煤矸石堆积下多环芳烃的淋溶污染特征

淋溶是使有害物质析出的主要途径之一。为查明煤矸石堆放淋溶造成的有机污染效应,对不同风化强度煤矸石进行了动态淋溶模拟实验,系统研究了煤矸石中US EPA优先控制的16种多环芳烃（PAH16）的析出规律和迁移方式。获得煤矸石中多环芳烃（PAHs）淋溶特征如下：煤矸石堆积期遭受短期降雨（500~1 600 mm）作用后,煤矸石溶出的PAH16总质量浓度达125.6~451.2 ng/L。PAH16溶出量初期较高,在一定降雨期后又达到峰值,酸雨条件下,煤矸石山淋溶出的PAH16可由线性累加转为指数快速累加的趋势。淋溶液中优势组分为萘、二氢苊、芴和菲,4种组分之和占所测PAHs总量的80%~90%。煤矸石溶出的PAHs环数分布为2环〉3环〉4环〉5环、6环。迁移方式上,2环PAHs多以溶解相迁移,3环PAHs主要以颗粒态迁移,存在少量溶解形式,而4环以上PAHs则以颗粒相形式迁移。

Leaching pollution characteristics of polycyclic aromatic hydrocarbons from piled coal gangue

Leaching process is one of key ways that extract contaminants from coal gangue.Dynamic leaching test was used in this study to investigate the leaching behavior of PAHs in coal gangue with various weathering degrees.The leaching behavior and migration pattern of 16 polycyclic aromatic hydrocarbons（PAH 16） preferentially controlled by US EPA leached from the coal gangue were detailedly analyzed.The experimental results show that suffering from the short-term mimic rainfall（500 mm to 1 600 mm） during the open stockpiling of coal gangue,the total mass concentration of PAH 16 dissolved from the coal gangue was up to 125.6 ~ 451.2 ng / L.The total PAHs concentration from gangue was high in the initial stage,and reached the peak value after a certain rainfall.Under the conditions of acid rain,the PAH 16 leached from the coal gangue could be transformed from the linear accumulation into the rapid index accumulation trend.The dominant components in the leachate comprised naphthalene,acenaphthene,fluorene and phenanthrene,and the sum of those four components accounted up to 80% to 90% of the total measured PAHs.The ring distribution of dissolved PAHs in the coal gangue was ring-2 ring-3 ring-4 ring-5,ring-6.With respect to the migration pattern,two ring PAHs removed mainly in dissolved phase;three ring PAHs presenting a small amount of dissolved form,migrated mainly in the form of particles that became the dominant way to the multi-ring（≥4） PAHs.