Posted on Sunday, January 06, 2002 12:50:00 AM by Brian Kopp DPM
Flushed hormones change sex of fish
Synthetic estrogen in water from sewage causes male fish to produce eggs: study
Tom Spears
The Ottawa Citizen
Saturday, January 05, 2002
Women who take birth control pills or hormone therapy are flushing enough hormones down the toilet to make male fish downstream produce eggs, a Canadian study shows.
Synthetic estrogen in the women's urine goes through sewage treatment plants without being completely broken down, and the fish absorb it, with bad effects following.
Male fish produce eggs in their testes. Female fish are stimulated by the extra hormones to produce eggs at the wrong times of year.
And there are questions, still unanswered, about whether these chemically altered fish are capable of reproducing at all.
Scientists have seen this "gender-bending" effect in fish downstream from sewage plants, but lacked proof that birth control pills are a cause.
So Karen Kidd of Fisheries and Oceans Canada started dribbling bits of the synthetic hormone from birth control pills into a 34-hectare lake in northwestern Ontario, west of Dryden, to find out. The lakes are so remote they don't even have names (this one is called Lake 260) and are perfectly suited to act as giant experiments because they are practically untouched by pollution.
Sure enough, the male lake trout, white suckers, fathead minnows and pearl dace turned up this fall with proteins that females use to manufacture egg cells, and in some cases with the eggs themselves.
"The question now is whether this feminization is affecting the population size or sustainability," she said. "Can males with eggs in their testes reproduce effectively? Can they contribute to the population?"
It will take another summer of adding chemicals, and a couple of years of counting fish afterwards, to know the full effects. But Ms. Kidd is finding an interested audience in Vancouver this weekend, where she will show her early results to a conference of fisheries scientists.
"People consume the birth control pills and it's lost from their bodies and goes into the sewage," said Peter Leavitt, a biology professor at the University of Regina. "So we get this huge population in sources like cities, dumping this very high concentration of hormones into the water bodies. And the question is: Is it having an influence?
"It seems to be mimicking some of the reproductive hormones that other organisms use, and it's basically messing up their reproductive strategies," he said. "I think it's really significant," because no one thought of human sewage as a source of this type of pollution before, he said.
"And what Karen is showing is that there are consequence of large numbers of people living in an area ... It's not so much that we're destroying their (the wildlife's) habitat. But we're actually changing the chemical environment in which they live and breathe."
Ms. Kidd says both natural and synthetic estrogen go into sewage in urine, but bacteria take longer to break down the synthetic version, which means more of it gets into the fish.
For 10 years scientists have studied chemicals that act like estrogen in fish, other wildlife, and even humans that eat tainted fish. Many of these come from pesticides or industrial waste and are never intended to be like hormones at all. But this study is unique in looking at real hormones flushed down the drain.
Ms. Kidd says both natural and synthetic estrogen go into the sewage system in urine, but bacteria take longer to break down the synthetic version, which means more of it gets into the fish.
The Lake 260 experiment uses the amount of hormone that would come from 6,000 women taking the pill, she said.
So, along freshwater rivers which use river water for a water source, the male population is essentially consuming excreted estrogen in trace amounts from the use of the pill upstream....I wonder if the population of gender confused humans downstream is higher in proportion to the population than upstream.
“Ms. Kidd says both natural and synthetic estrogen go into the sewage system in urine, but bacteria take longer to break down the synthetic version, which means more of it gets into the fish.”