tested, and though the latter didn't display any sexual changes, the results revealed that males had stem cells that could potentially turn into eggs.

Estrone, a potent endocrine-disrupting chemical often found in sewage from wastewater plants and animal manure, was the most common hormone found in water and soil samples. By hindering the release of the hormones estrogen and testosterone, such chemicals affect the fish's ability to reproduce.

Such harmful pollutants find their way into Pennsylvania waters because under the Clean Water Act, agriculture is exempt from most water pollution standards and permitting requirements - even when it comes to pesticides.

Virginia Representative James P. Moran made a statement about the incident, citing it as "yet another example of the adverse effects on water pollution in this country and another reminder that lawmakers need to take chemical waste regulation more seriously."

In the meantime, the DEP will continue to sample waterways until it comes to a better understanding of how these compounds are impacting aquatic life.