杭埠河流域贝类重金属的污染特征及源解析

发布时间：2018-05-07 00:13

本文选题：杭埠河 + 重金属　；参考：《安徽大学》2016年硕士论文

【摘要】：杭埠河是巢湖最大的入湖支流(占总径流量的65%),其水环境质量状况一直饱受各方关注。本研究通过对杭埠河流域沉积物和双壳贝类背角无齿蚌(Anodonta woodiana)中重金属含量进行分析测定,探究重金属Cr、Cu、Zn、Cd、Pb、As、Hg在杭埠河水环境中的生物地球化学行为,并重点关注汞和甲基汞在背角无齿蚌中的污染特征及其生物富集效应,利用单项污染指数法、地积累指数法评价重金属在杭埠河流域的生态风险。研究结果表明：杭埠河冬季枯水期部分河段水质氮、磷超标,沉积物中的总氮和总磷含量也在某些河段超过了最低安全级别。杭埠河沉积物中Cr、Cu、Zn、Cd、Pb、As和Hg均值含量分别为64.5 mg/kg,21.4 mg/kg,89.1 mg/kg,0.152 mg/kg,30.6 mg/kg,7.16 mg/kg和0.065 mg/kg,以背景值作为参照,沉积物重金属污染爆发频次相对较高的是Zn、Cd、Pb,表明近年来流域内的人类生产活动加剧了这三种重金属向水环境的排放。沉积物中Cr浓度含量虽然低于自然背景值,但也超过了阈值效应含量TEC的限定并表现出较高的的污染响应。杭埠河背角无齿蚌中Cr、Cu、zn、Cd、Pb、As和Hg均值含量分别为80.4mg/kg,5.2 mg/kg,412.9 mg/kg,0.339 mg/kg,0.43 mg/kg,8.9 mg/kg和0.134mg/kg,其中Zn、Cd和Hg的生物-沉积物积累因子BSAF均值分别为5.43、2.71和2.82,表现出明显的生物富集,而背角无齿蚌对Cr、Cu、Pb和As的富集则相对较弱,其生物体内重金属浓度含量基本接近或者低于对应沉积物中重金属的含量。背角无齿蚌体内重金属含量与对应沉积物中重金属的含量呈现显著正相关,其相关系数高低排序为：HgCdZnCrCuAsPb。进一步研究发现,背角无齿蚌对汞和甲基汞均有较高的富集,两者含量分别为101.34-171.15μg/kg：干重)和54.22～89.63 μg/kg(干重),均符合GB18406.4-2001中汞的限量要求。背角无齿蚌各部分组织对汞的积累具有明显的选择性,具体表现为外套膜中汞浓度最高,内脏次之,腮和肌肉较低。贝类重金属污染评价结果显示,背角无齿蚌体内重金属含量与对应沉积物中重金属含量相关性良好,其中Cr、Zn、Pb和Cd在软组织中的含量超过了贝类安全标准的限定。除元素Pb外,背角无齿蚌体内Cr、Zn和Cd反映的贝类污染水平与沉积物中重金属污染趋势基本保持-致,表明背角无齿蚌可作为淡水环境重金属污染监测和预警的优良指示生物。杭埠河沉积物的TOC含量与重金属Cu、Zn、Cd和Hg的含量表现出良好的正相关性,而Cr、Pb、As则与TOC含量分布表现出负相关性,表明重金属污染可能来自于混合污染源。重金属污染源解析结果表明,杭埠河流域重金属污染主要受农村面源污染(52%)、航运污染(16%)和工业污染(14%)的影响。故应强化农业面源污染治理过程中对重金属输入负荷的调控,减少船舶运输过程中的燃油污染排放,同时加大对相关涉污企业的监管力度,并通过对贝类所在的底栖生态环境进行优先修复和多样性重构来增加和提升流域水生态系统的环境容量和自净能力。
[Abstract]:The Hangzhou port river is the largest tributary of Chaohu (65% of the total runoff), and its water environmental quality has been paid much attention by all sides. The heavy metal content of heavy metals in the sediments and Anodonta woodiana of the double shell shellfish (Anodonta woodiana) in Hangzhou port river basin was analyzed, and the heavy metal Cr, Cu, Zn, Cd, Pb, As and Hg were investigated in the river environment of Hangzhou port. The pollution characteristics of mercury and methylmercury in the non toothed mussels of the back angle and their bioaccumulation effect are focused on. The ecological risk of heavy metals in the Hangzhou port river basin is evaluated by the method of single pollution index and the index method of ground accumulation. The results show that the water quality nitrogen and phosphorus exceed the standard in the dry period of the winter season in the hang Bu river. The total nitrogen and total phosphorus content in the sediments also exceeded the minimum safety level in some river sections. The contents of Cr, Cu, Zn, Cd, Pb, As and Hg in the sediments of the Hangzhou River were 64.5 mg/kg, 21.4 mg/kg, 89.1 mg/kg, 0.152 mg/kg, 30.6 mg/kg, 7.16 and 0.065, with the background value as reference, and the heavy metal pollution eruptions were relatively high in the sediments. It is Zn, Cd, Pb, indicating that in recent years human production activities in the basin have intensified the emission of these three heavy metals to the water environment. Although the concentration of Cr in the sediments is lower than the natural background value, it also exceeds the limit of the threshold effect content TEC and shows a higher pollution response. The Cr, Cu, Zn, Cd, Pb, As, and Hg mean of the oyster on the back corner of the Hangzhou River The contents are 80.4mg/kg, 5.2 mg/kg, 412.9 mg/kg, 0.339 mg/kg, 0.43 mg/kg, 8.9 mg/kg and 0.134mg/kg. The BSAF mean of Zn, Cd and Hg is 5.43,2.71 and 2.82, respectively. The content of heavy metals in the body of mussels on the back angle showed significant positive correlation with the content of heavy metals in the corresponding sediments. The correlation coefficient of the heavy metals was ranked as: HgCdZnCrCuAsPb. further study found that the content of mercury and methyl mercury in the back angle mussels had high enrichment. 101.34-171.15 mu g/kg: dry weight) and 54.22 ~ 89.63 mu g/kg (dry weight) were all in accordance with the limit of mercury in GB18406.4-2001. The accumulation of mercury in various parts of the back angle mussels was obviously selective. The specific performance was that the concentration of mercury in the mantle was the highest, the viscera was second, and the gills and muscles were low. The evaluation results of heavy metal pollution in shellfish showed that the heavy metal pollution of shellfish was shown. Cr, Zn, Pb and Cd in soft tissues are more than the limit of shellfish safety standards. In addition to element Pb, the pollution levels of shellfish in Cr, Zn and Cd in mussels in the back angle of mussels and the heavy metal pollution in sediments are basically maintained. The TOC content in the sediments of the hang port river has a good positive correlation with the content of heavy metals Cu, Zn, Cd and Hg, while Cr, Pb and As are negatively correlated with the distribution of TOC content, indicating that heavy metal pollution may come from a mixed source of heavy metals. The analysis results of pollution sources indicate that the heavy metal pollution in the hang port river basin is mainly affected by rural non-point source pollution (52%), shipping pollution (16%) and industrial pollution (14%). Therefore, the control of heavy metal input load should be strengthened during the treatment of agricultural non-point source pollution, and the fuel pollution discharge in the process of ship transportation should be reduced, and the related pollution related enterprises should be increased. In order to increase and enhance the environmental capacity and self purification capacity of the water ecosystem in the basin, the supervision of the industry is strengthened and the ecological environment of the shellfish is rebuilt by priority restoration and diversity reconstruction.

【学位授予单位】：安徽大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X52

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