FDA: Don't Worry About the Arsenic in Your Rice...

much: Not enough arsenic in rice to cause immediate health fears, looking at long-term effects

The Food and Drug Administration says consumers shouldn’t worry too much about levels of arsenic in rice — but should vary their diets just in case.

The agency released a study Friday of arsenic in 1,300 samples of rice and rice products, the largest study to date looking at the carcinogen’s presence in that grain. Consumer groups have pressured the FDA to set a standard for the amount of arsenic that can be present in rice products.
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Rice is thought to have arsenic in higher levels than most other foods because it is grown in water on the ground, optimal conditions for the contaminant to be absorbed.

The water in the flood soil looses all it's oxygen, due to respiration of organic carbon in the soil, and becomes anoxic.  This, in turn, changes arsenic from a form predominantly bound to Fe in the solids (As V) to a form that is more soluble (As III), and readily taken up by the rice.

Arsenic is naturally present in water, air, food and soil in two forms, organic and inorganic. Organic arsenic passes through the body quickly and is essentially harmless. Inorganic arsenic — the type found in some pesticides and insecticides — can be toxic and may pose a cancer risk if consumed at high levels or over a long period.

The FDA is looking into how much organic and inorganic arsenic rice eaters are consuming and whether those levels are dangerous. The agency will conduct a risk assessment with the National Institutes of Health and the Environmental Protection Agency to further measure those effects.
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Average levels of arsenic in the study ranged from 2.6 to 7.2 micrograms of inorganic arsenic per serving. Though the long-term effects are still unknown, that amount is tiny — a microgram is one-millionth of a gram.

Still, it is almost impossible to say how dangerous these levels are without a benchmark from the federal government. The advocacy group Consumer Reports, which is pushing for FDA to create standards, has used New Jersey’s drinking water standard — a maximum of 5 micrograms in a liter of water — as an example of a benchmark because it is one of the strictest in the country. But the group acknowledges that it is difficult to compare standards for water and rice because one is a liquid and one is a solid and people drink more water than they eat rice.

The EPA drinking water standard is 10 micrograms per liter, and the average human consumes about 2 liters of water per day.  Thus, the standard effectively concedes that up to about 20 micrograms per day is a safe dose.  Having 3 to 7 micrograms in a rice meal in additions seems very little additional threat, especially when you know that most water supplies have much less than 10 micrograms per liter.  At least, I ain't skeered...