pesticide n : a chemical used to kill pests (as rodents or insects)

English

Noun

pesticide (pesticides)

1. A substance, usually synthetic although sometimes biological used to kill or contain the activities of pests

Related terms

• pest
• pesticidal
• fungicide
• germicide
• herbicide

Translations

• Finnish: tuholaismyrkky
• French: pesticide
• German: Pestizid
• Italian: pesticida
• Swedish: bekämpningsmedel , pesticid

Italian

Adjective

pesticide

1. Feminine plural form of pesticida

A pesticide is a substance or mixture of substances used for preventing, controlling, or lessening the damage caused by a pest. A pesticide may be a chemical substance, biological agent (such as a virus or bacteria), antimicrobial, disinfectant or device used against any pest. Pests include insects, plant pathogens, weeds, molluscs, birds, mammals, fish, nematodes (roundworms) and microbes that compete with humans for food, destroy property, spread or are a vector for disease or cause a nuisance. Although there are benefits to the use of pesticides, there are also drawbacks, such as potential toxicity to humans and other animals.

Types of pesticides

There are multiple ways of classifying pesticides.

• Algicides or Algaecides for the control of algae
• Avicides for the control of birds
• Bactericides for the control of bacteria
• Fungicides for the control of fungi and oomycetes
• Herbicides for the control of weeds
• Insecticides for the control of insects - these can be Ovicides (substances that kill eggs), Larvicides (substances that kill larvae) or Adulticides (substances that kill adult insects)
• Miticides or Acaricides for the control of mites
• Molluscicides for the control of slugs and snails
• Nematicides for the control of nematodes
• Rodenticides for the control of rodents
• Virucides for the control of viruses (e.g. H5N1)

Pesticides can also be classed as synthetic pesticides or biological pesticides (biopesticides), although the distinction can sometimes blur.

Broad-spectrum pesticides are those that kill an array of species, while narrow-spectrum, or selective pesticides only kill a small group of species.

A systemic pesticide moves inside a plant following absorption by the plant. With insecticides and most fungicides, this movement is usually upward (through the xylem) and outward. Increased efficiency may be a result. Systemic insecticides which poison pollen and nectar in the flowers may kill needed pollinators such as bees.

Most pesticides work by poisoning pests.

Uses, benefits and drawbacks

Pesticides are used to control organisms which are considered harmful. For example, they are used to kill mosquitoes that can transmit potentially deadly diseases like west nile virus and malaria. They can also kill bees, wasps or ants that can cause allergic reactions. Insecticides can protect animals from illnesses that can be caused by parasites such as fleas. Uncontrolled pests such as termites and mould can damage structures such as houses. One study found that not using pesticides reduced crop yields by about 10%.

DDT, sprayed on the walls of houses, is an organochloride that has been used to fight malaria since the 1950s. Recent policy statements by the World Health Organization have given stronger support to this approach. Dr. Arata Kochi, WHO's malaria chief, said, "One of the best tools we have against malaria is indoor residual house spraying. Of the dozen insecticides WHO has approved as safe for house spraying, the most effective is DDT." Scientists estimate that DDT and other chemicals in the organophosphate class of pesticides have saved 7 million human lives since 1945 by preventing the transmission of diseases such as malaria, bubonic plague, sleeping sickness, and typhus. A study for the World Health Organization in 2000 from Vietnam established that non-DDT malaria controls were significantly more effective than DDT use.

In the US, about a quarter of pesticides used are used in houses, yards, parks, golf courses, and swimming pools.

In 1939, Paul Müller discovered that DDT was a very effective insecticide. It quickly became the most widely-used pesticide in the world.

In the 1940s manufacturers began to produce large amounts of synthetic pesticides and their use became widespread. Some sources consider the 1940s and 1950s to have been the start of the "pesticide era." Pesticide use has increased 50-fold since 1950 and 2.5 million tons (2.3 million metric tons) of industrial pesticides are now used each year.

Regulation

In most countries, in order to sell or use a pesticide, it must be approved by a government agency. For example, in the United States, the Environmental Protection Agency (EPA) does so. Complex and costly studies must be conducted to indicate whether the material is safe to use and effective against the intended pest. During the registration process, a label is created which contains directions for the proper use of the material. Based on acute toxicity, pesticides are assigned to a Toxicity Class.

