环境中全氟辛基磺酸前体物好氧生物降解进展

目前，在土壤、大气、水体等各种环境介质中均检测到了全氟辛基磺酸（PFOS）及其前体物（PrePFOS）的存在.自然条件下，PrePFOS的非生物降解量可以忽略不计，其生物降解的途径和降解量是预测未来PFOS环境行为的基础.本文对PrePFOS在环境介质中的分布以及生物降解进行了综述.在所有的PrePFOS中，关于N-乙基全氟辛基磺酰胺乙醇（EtFOSE）的研究较深入，其在土壤、活性污泥、沉积物中的降解途径及PFOS产量均有报道，EtFOSE的降解速度及其PFOS产量与介质的理化性质、微生物群落结构密切相关，N-乙基全氟辛基磺酰胺乙酸（EtFOSAA）脱羧转化为N-乙基全氟辛基磺酰胺（EtFOSA）是EtFOSE转化为PFOS的主要限速步骤.最新关于EtFOSE在土壤中的好氧生物降解的研究首次提出全氟辛基磺酰胺乙酸（FOSAA）脱羧形成全氟辛基磺酰胺（FOSA）是EtFOSE转化成PFOS的另外一个可能的限速步骤.全氟辛基磷酸酯（DiSAmPAP）在沉积物中的半衰期>380d，其可能的降解途径是先降解为EtFOSE，之后降解为PFOS.最后，在已有研究基础上，提出目前PrePFOS研究存在的问题及今后的研究方向.

Aerobic biodegradation of perfluorooctane sulfonateprecursors in different environment media

As one of persistent organic pollutants, perfluorooctane sulfonate (PFOS) has been widely detected in various environmental media and shows multiple toxic effects on human and animals. One of its main sources is from the biotransformation of PFOS precursor (PrePFOS). PFOS and PrePFOS have been found in various environmental media like soil, air and water. Understanding the biodegradation pathway and PFOS yield of PrePFOS are useful to predict the environmental fata of PFOS due to that its PFOS yield from abiotic degradation could be ignored. In this study, the occurrence and biodegradation of PrePFOS in different environmental media were summarized. Of all the PrePFOS, N-ethyl perfluorooctane sulfonamidoethanol (EtFOSE) were mostly explored. Its biodegradation pathway and PFOS yield have been studied in soil, activated sludge, and sediment, which have found that its biodegradation mechanism is closely related with the physicochemical properties and microbial community structure of the medium. The decarboxylation of N-ethyl perfluorooctane sulfonamidoacetic acid (EtFOSAA) to N-ethyl perfluorooctane sulfonamide (EtFOSA) is the main rate-limiting step for the conversion of EtFOSE to PFOS. The latest research on aerobic biodegradation of EtFOSE in soil first proposed that decarboxylation of perfluorooctane sulfonamidoacetic acid (FOSAA) to perfluorooctane sulfonamide (FOSA) might be another rate-limiting step in the conversion of EtFOSE to PFOS. EtFOSE-Based Phosphate Diester (DiSAmPAP) had been widely used in various commercial products before 2003, and it had not been detected in sediment until 2012 due to its high Kow value and the lack of detection technology. Its half-life was predicted to be > 380d and it might be biodegradated into EtFOSE firstly and finally transformed into PFOS. And the existing problems and future research direction were discussed too.