华东某铀矿区稻米中放射性核素铀污染特征及健康风险评价

CONTAMINATION CHARACTERISTICS AND HEALTH RISK ASSESSMENT OF RADIONUCLIDE URANIUM IN RICE OF A URANIUM MINE IN EAST CHINA

为查明华东某铀矿区稻米中放射性核素铀污染现状及健康风险问题,测定铀矿区和对照区共136件稻米样品中放射性核素U含量,采用单因子污染指数法评价放射性铀污染,并开展U元素健康风险评价。结果表明:(1)研究区稻米中U含量平均值为1.46 ng·g^(–1),各亚区稻米中U含量平均值从大到小顺序为:开采矿井区>水冶场区>含矿未采区>废弃矿井区>江西省背景值>对照区;(2)稻米单因子污染指数为1.25,属于轻度污染。其中,开采矿井区和水冶厂区为轻度污染,废弃矿井区和对照区未受污染;(3)首次计算提出江西省大米U元素致癌风险最大斜率系数为1.04×10~3(d·kg)·mg^(–1)。各亚区稻米中成人和儿童致癌风险指数高低顺序均为:开采矿井区>水冶厂区>含矿未采区>废弃矿井区>对照区。儿童直接饮食稻米具有一定的致癌风险;开采矿井区和水冶厂区的成人存在一定致癌风险,含矿未采区和废弃矿井区以及对照区均无致癌风险。

In order to detect the contamination and health risk of radionuclide uranium in rice from a uranium mine in East China, a total of 136 rice samples from uranium deposit area and contrast area were analyzed. The method of Single Factor Index was used for assessing rice and carcinogenic risk （CR） for health risk of radionuclide uranium. The results showed that： （1） The average uranium concentrations in rice were 1.46 ng·g-1, with an order of exploiting mine area〉hydrometallurgy plant area〉unexploited deposit area〉abandoned mine area〉the background values of Jiangxi Province〉contrast area. （2） The average value of Single Factor Index （1.25） showed that the uranium contamination levels of rice in the whole uranium deposit area were mild concentration. The exploiting mine area and hydrometallurgy plant area were mild concentration and unpolluted in abandoned mine area and contrast area. （3） For the first time, the Slope factor（SF） of carcinogenic risk of rice in Jiangxi Province was 1.04× 10^3（d.kg）.mgl.The CR among adults and children in all sub regions both were exploiting mine area〉hydrometallurgy plant area〉unexploited deposit area〉abandoned mine area〉contrast area. By directly consuming rice, children might suffer a certain carcinogenic risk, and no risk for adults in unexploited deposit area, abandoned mine area and contrast area, a certain carcinogenic risk in exploiting mine area and hydrometallurgy plant.