Researchers have found unacceptably high levels of lead in rice imported into the U.S., particularly from China and Taiwan, BBC News reports.
Some samples exceeded the "provisional total tolerable intake" (PTTI) set by the Food and Drug Administration (FDA) by a factor of 120.
Dr Tsanangurayi Tongesayi of Monmouth University in New Jersey and his colleagues tested a number of imported brands of rice, including rice from Bhutan, Italy, China, Taiwan, India, Israel, the Czech Republic and Thailand -- which accounts for 65 percent of U.S. imports. (The U.S. imports about 7 percent of its rice.)
The scientists measured the lead levels in each country category and calculated the lead intake on the basis of average daily consumption. The results were presented at an American Chemical Society meeting, and will be published in the Journal of Environmental Science and Health, Part B.
Tongesayi and his colleagues found that the rice they tested contained lead amounts significantly higher than the FDA's approved PTTI levels.
"According to the FDA, they have to be more than 10 times the PTTI levels [to cause a health concern], and our values were two to 12 times higher than those 10 times," Tongesayi told BBC News. "So we can only conclude that they can potentially cause harmful effects" -- especially in children, who are more vulnerable to lead poisoning. Lead can damage organs and the central nervous system and cause serious developmental difficulties in children.
The factor of 120 (12 times higher than 10 times the PTTI) is for Asian children, who are most susceptible because of their age and comparatively high rice intake according to the study.
For non-Asian adults, the levels above the PTTI ranged from 20 to 40.
Rice from China and Taiwan had the highest lead levels, but all of the samples significantly exceeded the PTTIs.
The FDA says it will review the findings.
Because rice is grown in water, it is more susceptible than other crops to environmental pollutants found in irrigation water and groundwater. Previous studies have found high levels of arsenic in rice, particularly brown rice.
The problem, Tongesayi told the BBC, are unhealthy agricultural practices around the world.
"If you look through the scientific literature, especially on India and China, they irrigate their crops with raw sewage effluent and untreated industrial effluent," he said.
Wow, great idea.
"Research has been done in those countries, and concerns have been raised because of those practices, but it's still ongoing."
Heavy metals in rice can even be traced to the increasing practice of sending electronic waste to developing countries, and the air and water pollution it leads to, he said.
He urges international regulations to govern the production and distribution of food.
Can we please do that stat?
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