Scientist Retracts Lead-in-Rice Study


High lead readings in rice samples likely resulted from a measuring issue.

By Robby Gardner, Associate Editor


Tsanangurayi Tongesayi of Monmouth University has retracted his recent study that reported dangerously high levels of lead in U.S. rice imports. The study was presented to the American Chemical Society with coverage picked up by news groups including BBC, Time,and Prevention. It was pending publication in the Journal of Environmental Science and Health (Part B).

Tongesayi initially concluded that samples of store-bought rice brands exceeded FDA’s provisional total tolerable intake (PTTI) limits for lead in children and adults. But rice ingredients supplier Axiom Foods (Los Angeles) says its CEO David Janow has learned that Tongesayi was having an “issue” with his measuring instruments. In a press release, the company cites statements Tongesayi made to Janow:


The results from one of the places we had sent our samples just came in, and all levels are less than 1ppm using a different method, even though XRF results from another lab still gave high values in the ppm range. I will be raising the issue of the XRF instrument with the supplier…It is not the first time that [an] XRF instrument was used for analysis of heavy metals in food with levels of metals reported at levels less than 5 ppm. Because of the conflicting results, I will be recalling our accepted paper.


Axiom Foods says that rice does run a risk of contamination because rice is a translocator, meaning it soaks up whatever natural or environmental pollutants are in its immediate environment. But standards and technologies are available to ensure safe products.

“We recently created a technology which ensures that 50–70% of heavy metal residue can be removed,” says Janow. “Blanket statements about not trusting ‘rice from Asia’-a continent that makes up 8.7% of the earth’s surface-is not a responsible scientific statement.”

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