The use of pesticides is an integral part of today\u27s agriculture. In many cases, pesticides safeguard crops from severe pest infestation, or increase yield by suppressing competing weed growth. Pesticides often make the difference between profits and losses in farming operations. However, pesticides, even in extremely low concentrations, can pose a risk to human health and to the environment. Applied to plant or soil surfaces, or injected into the soil, pesticides may leach to the ground water or may be washed off with surface water. Pesticide contaminated surface water can reach ground water, or contaminated ground water can reach the surface and contribute to surface water pollution. Once in the ground water, pesticides can persist for years, rendering the water unsuitable for human and animal consumption. Effectively treating drinking water to reduce pesticide residues to acceptable levels or to restore ground-water quality can be difficult and expensive
