2种秸秆固定化M1对3环PAHs污染土壤修复效果研究

Study on remediation effect of immobilized M1 with two kinds of straw on 3-ring PAHs contaminated soil in coal mining area

试验采用"吸附-包埋-交联法"研究玉米秸秆和番茄秸秆固定化芽孢杆菌M1对河北唐山典型煤矿区农田土壤3环PAHs的修复效果。结果表明:玉米和番茄秸秆固定化M1(Y1M1、X1M1)显著提高了芽孢杆菌M1对煤矿区3环PAHs污染土壤的去除率,均以单体芴(Flu)降解效果最好,去除率高达95.78%和94.97%。玉米固定化M1菌比微球基质对照的降解提升幅度(22.13%~75.85%)远高于番茄秸秆固定化M1菌(13.69%~16.33%)。进一步分析与PAHs降解有关的土壤酶活性变化发现,土壤过氧化氢酶和多酚氧化酶活性在两种秸秆固定化M1处理之间存在着显著差异,X1M1处理土壤过氧化氢酶活性是Y1M1的1.15倍,而土壤多酚氧化酶活性Y1M1却比X1M1提高了29.21%。微生物多样性结果分析发现,接种固定化M1后土壤群落多样性和丰富度明显改变,固定化M1后两种秸秆对Chao指数和Shannon指数均表现为X1M1>Y1M;添加不同固定化M1处理的菌群在属水平的分布最广的是Bacillus(芽孢杆菌属),分布范围为1.31%~2.23%,而Bacillus(芽孢杆菌属)、Kaistobacter(幽门螺旋杆菌属)、Balneimonas(芽生杆菌属)、DA101和Aeromicrobium(气微菌属)优势菌属结构变化可能是诱导土壤3环PAHs降解的重要因素。综上,番茄秸秆也可作为固定化微生物载体材料,为原位土壤3环PAHs的修复技术应用提供理论依据,同时为作物秸秆的资源化利用开辟新途径。

In this research, maize and tomato straws were used as the immobilized carrier materials of Bacillus sp. M1, and the soil contaminated by 3-ring PAHs in coal mining area of Heibei Tangshan was used as the repair object. The soil repair experiment was used to study the repair effect of two kinds of straw immobilized M1. The results showed that the immobilized M1 (Y1M1, X1M1) of maize and tomato straws significantly increased the removal rate of Bacillus sp. M1 to the contaminated soil of 3-ring PAHs in coal mining area, and the best degradation rate was achieved by single strontium (Flu), with the removal rate as high as 95.78% and 94.97%. The degradation rate of maize immobilized M1 bacteria compared with microsphere matrix control (22.13%-75.85%) was much higher than that of tomato straw immobilized M1 bacteria (13.69%-16.33%). Further analysis of soil enzyme activity changes related to PAHs degradation revealed that soil catalase and polyphenol oxidase activities were significantly different between the two straw immobilized M1 treatments. Soil catalase activit of X1M1 treatment was 1.15 times of Y1M1 treatment, while soil polyphenol oxidase activity of Y1M1 was 29.21% higher than that of X1M1. The results of microbial diversity analysis showed that the diversity and richness of soil community changed significantly after immobilized M1. After immobilized M1, the two straws showed X1M1>Y1M1 for Chao index and Shannon index. The most widely distributed genus of bacteria treated with different immobilized M1 is Bacillus, with a range of 1.31%-2.23%, while the structural changes in the dominant genus of Bacillus, Kaistobacter, Balneimonas, DA101 and Aeromicrobium may be important factors in inducing the degradation of 3-ring PAHs in soil. In summary, tomato straw can also be used as an immobilized microbial carrier material, which provides a theoretical basis for the application of in situ soil 3-ring PAHs repair technology, and opens up new ways for the utilization of crop straw resources.