Pesticides Gone Wild

Everything you need to know about pesticides, their usage in America, and their impacts on human health.

According to a 2014 Gallup survey, nearly half of Americans actively try to include organic foods in their diets. Young people are even more likely to seek out organic foods, with over half of people aged 18–29 trying to include organic foods in their diets.

There hasn’t always been a two-class division between clean and dirty foods. Prior to the widespread adoption of industrial pesticides, most foods were organic by default.

In the mid-20th century, pesticide use rose dramatically with the discovery of new herbicide, fungicide, and insecticide formulations shortly after WWII. DDT was hailed as a chemical wonder-treatment that triumphed over insidious mosquitoes and saved many soldiers’ lives in Southeast Asia. The herbicide 2,4-D, still used today, was released to the market in 1945 and experienced a 5x increase in sales in less than a year.

In the golden age of man-made pesticides, farmers were astonished by the agents’ effectiveness, and pesticide sales skyrocketed. It wasn’t until 1996 that the U.S. federal government passed a law, the Food Quality Protection Act, to ban or restrict several dangerous chemical agents used in agriculture. As consumers’ awareness of the health effects has risen, the number of people seeking alternatives to pesticide-laden foods has surged. The USDA-accredited organic standard was officially introduced in 2002 after years of deliberation over what constituted organic food.

Photo courtesy of WiseGeek.

The USDA Pesticide Data Program provides insights into the numbers of different artificial pesticides present on common types of conventional produce. The USDA detected 47 pesticide residues on apples alone — 6 of which are known or probable human carcinogens. Apples’ pesticide residues are further characterized by neurotoxicity, reproductive toxicity, and hormone disruption.

But apples aren’t the only delivery vehicles for pesticides; a wide range of processed foods today are also tainted due to the high rates of pesticide usage on corn, wheat, and soy, ingredients common in the Western diet. Supermarkets typically offer organic options for fruits & vegetables, but they lack organic options for many other foods that also pose health risks.

The majority of U.S. produce contains numerous pesticide residues, and wheat is no exception. Wheat is a staple crop with a strong presence in many European and North American cuisines, so health implications of its contamination are far-reaching. United States agriculture yielded 120 billion pounds of wheat in 2015, and global production reached 1.6 trillion pounds during the same period, according to FAO statistics.

The Second Black Plague

Over 1.1 billion pounds of pesticides were applied nationwide in 2007, corresponding to 3.76 pounds per person. Imagine being forced to eat nearly four pounds of hydrazine per year: the results wouldn’t be pretty. Hydrazine is a rocket propellant classified alongside glyphosate and other pesticides as a probable carcinogen.

Of course, nowhere near every ounce of pesticides applied in the fields makes its way to our digestive systems, but residual pesticide levels are nonetheless startlingly high in meat, fruit & vegetables, prepared foods, and water.

A solid fraction of pesticide use — over 276 million pounds in 2014— was an organophosphorus compound known as glyphosate, applied ubiquitously to nearly ever major field crop in the US. As the active ingredient in Roundup, it was commercialized by mega-producer, Monsanto, in the 1970’s shortly after the ban of DDT. It is now the most widely used herbicide in the world.

According to tolerance limits set by the EPA, glyphosate levels of 20 and 30 ppm are acceptable on cereal grains and soybeans, respectively. A person eating 3/4 lbs per day of 50/50 wheat and soy would consume 17 mg/day of glyphosate.

Based on data from residual pesticide testing completed in the FDA Total Diet Study, a person eating a simple representative diet shown in the table below would ingest 0.476 mg/day of pesticides. For reference, OSHA considers 0.01 mg/L of 2,4-D aerosol to be the maximum safe limit before being hazardous to worker health. Glyphosate and atrazine, two widely used herbicides known to linger in foods, were mysteriously omitted from the FDA’s study.

Glyphosate and its most popular formulation, Roundup, have been implicated in a number of health conditions, including cancer. Evidence shows that the herbicide has induced tumors in mice and rats and may increase people’s risk for non-Hodgkin’s lymphoma due to its tendency to cause DNA damage. It was recently classified by the World Health Organization as a probable carcinogen.

Glyphosate is of particular importance to the discussion surrounding pesticides due to its potential connection with gluten sensitivity and gluten intolerance, collectively referred to as celiac disease for the sake of simplicity. The connection between these conditions and wheat was only discovered within the last century, and their prevalence has grown rapidly over the last few decades. In 2013, a major study was published by MIT scientists linking celiac disease to glyphosate (Samsel & Seneff, 2013).

Fish exposed to glyphosate develop digestive problems that are reminiscent of celiac disease. Celiac disease is associated with imbalances in gut bacteria that can be fully explained by the known effects of glyphosate on gut bacteria.

