 Given the level of arsenic and rice, how could we figure out how much rice is too much? There are no US standards for arsenic and rice, even though that's our main source of exposure. But look, there's limits on arsenic and apple juice and tap water, and 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, and people drink what, 4 to 8 cups of water a day and set the limit that way, right? OK, well, can't we just use there how much arsenic a day is too much, number, and based on the average arsenic content in rice, figure out how much rice a day is too much rice? Well, the allowable level established by the FDA for arsenic and bottled water, for example, is 10 parts per billion, assuming people might drink a liter a day. OK, so based on that 10 a day limit, how much rice is that? Well, each 1 gram 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. OK, 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 day instead of two? And if you boil rice like pasta, doesn't that cut levels in half two? 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 one 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 one in a million excess cancer cases. Of course, we have 300 million people in this country, 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 one 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 3,000 times higher than a commonly accepted cancer risk for an environmental carcinogen of one in a million. If we were to use the normally accepted one in a million odds of cancer risk, the water standard would have to be like 500 times lower, 0.2 instead of 10. Even the New Jersey standard is 250 times too high. It's a rather drastic difference, but underlies how little precaution is instilled in the current guidelines. OK, so wait, why isn't the water standard 0.02 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. OK, so why is the limit 10 and not 3? The decision to use a threshold of 10 instead of 3 was 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, and 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, a million 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 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. OK, 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 concentrations in rice, maybe we should curtail or strongly limit our consumption of rice.