ARS | Publication request: SOLID-PHASE EXTRACTION AND GC ANALYSES OF SELECT AGRICULTURAL PESTICIDES AND METABOLITES IN STREAM WATER

Submitted to: Journal of Environmental Science and Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 15, 1996
Publication Date: N/A

Interpretive Summary: The public is concerned that drinking water sources are safe; therefore, active monitoring for substances such as pesticides in drinking water sources are conducted. Since our concern is pesticide fate in southeastern Coastal Plain ecosystems, we developed an analytical procedure to extract and measure pesticides in both ground and surface water. We chose to examine our water samples for the presence of some pesticides that are commonly used in agricultural production in the North Carolina Coastal Plain region. Water samples were collected from a stream system and were passed through a small plastic cartridge containing resin that would specifically bind these certain pesticides. The bound pesticides were removed with a solvent and were measured with an instrument that converts the solvent and pesticides to a gas. To verify that our procedure was correct, we added known concentrations of pesticides to water samples and extracted the samples. The results were very close to the predicted values. Thus, environmental scientists have an improved procedure that can detect trace quantities of pesticides that might occur in either ground or stream water.

Technical Abstract: The occurrence of agricultural pesticides in surface waters around the USA has caused a concern over the status of safe drinking water. Solid-phase extraction (SPE) or liquid-liquid extraction is usually employed to concentrate trace levels of pesticides in water samples to levels that are measurable with advanced chromatographic instruments. Our work describes a SPE and capillary gas chromatographic (GC) procedure to extract and concentrate trace levels of select agricultural pesticides and metabolites from stream water. Our SPE and GC method provides low sensitivity, with recoveries between 85% to 95%, and high reproducibility for 9 of the pesticides studied. The described method provided marginal recoveries of 19% and 60% for the triazine metabolites.