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Tyrone Hayes


The most popular use for atrazine is on corn. As corn is the largest crop in the United States [1] and atrazine is used on up to 85% of all corn crops, the amount of atrazine applied in the United States each year (up to 80 million pounds) is significant [2] . In fact, until recently replaced by glyphosate (Round-up) in popularity, atrazine was the most popular herbicide applied in the US. The advantages of atrazine reportedly include increased corn yield and decreased soil erosion due to the ability to use no-till practices for corn-growing (with weed control by atrazine making up the potential yield losses associated with a no-till practice). The highest yield differentials for corn (11%), reported by Syngenta [3], are for atrazine-use compared to non-atrazine use on crops with no-till practices. In fact, in most areas, fewer than 25% of corn growers use no-till practices, so this increase in yield is not experienced for most farmers, nor are the benefits of decreased soil erosion (which require the use of no-till practices). The 4.3% increase in yield due to atrazine, reported by Syngenta [3], is more realistic, but the USDA reports a yield loss of only 1.2% if atrazine was eliminated. Further, independent studies report that when corn fields that used atrazine were compared with fields that did not use atrazine, they “...were equally effective in overall weed control…” and that “Corn yields were similar between atrazine and non-atrazine treatments…” [4]. Thus, the benefits of atrazine are questionable. It is my goal, however, to focus here on the risks of continued atrazine-use, not to debate the questionable benefits.

The levels of atrazine contamination in several situations are shown below.

Atrazine's risks greatly outweigh its benefits

1. What is Atrazine

2. Environmental Contamination

3. Ecological Impacts

4. Endocrine Disruption

5. Neural Damage

6. Pregnancy loss

7. Reproductive Cancers

8. Endangered Species

9. Risks and Benefits

Figure 1. Levels of atrazine in a variety of aquatic habitats as determined by literature review. Bars show minimum and maximum reported levels. The solid black horizontal line shows the concentration that chemically castrates and feminizes amphibians. The effective concentration in amphibians (0.1 ppb) is 30 times lower than the current EPA drinking water standard (3 ppb) and 3000 times lower than the current EPA maximum contaminant (SAFE) level. Also of note, enough atrazine returns to the earth in rainwater (.5 million pounds per year) at high enough concentrations to chemically castrate and feminize amphibians. Figure adapted from Hayes et al. [5].
Atrazine cannot be used in a way that prevents it from contaminating ground, surface and drinking water. In fact, it is for this reason that the European Union (including Switzerland, the home of Novartis/Syngenta [6]) voted to ban atrazine [7] in 2001, the same week that the US EPA allowed re-registration. In the US, the economic benefits of atrazine were considered over the many risks posed by continued atrazine-use.

What’s more, there are other incredibly important ethical and environmental issues that must be considered. In the case of atrazine, the supposed benefits are bestowed on one group of individuals, while the risks target others. The poor, who are already more likely to live in contaminated areas, less likely to be educated on the risks of atrazine and other chemicals, and less likely to have access to proper health care, are not likely to be able to afford water filters, bottled water, and organic produce. Further, the poor (by definition) are not the ones who receive the economic benefits of atrazine.

While men who live in agricultural areas suffer from decreased fertility associated with atrazine contamination (measured as 0.1 ppb in urine) [10], men who work in agriculture have atrazine levels more than 200 times higher and applicators have atrazine levels in their urine that are 24,000 times the level that chemically castrates and feminizes frogs and 24,000 times the level associated with low fertility in men in Missouri [13]. The fact that both Novartis and Astrazeneca (both formerly Syngenta [5]) are marketing drugs that inhibit aromatase as treatments for breast and prostate cancer [14], after selling and continuing to sell a pesticide that induces aromatase is itself an important ethical issue. What’s more, the same people who are more likely exposed in the environment, who are unable to purchase water filters, bottled water and organic produce, less likely to have adequate healthcare and access to education, are more likely to have the unskilled jobs in agriculture and industry that expose them to contaminates, such as atrazine. Already Mexican American agricultural workers and African American unskilled factory workers (the community surrounding Syngenta’s Saint Gabriel atrazine production plant is more than 80% African American) suffer from shorter life expectancies [15] and can be two times more likely to die from breast cancer [16-20] and four times more likely to die from prostate cancer [20-22], both cancers induced by atrazine in laboratory rodents and associated with human exposure to atrazine.

Despite these concerns, the Environmental Protection Agency has no capacity to deal with these issues. The EPA has never reviewed all of the evidence for atrazine’s adverse effects on wildlife and humans, but have rather had narrowly focused reviews of individual studies and effects. The current model for addressing the effects of atrazine on amphibians will take more than 40 years to complete. Further, the requirement that the molecular and biochemical mechanisms be completely understood in this model, will make it virtually impossible in our lifetimes to regulate any chemical of concern. The mechanism of action for many compounds already banned (e.g. DES, DDT, TBT) are still not completely understood. Thus, chemicals already proven dangerous and already banned, could easily re-enter the market, if we utilize this model.

Perhaps the biggest concern is the data showing that the daughters of laboratory rodents exposed in utero show poor breast development, an effect transferred to the granddaughters of the originally exposed mothers [23, 24]. Data from France, show that even once atrazine-use is stopped, atrazine is still detectable in aquifers after almost 20 years. Thus, even if we stopped today, our grandchildren would still be exposed, potentially leading to effects on their grandchildren…our grandchildren’s grandchildren.

Recently, in an article originally entitled “Chemical Roulette: What Price would you put on your liver, prostate or fertility?”, the EPA stated, “The ultimate decision is much bigger than science, it weighs into public opinion…”. It was ultimately this statement that inspired my header and this website…to inform you and hopefully move you to action…

Our world and our future are in your hands.