南四湖表层沉积物中PAHs的分布、来源及变化分析

Distributions,Sources and Trends of Polycyclic Aromatic Hydrocarbons in Surface Sediment in Nansihu Lake

采集南四湖4个湖区及入湖支流的9个站位的表层沉积物样品,利用气相色谱-质谱方法对样品中的16种多环芳烃(PAHs)进行了分析测定,结合已有文献对南四湖的PAHs浓度变化进行了对比分析。结果表明,南四湖表层沉积物中PAHs总含量范围在20.1-929.2 ng/g.在四个湖区中,分别位于独山湖和微山湖的表层沉积物中PAHs总含量远低于其他采样点位,采于昭阳湖的样品的PAHs含量最高,说明PAHs浓度的分布为湖区中部含量最高,湖区南北部相对较低。通过PAHs的环数丰度判断,南四湖中PAHs的主要来源为化石燃料的燃烧。入湖河流引入的工业污染对PAHs的含量有着正相关影响,对PAHs贡献较大的行业包括食品、造纸、化工等重污染行业和煤炭采矿企业。对比2002年的相关研究可知,总体而言2008年PAHs的总含量较之2002年呈减少趋势。这在一定程度上可以说明,近年来山东省在南水北调沿线区域实行水质排放新标准等一系列措施后,南四湖周围工业企业的污染处理技术措施有所改进,重污染企业被关停并转,使得南四湖PAHs的污染状况得到改善。此外,对比分析也表明结构复杂的PAHs含量有所增高,具体原因还需要进一步的研究。

Nine samples of surface sediments were collected from four areas of Nansihu Lake and the rivers that flow into the lake.16 kinds of Polycyclic Aromatic Hydrocarbons（PAHs） in surface sediment were analyzed using GC-MS technique.Together with the existing studies in the same area,the variations of PAHs in the lake area were studied.It suggested that total PAHs concentration in the surface sediment varies from 20.1 to 929.2 ng/g.Among the four lakes,the PAHs concentration in samples collected in Dushan Lake and Weishan Lake was much lower than that of other samples.The samples collected in Zhaoyang Lake has the highest PAHs concentration.These reflected that the PAHs concentration in the center of the lake was more than that in north and south.According to the number of rings in the PAHs structure,the main sources of these PAHs were produced from fossil fuels combustion.The concentrations of PAHs in surface sediments are positive correlated with industrial pollution discharged into rivers that flow into the lake.The industries having significant contribution to PAHs concentration in the lake sediment included food industry,paper manufacture,chemical industry and coal mining.Compared to the research results in 2002,total PAHs concentration in surface sediments of Nansihu Lake decreased in general.This indicated that improving measures especially carrying out the new water quality standards for discharge issued by Shandong Provincial Government had taken some effects;for instance, many plants with heavy pollution were forced to be closed or reorganized.In addition,the comparison showed that the concentrations of PAHs with complex structure increased since 2002.