Pesticides

Overview


Definition

The purpose of a pesticide is usually to kill or repel some form of life. The US Environmental Protection Agency's definition of a pesticide is as follows: "A pesticide is any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest. Though often misunderstood to refer only to insecticides, the term pesticide also applies to herbicides, fungicides, and various other substances used to control pests." Pesticide formulations contain both "active" and "inert" ingredients. Active ingredients are what kill the pest, and inert ingredients help the active ingredients to work more effectively. 

Types

The two largest classes of synthetic pesticides are insecticides, which are designed to kill insects, and herbicides, which are designed to kill plants. Other classes of pesticides include fungicides (for molds and fungi), rodenticides (for mammals), and antimicrobials (for microorganisms such as bacteria and viruses). Antimicrobial pesticides are used as preservatives, sterilizers, and disinfectants in home, institutional, and commercial environments. (For more information on antimicrobial pesticides, see this EPA website. Note that pharmaceuticals intended to kill organisms in the body, such as bacteria and parasitic worms, are not defined as pesticides and are regulated as drugs.)

How Pesticides Work

Pesticides work by interfering with an essential biological mechanism in the pests, but because all living organisms share many biological mechanisms, pesticides are never specific to just one species. While pesticides may kill pests, they may also kill or harm other organisms that are beneficial or at least not undesirable. They may also harm people who are exposed to pesticides through occupational or home use, through eating foods or liquids containing pesticide residue, or through inhaling or contacting pesticide-contaminated air. The ideal pesticide would be highly specific to only the target organism, be quick acting, and would degrade rapidly to harmless, inert materials in the environment. 

Contents



(Photo: pesticide application in Canada. Source: Wikimedia.)

Literature Review of Pesticides' Impact on Human and Environmental Health


In the Fall of 2009, Toxipedia was hired by the King County Local Hazardous Waste Management Program to do a literature review of published journal articles examining the impacts of pesticides on human and environmental health. We summarized fifteen articles to provide quick, easy-to-understand accounts of each study and its findings. Articles are separated into five categories as seen below. Each category contains an introduction and three article summaries.


Additional Resources



Breaking News


Pesticide News from *Environmental Health News*


Scientific studies


Controversy and Opinion