Han Xiumei, Scott Angela C, Fedorak Phillip M, Bataineh Mahmoud, Martin Jonathan W
Department of Laboratory Medicine and Pathology, Division of Analytical and Environmental Toxicology, 10-102 Clinical Sciences Building, University of Alberta, Edmonton, AB, T6G 2G3, Canada.
Environ Sci Technol. 2008 Feb 15;42(4):1290-5. doi: 10.1021/es702220c.
Large volumes of toxic aqueous tailings containing a complex mixture of naphthenic acids (NAs; CnH2n+ZO2) are produced in northern Alberta by the oil sands industry. Because of their persistence and contribution to toxicity, there is an urgent need to understand the fate of NAs under a variety of remediation scenarios. In a previous study, we developed a highly specific HPLC-high resolution mass spectrometry method for the analysis of NAs. Here we apply this method to determine quantitative structure-persistence relationships and kinetics for commercial NAs and NAs in oil sands process water (OSPW) during aerobic microbial biodegradation. Biodegradation of commercial NAs revealed thatthe mixture contained a substantial labile fraction, which was rapidly biodegraded, and a recalcitrant fraction composed of highly branched compounds. Conversely, NAs in OSPW were predominantly recalcitrant, and degraded slowly by first-order kinetics. Carbon number (n) had little effect on the rate of biodegradation, whereas a general structure-persistence relationship was observed indicating that increased cyclization (Z) decreased the biodegradation rate for NAs in both mixtures. Time to 50% biodegradation ranged from 1 to 8 days among all NAs in the commercial mixture, whereas half-lives for OSPW NAs ranged from 44 to 240 days, likely a result of relatively high alkyl branching among OSPW NAs. It is anticipated that these data will facilitate development of strategic solutions for remediating billions of cubic meters of OSPW stored, or predicted to be generated, in Northern Alberta.
艾伯塔省北部的油砂行业产生了大量含有环烷酸（NAs；CnH2n + ZO2）复杂混合物的有毒水性尾矿。由于它们的持久性和对毒性的影响，迫切需要了解在各种修复方案下NAs的归宿。在先前的一项研究中，我们开发了一种用于分析NAs的高特异性高效液相色谱 - 高分辨率质谱方法。在此，我们应用该方法来确定商业NAs以及油砂工艺水（OSPW）中的NAs在需氧微生物生物降解过程中的定量结构 - 持久性关系和动力学。商业NAs的生物降解表明，该混合物包含大量易降解部分，其迅速被生物降解，以及由高度支化化合物组成的难降解部分。相反，OSPW中的NAs主要是难降解的，并且通过一级动力学缓慢降解。碳原子数（n）对生物降解速率影响不大，而观察到一种普遍的结构 - 持久性关系，表明环化程度增加（Z）会降低两种混合物中NAs的生物降解速率。商业混合物中所有NAs的50%生物降解时间范围为1至8天，而OSPW中NAs的半衰期范围为44至240天，这可能是由于OSPW中NAs的烷基支化程度相对较高所致。预计这些数据将有助于制定战略解决方案，以修复在艾伯塔省北部储存或预计产生的数十亿立方米的OSPW。