The authors explain that glyphosate is known to inhibit a class of enzymes that are critical for gastrointestinal functions and detoxification of environmental toxins. It also leads to other forms of biological dysfunction.

Chemical structure of glyphosate.

Deficiencies in tryptophan, tyrosine, methionine and selenomethionine associated with celiac disease match glyphosate’s known depletion of these amino acids. Celiac disease patients have an increased risk to non-Hodgkin’s lymphoma, which has also been implicated in glyphosate exposure. Reproductive issues associated with celiac disease, such as infertility, miscarriages, and birth defects, can also be explained by glyphosate. Glyphosate residues in wheat and other crops are likely increasing recently due to the growing practice of crop desiccation just prior to the harvest.

The researchers make a final plea to government agencies to reign in the ill effects of glyphosate and improve food safety by lowering tolerance limits for glyphosate residues in foods.

While the EPA tolerates up to 30 ppm glyphosate residue in wheat (CFR Title 40, 180.364), the FDA restricts glyphosate to a maximum concentration of 0.7 ppm in bottled water (CFR Title 21, 165.3), and the European Union restricts it to 10 ppm on wheat (EU MRL 0500090).

Research has shown that concentrations as low as 0.15 ppm can be harmful to human health by disrupting the growth of beneficial microbes in the digestive tract (Shehata et al, 2012). Evidence indicates that glyphosate also causes direct harm to our health: in a study on human cell lines, the results were startling (Gasnier et al, 2009).

We tested sub-agricultural dilutions and noticed the first toxic effects at 5 ppm, and the first endocrine disrupting actions at 0.5 ppm, which is 800 times lower than the level authorized in some food or feed (400 ppm, US EPA, 1998). This confirms and enhances the potential toxic action of G-based herbicides…

Inert compounds in herbicide formulations, particularly Roundup, have been shown to amplify the negative health effects of glyphosate and caused adverse effects independently. In one study, researchers found that POEA, an “inert” ingredient in Roundup that fosters interactions with plant cell surfaces, was more toxic to human cells than glyphosate itself (Seralini et al).

Research has shown that inert ingredients are in many cases not inert at all. Furthermore, pesticide formulations are protected as trade secrets, so the inert ingredients are not required to be disclosed to the public.

In addition to its carcinogenicity, cellular toxicity, and capacity to cause autoimmune diseases, glyphosate has been linked to respiratory illness, reproductive issues, Parkinson’s disease, liver disease, IBD, colitis, autism, diabetes, kidney disease, and birth defects.

Despite being banned in Sri Lanka, restricted in Mexico and the Netherlands, and considered for restrictions in Canada and Brazil, glyphosate is still approved for use in the United States today.

Yet glyphosate, the best-selling pesticide in the world, is considered one of the safest and least toxic compared to others.

The overwhelming body of evidence demonstrating glyphosate’s hazards hasn’t stopped private interests from spreading misinformation. Consulting organizations, such as Exponent Inc, have published papers claiming the pesticide’s total safety in peer-reviewed journals. A brief review of papers written by author Amy Lavin Williams of Exponent Inc shows that, regardless of the chemical being evaluated, her public findings indicate that the agents of interest are either benign or environmentally present at much lower concentrations than researchers are evaluating. Companies like Exponent Inc are promoting pseudoscience on behalf of their clients, who are likely the pesticide manufacturers themselves.

Colossal monetary motivations fuel the lack of regulatory protections for the food supply, but as a unified block, consumers have the potential to overcome the misinformation spread by pesticide manufacturers.

Beyond Glyphosate

Regardless of the regulatory outcome for glyphosate, a quick count of pesticide tolerances set by the EPA shows that 391 pesticides would still be allowed in the U.S.

Researchers found that 2,4-dichlorophenol, a degradation product of an EPA-approved herbicide, is correlated with food and environmental allergies in the US population (Jerschow et al, 2012). A separate literature review posited that the prevalence of allergic-related diseases, food intolerance, and chemical sensitivities has risen dramatically over the last two decades as a result of a initial exposure to a primary toxin that overloads the body’s natural coping mechanisms (Genuis, 2010). The loss of tolerance to this initial toxin leads to elevated sensitivity to low levels of a broad range of unrelated triggers.

Photo credit: mazaletel / Flickr.

CDC data indicates that food allergies among children have increased by approximately 50% from 1997 to 2011, representing a $25 billion annual cost to society. In 2014, scientists found that a Canadian girl’s unusually serious allergic reaction to blueberry pie was not associated with any ingredients in the pie, but rather it was caused by exposure to streptomycin, an antibiotic used as a pesticide on fruit (Graham et al, 2014). These types of biological interactions with pesticides and other xenobiotics may explain the significant rise of autoimmune diseases among residents of developed countries within the last century.

