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If America Only Knew How Much Arsenic Ends Up on the Average Dinner Plate

Our government is perversely protecting the industries that release the killer chemical into society.

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Long before the days of DDT, the first synthetic pesticides were arsenicals. An arsenical paint pigment called Paris green was first used against Colorado potato beetles in 1867. Even then, arsenic’s deadly toxicity was well known – Will Allen tells in his book, The War on Bugs, how farmers lost cattle after they ate potato plants treated with Paris green. Other arsenic pesticides, London purple and lead arsenic, soon followed Paris green onto the market. By the 1930s, “well over a hundred million people in the United States suffered from mild to severe arsenic and lead poisoning,” writes Allen.

Yet the end of arsenic as a favored pesticide did not come from government – it came from nature and from the chemical companies. As pests evolved resistance to arsenical pesticides and as chemical companies supplanted arsenicals with newer products, arsenicals fell out of favor. Only then did the government begin canceling some of the registrations of arsenical pesticides.

And yet, even after arsenicals were displaced by other pesticides for most uses, half of the arsenic used in the U.S. has been in the last half century. Recent uses of arsenic fall into two categories: livestock drugs and pesticides.

Until recently, the arsenical livestock drugs roxarsone, nitarsone, carbarsone and arsanilic acid were all used in chickens, turkeys and swine. Roxarsone was widely used for disease prevention, weight gain, feed efficiency and improved pigmentation in chickens from 1944 until it was voluntarily removed from the market by Pfizer in 2011 following the revelation that chickens fed roxarsone had inorganic arsenic in their livers. The latter three are all still legal, regulated by the Food and Drug Administration.

Once used in chickens, the arsenic in roxarsone remained in the chickens’ litter, which consists of bedding, droppings, feathers, and dropped feed. Poultry litter, in turn, served as fertilizer on farms and – believe it or not – cattle feed. And, as it turns out, the top rice-producing state in the U.S., Arkansas, is in second place behind Georgia for broiler production. (Of the six rice-producing states, all rank among the nation’s top broiler producers, with Mississippi and Texas among the top five, and California and Missouri among the top 10.)

As pesticides, many arsenicals were phased out over the years, but some uses remain. In 2006, the EPA attempted to essentially ban the remaining uses of organic arsenicals, because "following application, these pesticides convert over time to a more toxic form in soil, inorganic arsenic, and potentially contaminate drinking water through soil runoff." Following outcry from industry, EPA backed away from its initial decision.

All organic arsenicals except one herbicide, monosodium methanearsonate (MSMA), were banned as of 2009. After that time, MSMA could still be used on sod farms, golf courses and highway rights of way until the end of 2013. After that, only one remaining us of any organic arsenical would be permitted: MSMA on cotton.

As luck would have it, the six rice-growing states are among the top cotton-growing states: Texas, Mississippi and Arkansas top the list, with California, Louisiana and Missouri each growing significant cotton acreage as well. Rice is so susceptible to taking up arsenic because it is often grown in fields flooded with water. In fact, a 2008 study found that growers can reduce the amount of total and inorganic arsenic in rice by growing it under “aerobic” (not flooded) conditions. And yet the same states that grow rice are also the cotton-growing states where MSMA is still used.

So why does the EPA still allow MSMA on cotton if arsenicals are so bad that they are banned on absolutely everything else? Two words: Palmer amaranth. Despite years of warnings, biotech and chemical companies and cotton growers have created the perfect weed. Palmer amaranth has evolved resistance to both ALS inhibitor herbicides and to glyphosate, the active ingredient in Monsanto’s Roundup, and one plant can produce half a million seeds.

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