Summary of Well Water Sampling in California to Detect Pesticide Residues Resulting from Nonpoint‐Source Applications

• Published in: Journal of environmental quality 2001-03, Vol.30 (2), p.448-459
• Main Authors: Troiano, John, Weaver, Don, Marade, Joe, Spurlock, Frank, Pepple, Mark, Nordmark, Craig, Bartkowiak, Donna
• Format: Article
• Language: English
• Subjects: Agriculture; Agronomy. Soil science and plant productions; Analysis methods; Applied sciences; Biological and medical sciences; Calibration; California; Cropping systems; Data Collection; Databases, Factual; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Monitoring - methods; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Groundwater data; Humans; Hydrologic data; Natural water pollution; Pesticide residues; Pesticide Residues - analysis; Pesticides; Policy Making; Pollution; Pollution prevention; Pollution, environment geology; Public Policy; Quality Control; Soil and water pollution; Soil Pollutants - analysis; Soil science; Water analysis; Water depth; Water Pollutants - analysis; Water sampling; Water Supply; Water treatment and pollution; Well water
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq2001.302448x

ABSTRACT This report summarizes well sampling protocols, data collection procedures, and analytical results for the presence of pesticides in ground water developed by the California Department of Pesticide Regulation (DPR). Specific well sampling protocols were developed to meet regulatory mandates of the Pesticide Contamination Prevention Act (PCPA) of 1986 and to provide further understanding of the agronomic, chemical, and geographic factors that contribute to movement of residues to ground water. The well sampling data have formed the basis for the DPR's regulatory decisions. For example, a sampling protocol, the Four‐Section Survey, was developed to determine if reported detections were caused by nonpoint‐source agricultural applications, a determination that can initiate formal review and subsequent regulation of a pesticide. Selection of sampling sites, which are primarily rural domestic wells, was initially based on pesticide use and cropping patterns. Recently, soil and depth‐to‐ground water data have been added to identify areas where a higher frequency of detection is expected. In accordance with the PCPA, the DPR maintains a database for all pesticide well sampling in California with submission required by all state agencies and with invitations for submission extended to all local and federal agencies or other entities. To date, residues for 16 active ingredients and breakdown products have been detected in California ground water as a result of legal agricultural use. Regulations have been adopted for all detected parent active ingredients, and they have been developed regardless of the level of detection.