Some pesticides are considered too hazardous for sale to the general public and are designated restricted use pesticides. Only certified applicators, who have passed an exam, may purchase or supervise the application of restricted use pesticides. The Ontario provincial government promised on September 24, 2007 to also implement a province-wide ban on the cosmetic use of lawn pesticides, for protecting the public. Medical and environmental groups support such a ban. On April 22, 2008, the Provincial Government of Ontario announced that it will pass legislation that will prohibit, province-wide, the cosmetic use and sale of lawn and garden pesticides. The Ontario legislation would also echo Massachusetts law requiring pesticide manufacturers to reduce the toxins they use in production. The Province of Prince Edward Island is also considering such legislation. On April 3, 2008, the Canadian Cancer Society released opinion poll results conducted by Ipsos Reid, which established that a clear majority of residents in the provinces of British Columbia and Saskatchewan want province-wide cosmetic lawn pesticide bans, and that the majority of respondents believe that cosmetic pesticides are a threat to their health.

Though pesticide regulations differ from country to country, pesticides and products on which they were used are traded across international borders. To deal with inconsistencies in regulations among countries, delegates to a conference of the United Nations Food and Agriculture Organization adopted an International Code of Conduct on the Distribution and Use of Pesticides in 1985 to create voluntary standards of pesticide regulation for different countries. The FAO claims that the code has raised awareness about pesticide hazards and decreased the number of countries without restrictions on pesticide use.

Two other efforts to improve regulation of international pesticide trade are the United Nations London Guidelines for the Exchange of Information on Chemicals in International Trade and the United Nations Codex Alimentarius Commission. The former seeks to implement procedures for ensuring that prior informed consent exists between countries buying and selling pesticides, while the latter seeks to create uniform standards for maximum levels of pesticide residues among participating countries. Both initiatives operate on a voluntary basis.

Environmental effects

Pesticide use raises a number of environmental concerns. Over 98% of sprayed insecticides and 95% of herbicides reach a destination other than their target species, including non-target species, air, water, bottom sediments, and food. Pesticide drift occurs when pesticides suspended in the air as particles are carried by wind to other areas, potentially contaminating them. Pesticides are one of the causes of water pollution, and some pesticides are persistent organic pollutants and contribute to soil contamination.

Health effects

Pesticides can present danger to consumers, bystanders, or workers during manufacture, transport, or during and after use.

The American Medical Association recommends limiting exposure to pesticides and using safer alternatives: '' Particular uncertainty exists regarding the long-term effects of low-dose pesticide exposures. Current surveillance systems are inadequate to characterize potential exposure problems related either to pesticide usage or pesticide-related illnesses…Considering these data gaps, it is prudent…to limit pesticide exposures…and to use the least toxic chemical pesticide or non-chemical alternative.''

Farmers and workers

There have been many studies of farmers with the goal of determining the health effects of pesticide exposure.

The World Health Organisation and the UN Environment Programme estimate that each year, 3 million workers in agriculture in the developing world experience severe poisoning from pesticides, about 18,000 of whom die.

Organophosphate pesticides have increased in use, because they are less damaging to the environment and they are less persistent than organochlorine pesticides. These are associated with acute health problems for workers that handle the chemicals, such as abdominal pain, dizziness, headaches, nausea, vomiting, as well as skin and eye problems. Additionally, many studies have indicated that pesticide exposure is associated with long-term health problems such as respiratory problems, memory disorders, dermatologic conditions, cancer, depression, neurological deficits, miscarriages, and birth defects. Summaries of peer-reviewed research have examined the link between pesticide exposure and neurologic outcomes and cancer, perhaps the two most significant things resulting in organophosphate-exposed workers.

According to researchers from the National Institutes of Health (NIH), licensed pesticide applicators who used chlorinated pesticides on more than 100 days in their lifetime were at greater risk of diabetes. In a paper appearing in the May, 2008, issue of the American Journal of Epidemiology, researchers said the associations between specific pesticides and incident diabetes ranged from a 20 percent to a 200 percent increase in risk. New cases of diabetes were reported by 3.4 percent of those in the lowest pesticide use category compared with 4.6 percent of those in the highest category. Risks were greater when users of specific pesticides were compared with applicators who never applied that chemical.

