Agricultural Chemical Groundwater Monitoring

The AgChem Program was established and developed as a result of special legislation passed in 1987, to determine the potential impact of agricultural chemcials on groundwater. The legislation charged MDEQ with the responsibility of establishing groundwater standards and monitoring groundwater for agricultural chemicals and other pollutants.

Program History and Activities

The monitoring began with sampling conducted on shallow drinking water wells located in areas of highest pesticide usage before expanding into other regions of the state. Sampling was then expanded to include other types of wells such as irrigation and fish culture wells in the Mississippi Delta. Through December 31, 2013, a total of 2056 wells have been sampled. Of this total 850 have been drinking water wells with all 82 counties represented.

In addition to its role in monitoring groundwater and assisting in the Pesticide Container Recycling Program, MDEQ is actively participating in the following other programs and activities:

Testing Criteria

Samples from all drinking water wells were tested for:

  • more than 100 pesticides and metabolites
  • 45 volatile organic compounds
  • 30 inorganic compounds including minerals, residues, nutrients, and metals

In addition – 1206 irrigation, fish culture, and wildlife management wells have been sampled in 17 counties in the Mississippi Delta.
These wells were analysed for pesticides as in the drinking water wells, but only chloride and nitrate analyses were conducted in addition to the pesticides.


Generally, the results appear to indicate that the overall quality of Mississippi’s groundwater supply is relatively unaffected by agricultural activities.

  • Of 2656 wells sampled – 1995 (97%) had no detectable concentrations of agricultural chemicals.
  • Of the 61 wells with detects, only four were found to contain concentrations exceeding safe levels (Maximum Contaminant Levels or MCL’s) as established for drinking water by the U. S. Environmental Protection Agency (EPA).

For the complete 1989-2013 MS AgChem Groundwater Monitoring Program report, click here.