水杨酸对多氯联苯污染土壤的修复和微生物群落结构的影响

Impacts of salicylic acid on polychlorinated biphenyl removal and microbial community structure in historically PCB-contaminated soil

以浙江省台州电子垃圾拆解地附近多氯联苯污染的农田土壤为研究对象,考察了施肥基础上添加不同剂量水杨酸（5、10、20 mmol·kg^-1）对土壤中多氯联苯的去除、脱氢酶活、微生物群落结构及联苯双加氧酶基因相对丰度的影响.结果表明,施肥和施肥基础上添加水杨酸均能显著提高多氯联苯的去除率（p〈0.05）,其中,三氯联苯的去除率最高（28.98%~34.53%）.土壤脱氢酶活与多氯联苯去除率随水杨酸添加量的升高呈先增大后减小的趋势,均在10 mmol·kg^-1水杨酸处理中达到最大.PCR-DGGE结果显示,水杨酸处理土壤中新增伯克氏菌属（Burkholderia）、潘多拉菌属（Pandoraea）、噬油脂极小单胞菌属（Pusillimonas）、鞘脂菌属（Sphingobium）、甲基杆菌属（Methylobacterium）和青枯菌属（Ralstonia）.Shannon指数表明,10 mmol·kg^-1水杨酸处理下土壤微生物最为丰富（p〈0.05）.荧光定量PCR显示,bph A基因在不同处理间没有显著差异,但施肥和施肥基础上添加10、20 mmol·kg^-1的水杨酸处理都显著提高了bph D.1.B、bph D.1.C、bph D.2.A和bph D.2.A/B基因的相对丰度.

This study evaluated the effects of nutrition and salicylic acid amendments on PCB removal,soil dehydrogenase activity,bacterial community structure and the relative abundance of bph A genes in long-term polychlorinated biphenyl-contaminated agricultural soil from an e-waste recycling center in Taizhou,Zhejiang Province. Nutrition and salicylic acid additions significantly increased PCB removal compared to the controls（ p〈0. 05） and trichlorinated biphenyls had the highest removal rates compared to higher chlorinated biphenyls. Similar trend was observed with PCB removal rate and soil dehydrogenase activity,and the highest PCB removal and soil dehydrogenase activity were observed in 10 mmol·kg^-1salicylic acid treatments. PCRDGGE profiles showed that Burkholderia sp.,Pandoraea sp.,Pusillimonas sp.,Sphingobium sp.,Methylobacterium sp. and Ralstonia sp. were only detected in salicylic acid treated soils. Shannon index showed that the microbial diversity was the highest in 10 mmol·kg^-1salicylic acid treatments（ p〈0. 05）. Real-time PCR revealed that no significant difference was observed in the relative abundance of bph A gene,while bph D. 1. B,bph D. 1. C,bph D.2. A and bph D. 2. A / B genes were significantly induced in nutrition and 10,20 mmol·kg^-1salicylic acid treatments.