洞庭湖湿地重金属生态风险及对越冬水鸟的暴露研究

发布时间：2018-06-23 18:18

本文选题：洞庭湖 + 重金属污染　；参考：《湖南大学》2015年硕士论文

【摘要】：洞庭湖是中国第二大淡水湖和国际重要湿地,是很多野生动植物的理想生境,具有重要的生态功能。由于洞庭湖受到人为影响,特别是造纸厂、电镀厂、化工厂等工业废水的排放,使得洞庭湖存在严重的重金属污染。重金属具有毒性、持久性、来源广泛性和不可生物降解性,它们在生态系统和食物链中的积累会对动植物和人类健康产生很大影响。因此,开展洞庭湖重金属污染潜在生态风险评价及来源解析,有助于明确重金属污染程度,开展重金属污染综合防治。另外,开展重金属对越冬水鸟暴露研究,对洞庭湖重金属风险管理和鸟类保护具有一定指导意义。首先,本研究于2011~2013年枯水期在洞庭湖10个采样点采集表层底泥,研究重金属分布的变化趋势、风险和来源。Cr、Cu、Pb、Cd、Hg、As三年的平均浓度分别为91.33、36.27、54.82、4.39、0.19、25.67 mg/kg,均高于相应的背景值。运用底泥质量基准(SQGs)、地累积指数(Igeo)和潜在生态风险指数(RI)评价重金属的污染程度,Cd、Hg、As的风险很高,Cr有明显的增加趋势。将污染负荷指数(PLI)与地理信息系统(GIS)相结合评价重金属污染的时空变化,结果显示来自湘江的污染贡献越来越大。运用多元统计分析方法确定重金属的来源,研究表明人为源主要来自采矿、冶炼、化工和农业活动。其次,本文整合了一个暴露模型用来评价重金属对越冬水鸟(白琵鹭、黑腹滨鹬、小白额雁)的暴露风险。在洞庭湖9个水鸟栖息地采集水样、植物、土壤和鱼样检测Cr、Cu、Pb、Cd、Hg、As重金属的浓度,数据显示通过饮水暴露途径的重金属摄入剂量很小,可以忽略不计。有一个敏感区位于湘江入湖处,Cd和As暴露剂量均超过了最保守的日耐受剂量。总的来说,黑腹滨鹬比白琵鹭有着更高的风险,Hg、Pb、Cr可能对肉食性水鸟产生不利影响,Cu和Cd相对较为安全。重金属对小白额雁基本没有风险。再次,本文以越冬水鸟栖息地相对聚集的东洞庭湖为例,进一步完善了重金属对鸟类的暴露风险评价模型,并提出了一种划分优先控制污染物和优先控制污染区域的方法。研究于东洞庭湖10个主要雁鸭类栖息地采集苔草和土壤样品,分析了Cr、Cu、Pb、Cd4种重金属。结果显示Cr和Pb对雁鸭类水鸟可能产生不利影响,而Cu和Pb较为安全。Cr风险最高,被确定为优先控制污染物;Pb存在低风险。基于地统计方法的空间插值图显示,春风湖有着较高的综合风险和较多的鸟类,应该引起关注。另外,危害商(HI)较高的区域被划分为优先控制区域,用于风险管理和水鸟保护。最后,结合本文研究结果,有针对性地提出了洞庭湖重金属污染综合防治和生态环境保护对策。
[Abstract]:Dongting Lake is the second largest freshwater lake in China and an important wetland in the world. It is an ideal habitat for many wild animals and plants and has important ecological functions. Due to the man-made influence on Dongting Lake, especially the discharge of industrial wastewater from paper mills, electroplating plants and chemical plants, there is serious heavy metal pollution in Dongting Lake. Heavy metals are toxic, persistent, widespread and non-biodegradable, and their accumulation in ecosystems and food chains can have a significant impact on plant and animal health and human health. Therefore, the evaluation of potential ecological risk of heavy metal pollution in Dongting Lake and the analysis of its source are helpful to clarify the degree of heavy metal pollution and to carry out comprehensive prevention and control of heavy metal pollution. In addition, the study of heavy metal exposure to overwintering waterfowl has certain guiding significance for heavy metal risk management and bird protection in Dongting Lake. Firstly, the surface sediment was collected from 10 sampling sites in Dongting Lake during the dry season from 2011 to 2013, and the variation trend of heavy metal distribution was studied. The average concentrations of the risk and the source of the heavy metal in the three years were 91.33 ~ 36.27 ~ 36.27 ~ 54.82 ~ 4.390.1925.67 mg / kg, respectively, which were higher than the corresponding background values. The application of sediment quality standard (SQGs), ground accumulation index (Igeo) and potential ecological risk index (RI) to evaluate the pollution degree of heavy metals, and the high risk of heavy metal pollution, has an obvious increasing trend. The pollution load index (PLI) and geographic information system (GIS) were combined to evaluate the temporal and spatial changes of heavy metal pollution. The results showed that the pollution from Xiangjiang River contributed more and more to the pollution. The sources of heavy metals were determined by multivariate statistical analysis. The results showed that the main sources of heavy metals were from mining, smelting, chemical industry and agricultural activities. Secondly, an exposure model was integrated to evaluate the exposure risk of heavy metals to overwintering waterfowl (White spoonbill, black-bellied snipe, small white goose). Water samples, plants, soil and fish samples were collected from 9 aquatic bird habitats in Dongting Lake to detect the concentration of heavy metals in Cr-CuCuPbPbCdCdHgAs. The data showed that the intake dose of heavy metals through drinking water exposure pathway was very small and could be ignored. In one sensitive area, the exposure dose of CD and as in Xiangjiang Lake exceeded the most conservative daily tolerance dose. Generally speaking, the black-bellied snipe had a higher risk than the white spoonbill, and Hgfus Pbcr may have adverse effects on carnivorous waterfowl, Cu and CD were relatively safe. Heavy metals have little risk to wild geese. Thirdly, taking East Dongting Lake, where overwintering waterfowl habitat is relatively concentrated, as an example, the model of risk assessment of heavy metals exposure to birds is further improved, and a method of dividing priority pollution control areas and priority pollution control areas is proposed. Carex spp and soil samples were collected from 10 main geese and ducks habitats in East Dongting Lake, and four heavy metals were analyzed. The results showed that Cr and Pb might have adverse effects on geese and ducks, while Cu and Pb were the safest. The spatial interpolation map based on geostatistical method shows that the spring wind lake has a higher comprehensive risk and more birds, which should be paid more attention to. In addition, high hazard quotient (HI) areas are classified as priority control areas for risk management and waterbird protection. Finally, combined with the results of this study, the countermeasures of comprehensive prevention and control of heavy metal pollution and ecological environment protection in Dongting Lake were put forward.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X524

【参考文献】