A variety of pharmaceuticals have been found to be present in rivers and tap water in the U.S.
The drugs include painkillers, tranquilizers, anti-depressants, antibiotics, birth control pills, estrogen replacement therapies, chemotherapy agents, anti-seizure medications and many others.
The pharmaceuticals are found in treated sewage effluents, surface waters, soil, and tap water, though at very low levels (measured in parts per trillion). These levels do not induce acute effects in humans, but have been found to affect aquatic ecosystems.
Water treatment plants are not set up to filter these chemicals. They find their way into the water when people or animals taking medications excrete them, in addition to people who flush medications into the toilet. In some cases, 50 to 90% of a pharmaceutical drug is excreted from the body in its original biologically active form.
Even if you drink bottled water or filter your water, you come into contact with municipal water through activities such as brushing your teeth or consuming beverages and foods that have been produced using municipal water. To avoid this, we recommed installing a rainwater catchment system for your house, and purchasing food and beverages of known quality.
In 2002, hydrologists with the U.S. Geologic Survey released the first nationwide government study about medicine and hormones, such as estrogen and other organic waste in streams around the United States.
They found low levels of 82 chemicals. The most common were steroids, such as cholesterol, nonprescription drugs, insect repellant, detergent chemicals and disinfectants.
Kelly A. Reynolds, a research scientist at the University of Arizona, writes: “The truth is, no one knows [the effects of pharmaceuticals and similar contaminants in the water]. Some scientists believe the exposure levels are so low they’re ineffective. Others are concerned about long-term, chronic and combined exposures to agents designed to cause a physiological effect in humans. Many more scientists agree we should be concerned about aquatic ecosystems where sperm levels and spawning patterns in aquatic organisms have been clearly altered in environments heavily polluted with a class of hormone-altering pharmaceuticals known as endocrine disrupters.”
More information can be found in these articles: Pharmaceuticals in Drinking Water Supplies and Hormones and pharmaceutical drugs found in wastewater in California.