Submitted to: Encyclopedia of Water
Publication Type: Book / Chapter
Publication Acceptance Date: 10/25/2004
Publication Date: 12/1/2005
Citation: Loague, K., Corwin, D.L. 2005. Groundwater vulnerability to pesticides: An overview of approaches and methods of evaluation. J.H. Lehr (ed.) In: Encyclopedia of Water (Volume 5). John Wiley and Sons, Inc. New York, NY. pp: 594-599. Interpretive Summary: Non-point source pollutants, such as pesticides and fertilizers, pose a potential threat to groundwater because they are characteristically applied over broad areas, cannot be easily removed once applied, and often times result in chronic health effects to humankind. Assessing the vulnerability of groundwater to NPS pollutants is a critical tool in understanding where problem areas will occur; thereby, helping to maintain the sustainability of agriculture. This article is part of the Encyclopedia of Water. It is an overview of the approaches and methods for evaluating groundwater vulnerability to pesticides and provides a general discussion of regional-scale groundwater vulnerability assessment models. A case study is presented to show the reader the usefulness of groundwater vulnerability assessment. The article is designed to provide general knowledge of assessing groundwater vulnerability from NPS pollutants using models that can be used over large areas (hundreds or thousands of square miles).
Technical Abstract: Groundwater vulnerability to non-point source (NPS) pollutants is a global environmental problem that has long-term, chronic consequences to human health. It is the objective of this encyclopedia article to provide an overview of the approaches and methods for evaluating groundwater vulnerability to pesticides. A general review of regional-scale groundwater vulnerability assessment models, uncertainty analysis, and a case study is provided. The case study is a groundwater vulnerability assessment of DBCP in the California's San Joaquin Valley, which encompasses a 2184-km2 area. Results show the evolution of DBCP plumes with time and indicate that DBCP concentrations in groundwater are a function of spatial and temporal variations in the application rates, application frequency, unsaturated profile thickness, soil-hydraulic properties, and near-surface sorption. The linkage of deterministic solute transport models to a geographic information system provides a viable means of assessing groundwater vulnerability to NPS pollutants.