Millions of pounds of pharmaceuticals that can act as mutagens have been released into American waterways, including those that provide drinking water. The drugs range from antibiotics and opiates to tranquilizers.
Based on secrecy agreements with the researchers, the treatment plants were not identified, AP reports.
Two studies have been performed to measure the level of harmful substances in sewage from 1,886 pharmaceutical manufacturing facilities.
One study revealed that the concentration of the muscle relaxant metaxalone in treated sewage was hundreds of times higher than the admissible level.
In another study, Environmental Protection Agency researchers tested sewage at a municipal wastewater treatment plant in Kalamazoo, Mich., that serves a major Pfizer Inc. factory. AP cites Bruce Merchant, Kalamazoo's public services director, as indicting that unusually high concentrations of the antibiotic lincomycin have been found in wastewater. The drug was removed, but some amounts still remained.
Lincomycin is known as a mutagen, changing genetic information in bacteria, algae, microscopic aquatic animals, and fish. Some researchers say it could be a potential hazard for pregnancy or infancy.