千岛湖表层沉积物中多环芳烃污染特征及生态风险评价

利用高效液相色谱法对采集于2012年12月的部分千岛湖表层沉积物中多环芳烃(PAHs)进行了分析.结果表明,千岛湖表层沉积物中共检出属于美国EPA优先控制16种PAHs中的15种,各采样点位PAHs总量的浓度范围在258~906ng/g(干重)之间,平均值为558ng/g,属低污染水平.空间分布特征受周边区域内点源污染和河流输入污染物影响.沉积物中的多环芳烃以高分子量组分为主,通过特征组分比例可确认其主要来源于周边地区煤炭、木材不完全燃烧及车船尾气排放.利用沉积物质量基准法、沉积物质量标准法分别对千岛湖表层沉积物中PAHs的风险评价表明,千岛湖沉积物中不存在严重的多环芳烃生态风险,但部分点位按照质量标准法评价已经超过临界效应浓度值,需加强监测查明污染源,并采取措施控制污染物输入.

Pollution characteristics and ecological risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments from Xin’anjiang Reservoir

Polycyclic aromatic hydrocarbons (PAHs) were quantitatively determined by HPLC in several surface sediment samples collected in December 2012 from Xin’anjiang Reservoir. The results showed that 15 of the 16 US EPA priority controlled PAHs were detected. Total concentrations of PAHs in surface sediments of the studied reservoir ranged from 258 to 906ng/g dry weight (dw), with average 558ng/g dw, lower pollution level. The distribution of PAHs is found to be influenced by riverine discharge and point-source pollution. The PAHs in the sediments were dominated by high molecular weight PAHs. According to the ratio of feature components, the PAHs in surface sediment from the Xin’anjiang Reservoir originated largely from coal and biomass incomplete combustion in the surrounding areas and exhaustion of boats or cars. In addition, the ecological risk of surface sediment in Xin’anjiang Reservoir was assessed with the methods of sediment quality guidelines and sediment quality standards (SQSs), and the result indicated that there was no great biological impact associated with the PAHs in the surface sediment of Xin’anjiang Reservoir. However, the concentrations of some points have been exceeded the threshold effect level evaluated in accordance with SQSs. It is necessary to identify the contamination source and control the pollution input.