A study by researchers at the University of Washington found that most American wines have arsenic levels higher than what’s allowed in drinking water--a threshold set by the U.S. Environmental Protection Agency (EPA).

The study included an analysis of 65 wines from four of the U.S.’s top wine producing states. Nearly all of them--64 to be exact--contained excessive levels of arsenic. The EPA allows for 10 parts per billion of arsenic in drinking water. In the wine samples, researchers discovered an average of 24 parts per billion, ranging from 10 to 76 parts per billion. Wines produced in the state of Washington had the highest levels of arsenic (average 28 parts per billion) and Oregon had the lowest (average 13 parts per billion).

A companion study done by the university seems to conclude that a person’s health risk from consuming arsenic depends heavily on how much of it is actually consumed. The risk is generally only high for very heavy drinkers who consume alcohol that also contains high concentrations of arsenic--and there aren’t many of them. Besides alcohol, researchers point to other sources of arsenic consumption--contaminated rice, organic brown rice syrup, seafood and apple juice. These foods and beverages are particularly high risk for pregnant women, children and the elderly.

Denise Wilson--an electrical engineering professor at the University of Washington and lead researcher--recommends that wineries in the U.S. test for arsenic and lead in both irrigation and processing water, then take the necessary steps to remove those contaminants. On the consumer front, Wilson suggests careful diet planning and consulting with one’s doctor to address any concerns.