SEATTLE— Conservation groups filed a notice today of their intent to sue the city of Tacoma, Washington, for discharging toxic wastewater at levels that harm Puget Sound Chinook salmon, protected as threatened under the Endangered Species Act.

The legal action takes aim at largely unregulated pollutants including pharmaceuticals, personal-care products, pesticides and industrial chemicals that have been shown to cause decreased growth and reproductive problems in the salmon.

In today’s notice Northwest Environmental Advocates and the Center for Biological Diversity cited numerous studies indicating that the contaminants discharged in Tacoma’s treated sewage are poisoning Puget Sound Chinook.

Based on those studies, the groups charge, Tacoma is causing illegal “take” of the protected Chinook in violation of the Endangered Species Act.

“Despite scientists’ years of having demonstrated harm to Puget Sound Chinook from Tacoma’s discharge of personal care products, synthetic hormones and industrial chemicals, EPA and the Department of Ecology have done absolutely nothing to prevent it,” said Nina Bell, executive director of Northwest Environmental Advocates. “We’re stepping up to stop Tacoma’s pollution because the regulatory agencies have long stepped away from doing their jobs.”

Studies conducted over the past decade show that Tacoma’s treated sewage reduces Chinook survival rates to nearly half that of juvenile fish moving through less contaminated Puget Sound estuaries. The studies identified a “dysfunction that appeared to mimic starvation” in Chinook exposed to the contaminants present in Tacoma’s treated sewage.

Tacoma’s discharges violate the Endangered Species Act because the pharmaceuticals and other toxic chemicals reduce the salmons’ ability to reproduce, grow and fight off diseases, according to the groups’ notice letter.

Puget Sound Chinook are also a key food source for highly imperiled Southern Resident killer whales, known to be among the most contaminated marine mammals in the world. The groups also charge that the Tacoma wastewater-treatment plant is violating its Clean Water Act stormwater permit.

“It’s extremely unfortunate that on a daily basis Tacoma has fouled waterways and harmed protected salmon with toxic wastewater,” said Lori Ann Burd, the Center for Biological Diversity’s environmental health director. “We’re determined to do what it takes to make sure the city stops discharging toxic contaminants into the Sound so that people, salmon and orcas can thrive.”

Tacoma officials have 60 days to respond to the concerns raised by today’s notice before a lawsuit can be filed in federal court.