Are pesticides present in stream water and ground water?
The simple answer is “yes”—pesticides are frequently present. However, this answer needs to be broken down by streams versus ground water, which have quite different levels of occurrence; and by currently used pesticides versus pesticides that are no longer used. In stream water, one or more pesticide compounds were almost always present at detectable levels (represented below by the upper bar in each land-use category). There were detectable concentrations in water more than 90 percent of the time across all streams sampled that had significant agricultural or urban land use in their watersheds. Undeveloped streams had detectable pesticides more than half the time. Most of the pesticides measured in water were in use during the study period. Ground water had less frequent detections in well samples compared to streams, but pesticides nevertheless were found in more than half the wells tapping shallow ground water in agricultural and urban areas (represented by the lower bar in each la
