鄱阳湖生态经济区典型城市多介质中PAHs分布特征及风险
发布时间：2018-11-14 09:56
【摘要】：多环芳烃(polycyclic aromatic hydrocarbons)是一类可以在环境中持久性存在的持久性有机污染物(POPs),通过环境迁移和食物链富集,对人类健康和生态环境产生有害影响的化合物。近年来随着鄱阳湖生态经济区煤炭的大量使用和机动车尾气的大量排放,环境中的PAHs污染加剧,鄱阳湖生态经济区城市圈中大气介质及城市农田土壤中均检出PAHs残留。现有的对鄱阳湖PAHs的研究都主要是针对单一介质,对区域尺度下大气、土壤、沉积物、水体等环境多介质中PAHs的污染特征及环境过程的研究相对较少,缺乏全面系统的认识。本次研究通过对鄱阳湖不同介质土壤、沉积物、水体和大气样品的采集,分析了不同介质中PAHs的污染水平、组成特征和分布特征。结果表明:鄱阳湖土壤、沉积物、水体、大气中∑PAHs的含量平均值分别为242.64ng/g,394.74ng/g,0.25μg/L和26.07ng/m3,均低于国内各介质中PAHs的平均水平,土壤和沉积物表现为鄱阳湖生态经济区PAHs的最终的汇。土壤、沉积物和大气PM2.5中PAHs主要以4环以上的大分子PAHs存在,而水体中主要以3环以下的小分子PAHs为主,利用比值法确定了鄱阳湖生态经济区PAHs污染物主要来自化石燃料燃烧,少量来自石油直接排放和生物质的燃烧排放。鄱阳湖生态经济区大气PM2.5中PAHs在时间分布上存在差异,呈季节性变化,表现为冬季大于夏季;在空间分布上存在差异,PAHs整体浓度水平表现为南昌大于九江。季节性的变化主要是因为冬天能源消耗量的增加从而增加了PAHs的输入量,空间分布差异与南昌、九江两地的能源消耗量不同和能源消耗结构不同有关。分析南昌大气PM2.5中PAHs年度变化可知,南昌市大气PM2.5中PAHs呈逐年增加的趋势,主要是因为近年来南昌市化石燃料的消耗能增多,同时也跟南昌市的气候变化有关,且研究发现PAHs的浓度与温度、相对湿度、降雨量呈负相关。利用潜在生态风险效应的区间低值(ERL)和效应区间中值(ERM)的方法和加拿大魁北克省淡水沉积物中PAHs的质量评价标准,对鄱阳湖沉积物进行生态风险评价,可知鄱阳湖沉积物PAHs浓度小于ERL,沉积物中PAHs产生负面效应几率很小,小于生物毒性的临界效应浓度值,鄱阳湖沉积物处于生态风险较低水平。同时利用加拿大魁北克省淡水沉积物中PAHs的质量评价标准和荷兰政府建立的一套标准对土壤中的多环芳烃进行生态风险评价。结果显示,土壤中的多环芳烃接近罕见效应浓度值,符合低风险标准。利用Ba P的毒性当量法(TEQ)对鄱阳湖生态经济区水体和大气进行风险评价,即把其它多环芳烃都换算为Ba P的浓度,再采用终身致癌风险,进行健康风险评价。经计算,水体终身致癌风险为2.70×10-4,为可接受水平;大气中成人和儿童的PAHs终身致癌超额危险度R分别为1.35×10-6和5.80×10-7,小于最大可接受风险水平10-6-10-5,为可接受风险水平。
[Abstract]:Polycyclic aromatic hydrocarbons (PAHs) (polycyclic aromatic hydrocarbons) are a class of persistent organic pollutants (POPs),) which can be persistent in the environment and have harmful effects on human health and ecological environment through environmental transport and food chain enrichment. In recent years, with the large use of coal and the emission of vehicle tail gas, the PAHs pollution in the environment has been intensified, and PAHs residues have been detected in both the atmospheric media and the farmland soil of the ecological economic zone of Poyang Lake. The existing studies on PAHs in Poyang Lake are mainly focused on the single medium, and the study on the pollution characteristics and environmental process of PAHs in the atmosphere, soil, sediment, water and other environmental multi-media at regional scale is relatively few, lacking of comprehensive and systematic understanding. Based on the collection of soil, sediment, water and atmosphere samples from different media in Poyang Lake, the pollution level, composition and distribution of PAHs in different media were analyzed. The results show that the mean values of 鈭，
本文编号：2330838
[Abstract]:Polycyclic aromatic hydrocarbons (PAHs) (polycyclic aromatic hydrocarbons) are a class of persistent organic pollutants (POPs),) which can be persistent in the environment and have harmful effects on human health and ecological environment through environmental transport and food chain enrichment. In recent years, with the large use of coal and the emission of vehicle tail gas, the PAHs pollution in the environment has been intensified, and PAHs residues have been detected in both the atmospheric media and the farmland soil of the ecological economic zone of Poyang Lake. The existing studies on PAHs in Poyang Lake are mainly focused on the single medium, and the study on the pollution characteristics and environmental process of PAHs in the atmosphere, soil, sediment, water and other environmental multi-media at regional scale is relatively few, lacking of comprehensive and systematic understanding. Based on the collection of soil, sediment, water and atmosphere samples from different media in Poyang Lake, the pollution level, composition and distribution of PAHs in different media were analyzed. The results show that the mean values of 鈭，
本文编号：2330838
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