At least one pharmaceutical chemical was detected in all 59 streams sampled
Released by Alex Demas and Paul Bradley, US Geological Survey
In a release dated May 25, 2016, and according to a new study by the US Geological Survey, pharmaceuticals are widespread in small streams in the Southeastern United States.
In 2014, the US Geological Survey sampled 59 small streams in portions of:
- North Carolina
- South Carolina
for 108 different pharmaceutical compounds and detected one or more pharmaceuticals in all 59 streams. The average number of pharmaceuticals detected in the streams was six (6).
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 US Geological Survey 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.”
The most common pharmaceutical chemicals detected are:
- Metformin — Used to treat Type II diabetes, this chemical was detected in 89% of samples.
- Lidocaine — Used as a pain reliever, this chemical was detected in 38% of samples.
- Acetaminophen — Used as a pain reliever, this chemical was detected in 36% of samples.
- Carbamazepine — Used to treat seizures, this chemical was detected in 28% of samples.
- Fexofenadine — Used as an anti-histamine, this chemical was detected in 23% of samples.
- Tramadol — An opioid pain reliever, this chemical was detected in 22% 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% 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.
The chemicals with the highest concentrations are those listed above, but none exceeded human health benchmarks. In addition to the individual chemicals listed, the two groups of compounds most frequently detected were nicotine-related compounds (71% of samples) and caffeine-related compounds (detected in 49% of samples).
This study is one of several regional stream-quality assessments by the US Geological Survey National Water Quality Assessment (NAWQA) Project. Findings will provide the public and policy-makers with information regarding which human and natural factors are the most critical in affecting stream quality. Regions studied include the Midwest (2013), Southeast (2014) and the Pacific Northwest (2015), and planning is underway for studies in the Northeast (2016) and California (2017).
Support for this work was provided by the US Geological Survey National Water Quality Program’s NAWQA Project.
Additional support was provided by the US Geological Survey Toxic Substances Hydrology Program.