Pesticide residue

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Pesticide residue refers to the pesticides that may remain on or in food, after they are applied to food crops. [1] The maximum allowable levels of these residues in foods are stipulated by regulatory bodies in many countries. Regulations such as pre-harvest intervals also prevent harvest of crop or livestock products if recently treated in order to allow residue concentrations to decrease over time to safe levels before harvest. [2]

Contents

Definition

A pesticide is a substance or a mixture of substances used for killing pests: organisms dangerous to cultivated plants or to animals. The term applies to various pesticides such as insecticide, fungicide, herbicide and nematocide. [3]

The definition of residue of pesticide according to the world health organisation (WHO) is:- Any specified substances in or on food, agricultural commodities or animal feed resulting from the use of a pesticide. The term includes any derivatives of a pesticide, such as conversion products, metabolites, reaction products and impurities considered to be of toxicological significance. The term “pesticide residue” includes residues from unknown or unavoidable sources (e.g. environmental) as well as known uses of the chemical. The definition of a residue for compliance with maximum residue limits (MRLs) is that combination of the pesticide and its metabolites, derivatives and related compounds to which the MRL applies. [4]

Background

Prior to 1940, pesticides consisted of inorganic compounds (copper, arsenic, mercury, and lead) and plant derived products. Most of these were abandoned because they were highly toxic and ineffective. Since World War II pesticides composed of synthetic organic compounds were the most important form of pest control. The growth in these pesticides accelerated in late 1940s after Paul Müller discovered DDT in 1939. The effects of pesticides such as aldrin, dieldrin, endrin, chlordane, parathion, captan and 2,4-D were also found at this time. [5] [6] Those pesticides were widely used due to their effective pest control. Problems with environmental issues of DDT became increasingly apparent, since it is persistent and bioaccumulates in the body and the food chain. [5] In the 1960s, Rachel Carson wrote Silent Spring to illustrate a risk of DDT and how it threatened biodiversity. [7] DDT was banned for agricultural use in 1972 and the others in 2001. Persistent pesticides are no longer used for agriculture, and will not be approved by the authorities. [8] [9] Because the half life in soil is long (for DDT 2–15 years [10] ) residues can still be detected in humans at levels 5 to 10 times lower than found in the 1970s. [11]

Regulations

Each country adopts their own agricultural policies and Maximum Residue Limits (MRL) and Acceptable Daily Intake (ADI). The level of food additive usage varies by country because forms of agriculture are different in regions according to their geographical or climatical factors.[ citation needed ]

Pre-harvest intervals are also set to require a crop or livestock product not be harvested before a certain period after application in order to allow the pesticide residue to decrease below maximum residue limits or other tolerance levels. [12] Likewise, restricted entry intervals are the amount of time to allow residue concentrations to decrease before a worker can reenter without protective equipment an area where pesticides have been applied. [13]

International

Some countries use the International Maximum Residue Limits -Codex Alimentarius to define the residue limits; this was established by Food and Agriculture Organization of the United Nations (FAO) and World Health Organization (WHO) in 1963 to develop international food standards, guidelines codes of practices, and recommendation for food safety. Currently the CODEX has 185 Member Countries and 1 member organization (EU). [14]

The following is the list of maximum residue limits (MRLs) for spices adopted by the commission. [15]

