Are U.S. children who drink fruit juice at risk of exposure to potentially harmful levels of arsenic?

No, said the U.S. Food and Drug Administration in September, in a paper titled “Apple Juice is Safe to Drink,” released by the FDA in response to an episode of the Dr. Oz Show that claimed tests commissioned by the show had found potentially unsafe levels of arsenic in certain U.S. apple juice brands. The FDA roundly criticized the Dr. Oz Show for its testing methods, claiming that the show did not take steps to distinguish between inorganic arsenic — which is a known carcinogen — and organic arsenic — which the FDA considers to be a less harmful form of the naturally occurring element.

Yes, says a Consumer Reports study released this week, in which ten percent of the samples of popular apple and grape juice brands tested came back positive for inorganic arsenic levels above the U.S. legal limit for safe drinking water. And it gets worse: one in four of the juice samples also tested positive for levels of lead above the legal drinking water limit.

In July of this year (months before, I should note, the Dr. Oz episode on arsenic in apple juice aired), I wrote that a study commissioned by the Empire State Consumer Project found potentially alarming levels of poisonous arsenic in certain brands of fruit juice that are commonly marketed to children. The Empire State study revealed that certain samples of Mott’s apple juice to be more than five times the U.S. legal limit for safe drinking water.

It was a small study, with a limited sample size, but the Empire State results echoed findings revealed in a March 2010 expose by the St. Petersburg Times: independent scientific tests commissioned by the newspaper showed that out of 18 samples of popular apple juice brands, more than one quarter contained between 25 and 35 parts per billion of arsenic — also well above the U.S.Environmental Protection Agency’s limit for safe levels in drinking water, which is just 10 parts per billion.

Where is the arsenic in fruit juice coming from? Some arsenic exists naturally at low levels in soil and water, but arsenic has also been used for decades as a wood preservative and as an ingredient in agricultural pesticides. Many pesticides that contain arsenic have been banned in the United States, but some soils here are still contaminated. And arsenic-based pesticides are still in heavy use in China — which now exports most of the apple juice concentrate used by U.S. juice companies.

In that same July post on arsenic in juice, I also noted that testing by the Environmental Law Foundation conducted on juice drinks and snack foods commonly marketed to children found significant levels of lead in 85% of 150 brands tested.

Lead contamination of plants and trees can occur where soil has contaminated by lead-based paint, industrial waste or leaded gasoline.

Arsenic and lead are both poisonous in large doses to humans, and chronic exposure at low levels can be harmful to both adults and children; both chemicals are linked to cancer, damage to the nervous system and heart disease.