Li Fei, Chen Yi-Dan, Zhou Zhen-Ming, Liao Xiao-Bin, Ma Hong-Fang, Yuan Bao-Ling
College of Civil Engineering, Huaqiao University, Xiamen 361021, China.
Huan Jing Ke Xue. 2016 Dec 8;37(12):4773-4779. doi: 10.13227/j.hjkx.201603155.
Perfluorooctanoic acid (PFOA), one of the most typical representatives of perfluoroalkyl surfactants (PASs), has relatively high detection rate and level of pollution, and the accumulation of PFOA in the environment has been a serious threat to human health and security of the whole ecological environment. Therefore, studies on anaerobic biodegradability of PFOA are very important for elucidation of its environmental fate. This study used anaerobic sludge from municipal sewage treatment plant (WWTP) and 5.0 mg·L vitamin B (VB) as catalysts for the degradation of PFOA in the anaerobic environment. The anaerobic biodegradability of PFOA was examined by liquid chromatography tandem mass spectrometry (LC-MS/MS) and ion chromatography while some indictors, such as molar recoveries of PFOA as well as concentrations of fluoride, acetate, 2H-PFOA (F(CF)CHFCOOH), and shorter chain (<C8) perfluorocarboxylates (PFCAs) etc., were selected according to the reductive degradation results reported by predecessors. The results indicated that the molar recoveries of PFOA significantly decreased from 101%±5% at the initial incubation (3 d) to 85.6%±3.9% at the end of incubation (250 d), while fluoride concentrations significantly increased from 0.59 mg·L±0.02 mg·L at the initial incubation (3 d) to 0.63 mg·L±0.02 mg·L at the end of incubation (250 d) in biodegradation samples. Meanwhile, certain amounts of acetate, 2H-PFOA, and short-chain PFCAs, the products of reductive degradation of PFOA reported by precursors, were detected in biodegradation samples. However, there was no significant difference between these indicators in biodegradation samples and their corresponding controls. Therefore, no evidences were found to certify the anaerobic biodegradability of PFOA under the conditions described in present study, though the microorganisms were able to obtain enough energy for growth from reductive defluorination of PFOA in the thermodynamic aspects.
全氟辛酸（PFOA）是全氟烷基表面活性剂（PASs）最典型的代表之一，具有较高的检出率和污染水平，其在环境中的积累已对人类健康和整个生态环境安全构成严重威胁。因此，研究PFOA的厌氧生物降解性对于阐明其环境归宿非常重要。本研究以城市污水处理厂（WWTP）的厌氧污泥和5.0 mg·L维生素B（VB）作为催化剂，在厌氧环境中降解PFOA。采用液相色谱串联质谱法（LC-MS/MS）和离子色谱法检测PFOA的厌氧生物降解性，并根据前人报道的还原降解结果，选择了一些指标，如PFOA的摩尔回收率以及氟化物、乙酸盐、2H-PFOA（F(CF)CHFCOOH）和短链（<C8）全氟羧酸盐（PFCAs）等的浓度。结果表明，在生物降解样品中，PFOA的摩尔回收率从初始培养（3 d）时的101%±5%显著下降至培养结束（250 d）时的85.6%±3.9%，而氟化物浓度从初始培养（3 d）时的0.59 mg·L±0.02 mg·L显著增加至培养结束（250 d）时的0.63 mg·L±0.02 mg·L。同时，在生物降解样品中检测到了一定量的乙酸盐、2H-PFOA和短链PFCAs，这些都是前人报道的PFOA还原降解产物。然而，生物降解样品中的这些指标与其相应对照之间没有显著差异。因此，尽管从热力学角度来看，微生物能够通过PFOA的还原脱氟获得足够的能量用于生长，但在本研究描述的条件下，未发现证明PFOA厌氧生物降解性的证据。
