(Bloomberg News) A rice-based ingredient that sometimes contains arsenic was found in infant formula, prompting researchers at Dartmouth College to say there is an "urgent need" for regulatory limits on the carcinogen in food.

Two of 17 infant formulas tested listed organic brown rice syrup, which may contain arsenic, as the primary ingredient, and one had a total arsenic concentration level up to six times the U.S. federal limit of 10 parts per billion for drinking water, according to a study published today in the journal Environmental Health Perspectives.

While arsenic has been recognized as a contaminant in drinking water, there are currently no federal thresholds for arsenic in juices or most foods. Legislation was introduced Feb. 8 in the U.S. House of Representatives calling on the Food and Drug Administration to establish standards for arsenic and lead in fruit juices.

"In the absence of regulations for levels of arsenic in food, I would certainly advise parents who are concerned about their children's exposure to arsenic not to feed them formula where brown rice syrup is the main ingredient," Brian Jackson, lead author of the study, said in a statement.

The study didn't name the infant formula brands it investigated.

Southern Rice

Nature's One Inc., a closely held manufacturer of baby foods, said in a statement on its website that its California- based supplier of organic brown rice syrup uses an independent lab to test arsenic levels. "Their testing results report undetectable amounts of arsenic at laboratory testing limits," it said. "Parents can rest assured that Nature's One will test arsenic levels for every lot" prior to production.

Rice is among plants that are efficient in taking arsenic from the soil, regardless of whether the resulting products are considered organic, the Dartmouth researchers said.

Most rice produced in the U.S. comes from Arkansas, Louisiana, Mississippi, Texas and Missouri, where the grain is grown on soil that was formerly treated with arsenical pesticides for cotton farming, according to a 2007 study by Andrew Meharg at the University of Aberdeen in Scotland. That study found that the arsenic level in rice grown in California was 41 percent lower than that from the south-central U.S.

Juice Samples

Arsenic is also present in some types of cereal and energy bars, as well as gel-like energy "shots," the Dartmouth researchers said.

In a study by Consumer Reports magazine published last month, about 10 percent of juice samples from five brands had total arsenic levels that exceeded federal drinking-water standards. Most of the arsenic was inorganic arsenic, a known carcinogen, according to the study.

The potential presence of the chemical element in formula is "particularly worrisome for babies because they are especially vulnerable to arsenic's toxic effects," the Dartmouth researchers said.