PesticideGroup or sub-group of spicesMRL (mg/kg)
Acephate Entire Group 0280.2
Azinphos-methyl Entire Group 0280.5
Chlorpyrifos Seeds
Fruits or berries
Roots or rhizomes		5
1
1
Chlorpyrifos-methyl Seeds
Fruits or berries
Roots or rhizomes		1
0.3
5
Cypermethrin Fruits or berries
Roots or rhizomes		0.1
0.2
Diazinon Seeds
Fruits
Roots or rhizomes		5
0.1
0.5
Dichlorvos Entire Group 0280.1
Dicofol Seeds
Fruits or berries
Roots or rhizomes		0.05
0.1
0.1
Dimethoate Seeds
Fruits or berries
Roots or rhizomes		5
0.5
0.1
Disulfoton Entire Group 0280.05
Endosulfan Seeds
Fruits or berries
Roots or rhizomes		1
5
0.5
Ethion Seeds
Fruits or berries
Roots or rhizomes		3
5
0.3
Fenitrothion Seeds
Fruits or berries
Roots or rhizomes		7
1
0.1
Iprodione Seeds
Fruits or berries
Roots or rhizomes		7
1
0.1
Malathion Seeds
Fruits or berries
Roots or rhizomes		2
1
0.5
Metalaxyl Seeds5
Methamidophos Entire Group 0280.1
Parathion Seeds
Fruits or berries
Roots or rhizomes		0.1
0.2
0.2
Parathion-methyl Seeds
Fruits or berries
Roots or rhizomes		5
5
0.3
Permethrin Entire Group 0280.05
Phenthoate Seeds7
Phorate Seeds
Fruits or berries
Roots or rhizomes		0.5
0.1
0.1
Phosalone Seeds
Fruits or berries
Roots or rhizomes		2
2
3
Pirimicarb Seeds5
Pirimiphos-methyl Seeds sub group
Fruits sub group		3
0.5
Quintozene Seeds sub group
Fruits or berries
Roots or rhizomes		0.1
0.02
2
Vinclozolin Entire spice group0.05

European Union

The European Union has a searchable database with the Maximum Residue Limits (MRLs) for 716 pesticides. Under the previous system, revised in 2008, certain pesticide residues were regulated by the commission; others were regulated by Member States, and others were not regulated at all. [16]

New Zealand

Food Standards Australia New Zealand develops the standards for levels of pesticide residues in foods through a consultation process. The New Zealand Food Safety Authority publishes the maximum limits of pesticide residues for foods produced in New Zealand. [17]

United Kingdom

Monitoring of pesticide residues in the UK began in the 1950s. From 1977 to 2000 the work was carried out by the Working Party on Pesticide Residues (WPPR), until in 2000 the work was taken over by the Pesticide Residue Committee (PRC). The PRC advise the government through the Pesticides Safety Directorate and the Food Standards Agency (FSA). [18]

United States

In the US, tolerances for the amount of pesticide residue that may remain on food are set by the EPA, and measures are taken to keep pesticide residues below the tolerances. The US EPA has a web page for the allowable tolerances. [19] In order to assess the risks associated with pesticides on human health, the EPA analyzed individual pesticide active ingredients as well as the common toxic effect that groups of pesticides have, called the cumulative risk assessment. Limits that the EPA sets on pesticides before approving them includes a determination of how often the pesticide should be used and how it should be used, in order to protect the public and the environment. [20] In the US, the Food and Drug Administration (FDA) and USDA also routinely check food for the actual levels of pesticide residues. [21]

A US organic food advocacy group, the Environmental Working Group, is known for creating a list of fruits and vegetables referred to as the Dirty Dozen; it lists produce with the highest number of distinct pesticide residues or most samples with residue detected in USDA data. This list is generally considered misleading and lacks scientific credibility because it lists detections without accounting for the risk of the usually small amount of each residue with respect to consumer health. [22] [23] [24] In 2016, over 99% of samples of US produce had no pesticide residue or had residue levels well below the EPA tolerance levels for each pesticide. [21]

Japan

In Japan, pesticide residues are regulated by the Food Safety Act.

Pesticide tolerances are set by the Ministry of Health, Labour and Welfare through the Drug and Food Safety Committee. Unlisted residue amounts are restricted to 0.01ppm. [25]

China

In China, the Ministry of Health and the Ministry of Agriculture have jointly established mechanisms and working procedures relating to maximum residue limit standards, while updating them continuously, according to the food safety law and regulations issued by the State Council. [26] [27] From GB25193-2010 [28] to GB28260-2011, [29] from Maximum Residue Limits for 12 Pesticides to 85 pesticides, they have improved the standards in response to Chinese national needs.

Health impacts

Accidental or inadvertent poisoning of agricultural workers due to exposure to pesticides is a very serious matter resulting in many deaths and hospitalizations. The effects of pesticides at high concentrations on human health is a thus a matter of much study, resulting in many publications on the toxicology of pesticides. However the maximum residue limits of pesticides in food are low, and are carefully set by the authorities to ensure, to their best judgement, no health impacts.

