Researchers testing water samples in the Great Lakes found alarming traces of prescription drugs, caffeine and other chemicals in Lake Michigan.

Scientists from the School of Freshwater Sciences at the University of Wisconsin-Milwaukee were examining water samples for PPCPs, chemicals that have been derived from pharmaceuticals and personal care products. The effects of these pollutants have been studied in rivers, harbors and other watersheds. But no previous studies ever assessed PPCPs offshore in Lake Michigan -- the world's sixth-largest lake by volume. It was thought human, industrial and agricultural wastewater contaminants would be diluted by the sheer amount of water that Lake Michigan holds.

"There's a belief with very large bodies of water that the solution to pollution is dilution," Rebecca Klaper, one of the co-authors of the study at the School of Freshwater Sciences, told The Huffington Post.

Instead, a cocktail of pharmaceutical drugs, caffeine and other toxins were found farther out from shore and at higher levels than the researchers expected.

"There's basically a soup of all these chemicals at very low levels," she said.

The researchers found 32 PPCPs, some located two miles offshore from two Milwaukee wastewater treatment plants, the Detroit Free Press reported. PPCPs are often present in wastewater, as the human body usually can't entirely absorb pharmaceutical chemicals, according to the EPA.

"It was surprising that [Metformin] was so prevalent and it wasn't broken down in the sewage treatment plant -- and we could find it three kilometers out in the lake," Klaper said.

The most frequently found PPCPs were Metformin, the diabetes medication found in every single water sample; caffeine, likely from energy drinks and soda; suflamethoxazole, an antibiotic used to treat urinary tract infections; and Triclosan, an antibacterial agent that's commonly used in soaps and toothpaste. These four pharmaceuticals and chemicals were all found in more than 50 percent of the offshore samples the team collected over the past two years.

All in all, 14 of the PPCPs present a “medium” or “high” ecological risk, the researchers say.

And given their prevalence so far out from shore, the researchers say the initial findings from the study have implications for other large bodies of water -- "the potential ecological risk for large lake systems in much higher than previously understood," the study concludes.

The researchers note that fish and animals who call Lake Michigan home could be in danger from exposure to these chemicals, but the EPA says that scientists haven't found any adverse human health affects of PPCPs.

A better understanding of the occurrence of PPCPs in large water systems, particularly in areas with substantial urban development, needs further investigation, the report said. Right now, Klaper and her team are looking for more funding. They'd like to go out to the middle of Lake Michigan to keep testing water samples, but they'd also like to pinpoint which of these chemicals should be targeted for removal or replacement.

She says there still isn't enough information about what happens when these chemical compounds combine and react, and what that does to the environment.

"The study doesn't suggest that people should stop taking these medications, or that all chemicals are bad," she said. "It's that we need some more information on the environmental effects, and to consider that when we put it out on the marketplace and target that for removal with our treatment technologies."

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