Researchers at the National Institute of Standards and Technology (NIST) have published an interesting study that sheds light on the fate of a familiar pharmaceutical as it enters the waste stream. In work initially described last year, NIST chemists investigated probable chemical reactions involving acetaminophen when the drug is subjected to typical wastewater processing. Acetaminophen is the most widely used pain reliever in the United States, and a study of 139 streams by the U.S. Geological Survey found that it was one of the most frequently detected man-made chemicals.

The scientists found that the drug readily reacts in chlorine disinfection to form at least 11 new products, at least two of which are known to be toxic. The results, according to lead author Mary Bedner, demonstrate that environmental scientists need to be concerned about downstream reaction products as well as the original waste materials. "The issue is what you should be looking for in the environment," she says. "When you are looking for the effects of pharmaceuticals in the environment, you need to ask what they're going to turn into."

From NIST