Groundwater contains naturally occurring radioactive materials (NORMs) through water–rock interactions. Although a recent study found that the NORMs are accumulated into the filters utilized in bottled mineral-water facilities, the accumulation mechanism and effects have rarely been studied. This study is, therefore, conducted to determine the mechanism of NORM accumulation in filters during water treatment processes and to provide a first estimate of the level of radiological risk for workers in five bottled-mineral-water facilities. The level of Rn-222 decreased dramatically at the first filters (FF) encountered after passing through water storage tanks, while surface radiation sharply increased. The increase of radioactivity on the FF was mainly caused by the accumulation of short-lived radon progenies through decay processes inside the water tanks. Although the estimated radiological risk was lower under certain circumstances compared to the public dose limit of 1 mSv yr−1, the radiological risk should be properly managed in case of direct and/or close handling of the used filters during filter replacement procedures.

中文翻译：

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天然存在的放射性物质在瓶装矿泉水设施过滤器中的积累机制和影响

地下水通过水-岩相互作用包含天然存在的放射性物质 (NORM)。尽管最近的一项研究发现 NORM 会积聚在瓶装矿泉水设施中使用的过滤器中，但很少有人研究积聚机制和影响。因此，本研究旨在确定水处理过程中过滤器中 NORM 积累的机制，并对五个瓶装矿泉水设施中的工人的放射性风险水平进行初步评估。在通过储水罐后遇到的第一个过滤器 (FF) 中，Rn-222 的水平急剧下降，而表面辐射急剧增加。FF 上放射性的增加主要是由于在水箱内通过衰变过程积累了短寿命氡后代。尽管在某些情况下估计的放射风险低于 1 mSv yr-1 的公共剂量限值，但在过滤器更换过程中直接和/或近距离处理使用过的过滤器的情况下，应妥善管理放射风险。