Scientists have noticed some disturbing changes in the water, and the reproductive organs of fish, in the St. Lawrence River near Montreal.

Concentrations of estrogen as high as 90 times the normal rate have been discovered just downstream from the island of Montreal, according to researchers from l'Université de Montreal.

"What we measured is about 100 times more than the level known to have significant endocrine-disrupting effects," said Sébastien Sauvé, a professor of environmental chemistry at the university.

While researchers found estrodiol, a naturally occurring hormone that all women — particularly pregnant ones — release, they discovered synthetic estrogenic compounds as well.

"They're really pharmaceuticals which are used either as contraceptives or in hormone replacement therapy," Sauvé said.

Sauvé said even though HRT use has dropped dramatically in Quebec in the past few years, what ends up in the wastewater is still significant. Some compounds are filtered out at the sediment plant, but most ends up in the St. Lawrence.

Also implicated are the byproducts of plastics as they break down, and effluent from pulp and paper mills.

Meanwhile, other researchers studying a common species of minnow downstream from Montreal are finding ovaries in the testes of one-third of the males.

Scientists at Quebec's National Institute for Science Research made the discovery while studying how excessive hormones in the water were affecting fish.

"What we saw was that in the male fish, many of the male fish were developing ovaries — true feminization," said Daniel Cyr, a reproductive toxicologist at the institute.

Environmentalists say the findings make a potent argument for better testing of drugs and how they affect the environment.

"Pharmaceuticals are present around every big city in the water and that water is being retrieved and given to us as drinking water, so we could be exposing ourselves to very small quantities of a large number of prescription drugs," said Anne Wordsworth, a research associated with the Canadian Environmental Law Association.

Environmental engineers are hoping the hormones and other pharmaceuticals in human waste will be destroyed for good once Montreal installs a new ozonation process at its plant.

The project will cost $200 million, and has never been tested in a treatment plant the size of Montreal's.

Sauvé's fellow researchers are among those now running tests to make sure the process will work on a grand scale.