土壤微生物活性对石油原油、铅镉及其复合污染的响应

随着工农业生产的迅猛发展、石油原油及重金属等原材料的广泛开采与使用,使石油原油、重金属及其复合污染日趋加重,对环境及人类的危害也越来越大.采用室内培养试验,利用人工模拟污染土壤,研究石油原油、铅镉及其复合污染胁迫对土壤微生物活性的影响.试验设置4个处理:1新鲜土壤(S)作为对照;21000 mg·kg~(-1)石油原油污染土壤(SP);3500 mg·kg~(-1)铅和50 mg·kg~(-1)镉污染土壤(SH);41000mg·kg~(-1)石油原油污染、500 mg·kg~(-1)铅和50 mg·kg~(-1)镉复合污染土壤(SPH).结果表明:与对照相比,SH、SP、SPH处理土壤基础呼吸强度最高分别增加约100.99%、36.61%、25.80%,铅镉污染(SH)对土壤基础呼吸影响最显著,反映出重金属污染对土壤基础呼吸的激活作用最强;石油原油污染(SP)与石油原油及铅镉复合污染(SPH)刺激土壤微生物量碳增加,SP处理最高增加了90.25%,而铅镉污染(SH)则使土壤微生物量碳减少.不同土壤酶对污染处理的响应不同,其中,石油原油污染(SP)对FDA水解酶及脱氢酶活性表现为激活作用;石油原油或石油原油及铅镉复合污染(SP、SPH)对脲酶及过氧化氢酶活性主要表现为激活作用,而铅镉污染(SH)对脲酶及过氧化氢酶活性主要表现为抑制作用.该研究表明,石油原油及铅镉复合污染对土壤微生物活性的影响与石油原油或铅镉污染的影响不同,它们之间存在着明显的交互作用.

Responses of soil microbial activities to oil, lead, cadmium and their combined contaminations

With rapid agricultural and industrial development, oil, heavy metal and their combined contaminations caused by wide use of oil and heavy metals worsened, posing increasing threats to environments and human beings. In this study, we set up a laboratory experiment to explore the effects of oil, lead, cadmium and their combined contaminations on soil microbial activities by simulating soil contamination. There were 4 treatments in this experiment:1soil (S) as the control, 21000 mg·kg^-1 oil contaminated soil (SP), 3500 mg·kg^-1 lead and 50 mg·kg^-1 cadmium contaminated soil (SH), and 4 1000 mg·kg^-1 oil, 500 mg·kg^-1 lead and 50 mg·kg^-1 cadmium combined contaminated soil (SPH). Compared with the control, the peaks of basal soil respiration in SH, SP and SPH increased by about 100.99%, 36.61% and 25.80%, respectively. The basal soil respiration was enhanced to the greatest extent in SH, suggesting a strongest impact of heavy metal contamination on basal soil respiration. Soil microbial biomass carbon (C_mic) was also enhanced in SP and SPH, with the most increase at 90.25% in SP compared to the control. In contrast, C_mic decreased in SH. In addition, various soil enzymes had different responses to soil contamination. Among them, the activities of FDA hydrolase and dehydrogenase were enhanced in SP. While the activities of urease and catalase were also enhanced in SP and SPH, they were inhibited in SH. These results show significant interaction in the effects of oil, lead and cadmium on soil microbial activities.