Elected officials and environmental advocates are poised to ask the city tough questions in the wake of a news report asserting that New Yorkers are likely consuming trace amounts of pharmaceuticals when they drink from the local water supply.

The report contends that traces of at least 15 pharmaceuticals or their byproducts — including hormones and mood stabilizers — have been discovered in the upstate watersheds that provide drinking water to the city, and that New York’s drinking water has never been tested for pharmaceuticals.

“This is very alarming,” a member of the City Council’s Committee on Environmental Protection, Peter Vallone of Queens, said. “Rather than sit back and be informed about this, New York City should have been proactive. I would hope we institute some sort of testing as soon as possible.”

Following requests for comment regarding the report by the Associated Press, the New York City Department of Environmental Protection released a statement yesterday afternoon acknowledging concerns about the issue: “Though nothing in the information we’ve seen presents a risk to this water supply, we understand and take very seriously public concerns about pharmaceuticals in drinking water and continue to closely monitor this emerging national issue, in cooperation with the New York City Department of Health and Mental Hygiene. DEP and DOHMH are working together to develop an education program about the best disposal methods for medications, targeting both watershed communities and city residents, and to consider appropriate next steps.”

The chairman of the council’s Committee on Environmental Protection, James Gennaro of Queens, said the federal government and the state government should first address the issue by undertaking a risk assessment.

“Once we have an understanding of the risks, than we can figure out how to deal with the problem,” he said.

The report points out that while the quantity of pharmaceuticals found in the watersheds is minute and has not been proved to be harmful to humans, a study found that feminized male flounder in Jamaica Bay were likely affected by discharged pharmaceuticals containing forms of estrogen.

A state senator who is a member of the state Senate Committee on Environmental Conservation, José Serrano of the Bronx, said he was especially concerned about how pharmaceuticals could affect young people drinking the water supply. The policy director for Riverkeeper, an environmental organization that advocates for protecting the city’s drinking water, Lisa Rainwater, said that with more people using increasing amounts of pharmaceuticals, the issue is likely to become one of the country’s most important environmental concerns moving forward.