Pesticides

The information on this page is adapted from toxipedia.org. To learn more about Toxipedia’s integration into our website, visit our Toxipedia webpage.

Pesticides kill unwanted organisms: animals, plants, fungi, microbes and more. The mechanisms by which they are able to kill may also be harmful to humans.

Pesticides are defined by the US Environmental Protection Agency as any substance intended for preventing, destroying, repelling or mitigating any pest. Though often misunderstood to refer to only to insecticides, the term pesticide also applies to herbicides, fungicides and various other substances to control pests.¹ Hundreds of pesticides are registered under the US Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).²

Uses

Pesticides are used mainly in agriculture, but large quantities are also used in many other places:

Site	Examples
Homes and gardens	Pest control or preservatives in home vegetable and fruit gardens and orchards, flower gardens, preservatives in wooden structures
Lawns and landscaping	Pest control on private lawns, golf courses, sports fields, parks, school grounds, church grounds, roadsides
Indoors	Insect control, rodent control, mold and mildew control, antimicrobial cleaners and clothing, flea sprays
Food	Disinfectants and preservatives, pest control applied to livestock
Bodies	Insect repellents, disinfectants, antibiotics, lice treatments, preservatives in cosmetics

An assessment in 1992 found that 85 percent of all US households have at least one pesticide in storage, and a survey the same year in Minnesota found that on a per-acre basis urban dwellers use herbicides for lawn care at rates equal to those used by farmers for food  production.⁷

Data source: US Environmental Protection Agency;8 click to zoom

Toxicity

Pesticides work by interfering with necessary biological mechanisms in pests. Because many organisms share similar biological mechanisms, the effects of pesticides often are not specific to one type of organism. Pesticides can kill their target pests but may also harm other organisms, including humans. Many pesticides are also considered endocrine disruptors (EDCs), noted for their effects on our endocrine systems, and/or persistent organic pollutants (POPs), noted for their longevity, toxicity to humans and animals, and ability to be transported around the globe through the atmosphere.

Human Health Effects

Acute Exposure (Poisoning)

In the United States, an average of more than 130,000 calls to poison control centers were reported from 2006 to 2010, with an average of more than 20,000 cases treated in health care facilities annually. The Agency for Healthcare Research and Quality reported an annual average of 7385 emergency room visits during 2006 to 2008, and 1419 annual hospitalizations during 2005 to 2009.⁹ Recent figures worldwide are elusive, but the WHO estimated in 1990 that there are around 3 million hospital admissions for pesticide poisoning each year, 2 million of which are as a result of deliberate ingestion, and these result in around 220,000 deaths. However, WHO also considered that "this necessarily reflects only a fraction of the real problem."¹⁰  

Specific health effects and toxicity symptoms vary across both general classes of pesticides and individual pesticides within classes. 

Organochlorine Pesticides

Health effects and symptoms following Ingestion:

• Loss of sensation around the mouth
• Hypersensitivity to light, sound, and touch
• Dizziness
• Tremors
• Nausea
• Vomiting
• Nervousness
• Confusion

Organophosphate or Carbamate Insecticides

Symptoms and health effects following exposure:

• Increased salivation
• Increased perspiration
• Narrowing of pupils
• Nausea
• Diarrhea
• Decrease in blood pressure
• Muscle weakness
• Fatigue

These symptoms can last up to a few days but decline as soon as acetylcholine levels return to normal in the body.

Pyrethroids

Symptoms and health effects following exposure:

• Allergic reactions
• Hyper-excitation
• Aggressiveness
• Incoordination
• Whole-body tremors
• Seizures

Other Pesticides

• Acute hepatocellular injury (hepatitis)
• Acute tubular necrosis

Long-term Health Impacts

Cancer

Carcinogenicity of some common pesticides, from PAN's Pesticides Database¹¹ and CHE's Toxicant and Disease Database¹² unless noted otherwise:

Category	Known Carcinogens	Probable Carcinogens
Fungicides	Maneb and nickel sulfate hexahydrate
Herbicides and insecticides	Arsenic and arsenic compounds	Permethrin Trichlorfon Organophosphates13
Wood preservatives	Chromium VI compounds (hexavalent chromium) Creosote

Reproductive and Developmental Effects

Pesticides linked to reproductive and developmental health impacts in summary.¹⁴ Specific associations, plus links with limited evidence, are listed in CHE's Toxicant and Disease Database. Information about more pesticides is available from Pesticide Action Network's Pesticides Database—Chemicals.