Consumers

There are concerns that pesticides used to control pests on food crops are dangerous to people who consume those foods. These concerns are one reason for the organic food movement. Many food crops, including fruits and vegetables, contain pesticide residues after being washed or peeled. Chemicals that are no longer used but which are resistant to breakdown for long periods may remain in soil and water and thus in food.

The United Nations Codex Alimentarius Commission has recommended international standards for Maximum Residue Limits (MRLs), for individual pesticides in food.

In the EU, MRLs are set by DG-SANCO. In the US, levels of residues that remain on foods are limited to tolerance levels that are established by the US EPA and are considered safe. The EPA sets the tolerances based on the toxicity of the pesticide and its breakdown products, the amount and frequency of pesticide application, and how much of the pesticide (i.e., the residue) remains in or on food by the time it is marketed and prepared. Tolerance levels are obtained using scientific risk assessments that pesticide manufacturers are required to produce by conducting toxicological studies, exposure modeling and residue studies before a particular pesticide can be registered, however, the effects are tested for single pesticides, and there is little information on possible synergistic effects of exposure to multiple pesticide traces in the air, food and water.

A study published by the United States National Research Council in 1993 determined that for infants and children, the major source of exposure to pesticides is through diet. A study in 2006 measured the levels of organophosphorus pesticide exposure in 23 school children before and after replacing their diet with organic food (food grown without synthetic pesticides). In this study it was found that levels of organophosphorus pesticide exposure dropped dramatically and immediately when the children switched to an organic diet.

In the US, the National Academy of Sciences estimates that between 4,000 and 20,000 cases of cancer are caused per year by pesticide residues in food in allowable amounts.

For example, on page 30 is comprehensive data on pesticides on fruits. Some example data: They were also able to test for multiple pesticides within a single sample and found that:

These data indicate that 29.5 percent of all samples tested contained no detectable pesticides [parent

compound and metabolite(s) combined], 30 percent contained 1 pesticide, and slightly over 40 percent

contained more than 1 pesticide. - page 34.

To reduce the amounts of pesticide residues in food, consumers can wash, peel, and cook their food; trim the fat from meat; and eat a variety of foods to avoid repeat exposure to a pesticide typically used on a given crop.

The public

Exposure routes other than consuming food that contains residues, in particular pesticide drift, are potentially significant to the general public.

The Bhopal disaster occurred when a pesticide plant released 40 tons of methyl isocyanate (MIC) gas, intermediate chemical in the production of some pesticides. The disaster immediately killed nearly 3,000 people and ultimately caused at least 15,000 deaths.

In China, an estimated half million people are poisoned by pesticides each year, 500 of whom die.

Children have been found to be especially susceptible to the harmful effects of pesticides. A number of research studies have found higher instances of brain cancer, leukemia and birth defects in children with early exposure to pesticides, according to the Natural Resources Defense Council. Often used for ridding school buildings of rodents, insects, pests, etc., pesticides only work temporarily and must be re-applied. The poisons found in pesticides are not selectively harmful to just pests and in everyday school environments children (and faculty) are exposed to high levels of pesticides and cleaning materials. "No testing has ever been done specifically pertaining to threats among children"

Peer-reviewed studies now suggest neurotoxic effects on developing animals from organophosphate pesticides at legally-tolerable levels, including fewer nerve cells, lower birth weights, and lower cognitive scores. The EPA finished a 10 year review of the organophosphate pesticides following the 1996 Food Quality Protection Act, but did little to account for developmental neurotoxic effects, drawing strong criticism from within the agency and from outside researchers.

Some scientists think that exposure to pesticides in the uterus may have negative effects on a fetus that may manifest as problems such as growth and behavioral disorders or reduced resistance to pesticide toxicity later in life.

A new study conducted by the Harvard School of Public Health in Boston, has discovered a 70% increase in the risk of developing Parkinson's disease for people exposed to even low levels of pesticides.

