【作者】 陆强；

【导师】 林匡飞；

【作者基本信息】 华东理工大学 ， 环境科学与工程， 2016， 博士

【摘要】 氯代脂肪烃（CAHs）作为高效的有机脱脂溶剂,广泛地用在金属表面的清洗上,由于不恰当的使用和无组织的排放,造成土壤和地下水的污染,特别是在地下水埋藏较浅,制造业较发达的长三角地区,更易出现CAHs污染场地,而高毒性和高挥发性的CAHs对生态环境和人体健康都存在危害。因此,针对长三角地区,开展典型行业CAHs污染场地调查监测及其对生态环境和人体健康风险的研究显得尤为必要和重要。本研究选取了上海某典型制造业CAHs污染场地为对象,在建立了土壤和地下水中CAHs分析检测方法的基础上,首先调查分析了该场地的土壤地质条件和水文地质条件,详细采样检测了土壤和地下水中的CAHs的组成和含量,系统阐述了土壤和地下水中CAHs的水平和垂直分布特征,在此基础上,通过建立场地人体健康风险概念模型,评估了土壤和地下水中CAHs对人体的健康风险；接着根据地下水中CAHs的跟踪监测,结合地下水中环境因子的存在特点,阐释了地下水中CAHs的自然衰减规律,并依此为基础,利用模型预测了地下水中CAHs的迁移转化规律；最后采用生态毒理学手段探讨了地下水中CAHs的环境毒理效应,以期结合人体健康风险全面判定场地CAHs的污染程度,为进一步的修复工作提供详实可信的基础数据。主要结论如下：（1）根据场地1,1,1-TCA历史污染情况,将该场地分为五个疑似污染区（A1,A2,A3,A4,A5）,布置了56个土壤采样点和对应的地下水监测井,调查分析土壤地质条件和水文地质条件,结果显示该场地的地层结构为回填土、粉质粘土/粘质粉土、砂质粉土、淤泥质粉质粘土、淤泥质粘土、粉质粘土和砂质粉土。在粉性土层中,水平渗透系数是垂直渗透系数的1.7到4.5倍（地面5 m以下的砂质粉土）。在粘土地层中,水平渗透系数和垂直渗透系数总体上较为接近。粉土地层（粘质粉土或砂质粉土）的渗透系数约为其下面的粘土地层（粉质粘土或粘土）的1-2个数量级。场地内浅层地下水流向总体上由东南流向西北,地下水流动不明显,地下水标高总体上在2.70 m到3.35 m之间,相差较小。承压含水层分布在淤泥质粘土层。浅层地下水的水平水力梯度大约在0.0010-0.0040 m/m之间。垂直水力梯度变化幅度较大,以监测井中滤管中间位置的距离计,从0.3 m到1.2 m向下垂直距离为4.1 m到7.6 m。（2）在56个点位中详细采样检测了土壤和地下水中CAHs的含量,结果表明,土壤和地下水中均检测到二氯代物和一氯代物,共有五种CAH,分别是1,1,1-TCA、1,1-DCA、 1,1-DCE、CA和VC。水平方向上,场地土壤中的CAHs集中分布在1,1,1-TCA清洗单元,该区域土壤CAHs含量最大值为2920312.00μg·kg^-1,其余区域土壤含量均值范围为3618.30μg·kg^-1-40007.50μg·kg^-1；场地地下水CAHs的分布特征与土壤类似水平分布,污染主要集中在老清洗单元A2和新清洗单元A3区域。该区域地下水CAHs含量最大值为1701700.00 μg·L^-1,其余区域地下水含量均值范围为232739μg·L^-1-81442.23.50μg·L^-1。造成土壤和地下水CAHs水平分布特点的可能原因是清洗单元在用1,1,1-TCA清洗金属表面的时候,可能存在不规范的操作,使得较大剂量的1,1,1-TCA泄露到地面,通过长时间的迁移扩散和积累,造成了土壤和地下水的严重污染。地面上贮存1,1,1-TCA桶罐的区域一般情况下不会出现桶罐倾倒的事故,很大的可能性是由于地下水的流动导致了这几个区域土壤的污染。垂直方向上,浅层土壤中CAHs的浓度远低于深层土壤（淤泥质粘土以上）中CAHs的浓度,在渗透系数较高的土层中,CAHs有较好的迁移能力,这可能与其本身密度较大、穿透性较好、脂溶性较强的理化性质有着密切关系；地下水中发现了DNAPL,DNAPL主要集中于地下6m-8m处,该处为淤泥质粉质粘土层上部的砂质粉土层。DNAPL污染范围总体上东西向80 m左右,南北向24 m左右,面积大约为1400 m2,而整个A2区域CAHs的污染面积大概为4500m2。DNAPL应该是A2区域的污染源,其源源不断地溶解到地下水中,造成周围区域地下水的污染。（3）在场地土壤地质和水文地质条件以及土壤和地下水中CAHs含量的基础上,建立了场地人体健康风险概念模型,评估了土壤和地下水中人体健康风险,结果显示,土壤和地下水中的污染源为五种CAH,其中1,1-DCA和VC具有致癌风险。土壤中CAHs的暴露途径为口腔摄入、皮肤接触和呼吸吸入,地下水中CAHs的暴露途径为呼吸吸入。暴露受体为厂区职工。根据风险评估,发现共有16个点位的土壤和地下水中CAHs的致癌风险和非致癌危害超过可接受水平（致癌风险：10-6,非致癌危害：1）,计算得出土壤和地下水中CAHs的风险控制值,分别为：土壤-VC 0.56 mg·kg^-1、CA 213 mg·kg^-1、 1,1-DCE 54 mg·kg^-1、1,1-DCA 5.8 mg·kg^-1、1,1,1-TCA 1865 mg·kg^-1；地下水-VC 0.79 mg·L^-1、CA3.26 mg·L^-1、1,1-DCE 2.27 mg·L^-1、1,1-DCA 1.67 mg·L^-1、1,1,1-TCA2.88 mg·L^-1。（4）结合地下水中环境因子的存在特点,多因子分析了地下水中CAHs与环境因子的关系,并对地下水中环境因子和CAHs含量进行了跟踪监测。结果表明,地下水中氯离子的累积说明CAHs在地下水中发生了自然衰减。该场地形成的CAHs污染羽分布,可能主要是由于污染源和自然衰减两个因素形成的。随着时间的推移,地下水中电导率和氯离子含量呈现增大的趋势。电导率与氯离子含量之间存在较好的正相关线性关系,通过这个线性关系可以根据电导率的数值推测氯离子的含量,为地下水的水质监测提供理论依据。该场地地下水中的主要污染物为1,1,1-TCA、1,1-DCA和CA,随着时间的推移,1,1,1-TCA和1,1-DCA浓度逐渐减小,当地下水中存在1,1,1-TCA和1,1-DCA的时候,CA浓度持续增大,一旦地下水中的1,1,1-TCA和1,1-DCA完全脱氯,CA将发生脱氯反应,浓度开始降低。CAHs较易发生一级脱氯反应,较难发生二级脱氯反应。脱氯指数的研究表明,当地下水中CAHs总量较高时,脱氯指数普遍较低,可能的原因是高浓度的CAHs抑制了以微生物为主要脱氯途径的自然衰减的过程,高浓度的CAHs本身对微生物的毒理效应降低了脱氯微生物的活性。