| 题名 | 基于砷、汞形态的生态风险评价研究 |
| 作者 | 杜萌 |
| 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 | 杜宇国,魏东斌 |
| 关键词 | 砷 汞 形态 毒性 生态风险评价 arsenic mercury species toxicity ecological risk assessment |
| 其他题名 | Ecological risk assessment of arsenic and mercury based on different species |
| 学位专业 | 环境科学 |
| 中文摘要 | 砷、汞是两种典型的重金属污染物，它们在自然界中以多种形态存在。由于重金属的形态不同，其毒性特征也存在较大差异，所引起的生态风险迥异。本文选取重金属污染物砷、汞为研究对象，首先收集、整理了不同形态砷、汞的毒性数据，借助物种敏感度分布等方法，计算出了不同形态砷、汞的预测无效应浓度阈值（PNECs）；其次，建立了环境样品中不同形态砷、汞的液相色谱-氢化物发生-原子荧光（LC-HG-AFS）联用的检测方法；在此基础上，采集了南方某流域的环境样品，对不同形态砷、汞的污染现状进行了检测，并结合不同形态砷、汞的 PNEC值，研究了该流域环境介质中不同形态砷、汞的风险分布情况；最后，对流域内典型行业废水中砷、汞的污染情况及风险分布进行了研究，主要研究成果如下： （1）收集、整理了不同形态砷、汞的毒性数据，利用物种敏感度分布法（SSD）和评价因子法（AF）分别计算了三价砷（As(III)）、五价砷（As(V)）和一甲基砷（DMA）的 PNEC值为 43.65 μg/L、250.18 μg/L和 2.00×103 μg/L，表明了不同形态砷化合物的毒性大小依次为 As(III)＞As(V)＞DMA，无机汞和甲基汞的PNEC值为 0.39 μg/L和 6.5×10-3 μg/L，甲基汞的毒性大于无机汞。 （2）通过优化前处理方法，采用 LC-HG-AFS 联用技术分别建立了不同形态砷、汞的检测方法，其中砷的四种形态在 11 min 内可实现分离检测，汞的三种形态在 7 min内实现分离检测，并均具有良好的回收率。 （3）采集了我国南方某流域的水和沉积物样品，利用 LC-HG-AFS 联用方法检测了砷、汞的污染水平，结果显示除一、两个采样点外，不同形态砷、汞在该流域水体中的浓度均未超过地表水环境质量标准（GB 3838-2002 Ⅲ类）的浓度限值。砷在丰水期和枯水期的浓度平均值分别为 6.51 μg/L和 20.16 μg/L，其中As(III)的平均值为 10.78 μg/L和 7.89 μg/L，As(V)的平均值为 0.91 μg/L和 14.83μg/L；无机汞在丰水期和枯水期的浓度范围为 0.02 μg/L-0.14 μg/L 和 ND-0.03μg/L，平均值分别为 0.05 μg/L和 0.01 μg/L。沉积物样品中总砷的含量低于国家海洋沉积物质量标准（GB 15618-1995 I类）的浓度限值 20 mg/kg，在丰水期和枯水期 As(III)的平均值为 0.48 mg/kg和 0.29 mg/kg，As(V)的平均值为 0.47 mg/kg和 0.42 mg/kg；样品中汞的检出浓度接近或高于国家海洋沉积物质量标准的浓度限值 0.20 mg/kg，在丰水期和枯水期的浓度范围分别为 ND-2.10 mg/kg和 ND-6.14mg/kg，其中无机汞在丰水期和枯水期的平均浓度为 0.33 mg/kg和 0.39 mg/kg，甲基汞的平均浓度小于 0.01 mg/kg。 （4）砷在该流域内的水体和沉积物介质中均为低生态风险， RQ 的平均值分别为 0.24 和 0.23；汞在该流域水体中为低风险，均为无机汞，RQ 值最大为0.36，但在沉积物中风险较高，Hg(II)和 MeHg的 RQ平均值为 14.61和 4.92，特别是在干流的下游和部分支流断面风险更高。 （5）采集了流域内典型行业排放的废水，检测了砷、汞的排放水平。结果发现流域废水中砷的排放浓度较低。而制药、造纸、城市污水处理及电子电镀等行业废水中，汞有一定程度的排放，可能是造成汞污染的主要来源。 综上，本研究主要针对不同形态砷、汞的毒性差异，提出了基于不同形态砷、汞的风险评价理念，克服了传统的基于总砷、总汞基础上进行生态风险评价的不足，可以更加准确的评价环境中砷、汞污染所造成的潜在生态风险。本研究将为有关部门制定相应的环境保护规划提供科学依据。 |
| 英文摘要 | Arsenic (As) and mercury (Hg) are two kinds of typical heavy metal pollutants.They exist in different chemical species in the environment. Due to the different chemical species of heavy mental, the toxicity and ecological risk they caused are also different. So arsenic and mercury were selected as research objects in this study.Firstly, the toxicity data of arsenic and mercury on different species were selected, the predicted no-effect concentrations (PNECs) of them were calculated according to the species sensitivity distribution (SSD) method. Then the liquid chromatography hydride-generation atomic fluorescence spectrometry (LC-HG-AFS) detection method was established. On this basis, the environmental samples of certain river basin in southern China were collected. And the pollution characteristics of arsenic and mercury on different species were analysed, then basing on the PNECs of arsenic and mercury, the risk distribution of them in certain river basin was studied. Lastly, the pollution distribution characteristics and ecological risk of arsenic and mercury on different species in the wastewater of representative industry were explored. The main works carried out in this research are as follows: (1) The toxicity data of arsenic and mercury on different species were selected, then the PNEC values of As(III), As(V), and DMA were 43.65 μg/L, 250.18 μg/L, and 2.00×103 μg/L according to the species sensitivity distribution (SSD) and assessment factor (AF) methods. The result indicated that the toxicity of different species of arsenic was As(III)＞As(V)＞DMA; the PNEC values of Hg(II) and methyl mercury (MeHg) were 0.39 μg/L and 6.5×10-3 μg/L, the result showed that the toxicity of MeHg was much higher than