微生物电化学修复中污染土壤生化特性变化

Changes of Soil Biochemical Characteristics in Microbial Electrochemical Remediation of Contaminated Soil

为探明土壤酶和pH在微生物电化学系统(MES)降解四环素过程中的作用,采集了黑土、潮土、黄棕壤和红壤4种类型土壤进行研究。结果表明:向黑土、潮土和红壤中添加10 mg/kg四环素后(TN处理)土壤pH较对照处理(CK,无抗生素添加)分别增加了0.08、0.15、1.09个单位,而经MES处理后(TC,四环素含量10 mg/kg)4种类型土壤中pH均呈降低趋势。尽管土壤脱氢酶、脲酶和多酚氧化酶活性在四环素污染土壤中展现出不同的变化规律,但其活性在MES中较TN处理分别增加了62.4%~72.1%、11.3%~80.9%(红壤除外)和12.6%~42.6%。与TN相比,四环素降解率在TC处理中分别增加了14%(黑土)、26%(潮土)、26%(黄棕壤)和17%(红壤)。相关性分析表明,脱氢酶活性与四环素降解率呈显著正相关,pH与降解率显著负相关,说明脱氢酶可能参与了降解四环素过程,且酸性条件可能更有利于降解。该试验从土壤生化特性角度揭示了MES对四环素的降解机理,可为土壤污染修复提供支撑。

To explore the role of soil enzymes and pH in the degradation of tetracycline in Microbial Electrochemical Systems(MES),four types of soils including black soil,moisture soil,yellow brown soil and red soil were collected for study.The results showed that after adding tetracycline(TN treatment,10 mg/kg)to black soil,moisture soil and red soil,the values of pH increased by 0.08,0.15 and 1.09 units respectively compared with the control treatment(CK,without tetracycline addition).However,in MES treatment(TC,tetracycline concentration 10 mg/kg),the values of pH in the four types of soil all showed downward trend.Although the soil dehydrogenase,urease and polyphenol oxidase activities exhibited different variation trends in tetracycline contaminated soil,their activities in MES increased by 62.4%-72.1%,11.3%-80.9%(except red soil)and 12.6%-42.6%compared with TN treatment,respectively.Meanwhile,the degradation rate of tetracycline in TC treatment was respectively increased by 14%(black soil),26%(moisture soil),26%(yellow brown soil)and 17%(red soil)compared with TN treatment.Correlation analysis indicated that dehydrogenase activity showed significant positive correlation with tetracycline degradation rate,while pH showed significant negative correlation with degradation rate,indicating that dehydrogenase might participate in the process of tetracycline degradation,and acidic conditions may be more conducive to degradation.This experiment revealed the degradation mechanism of tetracycline by MES based on soil biochemical characteristics,which could provide important support for soil pollution remediation.