Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/1998
Publication Date: N/A
Citation: Interpretive Summary: Shallow groundwater lysimeters (solution samplers) are commonly used for monitoring groundwater and water in soil solution. The water collected in these samplers is then often analyzed for trace levels of pesticides in order to determine the fate and mobility of these chemicals. Traditionally, lysimeters have been constructed of stainless steel bodies to eliminate the possibility of chemical adsorption. However, rigid PVC plastic bodies are a more inexpensive alternative. Considerable debate has taken place regarding the suitability of rigid PVC bodies due to concern over their potential interactions with chemicals present in the sample collected. The objective of this study was to test the suitability of a PVC body lysimeter for the analysis of six pesticides of varying chemical properties by quantifying pesticide adsorption to the lysimeter after 3 h and 14 h contact times. Pesticide concentrations were representative of those occurring in soil environments. Among all pesticides tested, only on demonstrated slight adsorption (9 percent of applied) on the lysimeter; none of the other pesticides adsorbed to the lysimeter. Scientist can save a lot of money using PVC lysimeters to monitor these selected pesticides in ground water and soil solution. However, for scientists concerned with the suitability of a PVC body lysimeter over a more expensive stainless steel body, we recommend testing a pesticide representative of its class in order to determine whether adsorptivity will bias sampling results.
Technical Abstract: Lysimeters have traditionally been made out of stainless steel and teflon tomonitor soil solutions and ground water. The possibility of adsorption of organic chemicals to polyvinyl chloride (PVC) lysimeters, a more economical alternative to stainless steel, has led to debate over their suitability for ground water sampling. The adsorption of different pesticide chemistries, alachlor, atrazine, imidacloprid, isophenfos, nicosulfuron, and triadimefon, on a lysimeter constructed from rigid PVC was determined to evaluate the suitability of PVC material for use in groundwater sampling. Among all pesticides tested, only isophenfos demonstrated slight adsorption (9 percent of applied) on the lysimeter; adsorption was rapid and isophenfos was not easily desorbed with methanol and water. None of the other pesticides adsorbed to the lysimeter. When selecting a lysimeter, potential adsorptive interactions between the pesticide and the materials used in the lysimeter construction should be evaluated.