煤矿区表层土壤中饱和烃污染物的组成与分布

COMPOSITION AND DISTRIBUTION CHARACTERISTICS OF SATURATED HYDROCARBONS IN SURFACE SOIL SAMPLES FROM A COAL-MINING AREA

应用GC-MS技术检测石龙区表层土壤中饱和烃馏分,共鉴别正构烷烃、甾类、萜类等系列的85种代表性化合物,分析了饱和烃在不同功能区域含量及分布特征,并结合分子有机地球化学参数对其污染来源作了初步探讨。结果表明,受煤矿开采活动影响的区域土壤中饱和烃含量远高于无矿区域,以矸石山周围和炼焦区最为严重;正构烷烃的高碳数部分较少、低碳数部分较多、主峰碳为C16或C18、姥植比和藿/莫比值大、地质构型甾烷和C29ααα20R-甾烷的含量较高,这些特征与煤岩中状况接近,表明石龙区表层土壤并非现代沉积物或是天然状态下的表层土壤。煤矿区煤及矸石等堆放、储藏、运输、加工过程中大量煤岩屑或煤灰长期沉降积累可能是矿区土壤有机质主要输入源。

Surface soil samples collected from Shilong coal-mining area were tested for saturated hydrocarbons by means of GC-MS, and 85 representative kinds of chemical compounds including normal alkanes, steroids, terpenoids, etc., were detected. Composition and distribution characteristics of the saturated hydrocarbons in soils of different functional zones were analyzed and their sources were explored, with their molecular organic geochemical parameters taken into account. Results show that the soils in the areas affected by coal-mining were much higher in content of saturated hydrocarbons than those in non-affected areas, especially higher in soils around the gangue damping grounds and coking plants; with normal alkanes, the portion high in carbon number was small, but the portion low in carbon number was great, and their Cmax were at 16 or 18, and their Pr/Ph and hopane/more- tane ratios were high;and the content of sterane of geological configuration type and C29aaa20R-sterane were high, too. These geo- chemical characteristics were quite close to those of raw coal, suggesting that the surface soil layer of the Shilong area is not of contemporary sediments or naturally formed surface soil. Deposition of large volumes of coal slack or dust generated from the coal mining operation, such as dumping, storage, transport and processing of coal and gangue may be the major source of organic manure in the soils of the coal mining area.