BALTIMORE, Maryland, August 21, 2002 (ENS) - Traces of ordinary
household products may be interfering with sexual development and reproduction
of fish in the Chesapeake Bay.
The large, shallow Bay, which has an average depth of less than 30 feet and
is fed by hundreds of tributaries, offers valuable habitat for fish spawning and
hatching. But, as scientists of the University of Maryland Biotechnology
Institute (UMBI) reported at the annual meeting of the Society for the Study of
Reproduction this week, runoff water carrying tiny amounts of common home and
garden chemicals is now rendering that habitat unsuitable for fish breeding.
"This is worse than we thought before," said Trant. "This is not simply
toxicology. It is interfering with the reproduction of the adults, and
potentially skewing sex ratios of the populations."
For almost 20 years, scientists have known that some environmental chemicals,
known as endocrine disrupting chemicals, disrupt reproduction by mimicking
natural estrogens. Now, many additional classes of chemicals, functioning as
endocrine disruptors, are interacting directly with genes that are critical for
reproductive success, the scientists reported.
Chemical disruption of a brain gene, which directly affects brain estrogen
production, may be a key mechanism for the disruption of the developmental and
reproductive capacity of fish. Unlike most animals, many fish produce two forms
of a gene responsible for aromatase, an enzyme that makes estrogen - one form in
the ovaries, the other in the brain.
Compounds in many detergents, plastics, pesticides, some medicines, and even
thalates that keep vinyl soft in cars were shown to disrupt the sexual
development of juvenile zebra fish in experiments at UMBI's Center of Marine
Biotechnology (COMB) in Baltimore. All of the environmental pollutants were
tested at concentrations that can be found in the Chesapeake Bay system.
"I would not say that it is severe enough that any population
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