TREATMENT OF POLLUTANTS SUMMARY
Runoff pollution is difficult to control. The best method of control is limited use of chemical pesticides.
The speed and amount of movement depends on whether
the pesticide is water-soluble,
the soil type,
the amount of rain, and
the proximity of the water table to the surface.
Over time, nearly all pesticides break down to other chemicals as they are exposed to sunlight and air. Generally, it is these base chemicals that are detected in groundwater.
Some agricultural drainage wells provide direct pathways for pollutants to enter groundwater.
The forms of nitrogen that cause problems as pollutants are the nitrate and ammonium forms. The nitrate form is water-soluble and moves with the water into surface water or groundwater. The ammonium form attaches to soil particles.