At a conference in April 2013, researchers reported preliminary results that the lead level in rice was many times (20-40) above the FDA "provisional total tolerable intake" for adults. The researchers sampled packaged rice from Bhutan, Italy, China, Taiwan, India, Israel, the Czech Republic and Thailand, which accounts for 65% of U.S. imports. Their explanation was that rice fields are irrigated with raw sewage effluent and untreated industrial effluent in many countries. The media was, of course, full of horror stories about lead and rice.
Preliminary checks on the findings have failed to replicate the test results. The researchers originally used X-ray fluorescence; followup tests using a different technique produced much lower results. The original equipment was sent to back to the manufacturer, who confirmed the presence of a calibration problem.
Dutch regulators tested 26 samples of imported rice from various Asian nations and found lead present at 7 ppb, which is 1/1000 of the original test results. The International Rice Institute weighed in, noting that a number of studies have shown that rice plants do not take up significant amounts of lead or move it to the grains. An earlier EU study of 612 rice samples found lead in the few tens of ppb range. Consumer Reports sampled rice and rice-based products (e.g., rice cakes, rice drinks); a majority of the samples were under 5 ppb.
This episode is an excellent example of what is real in the environmental and toxic tort arena. One is no better than a well executed laboratory method that accurate AND precisely measures that which one is seeking to ascertain.
Articles on this topic can be found at: http://www.redorbit.com/news/health/1112829615/lead-in-rice-study-retracted-truth-about-heavy-metals-in/; http://www.bbc.co.uk/news/science-environment-22448696; http://www.prnewswire.com/news-releases/lead-in-rice-study-retracted-truth-about-heavy-metals-in-rice-revealed-204395941.html.