Microbial PAH-Degradation in Soil： Degradation Pathways and Contributing Factors

Adverse effects on the environment and high persistence in the microbial degradation and environmental fate of polycyclic aromatic hydrocarbons （PAHs） are motivating interest. Many soil microorganisms can degrade PAHs and use various metabolic pathways to do so. However, both the physio-chemical characteristics of compounds as well as the physical, chemical, and biological properties of soils can drastically influence the degradation capacity of naturally occurring microorganisms for field bioremediation. Modern biological techniques have been widely used to promote the efficiency of microbial PAH-degradation and make the biodegradation metabolic pathways more clear. In this review microbial degradation of PAHs in soil is discussed, with emphasis placed on the main degradation pathways and the environmental factors affecting biodegradation.     

土壤-植物系统铜污染与修复的研究进展

综述了近几年来国内外土壤-植物系统铜污染的研究态势,包括铜胁迫下土壤生态系统的响应、铜的土壤行为、铜污染土壤的生物修复特别是植物修复、以及未来的研究展望,以推动国内铜污染土壤治理的进一步研究.     

Plant- and microbe-assisted biochar amendment technology for petroleum hydrocarbon remediation in saline-sodic soils: A review

Soil degradation through salinization and pollution by toxic compounds such as petroleum hydrocarbons(PHCs) in the coastal wetlands has become a significant threat to ecosystem health, biodiversity, and food security. However, traditional remediation technologies can generate secondary pollutants, incur high operating costs, and consume significant quantities of energy. Bioremediation, using plants, biochar, and microbes, is an innovative and cost-effective option to remediate contaminated soils. Biochar, as a plant/microbe growth enhancer, is a promising green approach for the sustainable phytoremediation of PHCs in salinized soils. This review therefore summarizes the effect of plant-and microbe-assisted biochar amendment technology for the remediation of PHCs and salinization. Plant-microbe interactions mediated rhizodegradation despite increasing hydrocarbon sorption. Overall, microbial respiration is more active in biochar amendments, due to faster biodegradation of PHCs and improved soil properties. The use of biochar, plants, and microbes is recommended,as it offers a practical and sustainable option, both ecologically and economically, for the remediation of PHCs and excess salinity. Further development of new green technologies is to be encouraged.     

污染底泥修复技术进展

综述污染底泥的修复技术,探讨其发展状况及存在的问题。目前主要有疏浚、掩蔽等物理修复技术和生物修复技术。物理修复效果明显,但工程量大,投入大;生物修复具有投入低,处理量大,但速度慢,且难以达标。从经费投入和处理效果来看,底泥修复应发展疏浚和生物处理相结合,实现底泥的资源化再利用。在做好污染底泥处理的同时,关键要控制污染源的排放。     

生物通风技术中微生物对污染物甲苯二种形式降解的对比研究

在实验室，用一维土柱模拟地下土壤环境，对不饱和区甲苯的2种污染形式的去除进行了研究。通过试验结果计算表明，土壤中污染物甲苯的总修复效率达到95．1％～98％，甲苯在土壤中以水相和非水相液体(NAPL)存在时，修复时间分别是220h和500h．约有42％和20．6％的甲苯是被微生物降解。由于NAPL试验初始阶段较高浓度甲苯对微生物有毒性或抑制作用，在试验初期主要是通风修复，试验后期生物降解作用才更加明显。     

芘降解菌株的筛选及降解条件的研究

为了筛选高效多环芳烃芘的降解菌株并研究其降解条件,为生物修复多环芳烃污染土壤提供科学依据和实验材料,从长期受石油污染土壤中分离筛选得到一株芘降解菌B4,初步鉴定为假单胞菌属(Pseudomonassp.)。并采用室内培养方法,研究了该菌株降解芘的特性及各种环境条件对降解效能的影响。结果表明,菌株B4在28℃振荡培养条件下,对50mg.L-1的芘降解率为91.70%,芘的降解与细菌数量的增长呈正相关关系。加入水杨酸(50mg.L-1)作为共代谢底物,降解率可达到95.55%。当pH为4、盐浓度高于5%时,菌株B4不生长。对菌株B4在重金属离子胁迫下对芘的降解研究发现,在一定浓度下,Pb2 与Zn2 的存在对B4的降解效能影响较小,Cu2 对菌株的生长具有一定的抑制作用,Cd2 对菌株B4有毒性。     

In situ remediation of petroleum hydrocarbon contaminated groundwater using a novel biobarrier

A novel biobarrier, whose reaction media consist of functional microbes, peat and coarse sand, is tested in laboratory to study the effect and the related mechanism in remediation of petroleum hydrocarbon contaminated groundwater. The results show that the removal efficiency for BTEX, naphthalene hydrocarbons and phenanthrene are 83.6%~99.85%, in which 71.23%~99.71% contaminants are removed at the first half part of biobarrier. The peat and functional microbes function steadily in contaminant sorption and biodegradation. 32.63%~77.98% BTEX and 97.14%~99.81% target PAHs are absorbed by peat and 18.96%~50.98% BTEX and almost all of the peat-absorbed petroleum hydrocarbon contaminants are degraded by microbes. Contaminant biodegradation can efficiently prolong the sorption life of peat barrier, and the efficient nutrients supply from peat to functional microbes can maintain the biomass at a relatively high level in the biobarrier, i.e. about 3.46×106~6.16×109 per gram dry media. Therefore, the novel biobarrier technology can be efficiently used in in-situ remediation of petroleum hydrocarbon contaminated groundwater.     

污泥农用后有机复合污染土壤强化修复初步研究

通过室内模拟试验,以持久性有机污染物（POPs）中毒性较强的多氯代有机污染物多氯联苯（PCBs）和有机氯农药（OCPs）为目标污染物,以不同碳源和水分条件为调控因子,研究了淀粉和葡萄糖等不同来源的碳、水分条件及其联合措施对污泥农用后多氯联苯（PCBs）和有机氯农药（OCPs）复合污染的长江三角洲地区土壤中两种有机污染物的削减影响及其贡献大小.结果表明,土壤水分含量为正常田间持水量时,加入淀粉和葡萄糖等碳源均一定程度地促进了真菌和细菌数量的增加,从而促进了土壤中PCBs和OCPs的降解;淹水可促进土壤中PCBs的降解,在一定程度上也促进了土壤中OCPs的降解.     

土壤污染的防治技术

本文概述了土壤铅污染的特点及现状,并分析评论了铅污染防治的三种主流技术,即:物理控制法、化学控制法和生物修复法,指出了各自优缺点.并在此基础上提出一些见解和看法,为今后这方面的研究提供一些参考.     

农药污染土壤的生物修复技术介绍

介绍了农药污染土壤的几种常用的生物修复技术,如反应器处理、堆肥、土地耕作等,并列举了各类技术的典型工艺及其运行的效果。