Bernot, M.J., et al., Science of the Total Environment, 572:422-433, December 2016
We collaborated with 26 groups from universities across the United States to sample 42 sites for 33 trace organic compounds (TOCs) in water and sediments of lotic ecosystems. Our goals were 1) to further develop a national database of TOC abundance in United States lotic ecosystems that can be a foundation for future research and management, and 2) to identify factors related to compound abundance. Trace organic compounds were found in 93% of water samples and 56% of sediment samples. Dissolved concentrations were 10–1000 × higher relative to sediment concentrations. The ten most common compounds in water samples with detection frequency and maximum concentration were sucralose (87.5%, 12,000 ng/L), caffeine (77.5%, 420 ng/L), sulfamethoxazole (70%, 340 ng/L), cotinine (65%, 130 ng/L), venlafaxine (65%, 1800 ng/L), carbamazepine (62.5%, 320 ng/L), triclosan (55%, 6800 ng/L), azithromycin (15%, 970 ng/L), diphenylhydramine (40%, 350 ng/L), and desvenlafaxine (35%, 4600 ng/L). In sediment, the most common compounds were venlafaxine (32.5%, 19 ng/g), diphenhydramine (25%, 41 ng/g), azithromycin (15%, 11 ng/g), fluoxetine (12.5%, 29 ng/g) and sucralose (12.5%, 16 ng/g). Refractory compounds such as sucralose may be good indicators of TOC contamination in lotic ecosystems, as there was a correlation between dissolved sucralose concentrations and with the total number of compounds detected in water. Discharge and human demographic (population size) characteristics were not good predictors of compound abundance in water samples. This study further confirms the ubiquity of TOCs in lotic ecosystems. Although concentrations measured rarely approached acute aquatic-life criteria, the chronic effects, bioaccumulative potential, or potential mixture effects of multiple compounds are relatively unknown.
Source: Water Feed
Frequently Asked Questions
What are trace organic compounds (TOCs) found in water?
Trace organic compounds (TOCs) are a diverse group of contaminants found in water, including pharmaceuticals, pesticides, and industrial chemicals. These compounds are typically present at very low concentrations in lotic ecosystems like streams and rivers. While often unregulated, they pose potential long-term health risks and environmental concerns.
How prevalent are trace organic compounds in U.S. streams and rivers?
A national USGS study found trace organic compounds in 80% of sampled U.S. streams and rivers. The collaborative study mentioned in the blog post further confirmed this ubiquity, detecting TOCs in 93% of water samples across 42 sites. These findings highlight the widespread presence of these contaminants in lotic ecosystems.
What are the most common trace organic compounds detected in U.S. waterways?
The study identified sucralose (87.5% detection), caffeine (77.5%), sulfamethoxazole (70%), cotinine (65%), and venlafaxine (65%) as some of the most common TOCs in water samples. Other frequently detected compounds included carbamazepine, triclosan, and azithromycin. Sucralose, a refractory compound, was also noted as a potential indicator of overall TOC contamination.
How effective is reverse osmosis at removing trace organic compounds from water?
Reverse osmosis (RO) membranes are highly effective at removing trace organic compounds, achieving 90–99% rejection of most TOCs. This makes RO the most reliable point-of-use treatment technology for communities dealing with contaminated source water. AMPAC USA designs and manufactures advanced RO systems capable of addressing these complex contaminants.
Are trace organic compounds in water currently regulated in the United States?
Most trace organic compounds (TOCs) found in U.S. waterways are largely unregulated, despite their widespread presence and potential health implications. While concentrations rarely approach acute aquatic-life criteria, the chronic effects, bioaccumulative potential, and mixture effects of multiple compounds remain relatively unknown. This lack of regulation underscores the importance of advanced purification methods like reverse osmosis.
Related Articles
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- Nationwide reconnaissance of contaminants of emerging concern in source and treated drinking waters of the United States
- Review of perchlorate occurrence in large public drinking water systems in the United States of America
- Environmentally Relevant Chemical Mixtures of Concern in Waters of United States Tributaries to the Great Lakes
Conclusion
This national reconnaissance data confirms what water utilities have suspected for years — trace organic compounds like sucralose, caffeine, and pharmaceuticals show up in the large majority of US surface water samples, usually at concentrations too small to see but not necessarily too small to matter over time. Because these compounds are still largely unregulated, treatment technology has to do the work that policy hasn’t caught up to yet, and reverse osmosis membranes are one of the few methods that reliably reject 90-99% of them. For more on how contaminants like these are tracked nationally, see our related coverage of contaminants of emerging concern in US drinking water. If you’re evaluating treatment options for a water source with known or suspected TOC contamination, contact our team at info@ampac1.com or (909) 548-4900.
AMPAC USA engineers custom water purification systems for commercial, industrial, and emergency applications — from 500 GPD to multi-million GPD. Trusted by municipalities, military, and industry worldwide.
