Trace amounts of 16 different drugs and personal care products were found in Illinois drinking water, but at such low levels that they do not pose a risk for public health at this time, according to a report from the Illinois Environmental Protection Agency released in August.

The Illinois EPA launched the study in March after media attention surrounding the issue prompted the state to take action. The Associated Press published a three-part investigative series in March that found drug traces in the drinking water of 24 major U.S. cities and the Chicago Tribune ran a story in April that found similar results in Chicago.

“As the state agency responsible for overseeing the public drinking water supplies, we decided it was the right thing to do just to find out what was out there,” said Maggie Carson, Illinois EPA spokesperson.

Some of the chemicals detected in the water samples include insect repellent, pain reliever, veterinary growth hormone, blood pressure medicine, blood lipid regulator and both veterinary and human antibiotics.

“Based on what we know about these chemicals, there does not appear to be a health threat,” said Roger Selburg, division of public water supplies manager with the Illinois EPA. “That can be said for the here and now.”

But as uncertainties remain, it’s premature to suggest that the issue of drugs and personal care products in drinking water is resolved at this time, according to the report.

The Alliance for the Great Lakes, a nonprofit interest group that focuses on conserving the Great Lakes, agreed with the Illinois EPA’s assessment that the state’s water supply remains safe to drink, according to the group’s water quality program manager Lyman Welch. But Welch also said he sees areas of concern and potential warnings.

“The levels are very low, but sometimes with hormones, I understand, even at a very low level they can act like an on/off switch and might have an impact,” Welch said. “That’s something that is still being studied.”

EPA toxicologists and public health professionals are looking at what trace amounts of the drugs could mean for human health, Carson said. Right now it appears unlikely that there is an effect because the amounts are so minuscule, she said.

But there are still uncertainties and unanswered questions that the study did not address.

Mike Davis, chair of physical sciences at Harold Washington College, said he would like to see the EPA look at things like soda and sports drinks, in which water is the predominant ingredient to see if they also have trace amounts of drugs in them.

The reports about drugs getting into the water supply are probably an early warning sign that as Americans buy and use more drugs, the levels are likely to increase, Welch said.

There are also concerns about bioaccumulation, which is what happens when substances become more concentrated in organisms as they build up in the food chain .

“[Substances] get into water and then they are taken in by zooplankton or phytoplankton, which are then eaten by larger species, like fish.” Davis said. “By the time you get up to some of the largest species, like predatory fish for example, they might have a lot of this stuff in them.”

Water samples collected in March in Chicago and around the state were tested for 56 chemicals found in drugs and personal care products. These drug traces are mainly entering the water supply through human excretion or improper disposal of unused medication, such as flushing old pills down the toilet.

“There is considerably more research that’s needed before developing any sort of regulation,” Selburg said. “This is going to take a very large number of highly qualified people to work on this program, and it is work that is being done.”

This is not just an issue in the United States or Illinois, but something that is being studied worldwide. As more research is done, scientists and public health officials need to share their findings with each other, Selburg said.

“There is so much information out there right now that it needs to be ordered and put in some sort of package that makes sense so that some conclusions can be reached about what are acceptable levels for these materials to be present in the water,” Selburg said.

Carson said there are no federal standards or health guidelines for drugs and personal care products in drinking water, and the government does not require water to be monitored for these types of chemicals.

“Hopefully what [the study] shows doesn’t get interpreted by people as nothing to worry about. Feel free to dump whatever you want,” Davis said. “But we are not at the danger point yet.”