Hg(II). (2) By optimizing the pre-treatment method, the detection method of LC-HG-AFS about different species of arsenic and mercury was established. Using this method, the four forms of arsenic could be separated within 11 minutes, the three forms of mercury could be separated within 7 minutes. The average recovery was good. (3) The water and sediment samples in certain river basin in southern China were collected, and the pollution distribution of arsenic and mercury were detected by LC-HG-AFS method. The results showed that except for individual sampling points, the concentration of arsenic and mercury in water of this river basin was below the limit value of the Chinese environmental quality standards for surface water (GB3838-2002, ClassⅢ). The average concentrations of arsenic in wet season and dry season were 6.51 μg/L and 20.16 μg/L, respectively. And the average concentration of As(III) was 10.78 μg/L and 7.89 μg/L, the average concentration of As(V) was 0.91 μg/L and 14.83 μg/L. The concentration range of inorganic mercury in wet season and dry season were 0.02 μg/L-0.14 μg/L and ND-0.03 μg/L,respectively. And the average concentrations were 0.05 μg/L and 0.01 μg/L. The concentrations of total arsenic in sediments were below the limit value (20 mg/kg) of the Chinese environmental quality standard for soils (GB15618-1995 Class I). The average concentrations of As(III) in wet season and dry season were 0.48 mg/kg and 0.29 mg/kg, and the average concentrations of As(V) were 0.47 mg/kg and 0.42 mg/kg. The concentrations of mercury in sediments were close to or a little higher than the limit value (0.20 mg/kg) of the Chinese environmental quality standard for soils. The concentration ranges of mercury in wet season and dry season were ND-2.10 mg/kg and ND-6.14 mg/kg, respectively. And the average concentrations of inorganic mercury in wet season and dry season were 0.33 mg/kg and 0.39 mg/kg, the average concentration of MeHg was lower than 0.01 mg/kg. (4) There was a low risk from arsenic in water and sediments in the studied river basin, and the average values of RQ were 0.24 and 0.23 respectively. The risk of inorganic mercury in water was low, the maximum value of RQ was 0.36. But there was a high risk of mercury in sediments, the average RQ values of Hg(II) and MeHg were 14.61 and 4.92 respectively. And the ecological risk was much higher especially on the downstream side of the river basin and part of the tributaries. (5) The wastewater discharged by representative industry in certain river basin was collected and the pollution distributions of arsenic and mercury were analysed. The results showed that the concentrations of arsenic in wastewater were low. Pharmacy, paper making, urban sewage treatment and electronic industry should be the main source of mercury pollution. In conclusion, because that the toxicities of arsenic and mercury on different species are not the same, the idea that ecological risk assessment should be based on arsenic and mercury with different species was proposed. Comparing with traditional ecological risk assessment method focused on total arsenic and mercury, the ecological risk assessment of arsenic and mercury based on different species could be much more accurate. The study provides a scientific basis for relevant departments to formulate the corresponding environmental protection planning. |
| 公开日期 | 2015-07-07 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/15642]  |
| 专题 | 生态环境研究中心_环境化学与生态毒理学国家重点实验室 |
| 推荐引用方式 GB/T 7714 | 杜萌. 基于砷、汞形态的生态风险评价研究[D]. 北京. 中国科学院研究生院. 2014. |
| 个性服务 |
| 查看访问统计 |
| 相关权益政策 |
| 暂无数据 |
| 收藏/分享 |
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。
修改评论