THE TOXIC RISK AT HOME

BY DALE SPRUSANSKY

Vietnam veterans struggle with a wide array of physical ailments resulting from exposure to Agent Orange. That they were exposed to this toxic herbicide by their own government adds pain, confusion, and anger to the range of emotions.
As Americans mull the suffering caused by Agent Orange, many are unaware that they and their loved ones are exposed to potentially dangerous herbicides on a daily basis. Indeed, government-approved herbicides—many of which contain ingredients that were used in Agent Orange and are manufactured by the same companies that produced them for use in Vietnam—are widely and frequently used on farms and yards across the United States today.

This widespread use of herbicides has made it particularly difficult for medical professionals to deduct with certainty the side-effects of Agent Orange. Because so many Americans have been exposed to a wide array of chemicals, forming control groups that have not been exposed to toxins is a major challenge for researchers. Lacking “clean” control groups, the medical community will only with great difficulty come to a clear, truthful, and scientifically sound understanding of Agent Orange’s side-effects.

A 2008 congressionally mandated study, Veterans and Agent Orange, pointed to this dilemma. The authors noted that studies of individuals exposed to herbicides in chemical plants “provide stronger evidence about health outcomes than do studies of veterans because the industrial exposures [are] measured sooner after occurrence and [are] more thoroughly characterized.”

In order to understand the rise in the use of herbicides in the U.S., one must examine the exponential growth in the popularity of genetically modified (GM) crops. Beginning in the 1990s, GM crops, which have altered DNA that makes them resistant to specific herbicides, began to dominate U.S. agriculture. Recent estimates suggest that between 86 to 93 percent of the soybean, cotton, and corn crops in the U.S. are genetically modified.

While experts had believed that the proliferation of GM crops would decrease the need for herbicides, evidence suggests that the opposite is true. According to a 2009 study released by the Organic Center, the amount of herbicides used on GM corn, cotton, and soybeans increased by 7 to 8 percent between 1996 and 2008.

Scientists attribute this spike in herbicide use to the fact that more than 130 weed species have developed a resistance to herbicides such as Roundup. The world’s top-selling herbicide since 1980, Roundup, manufactured by Monsanto (the producers of Agent Orange), is the trade name for glyphosate, the most widely used herbicide in the U.S. According to the USDA, the use of glyphosate doubled between 2005 and 2010. It is estimated that 94 percent of soybean crops and 70 percent of cotton crops are treated with Roundup.

In order to contain and limit the growth of herbicide-resistant weeds, many farmers have increased the amount of Roundup they apply to their crops and also have turned to herbicides with higher toxicity levels than Roundup.

2,4-Dichlorophenoxyacetic acid (2,4-D), an herbicide that was a key ingredient in Agent Orange, is the most notorious toxin farmers have turned to in the wake of Roundup’s increasing ineffectiveness. Because 2,4-D has proven to be so reliable at killing weeds, some in the agriculture industry see it as a critical part of the industry’s future. Indeed, Dow Chemical Company, the world’s second largest chemical manufacturer, has applied to USDA to gain approval for a new variety of GM corn that is resistant to 2,4-D. The chemical is also commonly found in weed-and-feed products that are applied to areas such as lawns, playgrounds, and school yards.

Citing studies that link exposure to 2,4-D with birth defects, cancer, nerve damage, non-Hodgkin’s lymphoma, circulatory and respiratory anomalies, hormone disruption, and Parkinson’s disease, many scientists and health advocates have reacted to the increased popularity of 2,4-D with great apprehension. George Claxton, former chair of VVA’s Agent Orange/Dioxin Committee, said that 2,4-D is a “very dangerous chemical” that “should be off the market.” Natural Resources Defense Council senior scientist Gina Solomon said that individuals “can be inadvertently exposed to chemical residues” from toxins such as 2,4-D every day. “There’s no reason to continue allowing a toxic Agent Orange ingredient in the places our children play, our families live, and our farmers work,” she said.

While less toxic than 2,4-D, Roundup and other glyphosate-based herbicides also draw a wide array of criticism from health advocates. Birth defects, liver dysfunction, and cancer are some of the diseases that studies have linked to exposure to Roundup. A recent study published in the Journal of Toxicology in Vitro found that Roundup also harms male fertility by destroying testosterone.

In 2009 researchers in France found that one of Roundup’s inert, or “inactive,” ingredients—polyethoxylated tallowamine (POEA)—is capable of killing embryonic, placental, and umbilical cord cells in humans. According to the authors of the study, POEA can have a harmful effect on human cells at concentrations far lower than those used on farms and lawns. Due to the fact that it is classified as an inert ingredient by the EPA, the USDA permits the use of POEA, which is used to help herbicides penetrate the surfaces of plants, in products the agency certifies as organic. Due to increased concerns regarding the safety of POEA, the EPA announced in 2011 that it will reevaluate the safety of glyphosate in 2015. In the meantime, some cities such as Boulder, Colorado, have banned the use of Roundup on public property.

