【作者】 帅伟；

【导师】 韦朝海；

【作者基本信息】 华南理工大学 ， 环境工程， 2010， 硕士

【摘要】 北京市地处华北平原西北部,属温带半干旱湿润性季风气候,城市长期缺水的现实让污水灌溉成为北京弥补农业用水不足的重要措施。凉水河作为北京市第二大排污河和南城主要污灌渠,大量未经处理的工业废水和生活污水直接排入河道,造成河水恶臭,水质严重恶化。其中所含的有毒有机物质可能随灌溉进入农田中,不仅污染土壤环境,还会通过水-土壤-植物-动物等途径进入食物链危害人体的生命和健康。因此,针对凉水河通州河段水环境,采用野外GPS定点采集环境样品,以通州段水、悬浮物和沉积物中典型有机污染物种类、含量和分布特征为切入点,探明凉水河（通州段）水体污染现状、有机污染物的分布特点和迁移转化规律,评价河流隐形污染源对水环境的影响,以及凉水河作为农田灌溉用水的安全性。同时,选用多环芳烃萘作为代表污染物,考察沉积物浸出液对污染物在沉积物上吸附-解吸行为特征的影响。结果表明,凉水河（通州段）所有监测断面水体中COD的含量超过了地表水V类标准,挥发酚的含量符合V类标准,二者的浓度均满足农田灌溉水质标准的要求。水中氮、磷营养盐的浓度亦超过了V类标准,采用修正后的卡尔森营养状态指数（TSI）评价凉水河通州段水体营养程度,发现所有监测断面的水体均处于富营养化状态;环境样品中共检测出苯系物、酚类、多环芳烃类、酯类、烷烃类、含氮杂环类和含氧杂环类7大类有机污染物。选择多环芳烃、酚类、苯系物和酞酸酯类物质进行定量分析,发现水体中的主要组成物质为酚类和苯系物,悬浮物和沉积物中以多环芳烃和苯系物为主。这4类有机污染物在悬浮物中的含量最高,平均浓度分别为72.70、3.94、12.45和3.00 mg·kg^-1;传统以背景电解质溶液作为解吸介质来研究有机污染物解吸行为的方法会导致解吸体系的TOC值比吸附平衡体系减少74.68%-85.01%,这种吸附-解吸水化学条件的差异会增强污染物在沉积物上的滞后性,具体表现为萘在沉积物L和D浸出液中的平均解吸量相比其在背景电解质溶液中分别增加了3.14和2.40 mg·kg^-1(Ce=0.2 mg·L^-1),平均解吸滞后系数由在背景电解质溶液中的0.04和0.135降低至沉积物浸出液中的0.012和0.072,滞后现象显著变弱。此现象表明,在实际天然水体环境中,疏水性有机污染物在沉积物上具有更强的解吸能力,能够更容易的转移至水环境中,造成水体的二次污染,增加水体污染控制和治理的难度,从而威胁水生生物和人体健康安全。更多还原

【Abstract】 Beijing is located in the northwest of north China plain and characterized by temperate semi-arid-humid monsoon climate. The lack of nature resource and the scale of urban development lead to the situation that sewage irrigation has been an important measure to solve the problem of agriculture water shortage in Beijing. Liangshui River is the second drainage river of Beijing, and it is also the main sewage-irrigated canal in Tongzhou area. The discharge of industrial wastewater and domestic sewage deteriorate the water environment, and organic pollutants can transfer into soil through sewage irrigation, to plant and/or animals subsequently, ultimately hazard human health.Samples were taken separately along the Liangshui River of Tongzhou area （Beijing） to investigate the water quality and study the transport, distribution and characteristics of organic contaminants in water, suspended solids and sediments, analyse the effects of invisible pollution on water environment and ecosystem, and estimate the security of using sewage for irrigation. At the same time, blank electrolyte was replaced with sediment extract to guarantee the aqueous chemical consistency. Batch equilibrium experiments were carried out to investigate the sorption and desorption behavior of naphthalene on and from two representative sediments （denoted as L and D, respectively）, found out the significance of aqueous chemistry consistency on sorption and desorption process.The results indicated that the average concentration of COD exceeded the values stipulated for water of Class V in all sections, while the phenols concentrations in water were below Class V , both of them met Standards for irrigation water quality. The NH3-N, TN, TP concentrations exceeded the values stipulated for water of Class V too, trophic state index showed that the Liangshui River in Tongzhou area was in serious eutrophication condition; There were 7 kinds of organic compounds detected in Liangshui River, including PAHs, benzene series, esters, phenols, alkanes,nitrogenous heterocyclic and oxygen heterocyclic. Choose PAHs, phenols, phthalic acid esters, benzene series as target pollutants to conduct quatitative analysis. It is found that phenols and benzene series were the dominant pollutants in water, but the suspend solids and sediments contained more PAHs and benzene series. The average concentration of these pollutants in suspended solids were 72.70、3.94、12.45 and 3.00 mg·kg^-1, more than that in the water and sediments; Sorption and desorption of naphthalene from sediments exhibit obvious hysteresis as described by the hysteresis index （HI）. Traditional desorption method decreased the TOC by 74.68%-85.01% as compared with extracts. Greater hysteresis exists in blank electrolyte than that in the sediment extracts, as indicated by the larger HI values of 0.04 and 0.135 in blank electrolyte than those of 0.012 and 0.072 in the sediment extracts for the sediment L and D respectively. Meanwhile, the average concentration of TOC in the extracts increases 3.14 and 2.40 mg·kg^-1 more than in blank electrolyte. This research demonstrates that the average desorption of naphthalene increased significantly in sediment extract, and the results would be more accordant with the condition of nature water.更多还原