利用Visual MODFLOW预测模型模拟出15年左右1,1,1-TCA污染羽扩散到厂区西边界,最高浓度从9000000 μg·L^-1左右下降到1000000μg·L^-1左右；1,1-DCA经过20年左右最高浓度从200000 μg·L^-1左右下降到80000 μg·L^-1左右；25年后,CA最高浓度从150000 μg·L^-1左右下降到50000 1μg·L^-1左右。（5）采用发光细菌急性毒性和酶活性的手段探讨了地下水中CAHs的环境毒理效应。结果表明,发光细菌急性毒性随着CAHs总量增加而增强。从发光细菌毒性的角度初步分析,当地下水中CAHs含量低于1000μg·L^-1时,其对地下水生态毒理效应较低,对地下水生态系统的危害较小,可以不用考虑CAHs的生态毒理；当地下水中CAHs总量大于1000 gg·L^-1时,要开始关注CAHs对地下水生态系统造成的毒理效应。总体上,CA的发光细菌毒性比1,1,1-TCA和1,1-DCA的发光细菌毒性大,在考虑生态风险的时候,建议重点关注CA的风险。由于1,1,1-TCA和1,1-DCA的毒性大小关系不明显,也应一并关注。乳酸脱氢酶、碱性磷酸酶和蛋白酶的活性随着CAHs总量的减少而升高,当CAHs总量减少至200 μg·L^-1以下时,三种酶的活性有个较大幅度的升高,且之后随着CAHs总量减少酶的活性升高缓慢。从三种酶活性的角度分析,当地下水中CAHs含量低于200 μg·L^-1时,其对地下水生态毒理效应较低,可以不用考虑CAHs的生态毒理；当地下水中CAHs总量大于200 μg·L^-1时,要开始关注CAHs对地下水生态系统造成的毒理效应。以期结合人体健康风险全面判定场地CAHs的污染程度,为进一步的修复工作提供详实可信的基础数据。更多还原

【Abstract】 As an efficient organic solvent degreasing, CAHs were widely used in metal surface cleaning. However, due to the inappropriate use and unorganized emissions, CAHs lead to soil and groundwater pollution, especially in the shallow groundwater in Yangtze river delta region where manufacturing was developed. There were more likely to appear CAHs contaminated site, CAHs were highly toxicity and highly volatile, harmful to ecological environment and human health. Therefore, for the Yangtze river delta region, it’s necessary and important to carry out investigating and monitoring the typical CAHs polluted site, and study the risk of CAHs to the ecological environment and human health.In this study, we selected a typical CAHs of manufacturing contaminated site in Shanghai as an object, on the basis of analysis method for CAHs in soil and groundwater. First, investigated and analyzed the geological conditions and the hydrogeological conditions in the soil:Second, sampled and tested the concentration of CAHs in soil and groundwater, and made sure the horizontal and vertical distribution characteristics of CAHs in soil and groundwater. On this basis, established the human health risk model to evaluate the risk of CAHs in soil and groundwater to the health of human; Then, according to the monitoring of CAHs in groundwater, combined with the characteristics of the existence environmental factors in groundwater, elaborated the natural attenuation regularity of CAHs in groundwater, predicted CAHs migration transformation rule in the groundwater by using this model; Finally, discussed the environmental toxicology effect of CAHs in the groundwater by using ecotoxicology, combined with human health risk comprehensive to judge the CAHs pollution level of the site, provided detailed reliable basis for further repair work data. As follows were the main conclusions:（1） According to history contamination condition of 1,1,1-TCA in the site, divided the site into five suspected pollution areas （A1, A2. A3. A4, A5）, set up 56 soil sampling points and the corresponding groundwater monitoring well, investigated and analyzed the geology and hydrogeology conditions of the