南方某铀矿山尾矿库周边水环境污染与评价

发布时间：2018-06-05 17:00

  本文选题：铀矿山 + 尾矿库　； 参考：《东华理工大学》2015年硕士论文

【摘要】：铀矿山开采过程中会产生的大量酸性废水和废渣均排到尾矿库中,由于酸性矿山废水和废渣一般都含有大量的重金属、放射性核素以及氟化物等有毒有害物质,对尾矿库周边地表水以及浅层地下水都会造成重大污染。本文选取南方某铀矿山尾矿库周边地表水及浅层地下水为研究对象,通过野外取样,室内测定等过程,研究了浅层地下水和地表水的水化学性质和形态,重金属及放射性核素的含量特征及分布,运用单指标评价法评价了水质量状况并对进行了污染评价。主要成果如下:(1)尾矿库的水化学类型表现为Ca SO_4型水,浅层地下水的水化学类型是Ca-Na-SO_4型水,且研究区浅层地下水的水化学类型很可能受到尾矿库的影响。研究区内浅层地下水p H为5.75-6.70,排放水p H为4.65-7.40,渗滤水p H为4.50-8.70。浅层地下水中TDS主要受Ca2+和F-的影响,与Na+和Mg2+呈较强的正相关关系,与Cl-和SO_42-呈弱正相关关系,与HCO3-呈负相关关系。(2)浅层地下水中Cd和Cr的相关系数达到0.714,在0.05水平上呈显著正相关,Cd和Pb的相关系数达到0.619,Cr和Pb的相关系数达到了0.625,互相都呈很强的正相关关系。地表水中,Cd和Pb的相关系数达到了0.725,两者在0.05水平上呈显著正相关,Cu和Cr的相关系数为0.595,也呈较强的正相关关系。(3)尾矿库排放水氟的含量均未达到排放要求;周边浅层地下水氟污染严重。影响铀尾矿库周边水系中氟含量的最主要因素是人为开采铀矿山,使氟元素释放进入水体。p H值、TDS以及气候条件对水系中氟含量影响可能较大,水系包括HCO3-在内其它阴阳离子对氟含量也有一定影响。(4)~(226)Ra在地下水中的迁移可能受到岩石的性质、生物吸附、温度、水化学特征、水动力条件等多种因素的影响。尾矿库排放水中~(226)Ra的浓度最高,达到5.73 Bq·L-1,可能是尾矿库周边地表水和地下水中~(226)Ra的主要污染源。(5)运用单指标评价法得出,研究区浅层地下水中Ⅴ类水占100%,不能直接饮用,需经过特殊处理后才能饮用。研究区地表水中Ⅴ类水占80%,需经过特殊处理后才能饮用,Ⅳ类水占20%,经适当处理后可饮用。研究区浅层地下水中U和NO_2~-的污染最为严重,超标率均达到100%,U污染最高倍数达到了112。氟化物的超标率达到85.71%,Pb的超标率达到14.29%。同样,研究区地表水中U、NO_2~-及氟化物的污染最为严重,超标率均达到100%,U污染最高倍数达到了219.3。NO3-的超标率达到20%。
[Abstract]:A large amount of acid waste water and waste residue produced in uranium mining process are discharged into tailings. Because acid mine wastewater and waste slag generally contain a large number of toxic and harmful substances, such as heavy metals, radionuclides, fluoride, etc. It can cause serious pollution to surface water and shallow groundwater around the tailings reservoir. In this paper, the surface water and shallow groundwater around the tailings reservoir of a uranium mine in the south of China are selected as the research objects. The hydrochemical properties and forms of the shallow groundwater and surface water are studied through field sampling and indoor measurement. The content and distribution of heavy metals and radionuclides were evaluated by single index evaluation method and pollution was evaluated. The main results are as follows: (1) the hydrochemical type of tailings reservoir is Ca SO_4 type water, and the hydrochemical type of shallow groundwater is Ca-Na-SO_4 type water, and the hydrochemical type of shallow groundwater in the study area is probably affected by the tailings reservoir. In the study area, the pH of shallow groundwater is 5.75-6.70, that of discharged water is 4.65-7.40, and that of leachate is 4.50-8.70. TDS in shallow groundwater is mainly affected by Ca2 and F-, and has strong positive correlation with Na and Mg2, and weakly positive correlation with Cl- and SO42-. The correlation coefficient of CD and Cr in shallow groundwater is 0.714, and the correlation coefficient of CD and Pb in shallow groundwater reaches 0.619, Cr and Pb at 0.05 level. The correlation coefficient between CD and Pb is 0.625, and there is a strong positive correlation between CD and Cr. The correlation coefficient of CD and Pb in surface water is 0.725, and the correlation coefficient of Cu and Cr is 0.595.The correlation coefficient of Cu and Cr is 0.595. The fluorine pollution of peripheral shallow groundwater is serious. The main factor affecting the fluorine content in the water system around the uranium tailings reservoir is the artificial mining of uranium ore mountains, which releases fluorine elements into the water body. The pH value of TDs and the climatic conditions may have a great influence on the fluoride content in the water system. The migration of 226Ra in groundwater may be affected by the properties of rocks, biosorption, temperature, hydrochemical characteristics, hydrodynamic conditions and so on. In the tailings reservoir, the highest concentration of Tempe 226Ra is 5.73 Bq / L -1, which may be the main source of pollution in the surface water and groundwater around the tailings reservoir. (5) by using the single index evaluation method, it is concluded that in the shallow groundwater of the study area, V type water accounts for 100% and cannot be drunk directly. It needs special treatment before drinking. In the surface water of the study area, the proportion of class V water is 80%, which needs special treatment before drinking, and the proportion of category 鈪，

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