Love red wine? Studies show that for many people, drinking it in moderation may offer heart health benefits, probably because of the alcohol itself as well as the wine's powerful antioxidants. But one researcher has raised concerns about a substance in wine you probably didn’t know it contained: arsenic.

The same chemical element, found in some rocks and also soil and water — and therefore foods — grabbed headlines years back when scientists scrutinized arsenic levels in apple juice and rice-based baby food. According to the Food and Drug Administration (FDA), long-term exposure to high levels of arsenic is associated with an increased risk of cancers of the skin, lung, liver and bladder, as well as heart disease.

So is the arsenic in wine worth worrying about?

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Wines put to the test

In the new study, four samples of 65 wines, mostly red, were tested for levels of arsenic, says Denise Wilson, PhD, professor of electrical engineering at the University of Washington, Seattle, and managing director of Coming Alongside, a nonprofit environmental organization.

All 65 wines contained arsenic. The bigger surprise: All but one wine exceeded the maximum level allowed in drinking water by the U.S. Environmental Protection Agency (EPA), set at 10 parts per billion (ppb). The average arsenic detected among all samples was about 24 ppb, Wilson says. The range was 10 to nearly 76 ppb.

But don’t swear off wine just yet. "We are not issuing a widespread alarm to stop drinking red wine or to stop drinking American wines," says Wilson.

Wilson explains it’s the total amount of arsenic you take in through all the foods and drinks you consume that matters. "It's extremely unlike that arsenic from red wine alone is going to cause a long-term problem."

How the wines tested stacked up by region

Wilson tested wines from the four top wine-producing states — California, Washington, Oregon and New York.

Washington's wines had the highest levels, on average 28 ppb, while Oregon wines had the lowest, about 13 ppb. The report is published in the October issue of the Journal of Environmental Health.

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Putting wine in perspective

In a companion study, also published in the Journal of Environmental Health, Wilson looked at people’s intake of other beverages, as well as foods, known to have arsenic, including juice, milk, bottled water, cereal bars, infant formula, rice and seafood.

Wilson says she looked at these consumption patterns because it's a way to put arsenic levels from wine in perspective. And, she says, gauging health risk by comparing arsenic in wine to levels in drinking water is imperfect since we drink more water than wine.

She found that among adults, heavy rice eaters would be exposed to the most arsenic. In kids, children fed formula with organic brown rice syrup would have the most exposure.

Most foods and drinks don't have enough arsenic to surpass what experts view as minimal risk levels, she says. However, people whose diets are high in foods and drinks with the highest arsenic levels may want to alter their diet, she says.

Arsenic: second opinions

For most people, arsenic from the diet is not a health concern, says Carl Winter, PhD, an extension food technologist at the University of California Davis and a spokesperson for the Institute of Food Technologists. He has also published research on arsenic content in foods. He reviewed the new findings.

Winter says Wilson’s estimates of arsenic in the total diet do not seem as comprehensive as some other research that looked at a wider range of foods. And even if people's overall consumption of arsenic exceeds minimal risk levels, that does not necessarily mean they will experience adverse health effects. "It says exposures are higher than we are comfortable with, but that doesn't [necessarily] mean people are getting sick."

Established safe levels are generally on the conservative side, he says.

The sample used in the University of Washington study is small, notes Gladys Horiuchi of the Wine Institute. She says the results "are not supported by decades of previous analysis under stringent laboratory conditions." Other researchers have found levels far below what Wilson's study found, she says.

Bottom line?

Wilson suggests the wine industry could improve by reducing the levels of arsenic in their products. For red wine drinkers, she suggests drinking wines from a variety of sources, not the same variety from the same vineyard each time. Look at your entire diet, she advises, paying special attention to apple cider, apple juice, grape juice, milk, bottled water and wine.

If you’re worried you may be getting too much arsenic, Wilson suggests asking your doctor about having your arsenic level tested.

Winter disagrees, emphasizing that arsenic is not a concern for people who eat a balanced diet.

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Kathleen Doheny is a Los Angeles journalist specializing in health, behavior and fitness topics.