Categories and Common Pesticides	Strong Evidence	Good Evidence
Fungicides Hexachlorobenzene Maneb Thiram Vinclozolin		Altered sex ratio Decreased vision Fetotoxicity (miscarriage / spontaneous abortion, stillbirth) Hormonal changes Menstrual disorders (abnormal bleeding, short cycles, long cycles, irregular cycles, painful periods)
Herbicides 2,4-D Alachlor Arsenic and inorganic arsenic compounds Dichlorprop Methyl bromide Propachlor		Abnormal sperm Cognitive impairment Decreased coordination / dysequilibrium Fetotoxicity Low birth weight / small for gestational age / intrauterine growth retardation Menstrual disorders Seizures
Insecticides Chlordecone DDT Diazinon Hexachlorobenzene Methyl bromide Nicotine Parathion	Abnormal sperm Cognitive impairment Fetotoxicity Low birth weight Reduced male fertility	Abnormal sperm Cognitive impairment Decreased coordination / dysequilibrium Decreased vision Fetotoxicity Hormonal changes Low birth weight Menstrual disorders Preterm delivery Seizures
Nematicides Ethylene dibromide Methyl bromide	Abnormal sperm Reduced male fertility	Cognitive impairment Decreased coordination / dysequilibrium Decreased vision Seizures
Wood preservatives Pentachlorophenol (PCP)		Cognitive impairment Low birth weight

Other Health Effects

Health associations for selected pesticides; information is from CHE's Toxicant and Disease Database¹⁵ unless noted otherwise.

Pesticide	Strong Evidence	Good Evidence
Aldicarb	Peripheral neuropathy	Immune suppression
Carbamates	Arrhythmias Peripheral neuropathy	Asthma - irritant Immune suppression
Chlordane		Immune suppression Peripheral neuropathy Porphyria (toxic)
Chlordecone		Peripheral neuropathy
Chlorpyrifos		Immune suppression Psychiatric disturbances
Creosote	Hyperkeratosis / hyperpigmentation Leukoderma (hypopigmentation)
DDT	Chloracne	Hearing loss Peripheral neuropathy Porphyria (toxic) Psychiatric disturbances
Diquat	Pulmonary edema
Hexachlorobenzene	Hyperkeratosis / hyperpigmentation Porphyria (toxic)
Maneb		Peripheral neuropathy
Methyl bromide		Arrhythmias Peripheral neuropathy Psychiatric disturbances Pulmonary edema Spasticity / myoclonus
Nicotine		Behavioral problems
Paraquat	Pulmonary edema Pulmonary fibrosis	Chronic renal disease Parkinson's disease / movement disorders
Pentachlorophenol (PCP)		Aplastic anemia Chloracne Immune suppression
Pyrinuron (Vacor)16	Type 1 diabetes
Propoxur		Aplastic anemia
Pyrethroids	Peripheral neuropathy Pneumonitis (hypersensitivity)	Asthma allergen, sensitizer
Thimerosal	Contact dermatitis - irritant

Sensitive and Vulnerable Populations

image from Wes Peck at Creative Commons; click to zoom

As with many chemicals, fetuses and children are especially sensitive due to their continuing development. Brains, reproductive organs, and all other body systems are forming and growing, making them vulnerable to alterations. Pesticide use by parents before, during or after pregnancy can have long-term impacts on children, including birth defects, developmental disabilities, behavior and psychological effects, impaired reproductive function and cancer. Reviews have found that indoor pesticide exposure in childhood is associated with higher risk of leukemia and lymphoma,¹⁷ and occupational use of pesticides by parents is associated with a higher risk of brain tumors in children.¹⁸ An investigation in 2007 found that girls' exposure to DDT before age 14 increases their risk of breast cancer as adults five-fold. Girls exposed after age 14 did not have an increase compared to girls who were not exposed.¹⁹

Early indications of genetic susceptibility to exposures are found in studies of Parkinson's disease and cancer.²⁰ See the Gene-Environment Interaction webpage for more information.

People who live near or work where pesticides are produced or applied are at increased risk for exposure.

Routes of Exposure

Remote Exposures Exposures can be several steps removed from the intended use of the pesticide. For example, pesticides applied to lawns could be picked up by a pet's fur, transferred to human hands and then to food, and finally ingested. image from Peter Organisciak at Creative Commons

Typical routes of exposure are dermal (skin), inhalation and ingestion, but exposure through the eyes is also possible.

