U.S. Department of the Interior
U.S. Geological Survey
News Release
January 17, 2007 Douglas Chambers 304-347-5130, ext. 231 dbchambe@xxxxxxxx
Endocrine Disrupters Found in Fish and
Water in Potomac River Tributaries
Editors: The
report, A Reconnaissance for Emerging Contaminants in the South Branch
Potomac River, Cacapon River, and Williams River Basins, West Virginia,
April-October 2004, is available on:
http://pubs.usgs.gov/of/2006/1393/
The discovery of a high incidence
of intersex (male fish exhibiting female characteristics) in smallmouth
bass of the Potomac River Basin has prompted an investigation of water
quality and wastewater discharge into the upper Potomac, and blood-plasma
studies on this fish species. Recently, U.S. Geological Survey (USGS) scientists
found pesticides, flame retardants, and personal-care products containing
known or suspected endocrine-disrupting chemicals in several tributaries
to the Potomac River and in the smallmouth bass that inhabit them.
The endocrine system excretes hormones
in an organism that govern many functions, including sexual and reproductive
characteristics. Endocrine disrupters in the environment include pharmaceuticals
in untreated wastewater and agricultural runoff. Agricultural, industrial,
and household products often contain compounds that mimic estrogen when
ingested. Endocrine disrupters of this type may contribute to the
high percentage of male smallmouth bass found in the Potomac that exhibit
female characteristics.
“We analyzed samples of 30 smallmouth
bass from six sites, including male and female fish without intersex and
male fish with intersex,” said Douglas Chambers, USGS scientist and lead
investigator. “All samples contained detectable levels of at least one
known endocrine-disrupting compound, including samples from fish without
intersex.”
Known or suspected endocrine-disrupting
chemicals from pesticides, flame-retardants, and personal-care products
were also present in water samples taken from all eight sites, including
those where fish did not exhibit intersex. Wastewater from several sites
that discharge municipal effluent or from sites contributing runoff was
examined to identify point sources of these compounds. Antibiotics were
found in wastewater samples, with municipal effluent having at least seven
such compounds, but were not detected in water from other sites.
The reproductive anomalies in the
Potomac’s smallmouth bass population are not readily apparent on gross
examination of an affected fish -- they were discovered by accident. In
2003, scientists investigating massive fish kills and widespread lesions
found oocytes, precursors of egg cells that females normally produce, while
looking at tissues from the testes of male fish under the microscope.
High intersex occurrence in aquatic
species has been documented at other locations in the U.S. and in Europe.
It is not unique to the Potomac Basin, and not unique to smallmouth
bass. Previous studies have found that known or suspected endocrine
disrupters are widespread in the environment.
The USGS continues to examine the
occurrence of known or suspected endocrine disrupters in the Potomac Basin
to determine the potential for these compounds to interfere with the development
and reproduction of aquatic life.
USGS provides science for a changing
world. For more information, visit www.usgs.gov.
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Diane Noserale
Media Relations, Eastern Region
U.S. Geological Survey
150 National Center
Reston, VA 20192
phone: 703-648-4333
fax: 703-648-4588
