Of these contaminants, pesticides receive the most attention because of the potential toxicity to aquatic life and to humans.
Most farmers use pesticides to increase crop yields and values.
Herbicides prevent or inhibit the growth of weeds that compete for nutrients and moisture needed by the crops. Herbicides are applied before, during, or following planting. These herbicides are used for corn, sorghum, and soybean production. Insecticides are used to protect the crop seeds in storage prior to planting and also to protect the plants from destruction once the seeds have germinated. Like herbicides, insecticides are also used in urban areas to protect lawns, trees, and ornamentals.