Modern medicines are moving through sewage treatment systems and into aquatic insects and the animals that eat them, according to an environmental study in Australia that involved a Hudson Valley researcher.

Tests of six Australian streams near the city of Melbourne found animals there contained high doses of painkillers, antidepressants and other drugs that had gotten into the water after passing through municipal sewer systems that are unequipped to remove them.

"Stream life is swimming in a mixture of pharmaceuticals," said Emma Rosi, an aquatic ecologist at the Cary Institute of Ecosystem Studies, based in Milbrook, Dutchess County. "While this study was in Australia, there is no reason to think it would be any different in the Hudson River — or any other place where there are people and drugs."

Rossi, along with Australian and Swedish researchers, examined caddisflies, spiders, and other insects, as well as platypus and brown trout, which are predators of such aquatic life in that region, for 98 different medical drugs between 2014 and 2015. They found 69 of the drugs.

Chemicals were being taken up by insects that lived in the water, and then passed into the predators that ate the inspects, including spiders, trout and platypus.

Results showed, for example, that brown trout in one creek were being exposed each day to the equivalent of a quarter of a daily human dose of antidepressants. In another location, a platypus eating its normal diet of aquatic insects was being exposed to half of the daily dose for antidepressants.

The most commonly found drugs in the insects were tramadol, a form of synthetic opiate; codeine, an opiate painkiller; fluconazole, an anti-fungal drug; the high blood pressure medication metoprolol; and clomipramine, an antidepressant.

Drugs are likely entering the sewage systems after being excreted by people who are taking the medicines.

"Our study is the first to show that this chronic drug pollution can concentrate in aquatic insects and move up food webs, in some cases exposing top predators to therapeutically-relevant doses," Rosi said.

"Pharmaceutical use is increasing worldwide," she said. "We don't know the ecological consequences of exposure to this pollution. What does it mean to be a platypus or trout with more than 60 drugs in your tissues? If you told your doctor that you were taking 60 different drugs, they would be very concerned."

The work was supported by the Australia Research Council, the Society of Freshwater Science Fellows endowment award, and the Millbrook Garden Club in Dutchess County. It was published Tuesday in the peer-reviewed journal Nature Communications.

The study reinforces findings in a recent report on the Hudson River that found river water contained elevated levels of caffeine, artificial sweetener and medications for high blood pressure, ulcers, heartburn and pain relief.

In that analysis, researchers found varying and sometimes concerning levels of 16 different pharmaceuticals, including antibiotics, drugs for treating high blood pressure, high cholesterol, epilepsy, ulcers and heartburn, and the common aspirin substitute acetaminophen.

Results were based on samples taken from the Hudson by the environmental group Riverkeeper at more than 70 spots along the river — from Troy to New York City — between May and July 2016. Some of the highest chemical levels were found near sewage discharge pipes for Kingston, where some drugs were found in what the report termed "potentially worrisome quantities."

That study was a collaboration of the U.S. Environmental Protection Agency, Riverkeeper, Columbia University's Lamont-Doherty Earth Observatory and Queens College.

Earlier studies have confirmed the presence of pharmaceuticals in river water in the Hudson and elsewhere in the United States. Recently, researchers found high concentrations of antidepressants in the brains of fish from the Niagara River in western New York.

A 1999-2000 study by the U.S. Geological Survey found measurable amounts in 80 percent of water samples taken from 30 states. A 2008 investigation by The Associated Press found detectable levels of various medications in the drinking water of some 40 million Americans.

Rosi said such studies support increased funding to upgrade municipal sewer systems. "There are ways to treat water for some of these drugs," she said. "We have to invest in our infrastructure."