Pharmaceutical Chemicals in Southeastern Streams

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Pharmaceuticals are widespread in small streams in the Southeastern U.S., according to a new study by the U.S. Geological Survey.

In 2014, the USGS sampled 59 small streams in portions of Alabama, Georgia, North Carolina, South Carolina, and Virginia for 108 different pharmaceutical compounds and detected one or more pharmaceuticals in all 59 streams.

Previous research indicated that wastewater treatment facility discharges were the most likely source for pharmaceutical chemicals in surface water. However, the findings in this study, reported in the journal Environmental Science and Technology Letters, indicate other sources as well. Only 17 of the 59 streams have any reported wastewater discharges.

“The widespread occurrence of pharmaceuticals in these small streams irrespective of wastewater discharges indicates the need for approaches for preventing pharmaceutical contamination that extend beyond effluent treatment,” said Paul Bradley, a USGS research hydrologist and the lead author of the study. “Sources of pharmaceuticals to these small streams likely include aging sewer infrastructure and leakage from septic systems.”

Common pharmaceutical chemicals detected included:

Metformin: Used to treat Type II diabetes, this chemical was detected in 89 percent of samples

Lidocaine: Used as a pain reliever, this chemical was detected in 38 percent of samples

Acetaminophen: Used as a pain reliever, this chemical was detected in 36 percent of samples

Carbamazepine: Used to treat seizures, this chemical was detected in 28 percent of samples

Fexofenadine: Used as an anti-histamine, this chemical was detected in 23 percent of samples

Tramadol: An opioid pain reliever, this chemical was detected in 22 percent of samples

Although much uncertainty remains as to how pharmaceuticals affect aquatic organisms, some adverse effects have been documented.

Antibiotic/antibacterial contaminants, detected in at least 20 percent of streams, can affect aquatic microbial communities, altering the base of the food web.

Antihistamines, frequently detected in this study, affect neurotransmitters for many aquatic insects. And metformin, nearly ubiquitous in the streams studied, can affect the reproductive health of fish.

Also frequently detected were were nicotine-related compounds (71 percent of samples) and caffeine-related compounds (detected in 49 percent of samples).

This study is one of several regional stream-quality assessments by the USGS National Water Quality Assessment (NAWQA) Project.

source: U.S. Geological Survey