Despite the fact that use of atrazine, an herbicide used heavily on corn crops, has remained relatively flat over the past ten years, it remains widely popular and the target of much criticism. Studies have linked the chemical to birth defects and disruption of the reproductive system. A 2011 Environmental Research study found evidence that atrazine could be causing menstrual irregularities and low estrogen levels in women. The study also found that the herbicide can be dangerous at levels far below the EPA’s limit. A 2011 independent EPA panel concluded that there is “suggestive evidence” that atrazine can cause ovarian cancer, non-Hodgkin’s lymphoma, and hairy-cell leukemia. The panel also found “strong” evidence linking the herbicide to thyroid cancer. Available data “failed to provide compelling evidence that atrazine is not carcinogenic,” according to the panel. The EPA is expected to officially review atrazine in 2013.

The fact that atrazine—which washes into surface water and groundwater because it does not cling to the soil—is the most commonly detected herbicide in America’s rivers and wells, fuels many of the herbicide’s opponents. In 2009 The New York Times reported that 33 million Americans have been exposed to atrazine through tap water. Nevertheless, the EPA maintains that it fully protects the public from excessive levels of the herbicide. “The exposure that the agency allows under its atrazine drinking water regulations is at least 300 to 1,000 times lower than the level where the agency saw health effects in the most sensitive animal species tested,” the EPA said in a statement.

Herbicide-producing companies such as Dow Chemical and Monsanto also adamantly maintain that their products pose no severe threat to the public’s health. Monsanto spokeswoman Janice Pearson, in response to a claim that Roundup causes infertility, said: “Regulatory authorities and independent experts around the world agree that glyphosate does not cause adverse reproductive effects in adult animals or birth defects in offspring…even at doses far higher than relevant environmental or occupational exposures.”

Such assurances do little to quell the concerns of Monsanto and Dow’s critics. “Because of the tremendous liability [associated with conceding the carcinogenic nature of their product], they’re never going to admit to it,” George Claxton said, dismissing the chemical manufacturers’ claims that their products are safe.

The fact remains that it is difficult to measure the extent to which human health is affected by exposure to herbicides. Because it is unethical to test herbicides on humans, scientific conclusions can only be based on circumstantial evidence and studies conducted on animals. Nevertheless, countless scientific studies—particularly those focused on people who work in the agricultural and chemicals industries—provide strong evidence that herbicides can have an adverse effect on human health.  

In 2010 University of California-Berkeley Professor Tyrone Hayes claimed that atrazine can chemically castrate frogs and cause male frogs to undergo a sex change. A spokesman for Syngenta, the Swiss company that produces the chemical tested in the study, dismissed the findings, saying the research was poorly designed and based on “bad data.” A 2012 study conducted by University of Pittsburgh ecologist Rick Relyea found evidence suggesting that exposure to Roundup causes tadpoles to experience abnormal hormonal shifts that result in the animals undergoing changes in their shape.

Purdue University professor Don M. Huber, an outspoken critic of GM crops, also believes that herbicides pose a major threat to the safety of livestock. According to Huber, farm animals that are fed Roundup-treated GM crops have high rates of miscarriages and spontaneous abortions. Huber alleges that 20 percent of American dairy heifers are infertile and that as many as 45 percent of cattle experience spontaneous abortions.

Studies also have shown that pets can be left vulnerable to an array of physical conditions as a result of being exposed to herbicides. For instance, a Purdue University study found that exposure to herbicide-treated lawns increases the risk of bladder cancer in Scottish terriers by four to seven times.

According to researchers, herbicides pose an especially high risk to children. A study released by the Research Triangle Institute noted that “children’s rapidly developing neurological, immunological, and other biological systems” make them highly susceptible to the adverse effects of herbicides. “Children’s behavior patterns—playing outside in the dirt and putting their hands in their mouths—put them in greater contact with environmental chemicals,” the study explained.  

Herbicides also are frequently dragged into homes by shoes and pets, where studies show they can remain on carpets and household surfaces for years, posing an added risk to children who play on the floor. Experts also express concern that even low levels of herbicide exposure can pose risks to unborn children.

“There are short, critical times—like when a fetus’s brain is developing—when chemicals can have disastrous impacts, even in very small concentrations,” explained Deborah A. Cory-Slechta, a professor at the University of Rochester.

While the extent to which herbicides pose an active risk to the human body remains the subject of much debate and scientific inquiry, one fact—that herbicide use has greatly expanded over the past two decades—is undeniable. As America struggles to care for those who suffer from the adverse effects of the use of Agent Orange in the Vietnam War, Americans once again may be exposed to toxic levels of carcinogenic herbicides with their government’s approval.

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