铀矿区周边典型食物中铅-210的污染特征及源解析研究

Lead-210 (Pb-210), as a highly toxic radionuclide from uranium decay chain, is one of the primary natural radionuclides of food radioactive contamination. With the intensified exploitation of underground uranium resources in recent years, the likelihood of food contaminated by Pb-210 is increasing. However, the activity concentrations and source of Pb-210 in food around the uranium mining area remain poorly understood. This project is conducted in the typical Qinglong uranium mining area in China. The activity concentrations of Pb-210 and lean isotopic compositions of some grain, vegetables, and environmental samples (soil, irrigation water and atmospheric dust) will be analyzed in detail. And then the contamination level and characteristics of Pb-210 in food in this area will be studied based on the methods of single factor, multiple pollution assessment and concentration ratio. Further, by means of lean isotope ratio technique and ternary mixed model, the relative contributions of soil, irrigation water and atmospheric dust on the activity concentrations of Pb-210 in food will be quantitatively determined to illustrate the main source of Pb-210 in food. This project aims to provide scientific evidences for accurately evaluating the internal radiation dose to the population caused by ingestion of the Pb-210 contaminated food as well as effectively preventing the Pb-210 contamination of food, and deepen the application of lead isotope ratio technique in the field of traceability of food contamination.

铅-210（Pb-210）作为放射性铀系中的一种高毒性放射性核素，是食物放射性污染的重要天然放射性核素之一。近年来，随着地下铀矿资源开采活动的加剧，食物Pb-210污染的可能性日益增加。然而，当前铀矿区周边食物中Pb-210的含量及其污染来源并不十分清楚。本项目选取我国代表性的青龙铀矿作为研究区域，详细分析矿区周边典型的粮食、蔬菜及环境介质（土壤、灌溉水和大气降尘）中Pb-210的含量和铅同位素组成。通过单因子、多重污染评价和浓集系数法，研究该地区食物中Pb-210的污染水平及污染特征；应用铅同位素比值技术，结合同位素三元混合模型定量判别土壤、灌溉水和大气降尘对食物中Pb-210含量的贡献，阐明食物中Pb-210的主要来源。本项目能够为铀矿区周边居民食入Pb-210所致的内照射剂量评估和有效防治食物Pb-210污染提供基础数据，深化铅同位素比值技术在食物污染源解析研究中的应用。

Pb-210作为放射性铀系中的一种高毒性放射性核素，是食物放射性污染的重要天然放射性核素之一，然而针对铀矿区周边食物中Pb-210的含量及其污染来源并不十分清楚。本项目通过分析铀矿区周边典型食物及环境介质中Pb-210的含量，评估了食物中Pb-210的污染水平及特征，结合铅同位素比值技术对食物中Pb-210的来源进行了分析。研究结果表明：1）谷子、山楂、白菜和萝卜中Pb-210的检出率比较高(≥50%)，其平均活度浓度分别为1.4Bq/kg、1.0Bq/kg、0.4Bq/kg和0.4Bq/kg，高于我国上世纪九十年代调查的食物中Pb-210的平均水平；2）不同食物对Pb-210的富集能力具有显著差异性，其中谷子、山楂、白菜和萝卜对Pb-210的富集能力较高，其浓集系数由大到小的顺序为白菜>萝卜>山楂>谷子；3）通过分析土壤、灌溉水和大气降尘中Pb-210的含量和铅同位素比值，发现土壤可能是食物中Pb-210的最主要来源。通过以上研究，初步了解了铀矿区周边食物中Pb-210的含量水平及其来源，为准确评价当地居民所受内照射剂量和有效防治食物Pb-210污染提供了科学依据。