Spatially distributed pesticide exposure assessment in the Central Valley, California, USA.

Field runoff is an important transport mechanism by which pesticides move into the hydrologic environment of intensive agricultural regions such as California's Central Valley. This study presents a spatially explicit modeling approach to extend Pesticide Root Zone Model (PRZM), a field-scale pesticide transport model, into basin level. The approach was applied to simulate chlorpyrifos use in the Central Valley during 2003-2007. The average value of loading as percent of use (LAPU) is 0.031%. Results of this study provide strong evidence that surface runoff generation and pesticide application timing are the two influencing factors on the spatial and temporal variability of chlorpyrifos sources from agricultural fields. This is one of the first studies in coupling GIS and field-scale models and providing simulations for the dynamics of pesticides over an agriculturally dominated landscape. The demonstrated modeling approach may be useful for implementations of best management practice (BMP) and total maximum daily load (TMDL).

[1]  R. Snyder.  California Irrigation Management Information System , 1984, American Potato Journal.

[2]  W. Rawls,et al.  Soil Water Characteristic Estimates by Texture and Organic Matter for Hydrologic Solutions , 2006 .

[3]  J. Domagalski.  Pesticides in Surface and Ground Water of the San Joaquin-Tulare Basins, California: Analysis of Available Data, 1966 Through 1992 , 1997 .

[4]  Minghua Zhang,et al.  A geo-referenced modeling environment for ecosystem risk assessment: organophosphate pesticides in an agriculturally dominated watershed. , 2009, Journal of environmental quality.

[5]  Devendra M. Amatya,et al.  DEVELOPMENT AND TESTING OF WATERSHED-SCALE MODELS FOR POORLY DRAINED SOILS , 2005 .

[6]  Andrew N. Sharpley,et al.  EPIC, Erosion/Productivity Impact Calculator , 1990 .

[7]  G. A. Matthews.  Water quality in the San Joaquin-Tulare Basins, California, 1992–95 , 1998 .

[8]  Miguel A. Mariño,et al.  Semidiscrete pesticide transport modeling and application , 2004 .

[9]  C. M. Cooper,et al.  Mitigation of chlorpyrifos runoff using constructed wetlands. , 2002, Chemosphere.

[10]  Bruce R. Johnson,et al.  Characterizing dependence of pesticide load in surface water on precipitation and pesticide use for the Sacramento River watershed. , 2004, Environmental science & technology.

[11]  J. Domagalski,et al.  Evaluation of Diazinon and Chlorpyrifos Concentrations and Loads, and other Pesticide Concentrations, at Selected Sites in the San Joaquin Valley, California, April to August, 2001 , 2003 .

[12]  G. Fellers,et al.  Comparative toxicity of chlorpyrifos, diazinon, malathion and their oxon derivatives to larval Rana boylii. , 2007, Environmental pollution.

[13]  D. K. McCool,et al.  SIMULATION OF PESTICIDE CONCENTRATIONS IN GROUNDWATER USING AGRICULTURAL DRAINAGE AND PESTICIDE TRANSPORT (ADAPT) MODEL , 1998 .

[14]  David C. Lampe,et al.  Evaluation of unsaturated-zone solute-transport models for studies of agricultural chemicals , 2005 .

[15]  U. S. Tim,et al.  Integrated modeling environment for statewide assessment of groundwater vulnerability from pesticide use in agriculture. , 2004, Pest management science.

[16]  John R. Williams,et al.  EPIC-erosion/productivity impact calculator: 1. Model documentation. , 1990 .

[17]  Jae-Pil Cho,et al.  Evaluating cell-based components of DANSAT for predicting surface and subsurface transport of pesticides , 2009 .

[18]  Jeffrey G. Arnold,et al.  Evaluation of Three Watershed‐Scale Pesticide Environmental Transport and Fate Models 1 , 2007 .

[19]  Minghua Zhang,et al.  Dynamic modeling of organophosphate pesticide load in surface water in the northern San Joaquin Valley watershed of California. , 2008, Environmental Pollution.

[20]  PETER A. VANROLLEGHEM,et al.  SWAT developments and recommendations for modelling agricultural pesticide mitigation measures in river basins , 2008 .

[21]  J. Gan,et al.  Synthetic Pyrethroids: Occurrence and Behavior in Aquatic Environments , 2008 .

[22]  Donna L. Knifong,et al.  Diazinon and chlorpyrifos loads in the San Joaquin River basin, California, January and February 2000 , 2002 .

[23]  Xiusheng Yang,et al.  A multimedia environmental model of chemical distribution: fate, transport, and uncertainty analysis. , 2007, Chemosphere.