Emerging Contaminants in Streams
Statement of the Issue
In 2002, smallmouth bass began experiencing significant skin lesions and spring mortality events in the South Branch of the Potomac River.1 More recently, such events have been observed in the James, Shenandoah and Monocacy Rivers. Scientists believe that this is an effect of a new broad class of pollutants called emerging contaminants.
In one study, 139 streams were monitored throughout the nation, revealing that 80% of them contained 31 different emerging contaminants. The most common of which were plant and animal steroids, pesticides, caffeine, disinfectants, fire retardants and detergent components.2 These chemicals pose a threat to ecological and human health. The full extent of that threat is not yet known, nor is the degree to which various combinations of these chemicals magnify risk.
Background
In one study, 139 streams were monitored throughout the nation, revealing that 80% of them contained 31 different emerging contaminants. The most common of which were plant and animal steroids, pesticides, caffeine, disinfectants, fire retardants and detergent components.2
The Consortium for Research and Education on Emerging Contaminants defines emerging contaminants as chemicals that occur widely in water resources and may pose a risk to the environment or human health. This broad definition reflects a high degree of uncertainty about the number and source of these chemicals and their likely effects on people and wildlife. These chemicals originate as pharmaceuticals, personal care products, pesticides and fertilizers or industrial chemicals then make their way into the environment. Many of these compounds are endocrine disruptors, meaning they affect hormone function within the body.
The diversity of chemicals and sources nevertheless yields a common set of concerns. Specifically, scientists are concerned about exposure risks, bioaccumulation and synergistic effects.3 The latter in particular prompts concern regarding the actual risks associated with uncertainty; which is to say, what we do not know about these chemicals and their aggregated effects could in fact do harm.
As there is little known about emerging contaminants, there are rarely controls on their discharge. Without such controls there is also no established method of measuring and accounting for their dispersion. Many of these chemicals enter streams and rivers via treated wastewater. While sewage treatment plants are making significant strides in the removal of nitrogen and phosphorus, pharmaceuticals, detergents, fragrances, and other compounds often remain. Rainwater runoff can transport pesticides, fertilizer and litter, including plastics, into streams. Runoff is also a primary means whereby the chemicals found in animal manure, including antibiotics and hormones, enter streams.
Because of the diversity of sources, the presence of emerging contaminants may spike and ebb within a given waterway. The effects of exposure are not immediate and may require prolonged exposure or a trigger such as a pathogen. Analyzing the health of fish populations provides a good method for judging the cumulative effects of environmental stressors. The results of this data are troublesome because fish populations in the Shenandoah and Potomac rivers are experiencing an increase in intersex characteristics, serious skin lesions and mortality. This is consistent with high levels of emerging contaminants in that estrogenic chemicals are believed to disrupt immune system function. In terms of human health, possible concerns include cancer, infertility, intersex disorders, asthma, autism, ADHD, diabetes and thyroid disorders.4 Humans can be exposed to emerging contaminants both by direct contact with a river and by consumption of treated technology.
References
1.V.S. Blazer, et. al. Mortality of Centrachid Fishes in the Potomac Drainage: Survey Results and Overview of Potential Contributing Factors. Journal of Aquatic Animal Health. (2010).
2.Kolpin et al. Pharmaceuticals, hormones, and other organic wastewater contaminants in U.S. streams, 1999-2000: a national reconnaissance. USGS (2002).
3. William Wombacher. There's Cologne in the Water: The Inadequacy of U.S. Environmental Statutes to Address Emerging Environmental Contaminants, 21 Colo. J. Int'l Envtl. L. & Pol'y 521 (2010).
4. Vicki Blazer - USGS. Contaminants of Emerging Concern in Rivers and Streams and Effects on Fish Health.
5. MassDEP. Emerging Contaminants Fact Sheet & Overview. http://www.mass.gov/dep/toxics/stypes/emercfs.htm.
Recommendations
The potential impact of this issue deserves the attention of Virginia’s lawmakers and further scientific study. Massachusetts established the Emerging Contaminant Workgroup in 2006. The program has defined emerging contaminants, established a list of substances and created a framework for screening and prioritizing contaminants. The effort relies on scientific standards, extensive collaboration and outreach programs. Importantly, the initiative considers health risks, the existence of published standards, available toxicological data and significant new sources.5This model provides a framework for Virginia to begin addressing the significant issue of emerging contaminants by establishing an interagency task force or legislative study.
Links Referenced
- Vicki Blazer - USGS. Contaminants of Emerging Concern in Rivers and Streams and Effects on Fish Health
- http://dls.state.va.us/groups/water/meetings/102810/contaminants.pdf
- Jacob Powell
- mailto: jacob@vcnva.org
- Emerging Contaminants in Streams Whitepaper
- http://vcnva.org/anx/ass/library/66/emergingcontaminants.pdf
- Common Agenda
- http://www.vcnva.org/commonagenda
Location
http://www.vcnva.org/anx/index.cfm/1,403,2354,0,html
Copyright © Virginia Conservation Network 2012