Sludge Watch ==> Estrogen Threatens Minnow Manhood

[Maureen Reilly]

Dr Kidd said municipalities need to build more advanced sewage treatment 
plants, which are able to degrade more of the estrogen into harmless 
chemicals.

..................
HORMONE POLLUTION

Estrogen threatens minnow manhood
Released into an Ontario lake as an experiment, tiny amounts of the hormone 
wreak havoc on male fish
MARTIN MITTELSTAEDT

ENVIRONMENT REPORTER

May 22, 2007

Back in the summer of 2001, a team of Canadian and U.S. researchers spiked a 
lake in Northwestern Ontario with traces of synthetic estrogen used in human 
birth control pills. They then repeated the unusual treatment for the next 
two years and sat back and watched what happened to minnows living in the 
lake.

The results were nothing short of frightening. Exposing fish to tiny doses 
of the active ingredient in the pill, amounts little more than a whiff of 
estrogen, started turning male fish into females. Instead of sperm, they 
started developing eggs. Instead of looking like males, they became 
indistinguishable from females. Within a year of exposure, the minnow 
population began to crash. Within a few years, the fish, which at one time 
teemed in the lake, had practically vanished.

Details of the unusual experiment, conducted by a team of Canadian and U.S. 
government scientists, are being published online this week in the 
Proceedings of the National Academy of Sciences. The dramatic results are 
likely to raise further concerns about the possible impact on wildlife and 
humans of drug residues in waterways.

In the experiment, the scientists added just enough estrogen to give the 
lake water the same level of the sex hormone found in water discharged from 
sewage treatment plants in Canada and in other countries where the birth 
control pill is widely used.

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Although the doses in the lake's water were thousands of times lower than 
the amounts women on the pill receive, even this slight exposure was enough 
to skew development in both male and female fish, with males far more 
affected.

After treatment, the lake water had estrogen concentrations of about 5 parts 
per trillion, the scientific equivalent of almost nothing. A part per 
trillion is the equivalent of a few grains of salt in an Olympic-size 
swimming pool. The amount of estrogen added was about a fifth of a gram a 
day, or about one-tenth the weight of a penny.

The lead researcher, Karen Kidd, who conducted the project while with the 
Department of Fisheries and Oceans and is now a biologist at the University 
of New Brunswick, was astonished that so little of a hormone used by people 
could harm fish.

"What's sobering for me is that we've shown such a dramatic response in fish 
population at these low concentrations," Dr. Kidd said in an interview.

It's not known what effect, if any, human exposure to estrogen in drinking 
water might have, although Dr. Kidd said it is an area that should be a 
research priority. Reproductive problems in human males, such as declining 
sperm counts and testicular cancer, have been rising in recent decades, and 
the causes are not known.

"When we see these kinds of responses in fish, it raises a red flag for what 
these compounds are doing to humans," she said.

There are currently no regulations in Canada covering estrogen or other drug 
residues in waterways. Municipalities typically don't check for them and it 
is not known if there are human health effects for people who draw drinking 
water from sources receiving sewage, a common practice in Canada.

Researchers with the U.S. Environmental Protection Agency also worked on the 
experiment, which was funded primarily by the federal government and the 
American Chemistry Council. One of the companies that manufactures birth 
control pills, Schering AG, donated the estrogen.

The researchers monitored fathead minnows, a species that breeds after about 
two years of life, making its population vulnerable to the reproductive 
effects of the drug sooner than longer-living fish.

After dosing the lake for three years, researchers monitored populations for 
the next two. It is expected that with time, estrogen levels in the lake, 
which was about 35 hectares, or about the size of a large farm field or a 
medium-sized cottage-country lake, will decline, allowing fish populations 
to recover.

To ensure that the population decline they were observing wasn't a natural 
phenomenon, the researchers tracked several other water bodies similar to 
the lake under investigation. There were no large population fluctuations 
elsewhere. The lake was located near Kenora.

Over the past decade, there have been a number of studies in North America 
and Europe showing skewed sexual development in aquatic life living near 
outfalls from sewage plants. This study is the first to show that exposure 
to drugs not only changes sexual characteristics, but can also destroy fish 
populations.

Dr. Kidd doesn't think women should stop taking the pill out of worry for 
wildlife. She said municipalities need to build more advanced sewage 
treatment plants, which are able to degrade more of the estrogen into 
harmless chemicals.

Because of the high expense of the project, estimated at $250,000 a year, 
the researchers didn't test the effects of lower estrogen levels on fish to 
determine if there is a safe exposure amount.

http://www.theglobeandmail.com/servlet/story/LAC.20070522.FISH22/TPStory/TPNational/Ontario/