Screening for contaminants of emerging concern in the Northern Colorado Plateau Network, 2010 and 2012

Weissinger, Rebecca; Thoma, David; Keteles, Kristen; Dahlin, Kenneth

Rivers and streams are the lifeblood of the Colorado Plateau, yet they can also serve to carry contaminants far away from their original sources. While NCPN parks generally lie far from metropolitan areas, human land-use activities within the parks and/or their watersheds include oil and gas development, livestock use, cultivated farmland, sparse to moderate human occupation, recreational use, and park management practices. Waters in the NCPN range from remote springs to inter-regional rivers and can be expected to have varying levels of exposure to these activities. So-called contaminants of emerging concern (CECs)—compounds such as pesticides, pharmaceuticals, personal care products, and wastewater indicators—are pollutants that have not traditionally been tested for during water quality sampling and may not be adequately cleansed by current wastewater treatment methods. The effects of CECs are often just beginning to be assessed, yet regional studies have shown that these compounds can be found in waters throughout western North America, including remote locations with no direct anthropogenic source. In 2010, in cooperation with the U.S. Environmental Protection Agency Region 8, Northern Colorado Plateau Network (NCPN) and park staff sampled a wide variety of network waters (30 sites selected by park staff in 11 parks) to identify potential hotspots for CECs. Follow-up sampling in 2012 focused on water bodies that were noted as hotspots during the 2010 sampling, either because multiple analytes were detected in a sample or because analytes were detected at levels of concern. Overall, the majority of CEC analytes were never detected in any sampled NCPN water body, and one-third of site visits had no analytes detected. Plasticizers, herbicides, and fire retardants were the most commonly detected types of analytes. Solvents and disinfectants were not detected as frequently, but were detected in higher concentrations than other analyte types. Herbicides, while detected frequently, were found at relatively lower concentrations than other common analyte types. In comparison to more urbanized watersheds, NCPN waters had fewer analytes and lower total analyte concentrations. However, some sites reported analytes at levels high enough to potentially affect aquatic ecosystems. The Yampa River (Dinosaur NM) remains a priority for NCPN sampling due to the high number of analytes detected despite its paucity of point sources. The Colorado River (Canyonlands NP) has chronic contamination by a few CECs and, in general, had more detections than the Green River (Canyonlands NP, Dinosaur NM). Sampling to further document the presence of CECs in NCPN waters will continue.

Screening for contaminants of emerging concern in the Northern Colorado Plateau Network, 2010 and 2012

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