WARNING!
This is an older article that may not reflect Dr. Mercola’s current view on this topic. Use our search engine to find Dr. Mercola’s latest position on any health topic.
By Dr. Mercola
In the U.S., farmers dependent on genetically engineered (GE) Roundup Ready soybean crops are increasingly running into a problem. Weeds are quickly becoming resistant to Roundup herbicide, leaving the farmers desperate for an effective chemical alternative.
Paraquat is being marketed as one such alternative, but this pesticide is highly toxic to humans, according to the U.S. Environmental Protection Agency (EPA), to the extent that just one sip can be fatal.1
Sadly, it's become an herbicide commonly used for suicide attempts,2 but in countries that have banned its use, such as South Korea, suicide rates dropped significantly.
The association was so strong that researchers wrote in 2015, "Paraquat prohibition should be considered as a national suicide prevention strategy in developing and developed countries."3
Europe is ahead of the game, as they've already prohibited the use of paraquat. In all, 32 countries have banned the chemical.4
In Switzerland, paraquat has been banned since 1989, but the country still allows it to be produced, as long as it's shipped for use elsewhere, like in the U.S., where use is actually growing dramatically.
Despite Parkinson's Concerns, Use of Paraquat in US Increases
Paraquat is banned in Europe not only because of its highly lethal nature but also because it's linked to Parkinson's disease. The EPA is aware of the issue, and reported "a large body of epidemiology data on paraquat dichloride use and Parkinson's disease."5
They're currently reviewing whether to allow continued use in the U.S., but not with the urgency one would expect; a decision isn't even expected until 2018. In the meantime, its connection to Parkinson's disease grows.
"Paraquat causes tissue damage by setting off a redox cycle that generates toxic superoxide free radicals," researchers wrote in the International Journal of Environmental Research and Public Health.6
In acute exposures, it typically kills by damaging lung tissue, as one biochemist and toxicologist explained in a warning about paraquat:7
"I should warn you that it probably has killed more people than all other pesticides combined. It is taken up by a transport system in the lung where it generates a variety of reactive oxygen species and burns the lungs; people normally drown several weeks later of pneumonia.
There is no antidote. Most deaths now are suicides and murders, with a few accidents thrown in."
Chronic exposures, however, are known to damage the nervous system. Paraquat is often applied in the same areas as another pesticide, maneb, and it's believed the two have synergistic effects.
One study published in the American Journal of Epidemiology revealed that exposure to both pesticides within 500 meters of the home increased the risk of Parkinson's disease by 75 percent.8
Even the EPA noted that paraquat may be a causative agent or contributor to the development of Parkinson's disease,9 and in 2011 a National Institutes of Health (NIH) study found people who used paraquat were 2.5 times more likely to develop Parkinson's than non-users.10
A meta-analysis of more than 100 studies similarly found a two-fold increased risk of Parkinson's with paraquat exposure,11 while those with a certain genetic variant (individuals lacking glutathione S-transferase T1, or GSTT1) may face a particularly increased Parkinson's risk — by 11-fold — with paraquat exposure.12
In the U.S., the use of paraquat has increased four-fold in the last 10 years. In 2015 alone, 7 million pounds of the herbicide were sprayed on close to 15 million U.S. acres.13
EPA Proposes Label Changes Due to Paraquat Poisonings
The EPA reported a "large number of human incidents" involving accidental and intentional consumption of paraquat that have been reported to U.S. poison control centers.
"There is a disproportionately high number of deaths resulting from accidental ingestion of paraquat compared to similar pesticides," they noted, which led to so-called "safening" agents being added to the chemical in the 1980s.14
The pesticide was dyed blue and now includes a special addition to make it smell terrible. It's also formulated to solidify when it contacts stomach acid and an emetic was added to induce vomiting should it be ingested.
Accidental poisonings have occurred nonetheless, particularly when farmers transfer the chemical into beverage containers for storage or sharing, despite warnings against doing so on the label.
The EPA therefore proposed a new set of changes they believe will make paraquat safer to use while again avoiding the burning question, which is why paraquat is still allowed in the U.S. at all.
Paraquat is already a restricted-use product in California, but EPA proposals would restrict its use nationally. Their proposed changes include:15
- New closed-system packaging that make it impossible to transfer the pesticide into other packaging
- Special training for applicators, emphasizing the importance of not transferring it to improper containers
- Warnings added to labels to highlight risks and toxicity
- Prohibiting application from hand-held and backpack equipment
- Restricting use to certified pesticide applicators only
A Potential Human Rights Issue
The practice of manufacturing hazardous substances explicitly for use far away from the manufacturing plant is being investigated as a potential human rights issue, paraquat included.
Paraquat manufactured by Syngenta in Britain, where it is banned, was shipped to more than two-dozen countries in 2016, including the U.S., The New York Times reported:16
"'This is one of the quintessential examples of double standards,' said Baskut Tuncak, a United Nations official who specializes in hazardous substances. 'Paraquat is banned in the U.K. and the E.U., but it's still being used, and resulting in serious harms outside the E.U. where it's being shipped.'"
