Pesticide Occurrence and Distribution in the Lower Clackamas River Basin
Pesticide Occurrence and Distribution in the Lower Clackamas River Basin, Oregon, 2000–2005
A study performed by the U.S. Geological Survey (USGS), in conjunction with the Clackamas Watershed Management Group, found a variety of pesticides present within the Clackamas watershed. From 2000 to 2005, water samples were collected from various locations on the lower Clackamas River main stem, as well as Eagle, Clear, Deep, Richardson, Rock, Sieben, Carli, and Cow Creeks. A total of 119 samples were analyzed, detecting the presence of 63 different pesticide compounds. Ninety-seven percent of samples collected from tributaries contained 2 or more types of pesticides, and the highest pesticide concentrations were found in Deep and Rock Creeks. Seven of the 8 tributaries sampled had pesticide levels that exceeded standards set to protect aquatic life. And, although the current levels of pesticides are well below US EPA drinking water benchmarks and other human health standards, they serve as a warning sign that the health of our waterways is threatened.
The pesticides detected in the Clackamas River watershed come from an variety of different sources. The exact source is hard to pinpoint because many pesticides have multiple uses, but common applications include nursery and floriculture crops, yards, golf courses, parks, forestlands, and along fences, roads, and other right-of-ways.
Often, pesticides are applied in residential areas to control weeds and insects in lawns and gardens, and in houses to kill pests, such as ants and fleas. One of the most frequently detected pesticides in the USGS study was glyphosate, the active ingredient in many urban, agricultural, and forestry herbicide products, including RoundUP™, Rodeo™, and Accord™.