A 2008 study from Duke University found that the Parkinson's patients were 61 percent more likely to report direct pesticide application than were healthy relatives. Both insecticides and herbicides significantly increased the risk of Parkinson's disease.

One study found that use of pesticides may be behind the finding that the rate of birth defects such as missing or very small eyes is twice as high in rural areas as in urban areas. Another study found no connection between eye abnormalities and pesticides.

Continuing development

Pesticide safety education and pesticide applicator regulation are designed to protect the public from pesticide misuse, but do not eliminate all misuse. Reducing the use of pesticides and choosing less toxic pesticides may reduce risks placed on society and the environment from pesticide use. For example, potato cyst nematodes emerge from their protective cysts in response to a chemical excreted by potatoes; they feed on the potatoes and damage the crop. and the gypsy moth. However, this can be a costly, time consuming approach that only works on some types of insects.

Some evidence shows that alternatives to pesticides can be equally effective as the use of chemicals. For example, Sweden has halved its use of pesticides with hardly any reduction in crops. In Indonesia, farmers have reduced pesticide use on rice fields by 65% and experienced a 15% crop increase.

See also

• Agrichemicals
• Avicide
• Biological pesticide
• Daminozide or Alar
• DDT
• Endangered arthropod
• Federal Insecticide, Fungicide, and Rodenticide Act
• Fungicide
• Herbicide
• Insecticide
• Integrated Pest Management
• List of environmental health hazards
• National Pesticide Information Center
• Non-pesticide management
• Nonpoint source pollution
• Organophosphate
• Pesticide application
• Pesticide formulation
• Pesticide misuse
• Pesticide poisoning
• Pesticide resistance
• Pesticide toxicity to bees
• Protectant
• Soil contamination
• Rodenticide
• The Pesticide Question: Environment, Economics and Ethics (book)
• Transgenic maize Bt corn
• UK Pesticides Campaign
• Water pollution

References

Further reading

Books

• Sittig's Handbook of Pesticides and Agricultural Chemicals
• Pesticide residues in food and drinking water
• Pesticides: problems, improvements, alternatives
• Pesticides in fruits and vegetables
• Pesticides: A Toxic Time Bomb in our Midst
• Pesticide Book
• Pesticide, veterinary and other residues in food

Journal Articles

• Tomlin, C.D.S. (Ed.) 2000 The Pesticide Manual 12th Edition, British Crop Protection Council, Bracknell, UK, 1250 pp.

News

External links

General information

• International Pesticide Application Research Centre (IPARC)
• PAN-UK. Working to eliminate the dangers of toxic pesticides, our exposure to them, and their presence in the environment where we live and work.
• National Pesticide Information Center (NPIC) Information about pesticide-related topics.
• Beyond Pesticides, founded in 1981 as the National Coalition Against the Misuse of Pesticides - Source of information on pesticide hazards, least-toxic practices and products, and on pesticide issues. Website has Daily News Blog relating to pesticides.
• Cdms.net. All Supporting Agro-Chemical Manufacturers a list of EPA pesticide labels for pesticides by trade name.
• Compendium of Pesticide Common Names: Classified Lists of Pesticides Lists of pesticide names by type.
• Pesticide Action Network. PAN Pesticides Database. Compilation of multiple regulatory databases into a web-accessible form.
• Croplifeamerica.org, US trade association representing the crop protection and pest control industry
• US Geological Survey's National Water-Quality Assessment Program. 1997 pesticide use map Shows estimates of pesticide type and intensity of pesticide use by business of mass food production.

Pesticide regulatory authorities

• US EPA
• UK Pesticides Safety Directorate
• European Commission pesticide information

Human health

• Centers for Disease Control Pesticides. Compiled information on health effects of pesticides.
• NIH encyclopedia pages with emergency treatment of Insecticide exposure
• Durango Software - Provides risk assessment tools for pesticide use
• Environmental Working Group (July 14, 2005), The Pollution in Newborns.
• Pesticide Residues in Food - Data and Summary reports from the USDA on pesticide residues in food sold in the United States.
• Pesticides: Use, Effects, and Alternatives to Pesticides in Schools (pdf) from the United States General Accounting Office
• Pesticides and Health -- Greenpeace China

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