Dermal exposure is most common in work situations where workers mix, load or apply pesticides. Dermal exposure can also occur from touching an item or person contaminated with pesticide residue.

Inhalation and absorption through the lungs occurs through airborne particles from powders or droplets. Inhalation is especially likely with high pressure, volume or fogging equipment. The smaller the particles or droplets, the farther they can travel on air currents. Low pressure application, producing larger droplets, is less hazardous.

Ingesting large quantities of pesticides can result in the most harmful and serious poisonings. Pesticides can also be accidently ingested through accidental drinking from a mislabeled or reused pesticides container, which is why great care should be taken not to mix or store pesticides in food containers and to maintain and follow instructions on pesticide container labels.²¹

Low-level, often chronic pesticide ingestion occurs through resides on pesticide-treated foods. Initial studies have shown measurable, and sometimes dramatic, differences in pesticide residues in urine when a diet of pesticide-treated food sources is compared to an organic food diet.²²

Reducing Exposures

Less Toxic Pest Control Visit these sites for detailed information about controlling pests with methods and materials that are less toxic to children, pets and non-targeted wildlife: From Beyond Pesticides: ManageSafe™  From the US EPA: Do you really need to use a pesticide? From Pesticide Action Network, three pages: Home, Pets, Garden image from Ariel Chang at Creative Commons

In Lawn, Garden and Home

The most effective way to reduce pesticide exposures is to use them as little as possible. There are safer alternatives for every use of chemical pesticides, such as Integrated Pest Management (IPM) for your home and garden. In a nutshell, IPM prevents household pests naturally by removing their sources of food, water, and shelter and also their access to your home:

• Fix leaky plumbing and prevent wet spots inside and outside your home.
• Wipe up food residues on countertops.
• Seal pet food containers.
• Keep garbage contained and covered.
• Rinse recyclable containers.
• Remove woodpiles from around or inside your home.
• Repair door and window screens.
• Remove diseased plants and fallen fruit that may attract pests to your garden.

Wipe shoes on doormats and leave them at the door to avoid tracking in pesticide residues. Control dust, which can also contain pesticide residues in your home. Vacuum regularly with a HEPA filter vacuum if possible. Use damp dust rags instead of feather dusters which stir up dust and disperse it into the air.

If you do store pesticides at home, lock them away from children's reach. Keep toxics in the original containers and follow all warning label directions.

Environmental Working Group's Dirty Dozen and Clean 15 lists

On Food

Always wash fruits and vegetables. Even after washing and cooking foods, pesticide residues may remain, so also peel fruits and vegetables when possible. Buy organically grown produce whenever you can, especially those foods most likely to contain chemical residues. See the Environmental Working Group's annual lists of the Dirty Dozen and Clean 15 foods.

In Lice Treatment

Prevent head lice from becoming unwelcome guests: see Head Lice Prevention from Healthline. If you do contract lice, avoid head lice treatments that contain lindane, especially with children or anyone weighing less than 110 pounds.²³

At Work

image from Walmart at Creative Commons

Follow all label instructions, including use of protective clothing and equipment. Measure, mix, apply and store pesticides as directed. Ventilate areas during use if recommended. Avoid use that will contaminate water or downwind neighborhoods. Clean up spills according to the manufacturer's instructions. Wash well after handling pesticides, and especially before handling food or eating. To avoid take-home exposures, leave contaminated clothing and gear at work if possible, and wash skin and hair thoroughly before going home or having physical contact with others. In case of an exposure, seek medical treatment promptly. If you suspect you are pregnant, take extra precaution or see if you can work away from pesticides if possible.²⁴

In Your Community

image from Duca di Spinaci at Creative Commons

Talk to neighbors, schools, businesses, and government officials about reducing pesticide use on playgrounds, lawns, roadsides, schools and other public areas.

Regulation

Worldwide

• Rotterdam Convention, 1998
• Stockholm Convention on Persistent Organic Pollutants, 2001
• Food and Agriculture Organization of the United Nations: The International Code of Conduct on Pesticide Management and Guidelines on Highly Hazardous Pesticides

European Union

• Regulation (EC) No 1107/2009

United States

• Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA)
• Federal Food, Drug and Cosmetic Act (FFDCA)
• Food Quality Protection Act
• Pesticide Registration Improvement Act of 2003 (PRIA)
• Endangered Species Act (ESA)

Case Studies: Selected Pesticides

Here we highlight a few pesticides that have captured popular attention. They are not necessarily the most hazardous pesticides, but they have achieved some notoriety.

