I am one of the fortunate few who grew up eating primarily products produced in my backyard. Growing up on a beef cattle farm in the Midwest, my family consumed almost exclusively products that we produced. There was beef and pork from our own animals, hand-selected for their quality meat and butchered locally, and vegetables produced in our garden, frozen or canned to be eaten in the months outside of the growing season. When I went away to college in Cambridge, Massachusetts, over 1,500 miles away from my family’s farm, I quickly realized what a luxury it was to know exactly where—and how—the food on your plate was derived.
One major criticism of the increasingly corporatized and fragmented food system is that it breaks down the information chain from farmer to consumer. Consumers cannot possibly know precisely what they are putting into their bodies each time they sit down to eat a meal. One example of this lack of consumer information about food was highlighted in a study released last fall by Consumer Reports, which found alarmingly high rates of arsenic, a known carcinogen, in rice products.
Although there is no federal limit for arsenic in foods, there is a federal limit of 10 parts per billion (ppb) for arsenic in drinking water, as prescribed by the EPA in accordance with the Safe Drinking Water Act. However, there is no “safe” level for arsenic: the EPA’s contaminant level goal is zero. The EPA states that it “has set this level of protection based on the best available science to prevent potential health problems.” New Jersey has the most protective standard for arsenic in drinking water, at 5 ppb. Consumer Reports tested 200 different products and concluded that a single serving of some rice products “could give an average adult almost one and a half times the inorganic arsenic he or she would get from a whole day’s consumption of water, about 1 liter.”
So, where does the arsenic found in rice products come from? Rice is known to be a “natural arsenic accumulator.” Typically, rice plants take up large amounts of silicon from the soil to strengthen the stems and husks, which protect the plant against pests. Arsenic and silicon are chemically similar in soil conditions found in flooded rice paddies. Thus, arsenic is literally integrated into a rice plant as it grows. This also explains why the Consumer Reports study found higher levels of arsenic in brown rice. Arsenic is concentrated in the outer layers, or husks, of the grain. The process of producing white rice involves polishing off the outer layers, which has the effect of reducing arsenic levels.
Soil where rice is grown becomes contaminated with arsenic in several ways. As my classmate, Caitlin, noted in her earlier post, arsenic exists naturally in the earth’s crust. So, some soils and water sources naturally have higher levels of organic arsenic. There is debate among scientists about the extent to which organic arsenic is hazardous to human health, because the human body is capable of metabolizing organic arsenic, making it less detrimental than inorganic arsenic.
However, the Consumer Reports study noted levels of inorganic arsenic, much of which ends up in rice due to farming practices. Fields in the American south—where 76% of American rice is grown—are tainted by lead arsenate and calcium arsenate, two popular compounds used in pesticides to beat insects like the boll weevil in cotton fields for a large part of the 20th century. Although many pesticides containing arsenic were banned in the 1980s, some arsenic-based products are still used today.
U.S. poultry farmers feed arsenic to chickens to control a common parasite. Chicken manure, often containing inorganic arsenic, is applied to fields where it accumulates in soil, according to the USDA. Although there is no data about the amount of chicken manure applied to rice fields, there is a notable geographic connection between rice farms and chicken producers.
What can consumers do to decrease their exposure to arsenic from rice? Consumer Reports recommends limiting rice in diets. The FDA agrees, giving consumers the advice to “continue to eat a balanced diet that includes a wide variety of grains.” This may not be so easy, as researchers at Dartmouth have also highlighted the fact that many foods contain brown rice syrup as a sweetener alternative to high fructose corn syrup. There has been particular concern about infant exposure to arsenic through rice because many first foods, such as cereals and even baby formulas, contain rice or brown rice syrup.
If you do eat rice, consumers can reduce arsenic exposure by choosing aromatic rice from Thailand or India, or U.S. rice grown in California, all of which seem to contain less arsenic. When cooking rice, the FDA recommends thoroughly rinsing rice until the water is clear and cooking rice in plenty of water and draining it, much like pasta. In the long term, arsenic levels in rice highlight the need for new laws limiting the amount of arsenic in foods and prohibiting the use of arsenic in agricultural production of animals and crops.