• 关键词：PAHs  沉积物  生物降解  解吸

• 基金项目：国家自然科学基金资助项目(No.40571138,40871228)

• 李亦然
• 北京师范大学环境学院, 水环境模拟国家重点实验室, 北京 100875

• 夏星辉
• 北京师范大学环境学院, 水环境模拟国家重点实验室, 北京 100875

• 冯承莲
• 中国科学院生态环境研究中心, 北京 100085

• 呼丽娟
• 北京师范大学环境学院, 水环境模拟国家重点实验室, 北京 100875

• 张平
• 北京师范大学环境学院, 水环境模拟国家重点实验室, 北京 100875

• 摘要：从长江武汉段采集4个沉积物样品,向样品中添加菲后采用XAD-2大孔树脂模拟研究沉积物中吸附态菲的非生物解吸过程,并且利用从长江水样中分离纯化的菲降解菌进行吸附态菲的生物降解试验,比较吸附态菲的生物降解和非生物解吸过程.结果表明,菲的非生物解吸大致可分为快速、慢速和极慢速解吸3个阶段.在慢速解吸阶段,生物条件下沉积相菲浓度降低速率是其非生物解吸速率的1.9～4.0倍,微生物加速了菲从沉积物中的释放过程.微生物的活性影响沉积物中吸附态菲的微生物可利用性,在降解后期通过向体系添加微生物和营养盐,在保持微生物活性的条件下,生物降解时菲的固相残留值远小于非生物解吸条件下菲的固相残留值,吸附态菲的平均生物降解速率约为其解吸速率的1.2倍,且沉积物中与黑炭结合的菲也能部分被微生物利用.由此说明,沉积物中吸附态菲的解吸过程并不完全限制其微生物降解,微生物能够部分利用沉积物中较难解吸的吸附态菲.

• Abstract：The desorption and polycyclic aromatic hydrocarbon (PAH) biodegradation processes in Yangtze River sediments was studied. Sediment samples were collected from four sites of the Wuhan reaches of the Yangtze River; then spiked with phenanthrene.The abiotic desorption process of attached phenanthrene was studied using Amberlite XAD-2. PAH-degrading strains were isolated from the natural water of the Yangtze River, then enriched in laboratory conditions before being introduced into the experimental system. The abiotic desorption process of phenanthrene could be divided into three stages: fast, slow and very slow desorption. During the slow desorption stage, the rate of desorption of attached phenanthrene under microbial conditions was 1.9 to 4 times of the abiotic desorption rate. That is to say, the microbes accelerated the release of attached phenanthrene from the sediments. Microbial activity influenced the micro-bioavailability of attached PAHs. When the microbial activity was enhanced by adding nutritive salts and fresh microbes into the system in the late period of biodegradation, the residual concentrations of phenanthrene in the sediments were much lower than under abiotic conditions. Moreover, the average biodegradation rate of attached phenanthrene was 1.2 times as high as the abiotic desorption rate, and the phenanthrene attached to black carbon was partially micro-bioavailable. Therefore, desorption of the attached phenanthrene in sediments incompletely restricted the biodegradation process; furthermore, microbes could partly utilize the attached phenanthrene which was difficult to desorb.

• Key words：PAHs  sediment  biodegradation  desorption

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