soil. The results showed that the stratigraphic structure of the site were backfill soil, silt clay/clayey silt, sandy silt muddy silt clay, silt, clay and silt clay and sandy silt. In the silt clay layer, the horizontal permeability coefficient was 1.7 to 4.5 times as that of vertical permeability coefficient （5 m below ground was sandy silt）. In the clay layer, horizontal permeability coefficient was close to vertical permeability coefficient. The permeability coefficient of the silt layer （glue powder soil or sandy silt） was one or two orders of magnitude to that of the underneath clay stratum （silt clay or clay）. On the whole, the shallow groundwater flew from southeast to northwest, the groundwater flow wasn’t obvious, the scale height of groundwater was between 2.70 m to 3.35 m. Confined aquifer distributed in the silt clay layer. The horizontal hydraulic gradient of the shallow groundwater was between 0.0010 to 0.0040 m/m. The vertical hydraulic gradient change was obvious, from one well to the neighbor, down from 0.3 m to 1.2 m vertical distance was 4.1 m to 7.6 m.（2） Detailed sampling in 56 points and tested the concentration of CAHs in soil and groundwater, the results showed that there had two-chlorinated aliphatic hydrocarbons and one-chlorinated aliphatic hydrocarbons in soil and groundwater. There were five kinds of CAHs which respectively were 1,1,1-TCA,1,1-DCA,1,1-DCE, CA and VC. Horizontally, the CAHs centrally distributed in the 1,1,1-TCA cleaning unit, the maximum concentration of CAHs was 2920312.00 μg·kg^-1 in this area, the average range of CAHs concentration was 3618.30 μg·kg^-1 -40007.50 μg·kg^-1 in the rest regional; The horizontal distribution of CAHs in the groundwater was similar to that in the soil. Pollution was mainly concentrated in the old cleaning unit A2 and new cleaning unit A3. The maximum concentration of CAHs was 1701700.00 μg·L^-1 in groundwater of this area, the average range of CAHs concentration was 2327.39 μg·L^-1 81442.23.50 μg·L^-1 in the rest regional. The main reason of the horizontal distribution characteristics of CAHs in the soil and groundwater might be that there had inappropriate operation in the cleaning unit with 1,1,1-TCA cleaning the metal surface, made large doses of 1,1,1-TCA leaked into the ground, by a long time of diffusion migration and accumulation, caused serious pollution in soil and groundwater. There wasn’t appear tank dumping accidents in the ground storage area of 1,1,1-TCA, the soil pollution in these areas was possibly caused by the groundwater flowing. Vertically, the CAHs concentration in shallow soil was far lower than in the deep soil （above silt clay）, CAHs had good migration ability in high permeability coefficient soil, this might be because of its higher density, good penetrability, strong fat-soluble physical and chemical properties; It’s found