According to the American Cancer Society there is no evidence that pesticide residues increase the risk of people getting cancer. [30] The ACA advises washing fruit and vegetables before eating to remove both pesticide residue and other undesirable contaminants. [30]

There are many studies on the health differences between consumers of organic foods vs consumers of organically grown foods. When the American Academy of Pediatrics reviewed the literature on organic foods in 2012, they found that "current evidence does not support any meaningful nutritional benefits or deficits from eating organic compared with conventionally grown foods, and there are no well-powered human studies that directly demonstrate health benefits or disease protection as a result of consuming an organic diet." [31]

Chinese incidents

In China, a number of incidents have occurred where state limits were exceeded by large amounts or where the wrong pesticide was used. In August 1994, a serious incident of pesticide poisoning of sweet potato crops occurred in Shandong province, China. Because local farmers were not fully educated in the use of insecticides, they used the highly-toxic pesticide named parathion instead of trichlorphon. It resulted in over 300 cases of poisoning and 3 deaths. Also, there was a case where a large number of students were poisoned and 23 of them were hospitalized because of vegetables that contained excessive pesticide residues. [32]

Child neurodevelopment

Many pesticides achieve their intended use of killing pests by disrupting the nervous system. Due to similarities in brain biochemistry among many different organisms, there is much speculation that these chemicals can have a negative impact on humans as well. [33] Children are especially vulnerable to exposure to pesticides, especially at critical windows of development. Infants and children consume higher amounts of food relative to their body-weight, and have a more permeable blood–brain barrier, all of which can contribute to increased risks from exposure to pesticide residues. [34] However, in 2008 the OECD report that the existing guideline represents the best available science for assessing the potential for developmental neurotoxicity in human health risk assessment. [35]

See also

Related Research Articles

<span class="mw-page-title-main">Pesticide</span> Substance used to destroy pests

Pesticides are substances that are used to control pests. They include herbicides, insecticides, nematicides, fungicides, and many others. The most common of these are herbicides, which account for approximately 50% of all pesticide use globally. Most pesticides are used as plant protection products, which in general protect plants from weeds, fungi, or insects. In general, a pesticide is a chemical or biological agent that deters, incapacitates, kills, or otherwise discourages pests. Target pests can include insects, plant pathogens, weeds, molluscs, birds, mammals, fish, nematodes (roundworms), and microbes that destroy property, cause nuisance, or spread disease, or are disease vectors. Along with these benefits, pesticides also have drawbacks, such as potential toxicity to humans and other species.

<span class="mw-page-title-main">Lindane</span> Organochlorine chemical and an isomer of hexachlorocyclohexane

Lindane, also known as gamma-hexachlorocyclohexane (γ-HCH), gammaxene, Gammallin and benzene hexachloride (BHC), is an organochlorine chemical and an isomer of hexachlorocyclohexane that has been used both as an agricultural insecticide and as a pharmaceutical treatment for lice and scabies.

<span class="mw-page-title-main">Chlorpyrifos</span> Chemical compound

Chlorpyrifos (CPS), also known as chlorpyrifos ethyl, is an organophosphate pesticide that has been used on crops, animals, and buildings, and in other settings, to kill several pests, including insects and worms. It acts on the nervous systems of insects by inhibiting the acetylcholinesterase enzyme. Chlorpyrifos was patented in 1966 by Dow Chemical Company.

<span class="mw-page-title-main">Codex Alimentarius</span> Collection of internationally recognized standards

The Codex Alimentarius is a collection of internationally recognized standards, codes of practice, guidelines, and other recommendations published by the Food and Agriculture Organization of the United Nations relating to food, food production, food labeling, and food safety.

<span class="mw-page-title-main">Federal Insecticide, Fungicide, and Rodenticide Act</span> US federal law governing pesticide regulation

The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) is a United States federal law that set up the basic U.S. system of pesticide regulation to protect applicators, consumers, and the environment. It is administered and regulated by the United States Environmental Protection Agency (EPA) and the appropriate environmental agencies of the respective states. FIFRA has undergone several important amendments since its inception. A significant revision in 1972 by the Federal Environmental Pesticide Control Act (FEPCA) and several others have expanded EPA's present authority to oversee the sales and use of pesticides with emphasis on the preservation of human health and protection of the environment by "(1) strengthening the registration process by shifting the burden of proof to the chemical manufacturer, (2) enforcing compliance against banned and unregistered products, and (3) promulgating the regulatory framework missing from the original law".