Considerable attention has been directed toward the adverse health impacts of nearly every synthetic pesticide on the market, notably neonicotinoids, paraquat, 1,3-D, atrazine, chlorpyrifos, malathion, and metolachlor, some of which are known carcinogens.

Several authors have written comprehensive reviews to summarize the current scientific knowledge of the health effects of various pesticides.

The level of agreement among scientists regarding concern toward pesticides is on par with the consensus that the Earth is round. David Pimentel and team found in 1992 that the economic costs of pesticide use could be $8 billion annually.

Widespread Contamination

Unfortunately for consumers that decide to make the transition to eating organic foods, pesticide residues still linger in organic produce due to water contamination, soil contamination, post-harvest processing alongside conventional foods, and pesticide applications on neighboring crops. It is difficult to find food products nowadays that are completely free of all pesticides.

According to an analysis by the Canadian Food Inspection Agency, nearly half of organic fresh fruits and vegetables tested contained pesticides, some of which violated Canada’s maximum allowable limits.

On the bright side, the quantity of pesticides is much lower in organic foods than in conventional foods, for which 78% of samples contained pesticides. The fungicide thiabendazole was present at an average level 15 times lower in organic apples than in non-organic apples.

In addition to soil and water contamination, foreign imports from countries with looser standards pose problems for regulators seeking to limit pesticides domestically. A study of produce in the early 1990’s found a 41% violation rate among green peas imported from Guatemala and an 18% violation rate for strawberries from Mexico, as well as violations among U.S. produce.

Photo credit: Josh Mazgelis / Flickr.

The concept of bioaccumulation, the build-up of toxins in animal tissues, has been well-established for several environmental contaminants, and pesticides aren’t immune to the phenomenon. When livestock are fed pesticide-contaminated feeds derived from conventional agriculture, their tissues collect the pesticides and increase the concentration of pesticides relative to the original feed.

Depending on a compound’s chemical structure, the concentration of some compounds is amplified in humans at the top of the food chain, which makes seemingly low concentrations in foods considerably more harmful to human health.

A study on fish, wildlife, and humans found substantial biomagnification factors for persistent organic pollutants in humans, wolves, polar bears, and killer whales, all apex predators in their respective food webs. Nonetheless, more research is needed to determine which pesticides have the highest potential for long-term bioaccumulation in humans and livestock.

Groundwater has been monitored more extensively for contamination by synthetic pesticides that are able to leach into subsurface water reservoirs from farmed soils. The threat is particularly challenging since pesticides are nearly impossible to clean up after they’ve leached into the groundwater.

Quantification of the impacts of particular pesticides on the groundwater supply is difficult because soil adsorption, water table depth, amount of irrigation, and precipitation all affect the extent to which a pesticide enters groundwater that typically leads into drinking water supplies. In a Cornell report, pesticides with the highest median concentrations measured in groundwater were 1,3-D, dacthal, diazinon, and methyl parathion.

Although atrazine has been banned in the European Union and multiple areas of Wisconsin, it still contaminates a third of drinking wells in the state. After one family’s son was diagnosed with a rare inflammatory disease that caused rashes all over his body, the family discovered that their well water contained three times the state limit for atrazine. Unfortunately, mysterious illnesses like this are relatively common throughout the U.S.

Pesticide use in agriculture can have significantly delayed effects on the water supply that can last for indeterminately long periods of time.

The Underlying Dilemma

There is a fundamental self-limiting nature of technological advancements. A sacrifice has been made to long-term human health to achieve gains in crop yields at all costs. A major fraction of technological advancements that have been designed to correct problems threatening human well-being have created secondary problems of their own.

DDT, once hailed as a life-saver and now banned for its toxicity, was originally proliferated to stop the spread of typhus and other insect-borne illnesses, especially among soldiers deployed to densely vegetated regions of the world, but DDT was eventually determined to be deadly. Fertilizers increased food production beyond what early farmers would have ever imagined, but they have also caused algal blooms that damage fisheries. By remembering history, it’ll be easier for us to acknowledge that today’s pesticides also have severe limitations.

Making the transition to organic is undoubtedly costly, but the benefits will outweigh the costs over the long run. Although difficult to quantify, the long-term healthcare savings from a completely organic diet will likely trump higher grocery expenses.

National Pesticide Usage

The USGS provides a great resource that maps the estimated agricultural use of nearly every synthetic pesticide across the country and graphs trends in pesticide application rates by crop. Glyphosate, in particular, has surged since the early 1990’s, especially on corn and soybeans.