Pesticides are substances which prevent, destroy, repel or moderate pests. Examples of pesticides include herbicides, insecticides and fungicides. These pesticides work in a way to disrupt a certain element in the life of the pest to either eradicate or inactivate it. Even though controlling these pests through pesticides means greater productivity and crop yield, their use or misuse has the potential to adversely affect the environment, according to multiple scientific studies.
Effects on Soil
Excessive use of pesticides can bring about soil pollution. When pesticides are retained in the soil, the general biodiversity of the soil is greatly reduced. This is because pesticides can obstruct chemical signals which facilitate functioning of nitrogen-fixing bacteria in soil. This may at times cause the soil to become infertile, which necessitates addition of fertilizers to boost productivity.
Effects on Water
Pesticides used in agriculture can cause pollution both to surface water and ground water. Pesticides generally reach water sources through four main ways: drifting outside the intended area, percolation in soil, through surface run off and accidental spills. Once water is contaminated, it may be unsafe for drinking and may cause adverse health effects when consumed. Contamination may also affect the water's pH level.
Effects on Indoor Air Quality
Pesticides also can contribute to air pollution. According to survey cited by the Environmental Protection Agency, 75 percent of U.S. households use at least one pesticide. The EPA reports that this pesticide use can have an impact on indoor air quality, and the agency adds that most exposure to pesticides occurs indoors. These pesticides can have serious effects on humans, such as damage to the kidneys and nervous system.
Effects on Flora and Fauna
Misuse of pesticides can cause death of bees and hoverflies. These insects are essential in the process of pollination, and any impact on their populations may affect crop productivity. In amphibians, pesticides such as atrazine cause sterility in males. In plants, the pesticides which affect nitrogen-fixing bacteria can cause death of higher plants such as legumes.
- Entweb: What is a Pesticide?; October 1997
- Natural Resources Conservation Service: Soil Quality Concerns; January 1998
- Pollution Issues: Pesticides; Clive A. Edwards
- Environmental Protection Agency: Pesticides
- Royal Society of Chemistry: Some Pesticides Can Reduce Soil Fertility; Lewis Brindley; June 2007
- Greenfootsteps: Pesticides and Pollution
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