that DNAPL in groundwater, DNAPL were main focused at 6 m-8 m underground, where was sandy soil layer upper the silt layer. The pollution range of DNAPL was overall around 80 m east to west, north to south about 24 m, the area was about 1400 m2, and the CAHs pollution area of A2 was about 4500 m2. DNAPL should be the pollution sources of A2 area, it continually dissolved into the groundwater and caused the pollution of groundwater in the surrounding area. （3） On the basis of soil geological, hydrogeological conditions of the site and the CAHs concentration in soil and groundwater, established the human health risk model, to evaluate the human health risk of soil and groundwater. The results showed that the pollution sources in soil and groundwater were five kinds of CAHs,1,1-DCA and VC had the risk of cancer. The exposed ways of CAHs in soil were oral intake, respiratory inhalation and skin contact, the exposure way of CAHs was respiratory inhalation. The exposed receptor were factory worker. According to the risk assessment, there had 16 points where the cancer risk and non-cancer hazard of a total of CAHs in soil and groundwater were higher than acceptable levels （cancer risk:10-6, carcinogenic hazards:1）, calculated the risk control values of CAHs in soil and groundwater, respectively:in soil-VC 0.56mg·kg^-1’, CA213 mg·kg^-1,1,1-DCE 54mg·kg^-1,1,1-DCA 5.8 mg·kg^-1,1,1,1-TCA 1865 mg·kg^-1; in groundwater-VC 0.79 mg·L^-1, CA 3.26 mg·L^-1, 1,1-DCE 2.27 mg·L^-1,1,1-DCA 1.67 mg·L^-1,1,1,1-TCA 2.88 mg·L（4） Combined with the characteristics of the existence groundwater environmental factors, analyzed the relationship between CAHs in groundwater and environmental factors using multiple factors, traced monitoring on the environmental factors and CAHs concentration in groundwater as well. The results showed that the accumulation of chlorine ions in groundwater meant the natural attenuation of CAHs in groundwater. The pollution sources and natural attenuation might be the two mainly factors that leaded to the distribution of CAHs in this site. Over time, the conductivity and the chloride ion concentration in groundwater increased. The relationship between chlorine and ion conductivity was good positive correlation, the concentration of chloride ions could be speculated by the conductivity of numerical through the linear relation, which provided the basis theoretical for monitoring of groundwater water quality. The main pollutants in the groundwater of this site were 1,1,1-TCA,1,1-DCA and CA, as time goes on, the concentration of 1,1,1-TCA and 1,1-DCA gradually decreased. When 1,1,1-TCA and 1,1-DCA existed in groundwater, the concentration of CA increased continuously. Once 1,1-TCA and 1,1-DCA in the groundwater were dechlorinated completely, CA would occur dechlorinating reaction, the concentration of CA would begin to reduce. It’s easy