Analytical study of 226Ra activity concentration in market consuming foodstuffs of Ramsar, Iran

BACKGROUND Ramsar, a city of Iran located on the coast of the Caspian Sea, has been considered to be enormously important due to its high natural radioactivity levels. People living in High Level Natural Radiation Areas (HLNRAs) have been exposed by several sources, one of which could be foodstuff. However, many studies have been carried out to measure the environmental radioactivity in Ramsar, but no survey has been conducted in all stapled consumed foods yet. This study was dedicated to determine 226Ra activity concentration in the daily diets of Ramsar residents as a probable exposure. METHODS Approximately 70 different market samples were collected during the four seasons based on the daily consumption patterns of residents which have the highest consumption and their availability in the seasons. All samples, after washing, drying and pretreatment, were analyzed for 226Ra radionuclide determination by α-spectrometry. RESULTS The mean radioactivity concentration of 226Ra ranged between 7 ± 1 mBq Kg-1 wet weight in meat, and 318 ± 118 mBq Kg-1 for tea dry leaves. The 226Ra activity concentrations in collected samples varied from below the minimum detectable activity up to 530 ± 30 mBq Kg-1. To compare the results with United Nations Scientific Committee on Effects of Atomic Radiation (UNSCEAR) reference values, the 226Ra activity concentrations concluded from the results appear to be higher in milk, chicken and eggs and less in grain products, vegetables, fruits and fish products. These results indicate that no significant 226Ra contamination is present in market foodstuffs and provide reference values for the foodstuffs in Ramsar. CONCLUSIONS Of the total daily dietary 226Ra exposure from market consuming foodstuffs for adults in Ramsar, the largest percentage was from wheat. The residents consuming wheat and manufacturing wheat products such as bread, pasta, porridge, crackers, biscuits, pancakes, pies, pastries, cakes, cookies, muffins, rolls, doughnuts, breakfast cereals and so on may receive an elevated dose in the diet. In conclusion, with regards to presence of 226Ra in foodstuffs it is necessary to monitor regularly the activity of 226Ra in foodstuffs including market and local foods.