When most people think about water pollution, they imagine fertilizer runoff, leaky factories, and city sewage. But there is growing concern about a host of “emerging contaminants,” unregulated, unmonitored chemicals in the water that might harm humans, animals, and the marine environment. These chemicals are in products we use every day: shampoo we rinse down the shower drain, suntan lotion that washes off in the lake, medication that passes through our bodies and into sewer lines. All these chemicals end up polluting our nation’s waterways. Collectively, they are known as Pharmaceuticals and Personal Care Products, or PPCPs. The U.S. Environmental Protection Agency (EPA) has identified over 100 individual PPCPs in environmental samples and drinking water.

The release of PPCPs into the environment is not regulated, and sewage systems are not equipped to remove them from the water. Because the concentrations are so low, scientists aren’t sure if these chemicals are dangerous to marine life or humans. But they worry that continuous exposure to the chemicals may lead to problems such as antibiotic resistance and disruption of the endocrine system—the glands that produce hormones and the receptors that react to them. Biologists have already found evidence of endocrine disruption in frogs and fish, such as the presence of both male and female characteristics within the same animal. They now wonder if effects already observed in people, such as the earlier onset of puberty, may be related to these new chemicals in drinking water.

There are other concerns, as well, such as the combinations of chemicals in the water. Toxicologists worry about chemical synergy: chemicals that are individually safe may have amplified or toxic effects when combined. Scientists also worry about scenarios such as fetal exposure to low levels of medications that a pregnant woman would ordinarily be avoiding.

What can we do to help? According to EPA, prescription drugs should not be flushed down the toilet or dumped in the drain unless the label specifically instructs you to do so. Some communities offer pharmaceutical take-back programs or household hazardous waste collection programs that accept pharmaceuticals.

What is most worrisome to scientists is the uncertainty. Because these chemicals are unregulated, nobody is sure how many and how much are in the drinking water supply and what they might do. So far, even though harm to animals has been documented, scientists have found no evidence of harm to humans from this chemical soup, but the full risks are still unknown.

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