"At one point during the reign of King Cotton, farmers in the south central United States controlled boll weevils with arsenic-based pesticides, and residual arsenic still contaminates the soil. Today, rice paddies cover fields where cotton once grew, and a large market basket survey published in the 1 April 2007 issue of Environmental Science & Technology now shows that rice grown in this area contains, on average, 1.76 times more arsenic than rice grown in California."

More interesting info too, follow the link.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1892142/


"The major contributors of inorganic arsenic are raw rice (74 ng/g), flour (11 ng/g), grape juice (9 ng/ g), and cooked spinach (6 ng/g) (Schoof et al., 1999)."

http://www.nap.edu/openbook.php?record_id=10026&page=504

"A team led by environmental chemist Brian P. Jackson found what Jackson called dangerous amounts of arsenic in organic powdered baby formula, intended for toddlers, whose top ingredient was brown rice syrup. That formula contained six times more arsenic than the Environmental Protection Agency considers safe for the water supply.

Jackson and his colleagues also reported elevated arsenic levels in some brown rice-sweetened cereal bars, energy bars and energy "shots"consumed by endurance athletes, according to a study published today in the journal Environmental Health Perspectives.The results, which do not identify any products by name, follow recent reports about trace levels of arsenic in apple juice and previous reports of arsenic in rice."

http://abcnews.go.com/Health/Diet/arsenic-organics-rice/story?id=15642428#.T0U5OlzOy7E

"Not all forms of arsenic are associated with serious health concerns. Organic arsenic, the less toxic form, is commonly found in most seaweed and other marine foods. Exposure to organic arsenic from most seaweed and other marine foods has not been associated with human illness, therefore organic arsenic from these sources is considered to be relatively non-toxic

Inorganic arsenic compounds are relatively toxic. Sample results have shown that hijiki seaweed is high in inorganic arsenic. Sample results for several other sea vegetables, including dulse, nori, kombu have been low."

http://www.inspection.gc.ca/english/fssa/concen/specif/arsenice.shtml



“All plants pick up arsenic,” John M. Duxbury, PhD, a professor of soil science and international agriculture at Cornell University in Ithaca, N.Y., says in an email. “Concentrations in leaves of plants are much higher than in grains of plants. Thus, leafy vegetables can contain higher levels of arsenic than rice, especially when they are grown on arsenic-contaminated soils."

But because we eat a much lower volume of leafy greens compared to other kinds of foods,
“arsenic intake from this source is also low,” Duxbury says.

Rice appears to be particularly vulnerable to arsenic contamination because it grows in water.

Arsenic dissolves easily in water. So drinking water has long been monitored as a source of exposure to arsenic.

Because rice is grown in paddies, which are flooded with water, it can be exposed to higher amounts of arsenic than plants grown in drier soils, Duxbury says.

Tracy Punshon, PhD, a research assistant professor at Dartmouth College in Hanover, N.H., has X-rayed rice grains to see where they store arsenic.

She found that arsenic concentrates in the part of the grain called the germ, which is removed to make white rice. That means brown rice has higher concentrations of arsenic that white rice.

Studies by Scottish researchers have found higher levels of arsenic in rice grown in the U.S. than in basmati or jasmine rice from Thailand or India.

The highest levels of arsenic in U.S.-grown rice came from Southern states. The lowest levels were detected in rice grown in California.

Seafood also has high levels of arsenic, though most experts believe the form of arsenic in seafood to be nontoxic. Calcium supplements made from seafood may also contain high amounts of arsenic.

http://www.webmd.com/diet/features/arsenic-food-faq

So, stick to California rice.