Pesticides

   Basic Profile

Overview

A pesticide is a chemical substance used to kill or control a pest. "Pest" is a simple catchall term that includes undesired insects, weeds, rodents, fungi, bacteria, and other organisms. Pesticides are commonly applied on farms, fruit orchards, golf courses, and residential lawns and gardens. Many pesticides are also used inside homes and other buildings.

Sources

Pesticides can enter ground water both directly and indirectly. Direct contamination may occur from pesticide spills around a poorly sealed well, improper application of pesticides through irrigation systems, and improper storage and disposal of pesticides or pesticide containers. Indirect contamination can occur as a result of normal application. Surface water, rain and snow can carry pesticides from areas such as agricultural fields, golf courses, and residential properties into lakes, rivers, reservoirs and aquifers. There are three ways in which you can be exposed to pesticides in drinking water:

  • by ingestion-either by drinking the water directly or eating foods cooked with water
  • by breathing in pesticide fumes in the shower or when cooking or washing
  • by absorbing the pesticides through the skin during showering, swimming, or washing

What factors contribute to contamination?

  • the distance between the well and a source of contamination
  • the application, frequency and quantity of pesticides used
  • the depth of a well
  • the local geology surrounding the well
  • the flow of the ground water