for CAHs to have level of dechlorinating reaction, but difficult to produce secondary dechlorinating reaction. Dechlorinating index showed that the concentration of CAHs was high in groundwater, the dechlorinating index was generally low, the possible reason was that high concentration of CAHs inhibited the main way of natural attenuation dechlorinating process of microorganisms, high concentrations of CAHs produced toxicology and effected on microorganism itself to low the activity of microorganisms. Using the Visual MODFLOW model simulated 1,1,1-TCA contamination spread to the west boundary in the 15 years or so. the highest concentrations decreased from about 9000000 μg·L^-1 to about 1000000 μg·L^-1; the highest concentration 1,1-DCA decreased from about 200000 μg·L^-1 to about 80000 μg·L^-1 after 20 years; the highest concentration of CA decreased from about 150000 μg·-1 to around 50000 μg·L^-1 in 25 years later. （5） Using acute toxicity of luminescent bacteria and enzyme activity to discuss the environmental toxicology effect of CAHs in groundwater. The results indicated that the acute toxicity of luminescent bacteria increased as the increase of CAHs concentration. Preliminary analysis from toxicity of luminescent bacteria, when the CAHs concentration was less than 1000 μg·L^-1 in groundwater, the ecological toxicology effect on groundwater was lower, the harm to ecosystem groundwater was less, the ecological toxicology of CAHs could be ignored; When the CAHs concentration was more than 1000 μg·L^-1 in groundwater, It’s necessary to pay close attention to CAHs toxicology effect on groundwater ecosystem.Overall, the luminescent bacteria toxicity of CA was higher than that of 1,1,1-TCA and 1,1-DCA. It’s necessary to pay more attention to the risk of CA, when considering the ecological risk. The relationship of toxicity between 1,1,1-TCA and 1,1-DCA was not obvious, both of them should be paid attention at the same time. The activity of lactate dehydrogenase, alkaline phosphatase and protease increased with the reduce of total concentration of CAHs, when the total concentration of CAHs dropped to less than 200 μg·L^-1 , the activity of this three enzymes increase highly, and then the enzyme activity increased slowly as the reducing of CAHs concentration. From the perspective of the activity of three kinds enzymes, when the CAHs concentration was less than 200 μg·L^-1 in groundwater, the ecological toxicology effected to the groundwater was low, the ecological toxicology of CAHs could be ignore; when the CAHs concentration was more than 200 μg·L^-1 in groundwater, the toxicology effects of CAHs on groundwater ecosystem should be pay close attention to. In order to combine with human health risk to judge the CAHs pollution level of the site comprehensively, providing detailed reliable basis data for further remediation work.更多还原