<span class="mw-page-title-main">Diphenylamine</span> Chemical compound

Diphenylamine is an organic compound with the formula (C6H5)2NH. The compound is a derivative of aniline, consisting of an amine bound to two phenyl groups. The compound is a colorless solid, but commercial samples are often yellow due to oxidized impurities. Diphenylamine dissolves well in many common organic solvents, and is moderately soluble in water. It is used mainly for its antioxidant properties. Diphenylamine is widely used as an industrial antioxidant, dye mordant and reagent and is also employed in agriculture as a fungicide and antihelmintic.

<span class="mw-page-title-main">Methoxychlor</span> Synthetic organochloride insecticide, now obsolete.

Methoxychlor is a synthetic organochloride insecticide, now obsolete. Tradenames for methoxychlor include Chemform, Maralate, Methoxo, Methoxcide, Metox, and Moxie.

<span class="mw-page-title-main">Food Quality Protection Act</span> US law about pesticides

The Food Quality Protection Act (FQPA), or H.R.1627, was passed unanimously by Congress in 1996 and was signed into law by President Bill Clinton on August 3, 1996. The FQPA standardized the way the Environmental Protection Agency (EPA) would manage the use of pesticides and amended the Federal Insecticide, Fungicide, and Rodenticide Act and the Federal Food Drug and Cosmetic Act. It mandated a health-based standard for pesticides used in foods, provided special protections for babies and infants, streamlined the approval of safe pesticides, established incentives for the creation of safer pesticides, and required that pesticide registrations remain current.

The maximum residue limit is the maximum amount of pesticide residue that is expected to remain on food products when a pesticide is used according to label directions, that will not be a concern to human health.

<span class="mw-page-title-main">Environmental impact of pesticides</span> Environmental effect

The environmental effects of pesticides describe the broad series of consequences of using pesticides. The unintended consequences of pesticides is one of the main drivers of the negative impact of modern industrial agriculture on the environment. Pesticides, because they are toxic chemicals meant to kill pest species, can affect non-target species, such as plants, animals and humans. Over 98% of sprayed insecticides and 95% of herbicides reach a destination other than their target species, because they are sprayed or spread across entire agricultural fields. Other agrochemicals, such as fertilizers, can also have negative effects on the environment.

<span class="mw-page-title-main">Organic food</span> Food complying with organic farming standards

Organic food, ecological food, or biological food are foods and drinks produced by methods complying with the standards of organic farming. Standards vary worldwide, but organic farming features practices that cycle resources, promote ecological balance, and conserve biodiversity. Organizations regulating organic products may restrict the use of certain pesticides and fertilizers in the farming methods used to produce such products. Organic foods are typically not processed using irradiation, industrial solvents, or synthetic food additives.

<span class="mw-page-title-main">Pesticides in the United States</span>

Pesticides in the United States are used predominantly by the agricultural sector, but approximately a quarter of them are used in houses, yards, parks, golf courses, and swimming pools.

Pesticide residues are of concern in New Zealand and foods are regularly checked to see if they are within set limits.

<span class="mw-page-title-main">Health effects of pesticides</span> How pesticides affect human health

Health effects of pesticides may be acute or delayed in those who are exposed. Acute effects can include pesticide poisoning, which may be a medical emergency. Strong evidence exists for other, long-term negative health outcomes from pesticide exposure including birth defects, fetal death, neurodevelopmental disorder, cancer, and neurologic illness including Parkinson's disease. Toxicity of pesticides depend on the type of chemical, route of exposure, dosage, and timing of exposure.

<span class="mw-page-title-main">Pesticide regulation in the United States</span>

Pesticide regulation in the United States is primarily a responsibility of the Environmental Protection Agency (EPA). In America, it was not till the 1950s that pesticides were regulated in terms of their safety. The Pesticides Control Amendment (PCA) of 1954 was the first time Congress passed guidance regarding the establishment of safe limits for pesticide residues on food. It authorized the Food and Drug Administration (FDA) to ban pesticides they determined to be unsafe if they were sprayed directly on food. The Food Additives Amendment, which included the Delaney Clause, prohibited the pesticide residues from any carcinogenic pesticides in processed food. In 1959, pesticides were required to be registered.

