多氯联苯复合污染土壤的土著微生物修复强化措施研究

通过室内模拟试验,以不同C源、C/N比、水分及通透性为调控因子,对多氯联苯(PCBs)长期复合污染土壤的土著微生物强化修复进行了初步研究。结果表明,PCBs长期复合污染土壤中,在土壤水分含量为田间持水量的60%时,加入淀粉、葡萄糖和琥珀酸钠均在一定程度上增加了细菌和真菌数量,从而促进土壤中PCBs的土著微生物降解。不同种类的C源对PCBs污染土壤的土著微生物降解效果存在明显差异,且其降解效果与C源的施用剂量密切相关。当淀粉加入量为C1.0g/kg土时,土壤中PCBs的降解效果较好,而葡萄糖和琥珀酸钠加入量为C0.2g/kg土时,PCBs的降解效果明显。土壤C/N比为10:1的处理效果优于C/N比为25:1和40:1。土壤人为翻动有利于PCBs污染土壤中细菌和真菌的生长,提高土著微生物的代谢活性,从而促进土壤中PCBs的自然降解。这为进一步探讨加速土壤中PCBs降解的最适条件和研发POPs污染土壤的生物修复技术提供了科学依据。

Enhanced Measures of Indigenous Microbial Remediation in Polychlorinated Biphenyls Polluted Soils

An incubation experiment was carried out with farmland soils severely contaminated by PCBs in the Yangtze River Delta Region under different carbon sources, ratios of carbon to nitrogen, and soil moisture contents. Starch, glucose and sodium succinate were beneficial to the growth of bacteria and fungi, thus accelerated the degradation of PCBs in polluted soils. The degradation effects of indigenous microorganism on soil PCBs were not only correlated with carbon sources, but also closely correlated with their starch, glucose and sodium succinate contents. When 1.0 gC/kg of starch, 0.2 gC/kg of glucose and sodium succinate were added to PCBs polluted soils, their effect on soil PCBs degradation increased. Effect of treatment at 10:1 carbon-to-nitrogen ratio was better than treatment at 40:1. The results also indicated that higher soil moisture content limited soil microbial growth and PCBs degradation, but soil stirring aided the growth of soil bacteria and fungi, enhanced the metabolic activities of indigenous microorganisms, and accelerated the natural degradation of soil PCBs. These results provided scientific evidence for further studies on the conditions under which natural degradation of soil PCBs occurs and could help to develop bioremediation techniques for POPs polluted soils.