Brown rice may be healthy for you, but it's also contaminated with a cancer-causing heavy metal.

Most people don't ask for a side of arsenic with their California rolls, but the heavy metal is pervasive in the world's rice supply. And the Food and Drug Administration (FDA) announced Wednesday that it is finally looking into whether the presence of arsenic in the food we eat poses as big a problem as past studies have suggested.

The FDA has come under criticism in the past because Consumer Reports magazine and other independent scientists have conducted their own tests on arsenic in food and found it in very high levels. Apple juice has been found to have arsenic at levels up to 24 times the Environmental Protection Agency's limit for arsenic in water (currently, there is no limit on the metal in food) and most recently, scientists from Dartmouth University detected arsenic in cereal bars at 12 times the drinking-water limit. The source in that study was brown rice syrup, a popular replacement for high-fructose corn syrup.

The agency announced on Wednesday that it had already tested 200 samples of rice and rice products and has plans to test at least 1,000 more before determining next year whether a limit on arsenic in rice is necessary. So far, plain rice has been shown to contain the highest amounts, while basmati rice and rice cereals have the lowest.

Arsenic is a cancer-causing heavy metal that winds up in a variety of foods. It exists naturally in soil and water, but it also is emitted from coal-fired power plants and burning oil, and it lingers in soil because it has been used in pesticides and wood preservatives. Furthermore, arsenic is a common additive to chicken feed, and about 75 percent of it passes through the chickens into their manure, according to Michael Hansen, PhD, chief scientist at Consumers Union. Also, it's not uncommon for farmers to use chicken manure as fertilizer. Rice is particularly vulnerable to arsenic contamination because it's grown in water and absorbs the heavy metal from both the soil beneath it and the water surrounding it, but it also shows up in trace amounts in other vegetables, fruits, and grains.

The FDA is currently looking just at rice and hasn't announced whether it will move to limit arsenic in other foods, such as apple juice. The agency also isn't recommending that people change their consumption of rice products right now. But if you're worried, here are two steps you can take:

• Switch to wild rice. It's technically a grass, not a grain, and is nutrient-dense with much lower levels of arsenic than rice.

• Vary your grains. Wheat has trace amounts of arsenic, but at lower levels than rice. You can also eat quinoa, buckwheat, millet, and amaranth in place of rice.