<span class="mw-page-title-main">2,4-Dichlorophenoxyacetic acid</span> Herbicide

2,4-Dichlorophenoxyacetic acid is an organic compound with the chemical formula Cl2C6H3OCH2CO2H. It is usually referred to by its ISO common name 2,4-D. It is a systemic herbicide that kills most broadleaf weeds by causing uncontrolled growth, but most grasses such as cereals, lawn turf, and grassland are relatively unaffected.

<span class="mw-page-title-main">Chlormequat</span> Chemical compound

Chlormequat is an organic compound with the formula ClCH
2CH
2N(CH
3)+
3 that is used as a plant growth regulator. It is typically sold as the chloride salt, chlormequat chloride (C5H13Cl2N), a colorless hygroscopic crystalline substance that is soluble in water and ethanol. It is an alkylating agent and a quaternary ammonium salt. Chlormequat is one of the onium-type growth regulators.

<span class="mw-page-title-main">Circle of Poison</span> Export of illegal pesticides

The Circle of Poison (COP) refers to the export of domestically banned pesticides for use on foods elsewhere, some of which returns by way of import. The "circle" is complete when the toxic chemicals that were exported are then used to grow fruit, meat, and produce that are imported and available for domestic consumption. This circle was first identified relative to the United States but the relationship also exists between other nations of the Global North and South.

Pesticide standard values are applied worldwide to control pesticide pollution, since pesticides are largely applied in numerous agricultural, commercial, residential, and industrial applications. Usually, pesticide standard value is regulated in residential surface soil, drinking water, foods, and other ecological sections.

<span class="mw-page-title-main">Regulation of pesticides in the European Union</span>

A pesticide, also called Plant Protection Product (PPP), which is a term used in regulatory documents, consists of several different components. The active ingredient in a pesticide is called “active substance” and these active substances either consist of chemicals or micro-organisms. The aims of these active substances are to specifically take action against organisms that are harmful to plants. In other words, active substances are the active components against pests and plant diseases.

