April 2007 — A new study from the
University of Pittsburgh Cancer Institute’s Center for Environmental
Oncology suggests that fish caught in Pittsburgh rivers contain
substances that mimic the actions of estrogen, the female hormone.
Since fish are sentinels of the environment, and can concentrate
chemicals from their habitat within their bodies, these results suggest
that feminizing chemicals may be making their way into the region’s
The study, abstract number 3458, being presented at the annual
meeting of the American Association for Cancer Research, April 14-18,
at the Los Angeles Convention Center, also demonstrated that the
chemicals extracted from the local fish can cause growth of
estrogen-sensitive breast cancer cells cultured in the laboratory.
Extracts of fish caught in areas heavily polluted by industrial and
municipal wastes resulted in the greatest amount of cell growth.
"We decided to look at pisciverous fish, those that eat other fish,
for this project because we know that they bioaccumulate contaminants
from water and their prey, which may include toxic metals, farm and
industrial runoff and wastes from aging municipal sewer systems," said
Conrad D. Volz, Dr.P.H., M.P.H., principal investigator, department of
environmental and occupational health, University of Pittsburgh
Graduate School of Public Health. "The goals of this project are to use
fish as environmental sensors of chemicals in the water and the aquatic
food chain, and to determine the origins of these chemical
contaminants," said Dr. Volz. The study examined white bass and channel
catfish caught in the Allegheny, Monongahela and Ohio Rivers. These
fish are among those commonly caught as a food source by local anglers.
The experiments to determine if estrogenic substances were present
in the fish were performed in the laboratory of Patricia K. Eagon,
Ph.D., co-principal investigator of the study with the Veterans Affairs
Medical Center and the University of Pittsburgh School of Medicine. Dr.
Eagon found that extracts from the fish acted like estrogen, a female
hormone, by binding to estrogen receptors — the proteins within cells
that render the cells sensitive to estrogen.
Of six bass extracts tested for estrogenic activity, four displayed
a strong or moderate ability to bind with the estrogen receptors. Of 21
catfish extracts tested, nine displayed a similar ability to bind with
the estrogen receptors. The researchers also examined whether the fish
extracts could result in growth of breast cancer cells cultured in the
laboratory, and they found that two bass extracts produced
strong-to-moderate cell growth, as did five catfish extracts.
"We know that there are hundreds, even thousands, of chemicals in
the environment that can have estrogenic activity," said Dr. Eagon.
"These chemicals usually come from industrial pollution, farm animals,
farm chemicals and municipal water treatment plants. What surprised us
most in this study was that these estrogenic materials are present in
such easily detected levels in local fish."
According to Dr. Volz, the next step in this research is to identify
the estrogenic chemicals and their sources in the local water and fish.
"These findings have significant public health implications, since we
drink water from the rivers where the fish were caught. Additionally,
the consumption of river-caught fish, especially by semi-subsistence
anglers, may increase the risk for endocrine-mediated health endpoints
like some cancers and developmental problems."
The work is part of a Community Based Participatory Research project
with several partners including Venture Outdoors and Clean Water
Action, as well as individual anglers who caught the fish. The members
of the research team include scientists from the University of
Pittsburgh School of Medicine, the University of Pittsburgh Cancer
Institute’s Center for Environmental Oncology, the University of
Pittsburgh Graduate School of Public Health and the VA Medical Center.
In addition to the above-noted investigators, other participants in
the work are Frank Houghton, Jr., Ph.D., Christopher Price, Mary Elm.,
Yan Liu; and Maryann Donovan, Ph.D., M.P.H., and Devra Davis, Ph.D.,
M.P.H., both of the University of Pittsburgh Cancer Institute’s Center
for Environmental Oncology. The DSF Charitable Trust and The Heinz
Foundation supported the study.