On the heels of two reports that have reignited worries about arsenic poisoning from rice, US lawmakers are taking steps to restrict the toxic substance.
On 21 September, US Representative Rosa DeLauro of Connecticut introduced a bill that would require the Secretary of Health and Human Services to set limits on allowable arsenic levels in rice and rice products. The proposal specifies that the heavy metal — which has been linked to increased risk of certain cancers — should be restricted to levels that would minimize such risks.
Arsenic occurs naturally in soil and can be taken up by plants such as rice. However, as Nature reported in 2005, in the United States, and particularly in some Southern states, arsenic may be concentrated in rice fields once used for cotton farming and treated with arsenic-based pesticides against boll weevils.
For the past year, the US Food and Drug Administration (FDA) has been studying arsenic in commercially available rice and rice products. The agency released its preliminary findings 19 September.
FDA researchers analysed arsenic levels in about 200 samples of rice and rice products from the US marketplace — including rice cakes, cereals and drinks — which originated in the United States and other countries. The report measured organic and inorganic arsenic, the latter of which is considered particularly toxic.
Average inorganic arsenic levels ranged from 3.5 micrograms per serving for basmati rice to 6.7 micrograms for non-basmati rice. In dry weight, the study found inorganic arsenic levels in some samples as high as 100–200 parts per billion.
Federal regulations limit arsenic in drinking water to 10 parts per billion. No such limits exist for food, according to the FDA.
Earlier this week, a parallel study appeared online in Consumer Reports, a publication of the New York-based consumer protection group Consumers Union. The advocates called their results “worrisome”, encouraging consumers to limit intake of rice and rice products. Consumers Union also pushed for federal standards on arsenic in rice.
FDA officials say that it is too early to recommend changes in food consumption on the basis of the new report, citing plans to collect about 1,000 more samples for a more comprehensive analysis by the end of the year. Further studies would be needed to assess the nature and magnitude of health effects, and to define threshold levels for human safety, they say.
“The science has to drive all the regulatory decision-making,” says Shelly Burgess, an FDA spokeswoman.