Agent Orange

The US military sprayed an estimated 20 million gallons²⁵ of Agent Orange and other herbicides on trees and vegetation during the Vietnam War. Several decades later, concerns about the health effects from these chemicals continue.²⁶ A mixture of the herbicides 2,4-D and 2,4,5-T, which was also contaminated with dioxin (TCDD), Agent Orange has been associated with these health impacts on the Vietnamese population:

• Birth defects²⁷ including spina bifida,²⁸ and elevated salivary and serum cortisol and cortisone levels.²⁹

Effects in US veterans:

• Increased incidence of diabetes, heart disease, hypertension and chronic respiratory conditions³⁰
• Good evidence of a link to cancer of the prostate and bladder and soft tissue sarcomas and B-cell lymphomas and also chloracne, and limited evidence of an association with Parkinson's disease; type 2 diabetes; hypertension, ischemic heart disease, and stroke; hypothyroidism; early onset peripheral neuropathy and porphyria cutanea tarda³¹

In 1969 the Federation of American Scientists submitted a petition to the White House with more than 5000 signatures of renowned scientists, including 17 Nobel laureates and 129 members of the National Academy of Sciences, to end the herbicide program. In April 1970, the US government restricted use of 2,4,5-T, and therefore Agent Orange, in both Vietnam and the US. In 1971 all the remaining stocks of Agent Orange were gathered and either shipped to Johnston's Island in the South Pacific or shipped and stored at the Seabees base in Gulfport, Mississippi, from which they were destroyed by an incinerator ship in September 1977.³²

Atrazine

image from Daniel_Bauer at Creative Commons

Atrazine is one of the most widely used herbicides in the US, with an estimated 70 million pounds used in agriculture in 2014, a majority on corn crops.³³ Sampling by the US Geological Survey has found atrazine in about 90 percent of streams and more than 40 percent of groundwater in agricultural areas, and also in about 70 percent of streams and about 35 percent or groundwater in urban areas.³⁴ It has been found in surface water used for public water supplies in the Midwest at levels greater than the standards established by the Environmental Protection Agency.³⁵

Health concerns associated with atrazine include birth defects³⁶ and its endocrine-disrupting potential to cause mammary gland tumors in rodents and alter male reproduction.³⁷

Atrazine's use has been banned since 2003 in the European Union and Switzerland due to concerns that it contaminates groundwater.³⁸

DDT

Hailed as the “wonder insecticide of World War II” for protecting troops from typhus and malaria, DDT (dichlorodiphenyltrichloroethane) is an organochloride insecticide that was widely used worldwide from the mid-1940s through the 1960s. Serious concerns about its impact on human health and the environment led the US EPA to issue a cancellation order for DDT in 1972. Use in the US and in most countries was discontinued, but because it was widely used, because it persists in the environment without breaking down, and because it bioaccumulates in fat tissue, residues are still a concern and exposures ubiquitous.³⁹ A 2002 review went so far as to state that “there is not a single living organism that doesn’t contain DDT."⁴⁰ DDT has been detected in the Arctic, far from any production or use, and in food from all over the world.⁴¹

American GI spraying DDT in an Italian home, 1945; image from Otis Historical Archives National Museum of Health and Medicine at Creative Commons

Although DDT use is banned under the Stockholm Convention on Persistent Organic Pollutants, an exemption is granted for vector control of malaria and other insect-borne diseases, primarily in India, China and sub-Saharan Africa.⁴²

DDT has been associated with cancer in laboratory animals, but no clear evidence has emerged in humans.⁴³ Based on all the available evidence, the US Department of Health and Human Services has determined that DDT is reasonably anticipated to be a human carcinogen, the International Agency for Research on Cancer (IARC) has determined that DDT is possibly carcinogenic to humans and US EPA has determined that DDT is a probable human carcinogen.⁴⁴

