Lawn Chemical Safety: Using Critical Thinking

Queen Anne’s lace, also known as wild carrot (Daucus carota), a wild edible plant.

If you casually surf the web to learn about the safety of a particular lawn chemical, you may walk away feeling comforted.  Perhaps you've heard that glyphosate, a popular herbicide in the US that's banned in the EU, is a possible endocrine disruptor. This Environmental Protection Agency (EPA) webpage about glyphosate, the active herbicide in Roundup, claims that "Glyphosate products used according to label directions do not result in risks to children or adults" (EPA 2020).

Or maybe you've heard that 2,4-D, a common lawn herbicide, is possibly carcinogenic. The EPA assures readers that "2,4-D generally has low toxicity for humans, except certain acid and salt forms can cause eye irritation. Swimming is restricted for 24 hours after application of certain 2,4-D products applied to control aquatic weeds to avoid eye irritation" (EPA 2019). After 24 hours, everything's fine, right? Doesn't sound so bad.

Seriously though, there's a solid body of research indicating that the health and environmental problems associated with these products are cause for concern. So what's with the conflicting information and apparent uncertainty?

In this article, we’ll explore some factors that contribute to our haziness around lawn chemical safety. Understanding these variables allows us to read safety claims with a critical eye. It also helps us hone in on some pieces of our system that need to change.

Image: Plaintain leaf harvest (Plantago major), a common edible and medicinal lawn “weed”

EPA-Approved Does Not Mean Safe

Ideally, companies would need to provide sufficient evidence that agricultural chemicals (or any chemicals) are safe to introduce into the environment before they could be sold. This approach is called the precautionary principle: if there is reason to believe that a substance may cause harm, its use should be restricted until there is enough data that demonstrates its safety (Wingspread Statement, 1998). Government regulations based on the precautionary principle value human and environmental health over corporate profit and ease. 

We have seen the precautionary principle pop up occasionally throughout US chemical regulation history.  But for the most part, toxic products have been taken off the market only after decades of use revealed undeniable human and ecosystemic harm (MacKendrick, 52). Rather than a company being responsible for funding quality research on their new chemical’s safety, this cost is externalized. Community members become test subjects without giving consent. 

When the Toxic Substances Control Act (TSCA) was passed in 1976, it grandfathered in 62,000 chemicals that were introduced before the law passed, and the EPA reviewed only 2 percent of these. Of the 85,000 chemicals registered in the US in 2005, only 5 chemicals had been restricted (MacKendrick, 38). In order for a chemical to be restricted, the EPA was responsible for demonstrating that the financial burden to industry did not outweigh harm to the environment or human health (MacKendrick, 37). Given the minuscule number of chemicals that have been restricted, we can see that this rarely flew.

 In 2016, congress did a good thing. They amended the TSCA, which now "requires new chemicals to undergo review by the [EPA], and the criteria for review no longer take[s] into account the burden of regulation on industry, effectively freeing the agency to review a compound for its health and safety impacts, independent of the impact on industry" (MacKendrick 50). Unfortunately, the Trump administration has severely weakened the ability of the EPA to enforce this law, partly by cutting the EPA's budget (52). 

For pesticides specifically, the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) requires all pesticides to be registered with the EPA, and they must be tested before being sold. The EPA has the ability to nix pesticides it deems dangerous. According to Norah MacKendrick in her book Better Safe Than Sorry, "In practice...this power is limited, as industry frequently challenges proposed EPA limitations via the courts" (39). 

This regulatory backdrop sets the stage for the following problems, which cloud the public's understanding of lawn chemical safety and keep unsafe products on the market.

Shady Business: The Agrochemical Industry 

The Pesticide Action Network of North America (PANNA) points out that "In reviewing the health and environmental impacts of pesticide products, EPA relies almost entirely on industry-funded studies" (PANNA, "Corporate Science and Spin"). This data is typically not made available for public viewing, or for peer review--a standard procedure in respectable scientific research. Protecting confidential formulas and business information is the rationale (PANNA).

When harmful effects of lawn chemicals are demonstrated by research, corporations work to discredit or suppress this information (PANNA). One strategy used by this and other industries is to create trade coalitions or separate companies with deceptive names to push their agenda. For example, the benevolent-sounding Global Climate Coalition is actually an industry group that works to undermine confidence in and access to climate science. This article describes the work that CropLife America, an industry-backed group, has done to discredit and cloud evidence that neonicotinoid pesticides have contributed to honeybee colony collapse. In his book Lawn People, Paul Robbins offers this quote from Dr. Ronald Gots of the International Center for Toxicology and Medicine:

Chlorpyrifos has generated fewer health complaints than have the insects that it is designed to control...Nevertheless, activists are trying to build a case against the vast body of existing science showing chlorpyrifos is safe (Robbins, 72). 

