The consumer-advocacy organization Consumer Reports tested 45 fruit juices, including apple, grape and juice blends, and found that 21 of them had "concerning levels" of cadmium, arsenic and/or lead, according to a new report. Juice samples came from 24 national and private-label brands.

For instance, two Welch's products contained levels of lead that exceed the standard for bottled water set by the Food and Drug Administration. And a sample of Trader Joe's Fresh Pressed Apple Juice exceeded a 10 parts-per-billion threshold for arsenic that has been recommended as an allowable level.

"We know there are no safe levels of exposure to these heavy metals," says Aparna Bole, a pediatrician in Cleveland who serves on the American Academy of Pediatrics' Council on Environmental Health. Bole says she agrees with the CR report's call for the FDA to update its standards.

Several years back, the FDA proposed a 10 parts-per-billion limit on arsenic in apple juice, but the agency has yet to issue a guideline.

In response to the new report, an FDA spokesperson said in an email, "We welcome the data provided by Consumer Reports and will review it in its entirety as part of our larger, comprehensive effort to reduce toxic element exposure."

Overall, the new test results point to a reduction in heavy metals, compared with results from tests performed several years ago. So, this is a sign of progress. But, the FDA says, "We know there is more work to be done to reduce these elements in our food supply and we place a high priority on reducing exposure among infants and children, as the very young are more susceptible to their potential adverse health effects."

The CR team reached out to food companies whose juices were tested; their responses are included in the report. A Welch's spokesperson said, "All Welch's juice is safe and strictly complies with all applicable legal requirements. Naturally occurring elements such as lead and arsenic are present in the soil, air, and water. Therefore, they are also found in very low, harmless levels in many fruits and vegetables." And Trader Joe's told CR: "We will investigate your findings, as [we are] always ready to take whatever action is necessary to ensure the safety and quality of our products."

So, how risky is exposure to low levels of these heavy metals, particularly arsenic? We put the question to scientists with the Dartmouth Toxic Metals Superfund Research Program.

"Research from Dartmouth and other institutions has shown that arsenic at levels below 10 parts per billion may have health effects on people and children," the researchers told us in an email. "Ultimately, reducing exposure to all sources of arsenic is important to keep exposure levels as low as possible and if you have a private well with arsenic in your water, eat a lot of rice and drink a lot of juice, it is recommended that you reduce or change those exposure sources."

"Arsenic is potentially harmful to human health in multiple ways," Margaret Karagas, an epidemiologist at Dartmouth College who focus on children's health, explains in an arsenic informational site curated by the Dartmouth group. "Higher exposures are related to increased risks of certain cancers and heart disease, and may impact growth, brain development and immune function. Scientists are learning that health effects may occur even at low levels of exposure."

On the same site, Dr. Carolyn Murray of Dartmouth offers this advice to consumers: "Take action to reduce arsenic if you're a pregnant woman, or have kids. Arsenic is harmful to child growth, development and brain function. Kids consume more food and water per pound of body weight, so they are more likely than other age groups to be exposed to too much arsenic."

It can be tricky to identify a specific risk threshold for arsenic in food and beverages other than water, because the science is not yet there to provide the epidemiological data needed to set a standard, according to the scientists at the Dartmouth toxic metals program. They note that such research is underway at a variety of institutions.

The Dartmouth scientists point out that trace levels of heavy metals can end up in food through a variety of sources. Metals can be naturally present in the soil. Past use of pesticides can also leave metal residues. Metals can also be present in the water used to irrigate crops, or they can be in water sprayed directly onto trees and plants, in countries outside the U.S.

And as the FDA points out, these heavy metals enter the food supply when plants take them up as they grow.

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