As an endocrine disruptor, DDT and its metabolite DDE have endocrine effects particularly during development, as demonstrated in animal tests. It can disrupt natural hormone signaling by binding to androgen receptors and blocking signals in cells, causing reproductive and developmental effects. Studies in humans suggest that high DDT/DDE burdens may be associated with hormonally controlled endpoints such as duration of lactation, fertility and maintenance of pregnancy. High blood levels of DDE during pregnancy have also been associated with increased odds of having preterm infants and small-for-gestational-age infants. Perinatal exposure of animals to DDT/DDE has caused alterations in the reproductive organs and infertility. In animals, DDT/DDE can produce embryotoxicity, fetotoxicity, and abnormal development of the sex organs. Adult mice administered DDT early in life showed neurobehavioral alterations when tested later in life.⁴⁵

Glyphosate

First introduced in 1974 under the trade name Roundup (but since also sold as Accord, Rodeo,  Touchdown and other products), glyphosate is a very popular nonselective herbicide, used both in agriculture and on lawns and gardens. It is one of the world’s most widely used broad-spectrum herbicides and accounts for around 25 percent of the global herbicide market.⁴⁸

Use of glyphosate-based herbicides (GBHs) can result in residues of glyphosate and its primary metabolite AMPA in crops at harvest and in processed foods. With the huge amount of GBHs used worldwide, exposures have become common in the food supply. A 2016 consensus statement on the risks of glyphosate exposure summarizes concerns:

• Damage to the liver and kidneys
• Cancer; the International Agency for Research on Cancer (IARC) has classified glyphosate as "probably carcinogenic to humans." However, an extensive review by the European Food Safety Authority in 2015 concluded that "glyphosate is unlikely to pose a carcinogenic hazard to humans."⁴⁹
• Congenital malformations in pigs fed glyphosate-contaminated feed, causing concern regarding similar human birth defects observed in populations living in and near farming regions.⁵⁰

History & Ethics

Early Pesticides

Pesticides have been used in different forms since about 1000 BC when the Chinese used sulfur as a way to control bacteria and mold. Sulfur is still used in many fungicides to control diseases in plants, to kill off unwanted bacteria in wine barrels and to remove unwanted yeast from wine. In addition to sulfur, the Chinese also utilized arsenic as both an insecticide and herbicide, and its use continues even now. See the Arsenic webpage.

Plant-produced pesticides include nicotine, pyrethrums from chrysanthemums and rotenone from the root of the Derris elliptica plant. These pesticides have been used to in kill insects and fish, with substantial use beginning in the late seventeenth century.  Nonsynthetic pesticides are often difficult to purify and produce in large qualities.

The regulation of pesticides by the federal government began in 1910 with the passage of the Federal Insecticide Act by Congress. This legislation ensured quality pesticides by protecting farmers and consumers from fraudulent and/or adulterated products by manufacturers and distributors.⁵¹

Synthetic Pesticides

In 1939 a Swiss Chemist named Paul Muller discovered that DDT, first synthesized in 1873, was a potent insecticide.⁵² By 1945 it had become the most widely used pesticide in the world, both in commercial agriculture and also in combatting insect-borne illness such as malaria and typhus. Muller won the Nobel Prize in 1948 for DDT's development as an insecticide.⁵³

Throughout the 1940s and 1950s, many new pesticides were created and marketed, including the class of organophosphates such as insecticides parathion and malathion, plus 2,4-D and carbamates.⁵⁴ Some pesticides, such as organophosphorus compounds, can also serve as chemical warfare agents,⁵⁵ and thus military interest promoted development.

In 1947, the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) was passed. This act extended the coverage of the Federal Insecticide Act to include herbicides and rodenticides and required that all pesticide products be registered with the USDA before their sale in interstate or foreign commerce.⁵⁶

image from Frank Hebbert at Creative Commons

During the 1960s, Monsanto developed an herbicide named Agent Orange, used widely by the United States during the Vietnam War.

Concerns Increase

In 1962 Rachel Carson’s book Silent Spring brought substantial attention to the harmful effects of several pesticides—including chlordane, heptachlor, dieldrin, aldrin, endrin, parathion, malathion and DDT—on humans, animals and the environment. This book both raised awareness and concern over pesticides' harmful effects on wildlife and humans and is credited with launching the environmental movement and awareness of the connections between environmental and human health.

In 1972, prompted by studies that determined continued massive use of DDT posed unacceptable risks to the environment and human health, the United States banned DDT, making its use in domestic agriculture and trade illegal.⁵⁷ This was widely viewed as spurred by Rachel Carson's 1962 book.

