Toxic rice harvested in southwestern Bangladesh
[DHAKA] Eating rice grown in southwestern Bangladesh could be as dangerous as drinking arsenic-contaminated water, according to research published last week (7 July).
The study, published online by Environmental Science & Technology, was the first detailed look at arsenic levels in food typically eaten in Bangladesh.
Lead researcher Andy Meharg of the University of Aberdeen, United Kingdom, says that health experts are underestimating arsenic intake and misjudging cancer rates by not considering people's dietary exposure from rice.
Many of the country's water supplies have exceptionally high levels of the toxic metal, which is linked to widespread health problems including skin diseases and cancer.
But as contaminated groundwater is also used to irrigate rice fields, Bangladesh's main subsistence food is making a significant contribution to dietary exposure to the toxin say the researchers.
The team measured arsenic levels in various vegetables, pulses and two types of rice grown in 25 districts. In only one district did rice contain, on average, less than 0.08 micrograms of arsenic per gram.
A typical daily intake of rice containing this much arsenic is the equivalent of drinking water with the maximum level of arsenic deemed safe by the World Health Organization, say the researchers.
But in most of the districts sampled, rice contained much more arsenic, rising to 0.51 micrograms per gram in Faridpur district.
"The situation is worst for subsistence farmers in the high arsenic regions as they both drink high levels of arsenic in the water and ingest it from rice," Meharg told SciDev.Net, adding that between 25 and 50 per cent of the country is affected.
"Even if drinking water were cleaned up tomorrow, the rice would still be contaminated for many years to come," he says. "It would be very difficult to find alternative sources of irrigation water for [rice fields] and, therefore, arsenic levels in rice will increase year on year."
Ainun Nishat of the National Arsenic Expert Committee says local research institutions should try to confirm the findings independently as they could have major implications for Bangladesh's water policy.
He notes that 70 per cent of all irrigation is through shallow tube wells that tap groundwater, much of which is contaminated with arsenic.
Mahmudur Rahman of the Dhaka Community Hospital Trust, who is also on the committee, says the UN Food and Agriculture Organization and World Health Organization should set safe limits of arsenic contamination in food, especially rice.