ARLINGTON — Hormone replacement pills and other drugs, along with dandruff shampoo, perfumes and other personal-care products that go down the drain could be hurting life in the Stillaguamish River.

The Stillaguamish Tribe is concerned that chronic, low-level exposure to chemical contaminants is creating a toxic environment that could hurt chinook salmon and cause reproductive problems for the fish.

The U.S. Geological Survey has figured out how to spot such chemicals in the water and has enlisted the help of the city of Arlington to do a two-year investigative study on what are called “emerging contaminants” in the river.

Until now these contaminants haven’t been commonly monitored in the environment. Some of these small amounts of chemicals have been in local waters for a long time, but haven’t been readily observed until the Geological Survey developed new detection methods, said USGS Washington water science center spokesman John Clemens.

No longer are people told to flush their expired pills down the toilet. Prescription drugs, however, get into the water as more people take medicines and send them flushing with human waste.

Besides pills, pharmaceutical waste includes such things as vitamins, food supplements and additives, veterinary medicines, ointments and sunscreen. Currently there is little information regarding the potential toxicological significance of these chemicals in ecosystems, particularly from long-term, low-level exposure.

“The study of these contaminants is just coming on the radar screen,” Clemens said. “We’ve only learned recently how to detect drugs and personal care products in the water. What we do know is that most treatment plants are not set up to deal with these chemicals.”

A major part of the study will be a look at how well Arlington’s wastewater treatment plant deals with such chemicals before releasing them into the river. Samples from the wastewater coming into the plant and from the treated water being discharged are being taken now.

Those samples will be compared with another set taken in 2011, about six months after Arlington’s upgraded and expanded plant begins treating wastewater.

The upgraded wastewater treatment plant should do a better job removing these chemicals than does the current treatment process, city public works director James Kelly said.

“The study is not so much a chance to show the efficiency of the new facility, but to find out what these chemicals do to the environment and to help educate people to show them how to keep chemicals out of the water,” Kelly said. “This is a new study. Though it’s not exhaustive, it will show trends and be of interest around the state and the country.”

Wild animal and farm animal waste, septic systems and storm-water runoff also play a part in the pollution of the Stillaguamish River, Kelly said.

“But if we can pull unwanted medicines and other products from the waste stream, we’ll be doing a better job,” he said. “Arlington is doing this study voluntarily because we want to be good stewards of the river.”

The study will provide information to add to another done by the tribe and the Geological Survey in 2008 to identify sources of emerging contaminants in the Stillaguamish watershed. The watershed covers about 700 square miles and 4,600 miles of streams and rivers before they flow into the inland waters of the Puget Sound region near Stanwood.

The city of Stanwood is not participating in the project because of the cost involved, public works director Andrew Bullington said.

“With the current economy, we elected not to participate in the study right now,” Bullington said. “But we are very interested to find out what happens in Arlington and how that plays out.”

Stillaguamish Tribe wildlife biologist Jennifer Sevigny said the tribe is grateful that the city of Arlington is participating in the study.

The tribe primarily is concerned about how emerging contaminants are affecting the hormonal health of fish in the river, she said.

“There’s some pretty incredible data that’s going to come out of the study that people need to know,” Sevigny said. “We need to reprogram ourselves to live differently and be more responsible.”

Gale Fiege: 425-339-3427; gfiege@heraldnet.com.