Also in 1972, the Environmental Protection Agency was created with the authority to regulate pesticides after weighing costs and benefits and evaluating risks. The 1996 amendment to the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) mandated that all pesticides distributed or sold in the United States be registered (licensed) by EPA.⁵⁸

The 1996, the Food Quality Protection Act amended FIFRA, requiring that special consideration be given to children’s exposure by using an additional tenfold safety factor when setting and reassessing tolerances.⁵⁹

In 1998 the Rotterdam Convention called on exporters of pesticides to use proper labeling and instructions for safe use on all products. This was one of the first international efforts to regulate hazardous chemicals/pesticides.⁶⁰

In 2001 the Stockholm Convention on Persistent Organic Pollutants, an international United Nations treaty, called for international action and cooperation on the restriction and elimination of 12 POPs determined to be hazardous, including pesticides aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, hexachlorobenzene (HCB), mirex and toxaphene. This treaty has been ratified by 180 nations worldwide.

Ethics Concerns

There's no question that pesticide use has saved hundreds of millions of lives: deaths from malaria dropped from 3.1 million worldwide in 1900 to fewer than 1.1 million in 1997, largely due to pesticide use against mosquitos. The gains are even more impressive if sub-Saharan Africa is excluded from the data, for malaria there has remained much more intractable than elsewhere. In the rest of the world, the percentage of deaths from malaria fell 99 percent from 1900 to 1997, from 8 percent of all deaths to 0.08 percent.⁶¹

Click to zoom.

Other types of pesticides are also important in safeguarding human health. Preservatives in food and cosmetics prevent bacterial growth that can lead to infection, illness, disability and even death.⁶²

However, pesticide use comes with a price. Because pesticide use has not only the potential but an established history of contaminating the food, water, soil and air on which all humans depend, their use impacts all humankind. The application of chemicals that cause death when used inappropriately and that degrade our health even when used appropriately needs high scrutiny and constant oversight. The almost giddy enthusiasm for their development and use following World War II seems now to have been short-sighted. The effective lifetime of many pesticides—the time until their targeted pests develop immunity or resistance—might be measured in decades or less. Insect resistance to DDT and other insecticides was evident by 1970, for example.⁶³ However, the toxic effects on human health persist for many generations. The benefits of pesticide use must be carefully weighed against their costs to current and future residents of Earth, both human and otherwise.

See more about pesticides and health in the list of CHE publications and Dig Deeper resources in the right sidebar.

1. US Environmental Protection Agency. Pesticides. 2016. Viewed August 17, 2016.
2. Scorecard. Registered Pesticides (Federal Insecticide, Fungicide, and Rodenticide Act). GoodGuide. Viewed August 17, 2016.
3. Sustainable Agriculture Network. List of Prohibited Pesticides. November 2011. Viewed August 17, 2016.
   
