厦门杏林湾水系表层沉积物中PAHs分析与风险评估

Risk Assessment and Analysis of Polycyclic Aromatic Hydrocarbons in the Surface Sediments of Xinglin Bay Suburb Rivers of Xiamen

利用ASE-GC-MS(加速溶剂萃取与气相色谱质谱仪联用)方法分析了USEPA(美国环保署)16种优控PAHs在厦门城郊杏林湾水系的19个表层沉积物样点中的含量,并对其组成、来源和风险进行了探讨.结果表明,杏林湾水系表层沉积物中PAHs含量介于413.00~2 748.81 ng·g-1,均值为949.56 ng·g-1;在检测出的13种PAHs中,强致癌性的Bk F和Bghi P检出率高达73.68%,均值分别为69.15 ng·g-1和49.86 ng·g-1;PAHs以2~4环为主,其中2+3环比例均值为61.03%,4环比例均值为23.53%;5和6环均值为15.82%.在所采集的沉积物样品中,中度污染占调查样品数的68.42%,高度污染的占31.58%.利用Ant/(Ant+Phe)和Fla/(Fla+Pyr)比值法和主成分分析方法对杏林湾流域中PAHs其来源进行分析,以及平均沉积物质量基准商(m SQG-Q)法进行生态风险评估,结果表明其PAHs的主要来源为石油源以及石油燃烧源;SQG-Q小于0.50;综合含量、组成特征以及沉积物质量基准商等评价表明,研究区域内靠近杏林工业区一侧的2、3、5和9号采样区以及13号港头采样区表层沉积物中PAHs具有较高的生态安全风险;值得进一步关注.

The concentrations of 16 polycyclic aromatic hydrocarbons( PAHs),declared as carcinogens by USEPA,were measured in the sediment samples( n = 19) collected along Xinglin Bay rivers / canals present in Xiamen. PAHs were extracted using accelerated solvent extraction system and analyzed using gas chromatography-mass spectrometry( GC-MS). The possible sources of PAHs and their health risk were investigated. Among selected PAHs,13 PAHs were detected in the surface sediments. Total concentrations of PAHs in the surface sediments ranged from 413. 00 to 2 748. 81 ng·g-1,with a mean value of 949. 56 ng·g-1. The mean concentration of highly carcinogenic compounds such as benzo[k]fluoranthene( Bk F) and benzo[g,h,i]perylene( Bghi P) were 69. 15 ng·g-1and 49. 86ng·g-1,respectively and counted for 73. 68% out of the total samples. The dominant PAH compounds were 2,3 and 4 rings and counted for 61. 03% and 23. 53%,respectively; while 5-6 rings containing PAHs were accounted for 15. 82%. According to the results,68. 42% of samples were moderately contaminated,while 31. 58% were highly contaminated with PAHs. Based on the ratios of Ant /( Ant + Phe) and Fla /( Fla + Pyr),it cleared that PAHs in surface sediments were mainly derived from fossil fuel and combustion products. Principal component analysis results and sediment quality benchmarks( m SQG-Q) were used for risk assessment of these PAH contaminated sediments. The risk SQG-Q of 16 PAHs were less than 0. 50. Comprehensive content,composition and SQG-Q showed that a certain degree of ecological risks of PAH pollution existed in the surface sediments,particularly in the sites close to Xinglin Industrial Zone( 2,3,5 and 9) and Gangtou( 13),which need further research work and proper attentions.