某氯碱厂污染场地土壤—地下水典型污染物污染特征及风险评估

发布时间：2018-07-11 14:24

本文选题：污染场地 + 典型污染物　；参考：《济南大学》2017年硕士论文

【摘要】：随着中国经济发展和城镇化进程的加快,城市中的土地性质的变更愈发频繁,许多城市的发展规划要求原城区中的工厂和企业迁入工业集中区,而原有工业用地逐步被规划开发为住宅或公共建设用地。工业企业生产过程中遗留的污染物可能对场地土壤、地下水等造成影响,危害人体健康。鉴于此情,为保障工业企业污染场地再利用安全,须对污染场地进行污染调查和风险评估。本文研究区域为原氯碱厂污染场地,拟改造为住宅用地,原氯碱厂主要采用电石法工艺生产聚氯乙烯。为保证土壤质量满足未来用地要求,保障敏感人群健康,本论文根据《展览会用地土壤环境质量评价标准(暂行)》、《场地土壤环境风险评价筛选值》、《地下水质量标准》等相关标准以及《污染场地风险评估技术导则》的技术要求,对研究场地开展环境现状调查,对污染场地土壤和地下水中典型污染物的浓度水平、空间分布特征、污染来源进行了研究,并开展了基于人体健康的风险评价,提出场地修复的建议目标值,以期为后续的场地修复、管理提供技术支持。主要研究成果如下:(1)研究场地土壤中超标污染物有镍、汞、铜、苯、三氯甲烷,其中汞、苯、三氯甲烷污染物超标相对严重,最大超标倍数分别为23.8倍、5.05倍、37.3倍;地下水中超标污染物有铁、氯化物、挥发酚类(以苯酚计),最大超标倍数分别为3.15倍、11.6倍、35.4倍。(2)研究场地土壤中污染物的分布存在典型的空间差异,与原厂区原料贮藏、生产活动过程、生产区域等高度相关,污染物浓度随土壤采样深度的增加呈整体降低趋势,个别采样点出现一定跳跃,与局部土层扰动有关;场地地下水中污染物的超标现象主要与原厂区卤水接收厂及生产活动污水排放有关,且由于污染物随地下水径流的主流迁移,位于地下水径流下游的监测井污染物超标相对较重。(3)场地健康风险评价结果表明,土壤中污染物苯、三氯甲烷的致癌风险超出可接受致癌风险水平(致癌风险范围分别为2.22×10-8~4.80×10-5和2.10×10-7~7.91×10-5),汞、苯污染物的危害指数超出可接受非致癌危害商(总危害指数范围分别为1.11×10~(-1)~7.57×100和3.66×10-3~3.89×100),需要进行土壤修复;场地地下水中污染物经三种地下水暴露途径的危害指数未超出可接受非致癌危害商,不存在非致癌风险,不会危害人体健康,但鉴于监测井中部分污染物未达到地下水Ⅱ类水质标准,不宜作为饮用水源。(4)对超出可接受风险水平,可能对人体健康产生危害的汞、苯、三氯甲烷污染物,计算基于致癌效应和非致癌效应的土壤风险控制值,并结合《场地土壤环境风险评价筛选值》中住宅用地的标准限值,确定基于健康风险的土壤修复建议目标值为:汞:2.41mg.kg~(-1),苯:0.02mg.kg~(-1),三氯甲烷:0.035mg.kg~(-1)。
[Abstract]:With the acceleration of China's economic development and urbanization, the changes in the nature of land in cities become more and more frequent. The development plans of many cities require factories and enterprises in the original urban areas to move to industrial concentration areas. And the original industrial land is gradually planned for residential or public construction land. The pollutants left over in the production process of industrial enterprises may affect the soil and groundwater of the site and endanger human health. In view of this situation, pollution investigation and risk assessment should be carried out to ensure the reuse safety of contaminated sites in industrial enterprises. In this paper, the original chlor-alkali plant pollution site, to be transformed into residential land, the original chlor-alkali plant mainly uses calcium carbide process to produce PVC. In order to ensure the quality of soil to meet the future land requirements and protect the health of sensitive people, In this paper, according to the relevant standards such as the Evaluation Standard of soil Environmental quality of Exhibition Land (temporary) >, the screening value of site soil Environmental risk Assessment, the Standard of groundwater quality, and the technical requirements of Technical guidelines on risk Assessment of polluted sites, etc. The environmental status of the study site was investigated, the concentration level, spatial distribution characteristics, pollution sources of typical pollutants in contaminated soil and groundwater were studied, and the risk assessment based on human health was carried out. The suggested target value of site restoration is put forward in order to provide technical support for subsequent site restoration and management. The main research results are as follows: (1) the pollutants in the soil of the study site are nickel, mercury, copper, benzene, trichloromethane, among which mercury, benzene and trichloromethane are relatively serious, the maximum excess multiple is 23.8 times, 5.05 times and 37.3 times respectively; The pollutants in groundwater are iron, chloride, volatile phenols (based on phenol), and the maximum surpassing times are 3.15 times, 11.6 times and 35.4 times respectively. (2) there are typical spatial differences in the distribution of pollutants in the soil of the site, which are stored with raw materials in the original plant area. The concentration of pollutants decreased with the increase of soil sampling depth, and a certain jump appeared in individual sampling points, which was related to the disturbance of local soil layer. The phenomenon of exceeding the standard of pollutants in ground water is mainly related to the discharge of wastewater from brine receiving plants and production activities, and the pollutants migrate with the main stream of groundwater runoff. The pollutants in monitoring wells located downstream of groundwater runoff are relatively heavy. (3) the results of site health risk assessment show that benzene is a pollutant in soil. The carcinogenic risk of trichloromethane exceeds the acceptable level of carcinogenic risk (2.22 脳 10 ~ (-8) 4.80 脳 10 ~ (-5) and 2.10 脳 10 ~ (-7) 渭 m 7.91 脳 10 ~ (-5), mercury, The hazard index of benzene pollutants exceeds the acceptable non-carcinogenic hazard quotient (the total hazard index ranges from 1.11 脳 10 ~ (-1) to 7.57 脳 100 and 3.66 脳 10 ~ (-3) C ~ (3.89 脳 100) respectively) and requires soil remediation. The hazard index of pollutants in ground water by three ways of groundwater exposure does not exceed the acceptable non-carcinogenic hazard quotient, and there is no non-carcinogenic risk and will not endanger human health. However, in view of the fact that some of the pollutants in the monitoring wells do not meet the water quality standards of groundwater class II and are not suitable for drinking water. (4) pollutants of mercury, benzene and trichloromethane, which are above acceptable risk levels and may cause harm to human health, The soil risk control value based on carcinogenic effect and non-carcinogenic effect was calculated, and the standard limit value of residential land was combined with the screening value of site soil environmental risk evaluation. The recommended target values for soil remediation based on health risk were: Mercury: 2.41 mg 路kg-1, benzene: 0.02 mg 路kg-1, trichloromethane: 0.035 mg 路kg-1.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X781.2

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