Endocrine Disrupting Chemicals in the Slick Scum that Covers Stones in Streams

USGS scientist, Jeffrey Writer, holding a stone from Boulder Creek, Colo., that's covered with a biofilm. USGS scientists found that the biofilm that coats many of the stones on the bottom of the creek absorbs endocrine-disrupting compounds. Photo credit: Ronald C. Antweiler, USGS. (Click on photo for larger version)

The slick scum or biofilm that covers most rocks in streams can accumulate contaminants that disrupt reproductive and other endocrine systems in fish. This is the finding of a team of U.S. Geological Survey (USGS) and University of Colorado Boulder scientists as described in a recent article in Environmental Science and Technology (Writer and others, 2011). Biofilms are a mixture of algae, microbes, and organic matter that grow on streambed material such as rocks and stones. The scientists determined that biofilms absorb endocrine disrupting chemicals faster than they can biodegrade them; therefore the chemicals accumulate. Since many fish and other aquatic animals feed on biofilms, the contaminants in biofilms have the potential to be transferred through the food web.

The study took place in Boulder Creek, Colorado. Boulder Creek is similar to many streams around the country in which wastewater contributes a substantial amount (10 to 80 percent) of the water to the stream. The scientists took samples of biofilms, streambed sediments, and water above and below the wastewater discharge outlet on Boulder Creek in hopes of defining the role of biofilms in controlling the movement of contaminants downstream. Previous studies have shown that wastewater contains a variety of contaminants including endocrine disrupting compounds, and that exposure to wastewater can cause endocrine disruption in fish. The scientists analyzed the samples for two classes of endocrine-disrupting chemicals—hormones (such as 17β-estradiol, estrone, and 17a-ethynylestradiol), and nonylphenols (detergent degradation products such as 4-nonylphenol, 4-nonylphenolmonoethoxylate, and 4-nonylphenoldiethoxylate). The scientists detected minimal levels of these compounds in biofilms in Boulder Creek upstream of the wastewater discharge. In contrast, many of the compounds downstream of the wastewater outlet were detected at much higher levels. It is interesting to note that many of the hormones were not detected in any of the water samples, both upstream and downstream, but were detected in the biofilms. This shows that the biofilms efficiently accumulate hormones from water and can play a major role in understanding the impact of these chemicals on aquatic organisms.

This study was funded by the USGS’s Toxic Substances Hydrology Program and National Research Program, and by the National Science Foundation (Grant No. CBET-0854527).

Reference

Writer, J.H., Barber, L.B., Ryan, J.N., and Bradley, P.M., 2011, Biodegradation and attenuation of steroidal hormones and alkylphenols by stream biofilms and sediments: Environmental Science and Technology, p. null-null, doi:10.1021/es2000134.

More Information

• Chemical Transformations in Water Reclamation and Reuse
• Water Quality of the Boulder Creek Watershed, Colorado
• Emerging Contaminants in the Environment - Endocrine Disruption

Related Headlines

• Antibiotics in Groundwater Affect Natural Bacteria
• Evidence of Endocrine Disruption Unexpectedly Found in Minnesota Lakes
• Antidepressants in Stream Waters! Are They in the Fish Too?
• Manufacturing Facilities Release Pharmaceuticals to the Environment
• Do Combined Sewer Overflows Increase or Decrease Wastewater-Related Chemicals in Receiving Waters?
• Are Fecal Indicator Bacteria Effective Indicators of Chemical and Pathogenic Contaminants Associated with Human and Animal Waste?
• Hormones Degrade in the Environment!
• Tackling Fish Endocrine Disruption
• Detergents in Streams May Just Disappear
• Wastewater Indicators Shown to Degrade in Streams
• Endocrine Disruption Found in Fish Exposed to Municipal Wastewater
• Pharmaceuticals Found in Soil Irrigated with Reclaimed Water
• Are Pharmaceuticals in Your Watershed? Understanding the Fate of Pharmaceuticals and Other Contaminants in Watersheds
• Glyphosate Found in Wastewater Discharged to Streams
• Tracing Wastewater - Using Unique Compounds to Identify Sources of Contamination
• USGS Scientists Contribute to New Book on Pharmaceuticals in the Environment
• USGS Scientists Develop New Method to Measure Pharmaceuticals in Water
• Developing Methods to Measure New Contaminants in Aquatic Environments
• National Reconnaissance of Pharmaceuticals, Hormones and Other Organic Wastewater Contaminants in U.S. Streams is Making an Impact
• "National Reconnaissance of Pharmaceuticals, Hormones, and Other Organic Wastewater Contaminants in Streams" Named as One of the Top 100 Science Stories of the Year
• What's in Our Wastewaters and Where Does it Go?

Back to Headlines page