The Thai rice industry, already reeling from a staggering stockpile thanks to the government's rice pledging programme, took a body blow courtesy of an analysis of commercially available rice imported to the US that was found to contain levels of lead far higher than regulations suggest are safe.
The report at the annual meeting of the American Chemical Society was by a group of researchers led by Tsanangurayi Tongesayi, an associate professor of chemistry at Monmouth University in New Jersey, and noted the imports, which make up 7% of the rice consumed in the US, contained higher than acceptable levels of lead.
The levels ranged from 6 milligrammes per kilogramme to 12 mg/kg, factoring in average consumption, meaning estimated lead exposure levels of 30 to 60 times greater than the Food and Drug Administration's provisional total tolerable intake (PTTI) levels for children, and 20-40 times greater than the standard exposure levels for adults.
Rice from Taiwan and China contained the highest levels of lead, although rice from Italy, India, Thailand, Bhutan and the Czech Republic also contained levels higher than the PTTI. The researchers are continuing their sampling with rice from Pakistan and Brazil as well as other countries.
Lead exposure can negatively affect cognitive development and performance in children, while adults with high lead exposure can also experience problems with blood pressure, heart disease and calcium deficiency.
The researcher believes the rice became contaminated during growing and harvesting. Processing can potentially add some contaminants, but from what the group studied, it seems the contamination is coming from tainted soil and irrigation water.
The findings come after concerns about arsenic contamination in rice, but the researchers say this should not discourage people from eating rice. Instead, Mr Tongesayi and his colleagues hope their work increases consumer awareness about food safety and prompts more stringent oversight of imported products.
Chookiat Ophaswongse, honorary president of the Thai Rice Exporters Association, said the report, if true, would be like adding fuel to the fire for fading Thai rice exports.
"We've never heard such a report on lead contamination in rice before, but Thai rice shipments are already in trouble from the government's rice pledging scheme, which is expected to reach a stockpile of 18 million tonnes this year, in addition to the baht appreciation," he said.
Mr Chookiat said Thailand has shipped around 300,000 tonnes of rice to the US, 90% of which is Thai Hom Mali.
He questioned why the US researchers only studied imported rice and not domestically grown grains.
"We're wondering whether the study aims to justify the US slowing rice imports," he said.
Tikhumporn Natvaratat, deputy director-general of the Department of Foreign Trade, agreed, saying the authorities need to investigate the study.
"Personally I find the findings hard to believe, as we have shipped rice for 30-40 years to the US market, and the rice quality and safety standards are certified by qualified surveyors before each shipment," he said.