References

  1. ↑ IUPAC , Compendium of Chemical Terminology , 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) " pesticide residue ". doi : 10.1351/goldbook.P04520
  2. ↑ "Pesticide Residue". Environmental Protection Agency. Archived from the original on 4 June 2013. Retrieved 9 November 2011.
  3. ↑ US Environmental (24 July 2007), What is a pesticide? epa.gov. Retrieved on 24 October 2012.
  4. ↑ Sheffer, Marla (2009). "Principles and Methods for the Risk Assessment of Chemicals in Food" (PDF). International programme on chemical safety. Retrieved 8 January 2024.
  5. 1 2 Pesticide Usage in the United States: History, Benefits, Risks, and Trends; Bulletin 1121, November 2000, K.S. Delaplane, Cooperative Extension Service, The University of Georgia College of Agricultural and Environmental Sciences "Archived copy" (PDF). Archived from the original (PDF) on 13 June 2010. Retrieved 10 November 2012.{{cite web}}: CS1 maint: archived copy as title (link)
  6. ↑ "A history of pesticide use", Patricia Muir at Oregon State University. Last updated 22 October 2012.
  7. ↑ Lobe, J (16 September 2006), "WHO urges DDT for malaria control Strategies," Inter Press Service, cited from Commondreams.org. Retrieved on 15 September 2007
  8. ↑ "About Pesticide Registration". EPA (environmental protection agency). 4 January 2024. Retrieved 6 January 2024.
  9. ↑ "Approval of pesticides and herbicides in the EU". European Commission . Retrieved 6 January 2024.
  10. ↑ "National Biomonitoring Program". Center for disease control and prevention. 7 April 2017. Retrieved 6 January 2024.
  11. ↑ "Dichlorodiphenyltrichloroethane (DDT) Factsheet". Center for disease control and prevention. 16 August 2021. Retrieved 6 January 2024.
  12. ↑ "Preharvest Interval". npic.orst.edu. National Pesticide Information Center. Retrieved 30 March 2018.
  13. ↑ "Pesticides - Re-entry Interval : OSH Answers". www.ccohs.ca. Government of Canada, Canadian Centre for Occupational Health and Safety. 15 November 2018. Retrieved 30 March 2018.
  14. ↑ CODEX International Food Standards (23 October 2012) Retrieved on October 28, 2012
  15. ↑ CODEX International Food Standards, Maximum Residue Limits for Spices (23 October 2012)[ permanent dead link ] Retrieved on 28 October 2012
  16. ↑ "Maximum Residue Levels". European commission. Retrieved 16 January 2024.
  17. ↑ "Food Standards". New Zealand Food Safety Authority. Retrieved 20 February 2009.
  18. ↑ CRD. "CRD | About PRiF | The Role of the PRiF". Pesticides.gov.uk. Retrieved 30 May 2013.
  19. ↑ "Protection of Environment". Access.gpo.gov. 1 July 2004. Archived from the original on 4 February 2012. Retrieved 30 May 2013.
  20. ↑ "Pesticides: Health and Safety". 17 October 2014. Archived from the original on 10 February 2003. Retrieved 8 February 2015.
  21. 1 2 "Pesticide Data Program". U.S. Department of Agriculture (USDA). Retrieved 6 January 2024.
  22. ↑ Winter, Carl K.; Katz, Josh M. (2011). "Dietary Exposure to Pesticide Residues from Commodities Alleged to Contain the Highest Contamination Levels". Journal of Toxicology. 2011: 589674. doi: 10.1155/2011/589674 . PMC   3135239 . PMID   21776262.
  23. ↑ Gribble, Gordon W. (3 March 2013). "Food chemistry and chemophobia". Food Security. 5 (2): 177–187. doi:10.1007/s12571-013-0251-2. S2CID   18802337.
  24. ↑ "How Organic Produce Can Make America Less Healthy". Bloomberg.com. 9 March 2017. Retrieved 20 May 2018.
  25. ↑ "The Japanese Positive List System for Agricultural Chemical Residues in Foods" (Press release). The Japan Food Chemical Research Foundation. May 2006.
  26. ↑ "Ministry of Health and Ministry of Agriculture Released MRL Standards". China Pesticide Information Network. Press Office of the Ministry of Agriculture. Archived from the original on 27 February 2015. Retrieved 16 November 2012.
  27. ↑ "China released 85 kinds of food pesticide maximum residue limits". World agricultural network Chinese network. Retrieved 16 November 2012.
  28. ↑ "Maximum Residue Limits for 12 Pesticides" (in Chinese). Archived from the original on 14 December 2012. Retrieved 16 November 2012.{{cite web}}: CS1 maint: bot: original URL status unknown (link)
  29. ↑ "Maximum Residue Limits for 85 Pesticides". Archived from the original on 14 December 2012. Retrieved 16 November 2012.{{cite web}}: CS1 maint: bot: original URL status unknown (link)
  30. 1 2 "ACS Guidelines on Nutrition and Physical Activity for Cancer Prevention – Common questions about diet and cancer". American Cancer Society. 9 April 2015. Retrieved 12 December 2015.[ permanent dead link ]
  31. ↑ Forman, Joel; Silverstein, Janet; Committee on Nutrition; Council on Environmental Health; American Academy of Pediatrics (November 2012). "Organic foods: health and environmental advantages and disadvantages". Pediatrics. 130 (5): e1406–1415. doi: 10.1542/peds.2012-2579 . ISSN   1098-4275. PMID   23090335.
  32. ↑ "Environmental Pesticide Pollution and Its Countermeasures in China" Xu Hui, Qian Yi, Peng Bu-zhuo, Jiang Xiliu and Hua Xiao-mei Ambio Vol. 32, No. 1 (February 2003), pp. 78-80 Published by: Springer
  33. ↑ Marina Bjørling-Poulsen; Helle Raun Andersen; Philippe Grandjean. (2008). "Potential developmental neurotoxicity of pesticides used in Europe". Environmental Health. 7 (1): 50. Bibcode:2008EnvHe...7...50B. doi: 10.1186/1476-069X-7-50 . PMC   2577708 . PMID   18945337.
  34. ↑ Bernard Weiss; Sherlita Amler; Robert W. Amler. (2004). "Pesticides". Pediatrics. 113 (4 Suppl): 1030–6. doi:10.1542/peds.113.S3.1030. PMID   15060196. S2CID   245062674.
  35. ↑ Makris, Susan L. (2009). "A Retrospective Performance Assessment of the Developmental Neurotoxicity Study in Support of OECD Test Guideline 426". Environmental Health Perspectives. 117 (1): 17–25. doi:10.1289/ehp.11447. PMC   2627860 . PMID   19165382 – via EHP publishing.
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