环渤海典型重金属的环境行为及模拟预警研究
文献类型：学位论文
| 作者 | 徐笠
|
| 学位类别 | 博士 |
| 答辩日期 | 2014-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 吕永龙 |
| 关键词 | 近海地区 水源地 影响因素 温度 模型 Offshore area Water source Influence factor Temperature Model |
| 其他题名 | Environmental behaviour, simulation and warning of heavy metals in the typical areas along Bohai Coastal Region |
| 学位专业 | 环境科学 |
| 中文摘要 | 论文选取环渤海典型地区(近海地区和水源地)为研究区域，通过野外调研及采集、测定大量环境样品，借助于地统计与数理统计方法，研究了研究区域 7种重金属(Cu, Zn,Ni, Pb, As, Cr和 Cd)在沉积物和土壤中的污染特征、空间格局、赋存趋势和相互关系，揭示了土地利用类型、土壤理化性质，土壤酶活性等因素对重金属残留的影响及相互之间的关系。从区域温度因子出发，设计了室内营养液培养实验结合植物生理研究，探讨了不同温度条件(18℃, 24℃, 30℃)重金属(Cd和 Cu)在植物体内的分布特征和化学形态的变化特点，阐明了不同温度下幼苗期玉米生理活动与体内重金属的化学行为的相关关系。依据重金属的不同来源，利用 IDMM（Intermediate Dynamic Model for Metals）模型模拟了水源地流域农田中重金属的累积规律，并预测了该区域在不同情境下，未来50年的土壤重金属含量变化趋势，为区域生态风险评估和管理提供理论基础和科学依据。具体的结果如下： 1.环渤海近海地区的沉积物和土壤中的重金属含量较高区域主要集中在天津地区、山东界河流域地区和辽宁葫芦岛地区，上游沉积物的中大部分重金属的含量高于下游地区。沉积物中的 Cr和 Ni主要来自于自然风化，而其余 5种重金属主要来自于人为污染。土壤中的 Cr、Ni和 As主要来自于自然风化，而其余 4种重金属主要来自于人为污染。沉积物生态风险评估表明， Pb、Cu和 Zn三种重金属的污染较严重，土壤生态风险评估表明，重金属单因子生态危害程度为 Cd>Pb>As>Cu> Ni>Cr>Zn，在所有的土壤位点中，有 8个位点属于严重生态危害，有 2个点会造成重的生态危害。 2.官厅水库流域土壤中 Cu、Zn、Cr、Ni、Cd、Pb和 As的平均值为 16.8，59.4，37.8，18.3，0.32，20.1和 8.67 mg/kg。在四种土地利用类型中，Cu在果园中的含量最高，而其余 6种重金属含量均在农田中最高。在不同质地土壤中，As、Pb、Cd和 Cr的最大平均值发现于壤土中，而 Ni、Zn和 Cu的最大平均值发现于中轻壤土。As、Ni、Zn、Cu和 Cr的最大值均在石灰性褐土中，Ni、Cr和 Cu的平均值在三种土壤中的大小顺序为石灰性褐土>潮褐土>潮土，As和 Zn的平均值在三种土壤中的大小顺序为石灰性褐土>潮土>潮褐土。通过重金属与酶活性的相关性系数表明：重金属主要刺激了过氧化氢酶和脲酶的活性。 3.在 0 µM-100 µM范围内，低温处理下，随着 Cu的浓度的升高，玉米幼苗根的生物量先升高后降低。适中和高温处理下，随着 Cu的浓度的升高，玉米幼苗根的生物量逐渐下降，温度越高，生物量下降越多。在 0 µM-100 µM范围内，三种温度处理下，随着 Cu的浓度的升高，玉米幼苗根中 Cu的含量逐渐升高，同一浓度下，温度越高，根里面的 Cu含量越高(除 Cu浓度为 5µM时)。玉米幼苗根系中 Cu在亚细胞的分布特征表明：在 0 µM-100 µM范围内，Cu主要分布在热稳定蛋白部分和含完整细胞或组织的部分。当 Cu浓度升高时，高温处理下热稳定蛋白部分中的 Cu含量比例最高。在0µM-100 µM范围内，适中温度处理下的玉米幼苗根系中 SOD酶活性要高于低温和高温处理下玉米幼苗根系中 SOD酶活性。不同温度处理对 Cu胁迫下 SOD酶活性的影响要大于对 Cu胁迫下 POD酶活性的影响。不同温度处理下，玉米幼苗根系亚细胞中的Cu含量与酶活性相关性不一样。 4.三种温度处理下，在 0 µM-40 µM范围内，随着 Cd的浓度的升高，玉米幼苗根和地上部分的生物量都逐渐降低。三种温度处理下，温度越高，玉米幼苗根系中的Cd含量越高；而地上部分则是适中温度处理下 Cd含量较高。不同温度处理对 Cd胁迫下玉米幼苗矿质元素吸收的影响结果如下：在 0 µM-40 µM范围内，Cd促进了玉米幼苗对 Zn的吸收，Cd抑制了玉米幼苗对 Mn的吸收，Cd对植物吸收 Ca的影响则比较复杂。同温度处理下对 Cd胁迫下玉米酶活性的影响结果如下：在 0 µM-40 µM范围内，Cd的存在刺激的玉米幼苗根和地上部分的 SOD和 POD酶的酶活性，除了高温处理下玉米幼苗地上部分 Cd对 SOD的影响。 5.经过与实际测定值的比较，结果表明：IDMM模型能够很好的预测研究区域土壤中 Cu、Cd和 Zn的累积情况。根据模型的预测结果以及相应的土壤易被吸收态的临界值，我们发现，Zn是该区域在 2060年的主要的风险源。在所有的重金属来源里面，大气沉降是所占的比例最大，所以控制该区域由大气沉降带来的 Zn污染将是今后一段时间内管理部分的工作重点。 |
| 英文摘要 | Two tyical areas in Bohai coastal region were selected as study areas. Lots of environmental samples were collected through field investigation. The residual characteristics, spatial pattern and ecological risk of Cu, Zn, Ni, Pb, As, Cr and Cd in sediments and soils were studied by geostatistical analysis and mathematical statistics methods. The relationships between soil metals concentrations and land uses, soil texture, soil type and soil enzyme activity were investigated. As we know, the temperture will affect the metal environmental behavior. So, indoor simulation experiments were designed to study the distribution characters of Cadmium and Copper in corn seedling at differernt temperatures (18℃, 24℃,30℃). The relationships between chemical behavior of metals and physiological activity in corn seedling at differernt temperatures were also investigated. The accumulation rules of metals in farmland soils along the watershed of Guanting Reservior were simulated by IDMM model based on differernt metal sources. The variation tendency of soil metals in the next 50 years at differernt scenario was also predicted. The results will offer theoretical basis and scientific basis for regional ecological risk assessment and management. The specific results were as follows: 1. The high concentrations of metals in sediments and soils along the offshore area of Bohai coastal region were mainly located in Tianjin City, Jie River watershed of Shandong Province and Huludao city of Liaoning Province. Most metals mean concentrations in the sediments from upstream area were higher than the downstream area. The Cr and Ni in sediments were mainly from natural wearhering, the rest 5 metals were mainly from anthropogenic sources. In soil, Cr, Ni and As were primarily natural sources, and Cu, Zn, Cd and Pb were mainly from anthropogenic sources. Pb, Cu and Zn were contaminated heavily in sediments based on ecological risk assessment. The soil ecological risk assessment indicated that the ecological damage of every metal were decreased in the order of Cd>Pb>As>Cu> Ni>Cr>Zn. In 73 soil samples, 8 sites have high ecological risk from metals, 2 sites have considerable ecological risk from metals. 