Gots's employer--unbiased as their name sounds--defends corporations against illness claims from toxic exposure. Its clients include Dow Chemical Company, which makes chlorpyrifos products (73). This chemical has since been banned for US residential use due to research demonstrating its harmful impacts on children's brains and development (Potera). Aerial applications are being phased out by New York State--the third state to take this action in the absence of a federal ban. Though a nationwide ban was planned for 2017,  former EPA administrator Scott Pruitt scratched it. Pruitt acted in opposition to EPA staff scientists, favoring the Trump administration's hefty donor, Dow Chemical (Union of Concerned Scientists).

In addition to the millions of dollars spent on lobbying each year, agrochemical companies are often members of committees that advise agencies creating regulations. Furthermore, former agrochemical industry leaders, scientists, and lawyers serve in government agencies designed to keep those industries in check (PANNA).

 This PANNA article about corporate influence over regulation lists additional strategies companies use to keep their products on the market.

Nasturtium (Tropaeolum majus), a popular edible flower in vegetable gardens.

Now we'll look at a few ways that the agrochemical industry manipulates scientific data in order to keep their products on the market.

Optimistic Assumptions, Oversimplified Analysis

In Lawn People, Robbins observes that "Some of the problems associated with lawn inputs, whether pesticides or fertilizers, can be downplayed if we operate under the assumption that what is put on the lawn stays on the lawn, and that it disappears from the lawn after it does its job" (65). He notes that there's some validity to the lawn care industry's argument that the density of turfgrass growth keeps chemicals from running off to some degree (65). However, if you suspect that rain, wind, slope, and critters might result in some chemical migration, you're correct. For example, research shows that pesticides can volatilize and be carried by the wind to surrounding areas (65). We also know that lawn chemicals get carried into homes by people, pets, and air (66). These factors are not properly measured or accounted for in the creation of chemical regulation.

Combinations of Chemicals & Metabolites are Typically Not Tested

In her excellent book Living Downstream, Sandra Steingraber writes:

Real-life exposures seldom involve single agents. And yet when testing chemicals for their potential to cause cancer or when deciding what the acceptable limit of exposure to suspected carcinogens should be, our regulatory system considers them in isolation from each other. Some chemicals operate down similar pathways; their effects may be additive. Others may interact in more complex ways, as when exposure to one pesticide alters the activity of enzymes in ways that cause a second pesticide to be metabolized into a more powerful toxicant. Mixtures of chemical exposures with other stressors--like obesity or poverty--may also create cancer risks not predictable by examination of each variable by itself (xx).

When it comes to lawn applications, chemical combinations may occur via numerous avenues. Products themselves may contain a mix of active ingredients--not to mention the "Other" ingredients not disclosed on the label, which make up the bulk of the product. A single lawn may see several products applied over the course of the season. Chemicals break down into other chemicals, whose effects often go untested--not to mention the effects of secondary chemicals when mixed with other secondary or primary chemicals. Toxins in air pollution from industry and farms miles away also mingle on our lawns--and in our homes.

As noted above, research has documented the routes that lawn and farm pesticides take to enter our homes. We track them indoors on our shoes and clothing, and our pets (and the wind) do the same. Living in a rural area, closer to farms, increases the likelihood of accumulation in the home due to drifting spray and the volitization of the product (Laquatra, 1).

Elevated levels of pesticides have been found in household dust, since the absence of soil microbes, rain, and sun significantly decreases the rate of these chemicals' breakdown or migration (Simcox, 1131). The household accumulation of chemicals is also not accounted for when regulations are created.

Only the Active Ingredient is Tested

When herbicides and pesticides are tested for safety, it's typically only the active ingredient that's studied. However, more than half of most products consist of undisclosed ingredients, which are listed as "Other." 

Lawncare formulations contain adjuvants, which are chemicals that help the active ingredient work better. They may help the active ingredient penetrate or stick to the leaf, spread more evenly over the leaf surface rather than beading, and more (Witt).

This journal article documents a study of 9 pesticides and herbicides, comparing the toxicity of the active ingredient alone versus in formulation (as they are typically sold). Here's what they found:

8 formulations out of 9 were up to one thousand times more toxic than their active principles. Our results challenge the relevance of the acceptable daily intake for pesticides because this norm is calculated from the toxicity of the active principle alone. Chronic tests on pesticides may not reflect relevant environmental exposures if only one ingredient of these mixtures is tested alone... Despite its relatively benign reputation, Roundup was among the most toxic herbicides and insecticides tested (Mesnage).

This article explores adjuvants further.

Safety Arguments That Defy Logic

The active ingredient in Roundup, glyphosate, is a non-selective herbicide. It works by disrupting an enzyme needed for amino acid production involved in plant growth (Robbins, 59). According to the Monsanto website,

This enzyme (EPSP) is not found in humans or animals, contributing to the low risk to human and animal health when using glyphosate-based products according to label directions. The presence of this enzyme in plants, but not in humans and animals, provides a basis for a specific selective toxicity to plant species.

