The U.S. Food and Drug Administration will try to develop a safety standard on arsenic found in rice.
The agency just released the results of a study of foods that showed that the amount of detectable arsenic is too low in the rice and rice product samples to cause any immediate or short-term adverse health effects.
The safety standard is important to Costa Ricans, who consume on average 56 kilos a year. Much of the local rice comes from areas where there is a high amount of naturally occurring arsenic in the groundwater.
Rice is particularly vulnerable to contamination because it is grown in water, taking up arsenic through its roots, the agency noted. The application of pesticides to rice also can contaminate the food with arsenic.
The Food and Drug Administration said it is not aware of any published quantitative assessment of risk for arsenic in rice.
Long-term exposure to arsenic has been associated with skin, lung, bladder, liver, kidney and prostate cancers, and low levels can cause skin lesions, diarrhea and other symptoms, according to other researchers. Arsenic also has been blamed for renal failure, and health authorities are looking into the deaths at a dialysis clinic in Cañas.
Some humans can develop an immunity to arsenic, but others can have their natural immunities to viruses reduced with exposure to the chemical, researchers have said.
Costa Rica does not check for arsenic in rice, officials have said.
The Food and Drug administration scientists tested the samples for levels of both organic and inorganic arsenic, the most toxic form of the chemical. They found the average levels of organic arsenic ranged from 2.6 to 7.2 micrograms per serving, with instant rice at the low end and brown rice at the high end of the range.
For inorganic arsenic, scientists found rice and rice products contain between .1 to 6.6 micrograms, with the lowest amount in infant formula and the highest levels of the toxic substance in rice pasta. A microgram is one-millionth of a gram. Serving sizes vary.
The Instituto Costarricense de Acueductos y Alcantarillados, the national water company, has been ordered by the Sala IV constitutional court to develop schemes to provide water low in arsenic to those areas of Guanacaste and northern Alajuela where there are higher concentrations.
In its June decision the court said that the World Health Organization sets the safe limit for human consumption of arsenic at 10 micrograms per liter of water. That’s 10 parts per billion. Acueductos y Alcantarillados provides water with up to 187 micrograms of arsenic per liter, said the court.
The Center for Safety and Applied Nutrition of the Food and Drug Administration said it will now analyze the risk to humans of eating arsenic contaminated rice and rice products, and ways to limit harm to vulnerable populations, including children and pregnant women. The results will be released after peer review, the agency said.