[Pharmwaste] Estrogen makes fish too feminine to reproduce

DeBiasi,Deborah dldebiasi at deq.virginia.gov
Tue May 22 15:06:22 EDT 2007

Estrogen makes fish too feminine to reproduce
Male minnows exposed to hormone found in sewage grew part-female sex
organs: Study
Tom Spears 
CanWest News Service 

Tuesday, May 22, 2007

Estrogen that goes down Canadian toilets -- some naturally from women,
some from the birth-control pill -- is enough to make entire fish
species too feminine to reproduce, a seven-year Canadian study shows.

Fish scientist Karen Kidd dripped small amounts of estrogen into a clean
lake in northwestern Ontario over several years, just as if urine with
the female hormone were running in via sewage from a nearby city. This
constant hormone bath made male fathead minnows produce eggs in
unnatural, part-female sex organs.

Even after she stopped adding estrogen and the water turned clean, the
minnows almost completely disappeared for several years. Even small
concentrations of estrogen can decimate wild fish populations, the
University of New Brunswick biology professor concludes, even at levels
found in some Canadian waters. She wouldn't name individual rivers.

And while the minnows were prone to fast extinction because of their
short lifespan (about two years), she says bigger fish such as trout or
pike might also be hurt if they are exposed for long enough.

The first dramatic news of "feminized" fish came from British rivers in
the 1990s where male fish near sewage plants were producing eggs and
carrying reproductive organs that were partly female.

"A lot of followup studies showed it was the natural estrogens that
women excrete and then the synthetic estrogens in birth control pills
that were the main causes of feminization in male fish," Kidd said.

"The pill is one of the most heavily prescribed pharmaceuticals in the
world. There are over a million women on it in Canada."

She chose an unpolluted lake with healthy fish to learn what damage
estrogen would cause.

Male minnows in water with estrogen just stopped looking male. Where
they should have distinct colours and bumps at spawning time, they
didn't have any visible sign of maleness.

"And then when you opened them up, their testes were much smaller than
they should have been" -- about one-third the normal size. By the third
year of adding estrogen to the lake, the testes had ovary-type tissue,
and were producing eggs -- a condition called "intersex."

It's exactly what scientists had seen in the wild. The achievement is in
reproducing this effect in a clean lake, proving that estrogen is the
cause. Meanwhile, the female fish produced eggs too slowly.

The seven-year study was funded by Fisheries and Oceans Canada, where
Kidd worked during most of it, and the American Chemistry Council. It's
published today in the Proceedings of the National Academy of Sciences.

"A lot of our [pollution] regulations tend to be centred around
chemicals that are persistent in the environment, and that accumulate in
fish," she said. These include pesticides such as DDT and industrial PCB
oils, both of which last for years.

Estrogen doesn't last long, but it, too, needs control through decent
sewage treatment, she said. The bacteria in a sewage plant chew up
estrogen effectively.

(c) Times Colonist (Victoria) 2007

Deborah L. DeBiasi
Email:   dldebiasi at deq.virginia.gov
WEB site address:  www.deq.virginia.gov
Virginia Department of Environmental Quality
Office of Water Permit Programs
Industrial Pretreatment/Toxics Management Program
Mail:          P.O. Box 1105, Richmond, VA  23218 (NEW!)
Location:  629 E. Main Street, Richmond, VA  23219
PH:         804-698-4028
FAX:      804-698-4032

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