How Risky Is the Arsenic in Rice?

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Given the level of arsenic in rice, how could we figure out how much rice is too much? “There are no [U.S.] standards for arsenic in [rice, even though that’s our] main source of exposure. But, look, there’s limits on arsenic in apple juice and tap water. So, to calculate those, they must have sat down and figured out how much arsenic a day was too much—too risky—and then figured people drink, what, four to eight cups of water a day, and set the limit that way, right? Okay, well can’t we just use their how-much-arsenic-a-day-is-too-much-arsenic-a-day number, and based on the average arsenic content in rice, figure out how-much-rice-a-day-is-too-much-rice?

Well, “[t]he allowable level established by the FDA for arsenic in bottled water [for example] is 10 [parts per billion].” Assuming people might drink a liter a day, okay. So, based on that 10-a-day limit, how much rice is that?

Well, “[e]ach 1 g increase in rice intake was associated with a 1% increase in…total arsenic [in the urine], such that eating [a little over a half a cup] of cooked rice [could be] comparable [to] drinking [a liter of that maximally contaminated water].” Well, if you can eat a half-cup a day, why does Consumer Reports suggest just a few servings a week? You could eat nearly a serving every day, and still stay within the daily arsenic limits set for drinking water.

Well, Consumer Reports felt the 10 parts per billion water standard was too lax, and so, went with “the most protective standard” in the world—found in New Jersey. Isn’t that cool? Good for New Jersey! Okay. So, if you use 5 instead of 10, you can see how they got down to their only-a-few-servings-of-rice-a-week recommendation. Presumably, that’s based on average arsenic levels in rice.

So, if you choose a lower-arsenic rice, with only half the level, can you have four servings a week, instead of two? And, if you boil rice like pasta, doesn’t that cut levels in half, too?  So, then you’re up to like eight servings a week. So, based on the water standard, you could still apparently safely eat a serving of rice a day, if you choose the right rice, and cooked it right.  And, I would assume the water limit is ultra-conservative, right? I mean, since people are expected to drink water every day of their lives, whereas most people don’t eat rice every day, seven days a week. I assumed that, but I was wrong. It turns out the opposite is true.

See, all this time I was assuming the current drinking guideline exposure would be safe, which in carcinogen terms, is usually “1 in a million,” as I mentioned before. That’s how we typically regulate cancer-causing substances. Some chemical company wants to release some new chemical; we want them to show us that it doesn’t cause more than “1 in a million” excess cancer cases. Of course, we have 300 million people in this country, and so, that doesn’t make the 300 extra families who have to deal with cancer feel any better, but that’s just the kind of agreed-upon acceptable risk.

The problem is, according to the National Research Council, with “the current [federal] drinking water standard for arsenic of 10,” we’re not talking an “excess cancer risk” of one in a million people, but as high as “1 case in 300 people.” What? My 300 extra cases of cancer just turned into a million more cases? A million more families dealing with a cancer diagnosis? “This is 3000 times higher than a commonly accepted cancer risk for an environmental carcinogen of 1 in [a million].” “[I]f we were to use the normally accepted” 1 in a million odds of cancer risk, the water standard would have to be like 500 times lower—.02 instead of 10. Even the New Jersey standard is 250 times too high. That’s a “rather drastic” difference, but “underlines how little precaution is instilled in the current guidelines.”

Okay; so, wait. Why isn’t the water standard .02 instead? Because that “would be nearly impossible.” We just don’t have the technology to really get arsenic levels in the water that low. The technologically feasible level has been estimated at 3. Okay. So, why is the limit 10, and not 3? The decision to use a threshold of “10 instead of 3 is…mainly a budgetary decision.” Otherwise, it would cost a lot of money.

So, the current water quote-unquote “safety” limit is “more motivated by politics than by technology.” Nobody wants to be told they have toxic tap water. If so, they might demand better water treatment, and that could get expensive. “As a result, many people drink water at levels very close to the current [legal] guideline,…not aware that they are exposed to an increased risk of cancer.” “Even worse,” millions of Americans drink water exceeding the legal limit: all these little red triangles. But, even the people living in areas that meet the legal limit must understand that the “current arsenic guidelines are only marginally protective.”

Maybe we should tell people that drink water, i.e., everyone, that the “current arsenic regulations are [really just] a cost-benefit compromise, and that, based on usual health risk [models], the standards should be much lower.” People must be made aware that the “targets…should really be as close to zero as possible,” and that when it comes to water, at least, we should aim for the reachable 3 limit. Okay, but bottom line: what does this mean for rice?

Well, first of all, so much for just trying to get rice down to the so-called safe water limit, since that already way exceeds standard carcinogen risks, and is more based on feasibility and cost-benefit compromises, allowing “for roughly a 500 times higher risk of cancer than is normally considered acceptable.” So, “while authorities ponder when and how they will regulate arsenic concentration[s] in rice,” maybe we “should…curtail or strongly limit our consumption of rice.”

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• Marcason W. What are the current findings concerning arsenic in foods? J Acad Nutr Diet. 2015 Jun;115(6):1028.
• Focazio MJ, Welch AH, Watkins SA, Helsel DR, Horn MA. U.S. Department of the Interior, U.S. Geological Survey. A Retrospective Analysis on the Occurrence of Arsenicin Ground-Water Resources of the United States andLimitations in Drinking-Water-Supply Characterizations. Water-Resources Investigations Report 99–4279.
• Hite AH, Arsenic and rice: a call for regulation. Nutrition. 2013 Jan;29(1):353-4.
• Lai PY, Cottingham KL, Steinmaus C, Karagas MR, Miller MD. Arsenic and Rice: Translating Research to Address Health Care Providers' Needs. J Pediatr. 2015 Oct;167(4):797-803.
• "[No authors listed] Arsenic in your food: our findings show a real need for federal standards for this toxin. Consum Rep. 2012 Nov;77(11):22-7. "
• Sauvé S. Time to revisit arsenic regulations: comparing drinking water and rice. BMC Public Health. 2014 May 17;14:465.
• Stanton BA, Caldwell K, Congdon CB, Disney J, Donahue M, Ferguson E, Flemings E, Golden M, Guerinot ML, Highman J, James K, Kim C, Lantz RC, Marvinney RG, Mayer G, Miller D, Navas-Acien A, Nordstrom DK, Postema S, Rardin L, Rosen B, SenGupta A, Shaw J, Stanton E, Susca P. MDI Biological Laboratory Arsenic Summit: Approaches to Limiting Human Exposure to Arsenic. Curr Environ Health Rep. 2015 Sep;2(3):329-37.

Icons created by Made by Made and Linseed Studio from The Noun Project.

Image credit: Wenchieh Yang via Flickr. Image has been modified.

Motion graphics by Avocado Video. 

• apple juice
• arsenic
• beverages
• cancer
• carcinogens
• Consumers Union
• environment
• FDA
• grains
• heavy metals
• rice
• safety limits
• water