Rice Contributes to Arsenic Exposure

In a study of a small group of pregnant women in New Hampshire, researchers from Dartmouth College found elevated urinary arsenic concentrations in those who had eaten rice in the two days prior to urine collection.

Of the 229 women who took part in the study, 73 had eaten rice in the two days prior. Upon testing, the urine of the rice eaters showed a median of 5.27 micrograms per liter; the 156 non-rice eaters showed 3.38 micrograms per liter. In a paper published in the Proceedings of the National Academy of Sciences, the researchers note that the women who had eaten rice consumed an average of 28.3 grams per day, which is equal to a 1/2 cup of cooked rice or 1 cup of rice cereal. Rice is susceptible to arsenic contamination due to its ability to extract arsenic from the environment into the rice plant.

Arsenic levels in the water of all subjects' homes were also tested, in order to separate the potential for exposure to arsenic from drinking water. The researchers say the women consumed a median of 0.27 μg of arsenic per day through home tap water.

The researchers conclude: "The large and statistically significant association we observed between rice consumption and urinary arsenic, in addition to earlier reports of elevated arsenic concentrations in rice, highlights the need to regulate arsenic in food. There are no statutory limits for the arsenic content of food sold in the United States and European Union, in stark contrast to China, where the maximum safe level of inorganic arsenic in rice is 0.15 μg/g (36). Setting such limits would protect consumers from unknowingly purchasing rice or rice products with high levels of arsenic. In addition, limits would encourage cultivation of rice strains that do not incorporate as much arsenic and reduce the use of arsenic-contaminated land for agriculture. Given the potentially adverse health consequences of arsenic at low levels of exposure, it is imperative that the health impact of arsenic exposure through rice consumption be characterized."