U.S. Geological Survey found U.S. waterways contaminated with pesticides.

waterways1Another study released by the U.S. geological survey has found that levels of pesticides continue to impact on aquatic life in many of the Nation’s rivers and streams in agricultural and urban areas. The United States used over half a billion pounds of pesticides in the U.S., mostly in agriculture and to reduce insect-borne disease. The government has expressed concern on the impact for aquatic life.

The survey analyzed the level of pesticides in U.S. waterways for two decades and determined that pesticides and their breakdown product are found in U.S. streams by an overwhelming 90% of the time.

The USGS survey published in the journal, Environmental Science and Technology differentiated the pesticide level by the two decades analyzed. During both decades, one or more pesticides or pesticide degradates were detected more than 90 percent of the time in streams across all types of land uses. For individual pesticides during 2002–11, atrazine (and degradate, deethylatrazine), carbaryl, fipronil (and degradates), metolachlor, prometon, and simazine were detected in streams more than 50 percent of the time.

During both decades, one or more pesticides or pesticide degradates were detected more than 90 percent of the time in streams across all types of land uses. For individual pesticides during 2002–11, atrazine (and degradate, deethylatrazine), carbaryl, fipronil (and degradates), metolachlor, prometon, and simazine were detected in streams more than 50 percent of the time. In contrast, alachlor, chlorpyrifos, cyanazine, diazinon, EPTC, Dacthal, and tebuthiuron were detected less frequently in streams during the second decade than during the first decade. During 2002–11, only one stream had an annual mean pesticide concentration that exceeded an HHB. In contrast, 17 percent of agriculture land-use streams and one mixed land-use stream had annual mean pesticide concentrations that exceeded HHBs during 1992–2001. The difference between the first and second decades in terms of percent of streams exceeding HHBs was attributed to regulatory changes. During 2002–11, nearly two-thirds of agriculture land-use streams and nearly one-half of mixed land-use streams exceeded chronic ALBs. For urban land use, 90 percent of the streams exceeded a chronic ALB. Fipronil, metolachlor, malathion, cis-permethrin, and dichlorvos exceeded chronic ALBs for more than 10 percent of the streams. For agriculture and mixed land-use streams, the overall percent of streams that exceeded a chronic ALB was very similar between the decades. For urban land-use streams, the percent of streams exceeding a chronic ALB during 2002–11 nearly doubled that seen during 1992–2001. The reason for this difference was the of fipronil monitoring during the second decade. Across all land-use streams, the percent of streams exceeding a chronic ALB for fipronil during 2002–11 was greater than all other during both decades.

“The information gained through this important research is critical to the evaluation of the risks associated with existing levels of pesticides,” said William Werkheiser, USGS for Water.

Source

Stone, W.W., Gilliom, R.J., and Martin, J.D., 2014, An overview comparing results from two decades of monitoring for pesticides in the Nation’s streams and rivers, 1992–2001 and 2002–2011: U.S. Geological Survey Scientific Investigations Report 2014–5154, 23 p., http://dx.doi.org/10.3133/sir20145154.

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