4. Scorecard. Chemical Profiles. GoodGuide. Viewed August 18, 2016.
5. Pesticide Action Network. Pesticides Database—Chemicals. Viewed August 19, 2016.
6. Australian Government Department of Environment and Energy. Viewed August 18, 2016.
7. Delaplane KS. Pesticide usage in the United States: history, benefits, risks, and trends. Southern Region Pesticide Impact Assessment Program. March 1996. Viewed August 20, 2016.
8. Grube A et al. Pesticides Industry Sales and Usage: 2006 and 2007 Market Estimates. Biological and Economic Analysis Division, Office of Pesticide Programs, Office of Chemical Safety and Pollution Prevention, US Environmental Protection Agency. February 2011.
9. Langley RL, Mort SA. Human exposures to pesticides in the United States. Journal of Agromedicine. 2012;17(3):300-15.
10. Jeyaratnam J. Acute pesticide poisoning: a major global health problem. World Health Statistics Quarterly. 1990;43:139–144.
11. Pesticide Action Network. Pesticides Database—Chemicals. Viewed August 19, 2016.
12. Janssen S, Solomon G, Schettler T. Toxicant and Disease Database. Collaborative on Health and the Environment. 2011.
13. Lerro CC et al. Organophosphate insecticide use and cancer incidence among spouses of pesticide applicators in the Agricultural Health Study. Occupational and Environmental Medicine. 2015 Oct;72(10):736-44.
14. Janssen S, Solomon G, Schettler T. Toxicant and Disease Database. Collaborative on Health and the Environment. 2011.
15. Janssen S, Solomon G, Schettler T. Toxicant and Disease Database. Collaborative on Health and the Environment. 2011.
16. Bodin J et al. Can exposure to environmental chemicals increase the risk of diabetes type 1 development? BioMed Research International. 2015, ID 208947, 1-19.
17. Quach P et al. A systematic review of the risk factors associated with the onset and progression of primary brain tumours. Neurotoxicology. 2016 May 17. pii: S0161-813X(16)30087-0; Turner MC, Wigle DT, Krewski D. Residential pesticides and childhood leukemia: a systematic review and meta-analysis. Ciência & Saúde Coletiva. 2011 Mar;16(3):1915-31.
18. Van Maele-Fabry G, Hoet P, Lison D. Parental occupational exposure to pesticides as risk factor for brain tumors in children and young adults: a systematic review and meta-analysis. Environment International. 2013 Jun;56:19-31.
19. Cohn BA et al. DDT and breast cancer in young women: new data on the significance of age at exposure. Environmental Health Perspectives. 2007 Oct;115(10):1406-14.
20. Disse M et al. A review of the association between Parkinson disease and malignant melanoma. Dermatolic Surgery. 2016 Feb;42(2):141-6; Sergentanis TN et al. Risk factors for multiple myeloma: a systematic review of meta-analyses. Clinical Lymphoma, Myeloma and Leukemia. 2015 Oct;15(10):563-77.e1-3; Tanner CM et al. The disease intersection of susceptibility and exposure: chemical exposures and neurodegenerative disease risk. Alzheimers & Dementia. 2014 Jun;10(3 Suppl):S213-25.
21. Canadian Centre for Occupational Health and Safety. Pesticides-working safely. August 1, 2016. Viewed August 20, 2016.
22. Curl CL et al. Estimating pesticide exposure from dietary intake and organic food choices: the Multi-Ethnic Study of Atherosclerosis (MESA). Environmental Health Perspectives. 2015 May;123(5):475-83; Magner J et al. Human exposure to pesticides from food: a pilot study. IVL Swedish Environmental Research Institute. 2015.
23. US Food and Drug Administration. FDA Public Health Advisory: Safety of Topical Lindane Products for the Treatment of Scabies and Lice. December 7, 2015. Viewed August 20, 2016.
24. Canadian Centre for Occupational Health and Safety. Pesticides—working safely.  August 19, 2016. Viewed August 20, 2016.
25. Agent Orange Record. America's most lethal secret weapon? 2010. Viewed August 22, 2016.
26. US Department of Veterans Affairs. Agent Orange. July 26, 2016. Viewed August 22, 2016.
27. Ngo AD et al. Association between Agent Orange and birth defects: systematic review and meta-analysis. International Journal of Epidemiology. 2006 Oct;35(5):1220-30.
28. Ngo AD, Taylor R, Roberts CL. Paternal exposure to Agent Orange and spina bifida: a meta-analysis. European Journal of Epidemiology. 2010;25(1):37-44.
29. Kido T et al. High cortisol and cortisone levels are associated with breast milk dioxin concentrations in Vietnamese women. European Journal of Endocrinology. 2013 Nov 29;170(1):131-9.
30. Kang HK et al. Health status of Army Chemical Corps Vietnam veterans who sprayed defoliant in Vietnam. American Journal of Industrial Medicine. 2006 Nov;49(11):875-84.
