Contamination of U.S. Rivers Fish with Common Drugs

Key Takeaways:

  • Freshwater fish in five major U.S. rivers appeared to be contaminated with residues of common drugs and chemicals.
  • Federal guidelines for treated wastewater do not currently cover pharmaceuticals or majority of personal care products, resulting in potential environmental and wildlife impacts.
  • This study is the first to detect multiple compounds in fish across different locations; the 7 most commonly discovered ones included diphenhydramine, gemfibrozil, diltiazem, carbamazepine, norfluoxetine, sertraline, galaxolide and tonalide.
  • The highest concentrations of these contaminants were found in fish tissues and livers, indicating that most foreign substances that infiltrate the body are processed by the liver.

Freshwater fish of five major rivers in America appeared to be contaminated with residues of widely used drugs and common chemicals, as per the findings of a new study carried out by the U.S. Environmental Protection Agency collaboratively with Baylor University.

Identifiable Pharmaceutical Traces

The traces of common antihistamine diphenhydramine, an anticonvulsant, and two categories of antidepressants, made up seven pharmaceuticals that were discovered in the tissues and livers of fish. The rivers under observation were located in or around major cities – Chicago, Dallas, Philadelphia, Phoenix, and Orlando.

These rivers are classified as “effluent-dominated,” receiving a substantial amount of wastewater discharge from nearby sewage treatment facilities.

Existing Federal Regulations and their Limitations

Federal guidelines have been established for treated wastewater. However, these do not cover pharmaceuticals or the majority of personal care products, and the impact these have on the environment and wildlife isn’t yet fully understood. This study is part of the government’s initiative to confront this issue.

According to previous research, vital fish behavior, such as mating and fighting, can be impacted if an excessive amount of antidepressant remains accumulate in their systems.

Unprecedented Discovery of Multiple Compounds

While other investigations in the past have discovered pharmaceuticals and personal care products in wild river fish, this research is unique in its detection of multiple compounds in fish across various locations. This revelation was divulged in a news release by co-lead investigator Bryan Brooks, an associate professor of environmental sciences at Baylor.

Details of Found Medications and Chemicals

The list of discovered medications and chemicals from the 36 potential contaminants they were examining includes:

  • diphenhydramine,
  • the cholesterol drug gemfibrozil, which has reportedly never been detected in wild fish before,
  • diltiazem, an antihypertensive medication,
  • carbamazepine, a medication used in the treatment of epilepsy and bipolar disorder,
  • norfluoxetine, an active ingredient in the antidepressant fluoxetine,
  • the antidepressant sertraline,
  • galaxolide and tonalide, prevalent scent-enhancing ingredients in soap and other hygiene products.

Highest concentrations of galaxolide and tonalide were located in the fish tissue, whilst the others were mainly concentrated in the liver which properly processes foreign substances that infiltrate the body.

The research was showcased at the American Chemical Society annual conference in Salt Lake City and is due to be published in a unique online edition of Environmental Toxicology and Chemistry.

Further Information

The U.S. Geologic Survey offers more details on this matter. Find out more about toxins in wastewater here.

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