The use of a wide range of chemicals to destroy pests and weeds is an important aspect of agricultural practice in both developed and developing countries. This has increased crop yield and reduced postharvest losses. However, the expanded use of such pesticides expectedly results in residues in foods, which has led to widespread concern over the potential adverse effects of these chemicals on human health. If pesticide residues are transported away from where they are intended to be active they may reach ecosystems such as groundwater or surface waters may harm non-target organisms and impair drinking water quality for human consumption. Pesticides may evaporate, be broken down by sunlight, or be carried away to surface water before reaching their targets. After reaching the soil, they may be taken up by plants, adsorbed to soil particles, broken down by soil microorganisms, or, in some cases, be moved off-target to water resources. The residue of OC pesticide can move thousand kilometers from the point of release through atmosphere as gases and aerosols. Herbicide drift on to non-target areas may affect other crops and wild plants alike, and is a common cause of economic injury to neighbouring farmers, which can reach up to 10% yield losses in the case of canola.