Syngenta, meanwhile, continues to refute the paraquat-Parkinson's link, enlisting the help of Dr. Colin Berry, professor emeritus at Queen Mary University in London and a known consultant for the pesticide industry, including Syngenta and Monsanto, to downplay the scientific evidence.
(Berry gained notoriety in 2000 for being at the center of a misdiagnosis case, in which two of his patients were wrongly diagnosed with breast cancer and received double mastectomies unnecessarily as a result.17)
Paraquat Is Absorbed 'Systematically' in Animals
The industry website Paraquat.com, hosted by the Paraquat Information Center on behalf of Syngenta Crop Protection AG describes the chemical as a "contact herbicide" that is not systemic, "meaning that it does not move inside plants."
This ability to use paraquat with precision on crops, targeting only problematic weeds or in between rows of vegetables, is one reason why it's promoted as a perfect alternative to glyphosate (the active ingredient in Roundup), which works systemically.18
"Using paraquat adds to the all-important diversity of mode of action necessary for successful weed control programs," Paraquat.com advertised in September 2016.19 Never mind the fact that spraying more pesticides onto crops is only setting the stage for increased weed resistance down the road.
In animals, meanwhile, paraquat does not stay contained to one precise area. Rather, according to a U.S. Fish and Wildlife Service report, it's absorbed systematically.20 The lungs are often the primary target, followed by absorption in the gastrointestinal tract and skin.
"Administration of paraquat by every route of entry tested frequently resulted in irreversible changes, in the lung," researchers wrote, continuing:
"Delayed toxic effects of paraquat occurring after the excretion of virtually all of the material have caused it to be classified as a 'hit and run' compound — that is, a compound causing immediate damage, the consequences of which are not readily apparent."
The U.S. Centers for Disease Control and Prevention (CDC) also described paraquat's systemic dispersal:21 "After paraquat enters the body, it is distributed to all areas of the body. Paraquat causes toxic chemical reactions to occur throughout many parts of the body, primarily the lungs, liver and kidneys."
Industry Site Touts Paraquat's 'Perfect Pastures'
If you're willing to overlook paraquat's ability to kill with a single sip and concerning link to chronic disease in humans, you might be wowed by paraquat's penchant for creating perfect pastures, according to Syngenta's site. Spraying the toxic chemical can lead to more productive pastures, including improved yield and quality of livestock grazing and forage, Syngenta claims.22
The site also touts paraquat's benefits to sugarcane fields, including higher sugar yields and improved soil structure. Syngenta wants farmers to use paraquat not only for weed control (including in combination with other herbicides that use different modes of action) but also promotes it as a desiccant useful for drying out leaves so that they may be returned to the soil "to increase organic matter levels."
Plus, when farmers douse their crops with more paraquat just prior to harvest, they can avoid the "adverse environmental impact" from burning, Syngenta gushes. They also suggest spraying the poison toward the end of daylight hours. "Paraquat diffuses through leaf tissue in the water in cell walls, but as cells desiccate this limits how far it can penetrate into weeds," Syngenta writes.23
With lower light intensity in the waning daylight, it slows paraquat's fast speed of action so that it can kill weeds more effectively. Further, Syngenta is hoping rice farmers will also embrace the use of paraquat and have touted its supposed environmental benefits in the cultivation of newer varieties of flood-resistant rice. According to Syngenta:24
"Rice farmers in Indonesia are taking advantage of paraquat's fast action to ensure weeds are controlled in fields that are subjected to frequent tidal flooding. Paraquat is the only herbicide that can act fast enough between tides to kill weeds because it is absorbed by leaves before it can be washed off — in just the same way that it is rainfast in less than half an hour."
In case you missed the last part, paraquat is "rainfast," meaning that within 15 to 30 minutes of application, it can no longer be washed off by the rain. It remains on the plant even after rainfall or washing.25
Warning on Paraquat Use in Batteries
A new organic flow battery technology has been developed that promises to cost 60 percent less than standard flow batteries, courtesy of the batteries' inexpensive synthesized molecules.26 Among them is methyl viologen, aka paraquat. Writing in Chemical & Engineering News, biochemist Bruce Hammock warned that such batteries pose considerable health risks:27
" … [I]ts high toxicity if consumed in even tiny amounts presents a health hazard that requires adequate warnings regarding accidents or end-of-life issues with the proposed batteries. In working some as a toxicologist with the computer industry, I saw highly trained people become very lax over some toxic chemicals. Anytime we have a high-volume use for a highly toxic material, I worry about a problem years downstream."
Eat Organic to Avoid Paraquat and Other Pesticides
Paraquat is not approved for household use in the U.S., but it is sprayed on more than 100 crops globally, including coffee, almonds and oranges. Its use in food crops may be particularly problematic when used as a pre-harvest desiccant, such as on cereal grains. When used in this way, levels of up to 0.2 mg/kg of plant matter have been reported, according to Pesticide Action Network UK, but the Acceptable Daily Intake is recommended as 0.004 mg/kg/day body weight.28
Until toxic chemicals like paraquat are no longer viewed as an acceptable and necessary tool in agriculture, your best bet, health-wise, is to support those farmers using organic farming methods and other alternative methods of non-chemical weed control. Remember, too, that you can control what's in the food you eat by growing some of your own fruits and vegetables in your own backyard.