If you're wondering why rice is a topic in a blog about "Harvey Park Plants", I'm writing about it precisely because rice does not grow here at all. Unlike many other grains like wheat and corn, and pseudo-grains like quinoa, rice is essentially impossible to grow in Colorado. Traditional practice requires that a rice field, or paddy, be totally flooded at least twice during the growing season, which is impractical if not impossible here. Because we can't grow rice, we are forced to buy it if we want to eat it, which means we don't always know where it came from or how it was grown.
Most rice available in the US comes from the Southeastern states, California, or Southeast Asia. Based on the study's findings, rice from the southeast had the most arsenic and rice from Asia had the least, while Californian rice was somewhere in the middle. Perhaps not surprisingly, brown rice, which contains more vitamins and minerals than white rice, also had more arsenic across the board. A more surprising finding is that there seems to be no difference between organic and non-organic rice.
The reason for this isn't due to how the rice is grown, so much as it is due to how cotton is grown (stay with me here). Cotton has historically been the major cash crop of the Old South. However, cotton just so happens to be one of the most pest and disease prone crops that we grow, so commercial cotton fields use more synthetic chemicals than just about any other farm industry. One of the pesticides with a long history of use in cotton is the fun-sounding lead arsenate. Because both lead and arsenic are elements, they don't degrade, and remain in the field forever, or at least until they leach out, wash away, or get taken up by plants. (Incidentally, lead arsenate was slowly phased out in the 1950s, in favor of the equally fun DDT, though it wasn't actually banned until 1988).
However, with the invention of polyester fabric in 1941, demand for cotton fell and fields began being converted to other uses, including rice, which became a much more attractive crop in the United States after malaria was eradicated (by DDT). Thus, American rice tends to be grown in places where cotton was grown just a few short decades earlier, with its host of chemical pesticides. Thus, its no surprise that even organic rice, which is getting no current chemical input, is still paying the price of our long legacy of pesticide use.
Asia, meanwhile, has grown rice organically for millennia, and never grew cotton. While its rice also has SOME arsenic, the levels are much lower, and are at least somewhat attributable to naturally occurring arsenic in soil.
To summarize, where and how your food was grown DOES matter, though not always in the ways you might expect. Buying Asian grown rice might be safer in terms of arsenic, but on the other hand, that rice has to be shipped much further to get to you, incurring other costs. There seems to be no "easy" or "right" answer here, though it does seem clear that our use of synthetic chemicals can have long-lasting unforeseen consequences.
For more information, you can also check out the FDA website devoted to arsenic in rice.
