It is very difficult to purify or clean contaminated groundwater or surface water. Treatment is complicated, time consuming, expensive and often not feasible. The best solution is to avoid contaminating groundwater and surface water in the first place. Field practices recommended by Michigan State University Extension can be implemented to effectively reduce pesticide runoff and leaching to protect groundwater and surface water.
Consider the geology of your area. When planning herbicide applications; be aware of the water table depth and the permeability of the geological layers between the surface soil and groundwater.
Consider soil and field characteristics. The susceptibility of the soil or field site to leaching or runoff should be determined. Soil texture and organic matter content, in particular, influence chemical movement into groundwater; the slope of the field also influences surface runoff.
Reduce compaction. Surface water runoff increases when soils are compacted.
Utilize conservation practices that reduce erosion and surface runoff. These practices include but are not limited to no-till and other forms of conservation tillage, increasing crop residues or planting cover crops, planting grass waterways to retard soil and water runoff, and keeping buffer strips to protect surface water boundaries.
Use integrated pest management programs. Minimize herbicide use by combining chemical control with other pest management practices such as tillage, cultivation, crop rotation and pest scouting.
Rotate crops. Crop rotation can improve water infiltration, which reduces runoff. Crop rotations also may provide more surface crop residue and may reduce the need for applications of specific pesticides repeatedly to a given field site.
Source: MSUE