滇池流域宝象河水库沉积物中多环芳烃的垂直分布特征及来源解析

采用GC-MS检测了滇池宝象河水库沉积物中16种美国环保署(US EPA)优先控制的多环芳烃(PAHs)的含量,并对其垂直分布特征及来源进行分析,以此了解宝象河水库近年来PAHs的变化.结果表明,水库沉积物中16种PAHs均有检出,其含量范围为162.26~762.24ng·g~(-1),平均值为423.30 ng·g~(-1).自底层50 cm至表层,沉积物中PAHs含量呈上升趋势.从多环芳烃环数来看,沉积物中的PAHs以2~3环为主,其含量为128.34~518.81 ng·g~(-1),平均值为279.88 ng·g~(-1),占PAHs总量的42.2%~84.1%,平均值为67.6%.FLA/(FLA+PYR)、Ba A/(Ba A+CHR)和Icd P/(Icd P+Bghi P)3组比值及PAHs各组分的分析结果表明,燃烧过程是沉积物中PAHs的主要来源,主要为煤炭、生物质的燃烧.PAHs含量与总有机碳(TOC)之间有显著正相关关系,TOC影响宝象河水库沉积物中PAHs的分布.

Vertical profile and sources of polycyclic aromatic hydrocarbons in a sediment core from Baoxianghe Reservoir in Dianchi Watershed

This study was designed to measure concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs) identified by the US EPA,in sediment core from Baoxianghe Reservoir of Dianchi watershed,using gas chromatography-mass spectrometry (GC-MS).The temporal distribution of PAHs was measured,and the possible sources of PAHs in sediment core also have been identified.The concentration of total PAHs in sediment ranged from 162.26 to 762.24 ng·g^-1,and roughly,increased continuously from the bottom (50 cm under the surface) to the surface sediment.The PAHs in sediment core were mainly composed of 2- and 3- rings.The concentrations of 2- and 3- ring PAHs in sediment core were 128.34~518.81 ng·g^-1,with an average of 279.88 ng·g^-1.Both of them accounted for 42.2%~84.1% of the total PAHs in the sediment.The profiles of FLA/(FLA+PYR),BaA/(BaA+CHR) and IcdP/(IcdP+BghiP) ratios suggested that the main source of PAHs was originated from the combustions of fossil fuels,coal and biomass.The concentrations of total PAHs were significantly correlated to the sediment total organic carbon (TOC) content,indicating that TOC had a great influence on PAH distribution in sediment.