2.The mean concentrations of Cu, Zn, Cr, Ni, Cd, Pb and As in soil along the watershed of Guanting Reservoir were 16.8，59.4，37.8，18.3，0.32，20.1and 8.67 mg/kg, respectively. In four kinds of land uses, the largest average values for Cu (19.4 mg/kg dw) were found in orchard soils, however the largest average values for rest metals existed in farmland soils. The highest mean levels of As, Pb, Cd and Cr were found in loamy soil, and the largest average concentrations of Ni, Zn and Cu were found in light loamy soil. The highest levels of As, Ni, Zn, Cu and Cr were found in the CCS. The mean concentrations of Ni, Cr and Cu decreased in the order of CCS > FCS > FAS, while the average contents of As and Zn decreased in the order of CCS > FAS >FCS. On the basis of the relationships between the metals concentrations and enzymatic activity, metals mainly stimulated the activity of catalase and urease. 3.The biomass of corn seedling root increased from 0 µM to 5 µM, and then decreased from 5 µM to 100 µM under Cu stressed at 18℃. The biomass of corn seedling root decreased from 5µM with increasing Cu level at 24℃ and 30℃. The copper concentrations in the corn seedling root increased with increasing Cu level at 18℃, 24℃ and 30℃. At the same Cu concentration, higher temperature led to higher Cu accumulation in corn seedling root, except when Cu concentration was 5µM. The subcellular Cu distribution in the corn seedling root indicated that the HSP-Cu and the cell debris-Cu were the major subcellular fractions. When Cu concentration increased, the relative Cu distribution in the fractions of HSP were highest of all at 30℃. The SOD activity in the corn seedling root at 24℃ were higher than the SOD activity in the corn seedling root at 18℃ and 30℃. Different temperture affected SOD activity severely than POD activity under Cu stress. The SOD activity under Cu stress was more sensitive than POD activity under Cu stress to different temperture treatments. The relationships between subcellular Cu concentrations and enzymatic activity in the corn seedling root were changed by different temperture treatments. 4.The biomass of the root and shoot of corn seedling decreased with increasing Cd level at 18℃, 24℃ and 30℃.At the same Cd concentration, higher temperature would lead to higher Cd accumulation in corn seedling root, however, higher Cd concentration in the shoot were found at 24℃.The mineral element absorption by corn seedling under Cd stress at different temperture treatments indicated that Cd would promote Zn uptake by corn seedling, Cd would restrain Mn uptake by corn seedling, Ca absorption by corn seedling affected by Cd were very complicated. The enzymatic activity of corn seedling under Cd stress at different temperture treatments indicated that the SOD and POD activity of the root and shoot of corn seedling were promoted by Cd, except SOD activity of the shoot of corn seedling at 30℃. 5. Compared to measured values indicated that the IDMM model could simulate the accumulation of Cu, Cd and Zn perfectly in the farmland soils in the study area. According to the prediction results and relevent critical limits values of labile Cu and Zn, we found that Zn could be the main source of risks in the 2060. Atmospheric deposition was the most important source of Cu, Cd and Zn in the study area. To control the atmospheric deposition of Zn in the study area will be the most important task for the local government in the next 50 years. |
| 公开日期 | 2015-07-07 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/15636]  |
| 专题 | 生态环境研究中心_城市与区域生态国家重点实验室 |
| 推荐引用方式 GB/T 7714 | 徐笠. 环渤海典型重金属的环境行为及模拟预警研究[D]. 北京. 中国科学院研究生院. 2014. |
入库方式： OAI收割
来源：生态环境研究中心
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