31. Committee to Review the Health Effects in Vietnam Veterans of Exposure to Herbicides (Tenth Biennial Update); Board on the Health of Select Populations; Institute of Medicine; National Academies of Sciences, Engineering, and Medicine. Veterans and Agent Orange: Update 2014. Washington (DC): National Academies Press (US); March 29, 2016.
32. Agent Orange Record. America's most lethal secret weapon? 2010. Viewed August 22, 2016.
33. US Geological Survey National Water-Quality Assessment (NAWQA) Program Pesticide National Synthesis Project. Pesticide Use Maps—Atrazine. August 3, 2016. Viewed August 22, 2016.
34. Gilliom RJ et al. Pesticides in the Nation's Streams and Ground Water, 1992–2001. US Geological Survey. February 15, 2007. Viewed August 22, 2016.
35. Ribaudo M, Bouzaher A. Atrazine: Environmental Characteristics and Economics of Management. US Department of Agriculture. May 7, 2013. Viewed August 22, 2016.
36. Brender JD, Weyer PJ. Agricultural compounds in water and birth defects,Current Environmental Health Reports. 2016 Jun;3(2):144-52.
37. Thompson PA et al. Environmental immune disruptors, inflammation and cancer risk. Carcinogenesis. 2015 Jun; 36(Suppl 1): S232–S253.
38. Sass JB, Colangelo A. European Union bans atrazine, while the United States negotiates continued use. International Journal of Occupational and Environmental Health. 2006 Jul-Sep;12(3):260-7.
39. US Environmental Protection Agency. DDT—A Brief History and Status. November 5, 2015. Viewed August 22, 2016.
40. Turusov V, Rakitsky V et al. Dichlorodiphenyltrichloroethane (DDT): ubiquity, persistence, and risks. Environmental Health Perspectives. 2002;110(2):125-128.
41. Stockholm Convention. The 12 initial POPs under the Stockholm Convention. Viewed August 22, 2016.
42. Global Malaria Programme. The use of DDT in malaria vector control
    WHO position statement. World Health Organization. 2011. Viewed August 22, 2016.
43. Harada T et al. Toxicity and carcinogenicty of dichlorodiphenyltrichloroethane (DDT). Toxicological Research. 2016 Jan;32(1):21-33.
44. Agency for Toxic Substances and Disease Registry. Public Health Statement for DDT, DDE, and DDD. Centers for Disease Control and Prevention. September 2002. Viewed August 22, 2016.
45. ATSDR. Toxicological Profile for DDT, DDE, and DDD. Centers for Disease Control. 2002. Viewed July 28, 2016.
46. Domingo JL. Safety assessment of GM plants: an updated review of the scientific literature. Food and Chemical Toxicology. 2016 Sep;95:12-8.
47. Benbrook CM. Trends in glyphosate herbicide use in the United States and globally. Environmental Science Europe. 2016;18(3).
48. National Pesticide Information Center. Glyphosate. 2015. Viewed August 23, 2016.
49. European Food Safety Authority. Glyphosate: EFSA updates toxicological profile. November 12, 2015. Viewed August 24, 2016.
50. Myers JP et al. Concerns over use of glyphosate-based herbicides and risk associated with exposure: a consensus statement. Environmental Health. 2016 Feb 17;15:19.
51. Toth SJ. Federal Pesticide Laws and Regulations. Southern Extension and Research Activity- Information
    Exchange Group 1. March 1996. Viewed August 22, 2016.
52. Debrow J. When did we start using so many pesticides? Rodale's Organic Life. February 26, 2014. Viewed August 21 2016.
53. Jacobs A. Timeline | History of Pesticides. Pesticides & University of Oregon. Viewed August 21, 2016.
54. Debrow J. When did we start using so many pesticides? Rodale's Organic Life. February 26, 2014. Viewed August 21 2016.
55. Biddle W. Nerve gases and pesticides: links are close. New York Times. March 30, 1984. Viewed August 21, 2016.
56. Toth SJ. Federal Pesticide Laws and Regulations. Southern Extension and Research Activity—Information Exchange Group 1. March 1996. Viewed August 22, 2016.
57. Jacobs A. Timeline | History of Pesticides. Pesticides & University of Oregon. Viewed August 21, 2016.
58. US Environmental Protection Agency. Summary of the Federal Insecticide, Fungicide, and Rodenticide Act. January 29, 2016. Viewed August 22, 2016.
    
59. US Environmental Protection Agency. Summary of the Food Quality Protection Act. November 17, 2015. Viewed August 17, 2016.
60. Jacobs A. Timeline | History of Pesticides. Pesticides & University of Oregon. Viewed August 21, 2016.
61. Carter R, Mendis KN. Evolutionary and historical aspects of the burden of malaria. Clinical Microbiology Reviews. 2002 Oct; 15(4): 564–594.
62. European Food Information Council. Preservatives to keep foods longer – and safer. Food Today. May 2004. Viewed August 26, 2016; Food and Drig Administration. Parabens. December 15, 2014. Viewed August 26 2016.
63. Quiñones ML et al. Insecticide resistance in areas under investigation by the international centers of excellence for malaria research: a challenge for malaria control and elimination. American Journal of Tropical Medicine and Hygiene. 2015 Sep 2; 93(3 Suppl): 69–78.