Arsenic in Food: FAQ
How arsenic gets into foods, and what it means for you.
Recent investigations have found the toxin arsenic in rice and apple juice.
Consumer Reports published results of their tests of 88 samples of apple and grape juices. Nine samples had more arsenic than the federal government allows in drinking water
In a separate analysis of government nutrition data, researchers commissioned by Consumer Reports also found that Americans who reported drinking apple or grape juice had arsenic levels in their urine that were 20% higher than people who didn’t drink those juices.
Similarly, researchers at Dartmouth Medical School found that pregnant women who reported eating rice had higher levels of arsenic in their urine than women who didn’t eat rice.
Eating just half a cup of rice a day, the researchers reported, could expose someone to just as much arsenic as if they had been drinking water at the government’s maximum allowable limit.
Should you be worried about being exposed to arsenic in food? WebMD consulted experts who study arsenic to answer your questions.
What is arsenic and how does it get into foods?
Arsenic is a naturally occurring element that’s found in soil and water. It has also been used by farmers as a pesticide and a fertilizer. It is also used to preserve pressure-treated wood.
Like lead, mercury, and other heavy metals, arsenic can persist in soil for years after it is applied to crops.
Much of the rice grown in the Southern U.S., for example, grows in paddies that were once cotton fields. Cotton farmers are known to have used arsenic-based pesticides to control bugs called boll weevils.
Other studies have shown that arsenic content in soil is higher around rivers and may be related to soil texture. Clay soils have more naturally occurring arsenic.
Because of its chemical structure, plants mistake arsenic for necessary nutrients and readily absorb it from the soil.
Are there particular foods that it’s in?
“All plants pick up arsenic,” John M. Duxbury, PhD, a professor of soil science and international agriculture at Cornell University in Ithaca, N.Y., says in an email. “Concentrations in leaves of plants are much higher than in grains of plants. Thus, leafy vegetables can contain higher levels of arsenic than rice, especially when they are grown on arsenic-contaminated soils."
But because we eat a much lower volume of leafy greens compared to other kinds of foods,
“arsenic intake from this source is also low,” Duxbury says.
Rice appears to be particularly vulnerable to arsenic contamination because it grows in water.
Arsenic dissolves easily in water. So drinking water has long been monitored as a source of exposure to arsenic.
Because rice is grown in paddies, which are flooded with water, it can be exposed to higher amounts of arsenic than plants grown in drier soils, Duxbury says.