多壁碳纳米管对土壤微生物的生态毒理效应

以多壁碳纳米管为研究对象,从生化作用、酶活性、微生物数量和群落结构4个方面系统评估其对土壤微生物的影响。设置两组实验,分别为碳纳米管组和对照组。对于碳纳米管组,按1mg碳纳米管·g-1土的浓度将多壁碳纳米管与土样均匀混合,对照组中不加入多壁碳纳米管。定期(每28d)取样测定两组土壤中的各项生态毒理指标。近5个月的实验结果显示,不同指标对多壁碳纳米管的响应不同。土壤呼吸作用初期受抑制但后期恢复,氨化作用初期被促进但后期被抑制,脱氢酶活性发生增强和抑制两次波动,荧光素二乙酸酯酶活性在整个实验期间一直被抑制,微生物量出现先减少后增加再减少的规律,群落结构在实验初期和后期均有较大变化。总体上,多壁碳纳米管对土壤微生物表现了一定的生态毒性,但除荧光素二乙酸酯酶活性外,各毒理效应在统计意义上并不显著(0.05水平)。

Ecotoxicological Effects of Multi-Wall Carbon Nanotube on Soil Microorganisms

The effects of multi-wall carbon nanotube on soil microorganisms were systematically investigated from four aspects including biochemical reactions,enzyme activities,microbial biomass and community structure.Two group experiments were set up,i.e.,the carbon nanotube group and the control group.In the carbon nanotube group,the multi-wall carbon nanotube was mixed well with the soil at a concentration of 1 mg carbon nanotube per gram soil.Peirodically (28 days),soils were analyzed using ecotoxicological parameters.After near five months of experiments,the results showed that the changes of various factors were differently in the addition of multi-wall carbon nanotube.The soil respiration was inhibited in the beginning and recovered later.The ammonification was stimulated in the beginning while inhibited later.The dehydrogenase activity experienced two cycles of stimulation and inhibition.The fluorescein diacetate enzyme activity was inhibited all the time.The microbial biomass showed reduce-increase-reduce.The community structure obviously changed in both early and later stages of the experiments.Although the multi-wall carbon nanotube eco-toxicologically affected on soil microorganisms to some degree,except for the fluorescein diacetate enzyme activity,the eco-toxicological effects were not statistically significant at 0.05 level.