表层岩溶泉水中多环芳烃污染特征及来源解析

对重庆市南川区4个典型表层岩溶泉进行连续采样观测,利用GC-MS定量分析泉水中16种优控多环芳烃(PAHs)含量,研究了表层岩溶泉水中多环芳烃含量、组成、来源的季节变化以及污染特征.结果表明,4个表层岩溶泉中16种PAHs均有检出.在一年的观测期间,泉水中的ΣPAHs含量变化较大,范围在341~4968 ng·L-1之间,平均值为1772 ng·L-1.7种致癌性PAHs的含量均表现为雨季大于旱季.泉水中PAHs组成以2~3环PAHs为主,其比例均超过了50%.泉水中的PAHs主要来自于煤、生物质以及石油的燃烧,但在2011年6~10月期间,来源于煤、生物质燃烧的PAHs对泉水中PAHs的贡献要更大一些.Ant/(Ant+Phe)和Fla/(Fla+Pyr)比值随季节变化的特点,表明Ant、Phe、Fla和Pyr在表层岩溶带土壤中易于迁移、传输.4个同分异构体比值中,Fla/(Fla+Pyr)比值对源信息的指示更灵敏.与其它地区相比,研究区表层岩溶泉水中的PAHs含量处于较高水平,泉水已受到多环芳烃的污染.

Contamination and Source of Polycyclic Aromatic Hydrocarbons in Epikarst Spring Water

The water samples were collected from four typical epikarst springs in Nanchuan District, Chongqing Municipality between October 2010 and October 2011.Sixteen priority polycyclic aromatic hydrocarbons in epikarst spring waters were quantitatively analyzed by the gas chromatography-mass spectrometer (GC-MS). The objectives of this study were to investigate the seasonal variations of polycyclic aromatic hydrocarbons'concentration, composition, source and contamination characterization in epikarst springs water. The results showed that the detection ratios of 16 PAHs in four springs were 100%. The total concentrations of 16 PAHs fluctuated greatly in epikarst spring water during one year observation, and the concentration ranged from 341 to 4968 ng·L^-1,with a mean value of 1772 ng·L^-1. The total concentrations of 7 carcinogenic PAHs in rain season were all higher than those in dry season in four epikarst springs. The PAHs profiles were dominated by (2-3) rings PAHs in spring water, which accounted for more than 50% of 16 PAHs. The PAHs in spring water mainly originated from the combustion of coal, biomass and petroleum, and during June to October 2011, PAHs originated from the combustion of coal and biomass had a larger contribution. The ratios of Ant/(Ant+Phe) and Fla/(Fla+Pyr) changing with seasons showed that Ant, Phe, Fla and Pyr were easy to migrate in epikarst soils. In 4 isomeric ratios, the ratios of Fla/(Fla+Pyr) were more sensitive to reflect the information of sources. Compared to other areas in the world, the concentration of 16 PAHs in epikarst spring water is at a higher level, which shows the epikarst spring water has been suffered the PAHs pollution.