Dr. Robert Hirsch, Associate Director for Water, said, "While the use of pesticides has resulted in a wide range of benefits to control weeds, insects, and other pests, including increased food production and reduction of insect-borne disease, their use also raises questions about possible effects on the environment, including water quality." Hirsch also commented that "the USGS assessment provides the most comprehensive national-scale analysis to date of pesticide occurrence in streams and ground water. Findings show where, when, and why specific pesticides occur, and yield science-based implications for assessing and managing pesticides in our water resources."
The USGS findings show strong relations between the occurrence of pesticides and their use, and point out that some of the frequently detected pesticides, including the insecticide diazinon and the herbicides alachlor and cyanazine, are declining.
USGS has worked closely with the U.S. Environmental Protection Agency (EPA) during the 10-year study. EPA uses the data extensively in their exposure and risk assessments for regulating the use of pesticides. For example, EPA used USGS data in its risk assessments for the reevaluation of diazinon, chlorpyrifos, cyanazine and alachlor. Uses of three of these pesticides (diazinon, chlorpyrifos and cyanazine) have now been significantly limited, and usage of
Source:United States Geological Survey