This is absurd. A parallel argument could have been made about the pesticide DDT, when citizens and ecologists noticed that several bird species' eggshells were thin and crushed by the mother as a result of DDT exposure. Humans don't lay eggs, so DDT must be safe for people, right? We now know that DDT is a carcinogen and endocrine disruptor. It accumulates in animal fat cells and is found in human breastmilk to this day, despite being banned in the US in 1972.

The fact that a chemical has a negative effect on a non-human creature is not proof that it's safe for us. If a chemical is toxic to other organisms, it should be assumed that it is toxic to all organisms until quality, unbiased research offers enough data to suggest otherwise. Our lack of an enforced precautionary principle leaves a lot of room for faulty logic to justify the presence of chemicals on the market.

Conclusions

PANNA states that "Myths about pesticides are a testimony to the power of advertising, marketing and lobbying. Pesticide corporations, like big tobacco and the oil industry, have systematically manufactured doubt about the science behind pesticides, and fostered the myth that their products are essential to life as we know it — and harmless if 'used as directed'" (PANNA, "Myths and Facts").

As I suggested above, despite this information, I don't feel I can lay the blame on the chemical industry for its unethical activity and products. We know that corporations are designed to make a profit, and the larger they are, the more costly and time-consuming it is to shift gears and offer more sane and ethical goods. Our government, however, is intended to represent and act in the best interests of its people--all people, not just the wealthy and powerful. It's there to create environmental and health regulations that safeguard the life, liberty, and pursuit of happiness of its citizens. Each problem discussed in this article boils down to the need for greater integrity in our government.

 If discrediting quality science and weaseling into government decision-making is legal--and easier than pulling a toxin off the market--we shouldn't be surprised that it's the path many companies have taken.

What should we do to hold our government accountable? I subscribe to the Environmental Working Group and receive action alerts from Beyond Pesticides. PANNA also offers an online action center that's worth checking out. I added the phone numbers of my state and local representatives to my phone so I can easily call when there's an action put forth by one of these groups. 

May we continue to learn how things work and push for positive change.

Never miss an article: Join the Sweet Flag Herbs newsletter to receive an email when a new A Nourishing Harvest article is posted.

Sources:

Ehrich, Paul, David S. Dobkin and  Darryl Wheye. "DDT and Birds."  Stanford University web. 1988. https://web.stanford.edu/group/stanfordbirds/text/essays/DDT_and_Birds.html 

 Environmental Protection Agency (EPA). "2,4-D." Updated February 20, 2019. www.epa.gov/ingredients-used-pesticide-products/24-d 

Environmental Protection Agency (EPA). "Glyphosate." Updated January 30, 2020. www.epa.gov/ingredients-used-pesticide-products/glyphosate 

 Laquatra, Joseph, Mark Pierce et al. "Common Pesticide Residues in Rural Homes of New York State." JSM Health Education & Primary Health Care. 2018.  www.jscimedcentral.com/HealthEducation/healtheducation-3-1042.pdf 

Mesnage, Robin, Nicolas Defarge et al. "Major Pesticides Are More Toxic to Human Cells Than Their Declared Active Principles." www.ncbi.nlm.nih.gov/pmc/articles/PMC3955666/

Monsanto Global. "What is Glyphosate?"  www.monsantoglobal.com/global/au/products/Documents/what_is_glyphosate.pdf 

Pesticide Action Network of North America. "Corporate Science and Spin." viewed April 15, 2020.  www.panna.org/gmos-pesticides-profit/corporate-science-spin 

Pesticide Action Network of North America. "Myths and Facts."  Viewed April 15, 2020. www.panna.org/pesticides-big-picture/myths-facts 

Potera, Carol. "Newly Discovered Mechanism for Chlorpyrifos Effects on Neurodevelopment." Environmental Health Perspectives. 120:7. July 1, 2012.https://ehp.niehs.nih.gov/doi/full/10.1289/ehp.120-a270a 

Robbins, Paul. Lawn People. Temple University: 2007.

Simcox, Nancy, Richard Fenske et al. "Pesticides in Household Dust and Soil: Exposure Pathways for Children of Agricultural Families." Environmental Health Perspectives. 103:12. December 1995. pg. 1131.

Steingraber, Sandra. Living Downstream. Da Capo Press: 2010.

Union of Concerned Scientists. "How Dow Chemical Influenced the EPA to Ignore the Scientific Evidence on Chlorpyrifos." Oct 11, 2017.  www.ucsusa.org/resources/how-dow-chemical-influenced-epa-ignore-scientific-evidence-chlorpyrifos 

"Wingspread Statement on the Precautionary Principle." January 25, 1998. Viewed at International Agriculture and Trade Policy website.  See document for list of participants. www.iatp.org/sites/default/files/Wingspread_Statement_on_the_Precautionary_Prin.htm 

Witt, James. "Agricultural Spray Adjuvants." Oregon State University. http://psep.cce.cornell.edu/facts-slides-self/facts/gen-peapp-adjuvants.aspx