to change the sexual characteristics of fish and other
animals have been found in West Virginia tributaries of the
Potomac River, which runs through Washington, D.C.,
and surrounding areas, the U.S. Geological Survey
regarding fish that had both male and female
characteristics turned up a range of chemicals including
pesticides, flame retardants, and personal care
products, the USGS said.
The Potomac is
fed by rivers and streams in Maryland, Virginia, and West
samples of 30 smallmouth bass from six sites, including
male and female fish without intersex and male fish with
intersex," said Douglas Chambers, a USGS scientist who
led the study.
contained detectable levels of at least one known
endocrine-disrupting compound, including samples from fish
disrupters affect the animals' hormone systems. They can
cause birth defects and sexual abnormalities called
intersex in species ranging from frogs to alligators
and perhaps humans as well.
detected in municipal wastewater, aquaculture, and
poultry-processing effluent, with the highest number of
antibiotics and the greatest concentrations found in
municipal effluent," the USGS wrote in the report,
The USGS said the
sexual changes in the fish were discovered by accident
in 2003, when scientists were investigating massive fish
sources of contaminants discharge to the South Branch
of the Potomac and Cacapon Rivers. Chief among these are
runoff from agricultural activities, municipal and
domestic wastewater effluent (both treated and
untreated), industrial wastewater, and gypsy moth control
programs using dimilin (diflubenzuron)," the report reads.