Traces of medications and common chemicals were found in fish in five U.S. rivers, a new study showed.

The study identified seven medications and common chemicals in the tissue and livers of fish such as antihistamine diphenhydramine (Benadryl), carbamazepine (a drug used for epilepsy and bipolar disorder), an anticonvulsant and two types of antidepressants.

The tainted fish were from waterways in or near cities of Chicago, Dallas, Philadelphia, Phoenix and Orlando, said the study published on Friday in a special on-line edition of Environmental Toxicology and Chemistry.

Each river is considered "effluent-dominated," because they receive large amounts of wastewater discharge from nearby sewage treatment plants, according to the study conducted by the U.S. Environmental Protection Agency and Texas-based Baylor University.

While other studies have found pharmaceuticals and personal care products in wild river fish, this is the first time multiple compounds have been found in fish from several different locations, said co-lead investigator Bryan Brooks, an associate professor of environmental sciences at Baylor.

The Federal government has set standards for treated wastewater, but such standards do not address pharmaceuticals or most personal care products, and little is known about the effects they have on the environment and wildlife, said the study.

Previous research has concluded that behavior vital for fish survival, such as mating and fighting, can be affected if too much antidepressant residue collects in their systems.

Source: Xinhua