Evaluating Groundwater Contamination Potential from herbicide use

Publisher Website
Google Scholar
Abstract
Potential herbicide loadings to groundwater are determined by soil, chemical, management, and climatic factors. Several simple assessment procedures to rank pesticides according to their potential impact on groundwater are available. Most of these procedures are not specific to any climatic region, cropping practice, or soil. Using a continuous simulation model, GLEAMS (Groundwater Loading Effects of Agricultural Management Systems), to assess potential herbicide leaching allows more condition-specific assessment. Simple relationships for relative comparisons in a specific soil/climatic setting were developed by relating simulated 50-yr mean leaching losses to the herbicide half-life/Koc ratio. Other criteria of herbicide leaching potential such as 50-yr maxima or other values based on probability distributions could be used. Although differences in soils were demonstrated in this exercise, the same procedures could be applied to different management systems.