At a press conference during a meeting of the American Chemical Society, researchers from Monmouth University claimed that they had found as much as 12 milligrams of lead per kilogram of rice imported from Taiwan and China, or 40 times what the FDA considers a tolerable level.

They then speculated that the use of untreated industrial wastewater and sewage in irrigation was the likely source of the contamination.

This prompted numerous major media outlets to report that some imported rice may have dangerous levels of lead, triggering widespread concerns about food safety both in the US and abroad.

However, Monmouth’s results, acquired using X-ray fluorescence (XRF), were several orders of magnitude greater than previous research on lead in rice – provoking skepticism and even denials from Taiwanese officials.

When analyzed by the more precise technique of inductively coupled plasma – mass spectrometry (ICP-MS), it was determined that all of the samples had less than 1 milligram of lead per kilogram of rice and the researchers from Monmouth have since retracted their findings.

In an unrelated matter, a story in the New York Times last month regarding legitimate concerns over rice contaminated with cadmium served at restaurants in China inadvertently used the wrong unit of mass when they reported that

One seafood restaurant served rice with an average 0.4 micrograms of cadmium per kilogram, double the maximum permitted by government standards.

Cadmium concentrations this low would not normally be a matter of concern and are well within even the most stringent regulations.

Once the error was brought to their attention the article was revised to correctly reflect the concentration as 0.4 milligrams of cadmium per kilogram (see the bottom of the article for the correction), a level sufficient to raise health concerns.