硝酸盐对土壤PAHs去除及反硝化过程的剂量效应  

Dosage effect of nitrate on the anaerobic PAHs removal and denitrification process in soil

作　　者：宋可歆 程永毅[1] 王明霞[1] 周志峰[1] SONG Kexin;CHENG Yongyi;WANG Mingxia;ZHOU Zhifeng(College of Resources and Environment,Southwest University,Chongqing 400716)

机构地区：[1]西南大学资源环境学院,重庆400716

出　　处：《环境科学学报》2023年第10期187-194,共8页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金(No.41771501)。

摘　　要：为探究反硝化电子受体(硝酸根,NO_(3)^(-))与土壤多环芳烃(Polycyclic aromatic hydrocarbons,PAHs)去除及反硝化过程间的剂量效应关系,开展了添加梯度浓度NO_(3)^(-)(单批添加0、5、10、20、40 mg·kg^(-1);间歇式添加20 mg·kg^(-1),每次添加5 mg·kg^(-1))和典型PAHs(菲和苯并芘)的厌氧土壤微宇宙培养实验.期间,动态监测土壤N_(2)O和CO_(2)的产生速率;培养结束后,测定土壤PAHs含量并计算其去除率,同时利用定量PCR检测土壤样品的反硝化功能基因(cd_(1)-nitrite reductase gene,nirS;cooper-containing nitrite reductase gene,nirK)丰度.结果表明,在0~40 mg·kg^(-1)的NO_(3)^(-)添加范围内,均能促进土壤菲(最高促进率为88.46%)或苯并芘(最高促进率为15.93%)的厌氧去除;对低分子量PAHs(菲)去除的促进作用更为明显,并表现出明显的正剂量效应关系.NO_(3)^(-)的添加显著增强了各PAHs处理土壤的N2O及CO_(2)产生速率,且对高分子量PAHs(苯并芘)处理土壤的效应更为强烈(40 mg·kg^(-1)硝酸盐处理下,其N2O和CO_(2)产生速率分别较菲处理土壤高5.7和3.9倍);此外,苯并芘处理土壤的nirS及nirK基因丰度均显著高于菲处理土壤,表明土壤反硝化活性(N2O产生速率)与其中反硝化微生物丰度之间的对应关系.与单批添加相比,间歇式添加NCO_(3)^(-)处理未能显著提升土壤PAHs的去除率,但其在培养后期具有显著高于其它处理的反硝化基因丰度及CO_(2)产生速率.综上,NO_(3)^(-)与土壤PAHs厌氧去除及反硝化活性之间的剂量效应因PAHs的类型而异,即在0~40 mg·kg^(-1)的NO_(3)^(-)剂量内,更有利于促进土壤低分子量PAHs的厌氧去除,但更能激发高分子量PAHs处理土壤的反硝化活性.To investigate the relationships among the electron acceptor(nitrate,NO_(3)^(-))dosage,anaerobic removal of polycyclic aromatic hydrocarbon(PAHs),and denitrification process in soil,the soil samples spiked with representative PAHs(phenanthrene,PHE;benzopyrene,BEN)were prepared,and then a soil microcosm-incubation experiment amended with a gradient of nitrate(single batch addition:0,5,10,20,40 mg·kg^(-1);multiple batch addition:5 mg·kg^(-1)·7 d^(-1),five times of addition)was conducted.During the incubation,the dynamic changes of soil N_(2)O and CO_(2) emission were monitored,and the soil PAHs contents and abundances of denitrification-related genes(cd1-nitrite reductase gene,nirS;coopercontaining nitrite reductase gene,nirK)were detected at the end of incubation.The results showed that nitrate addition within the range of 0~40 mg·kg^(-1) promoted the anaerobic removal rates of PHE(with the highest promoting rate of 88.46%)and BEN(with the highest promoting rate of 15.93%),and a more efficient promotion was observed for the low-molecular-weight PAHs(PHE),showing a significantly positive relationship with the dosage of nitrate.Although nitrate amendment significantly promoted the generation rates of N_(2)O and CO_(2) in each PAHs-spiked soil,a stronger promotion was detected in the high-molecular-weight PAHs(BEN)treatments,which were 5.7(NO_(2))and 3.9(CO_(2))times higher than those of the PHE treatment with the nitrate addition of 40 mg·kg^(-1),respectively.The BEN treatments had higher abundances of nirS and nirK than the PHE treatment,indicating a positive relationship between soil N_(2)O generation rate and denitrification gene abundance.Compared with the single-batch addition,the treatments with multiple-batch addition of nitrate did not increase the PAHs anaerobic removal rate but improved the abundances of denitrifier genes and CO_(2) generation rate in the middle and late stages during the incubation.In summary,the dosage effect of nitrate on soil PAHs anaerobic removal and denitrification process vari

关 键 词：反硝化 PAHs去除 硝酸盐 剂量效应 

分 类 号：X53[环境科学与工程—环境工程]