[关键词]
[摘要]
为了查明制革污泥对包气带土壤的污染状况,以某制革污泥堆存场地内典型土壤剖面为研究对象,研究污泥渗滤液中特征污染物在包气带土壤埋深0~200 cm内的垂向分布特征,探讨不同形态氮及铬的分布规律,并采用高通量测序对土壤中的菌群组成进行了初步分析。结果表明:制革污泥成分复杂、浓度高,高浓度的含盐量(99000 mg/kg)、氮素(30900 mg/kg)及铬(30970 mg/kg)已对埋深20 cm以上的浅层土壤造成严重污染,污泥中大量有机质及酸性物质导致浅层土壤pH降低和总有机碳(TOC)增大。随着土壤埋深增加,各污染物浓度呈明显下降趋势,但在埋深200 cm处土壤中仍有一定浓度的有机氮(723 mg/kg)及含盐量(7070 mg/kg)检出。研究区呈碱性的壤土对铬迁移具有明显的阻滞作用,当土壤埋深大于40 cm,Cr(Ⅲ)浓度即下降至200 mg/kg,Cr(Ⅵ)浓度下降至小于2 mg/kg。高盐度、高铬污染对土壤中部分微生物生长具有抑制作用,变形杆菌门(Proteobacteria)、厚壁菌门(Firmicutes)及拟杆菌门(Bacteroidetes)成为受污染土壤中的优势种群。
[Key word]
[Abstract]
To find out the pollution status of tannery sludge to the soil in the unsaturated zone, we investigated the soil samples at the depth of 0-200 cm in a typical soil profile, and identified the vertical distribution characteristics of the main pollutants, especially the different forms of nitrogen and chromium. High-throughput sequencing was further applied to reveal the bacterial community structures of the soils. The results showed that the tannery sludge contained a variety of high-concentration contaminants, such as high salinity (99000 mg/kg), total nitrogen (30900 mg/kg) and total chromium (30970 mg/kg), which had caused heavy contamination to the surface soil above 20 cm depth. The sludge leachate containing a large amount of organic matter and acid compounds caused a decrease in pH and an increase in TOC of the surface soil. The concentration of pollutants decreased obviously with the increase in soil depth. However, low-concentration organic nitrogen (723 mg/kg) and salinity (7070 mg/kg) were still detected in the soil at the depth of 200 cm. The alkaline soil in the study area had a distinct retardation effect on the transfer of chromium. When the soil depth was deeper than 40 cm, the concentrations of Cr(Ⅲ) and Cr(Ⅵ) decreased to less than 200 mg/kg and 2 mg/kg, respectively. High-salinity and high-chromium contamination can inhibit the growth of some microorganisms in the soil, and Proteobacteria, Firmicutes and Bacteroidetes will become the dominant microbial population in the contaminated soil.
[中图分类号]
[基金项目]
河北省自然科学基金资助项目(D2016504014);中国地质科学院水文地质环境地质研究所基本科研业务费(SK201613)