Applied Environmental Research Laboratories, Department of Chemistry, Vancouver Island University, 900 Fifth Street, Nanaimo, British Columbia V9R 5S5, Canada; Department of Chemistry, University of Victoria, PO Box 1700 Stn CSC, Victoria, British Columbia V8W 2Y2, Canada.
Natural Resources Canada, CanmetENERGY Devon, 1 Oil Patch Drive, Devon, Alberta T9G 1A8, Canada.
Sci Total Environ. 2021 Apr 15;765:144206. doi: 10.1016/j.scitotenv.2020.144206. Epub 2020 Dec 25.
Crude oil spills have well-documented, deleterious impacts on the hydrosphere. In addition to macroscopic effects on wildlife and waterscapes, several classes of petroleum derived compounds, such as naphthenic acids (NAs) and polycyclic aromatic hydrocarbons (PAHs), may be released into the water and present aquatic contamination hazards. The concentrations of these contaminants may be affected by both oil type and water chemistry. We characterize the concentrations of NAs and PAHs in natural and constructed waters, spanning a range of pH and salinity, and directly compare the influence of diluted bitumen (DB) and conventional crude (CC) oil, using condensed-phase membrane introduction mass spectrometry (CP-MIMS) as a direct sampling, on-line technique. The concentration and isomer class profiles of classical NAs in the aqueous phase were assessed using electrospray ionization in negative-ion mode as [M-H] whereas PAH concentrations were monitored using liquid electron ionization (LEI) in positive-ion mode as [M]. NA concentrations (0.03-25 ppm) were highly pH-dependent, and an order of magnitude greater in water samples contaminated with DB than CC. Conversely, concentrations of naphthalene (10-130 ppb) and alkyl-naphthalenes (10-90 ppb) were three to four-fold higher in water samples exposed to CC. We demonstrate that naturally occurring dissolved organic matter does not bias results from the membrane sampling approach employed, and that DB and CC contaminated waters can be differentiated using principal component analysis of the NA isomer class distribution in both constructed and natural waters. Finally, we describe the first demonstration of the concurrent analysis of trace NAs and PAHs in the same water sample by controlling perm-selectivity at the membrane and the ionization mode of the mass spectrometer. The techniques employed here for trace analysis of petroleum derived compounds in water can be applied to rapid screening and real-time monitoring of contamination and remediation processes.
原油泄漏对水圈造成了有充分记录的有害影响。除了对野生动物和水域景观的宏观影响外，几类石油衍生化合物，如环烷酸（NAs）和多环芳烃（PAHs），可能会释放到水中，造成水生污染危害。这些污染物的浓度可能会受到油类型和水化学的影响。我们对天然和人工水中的 NAs 和 PAHs 浓度进行了特征描述，涵盖了一系列 pH 值和盐度范围，并使用凝聚相膜导入质谱（CP-MIMS）作为直接采样、在线技术，直接比较了稀释沥青（DB）和常规原油（CC）油的影响。采用负离子模式电喷雾电离（ESI）作为[M-H]评估水相中典型 NAs 的浓度和异构体类分布；采用正离子模式液体电子电离（LEI）作为[M]监测 PAH 浓度。NA 浓度（0.03-25 ppm）高度依赖于 pH 值，且受 DB 污染的水样中的浓度比 CC 高一个数量级。相反，在接触 CC 的水样中，萘（10-130 ppb）和烷基萘（10-90 ppb）的浓度则高 3 至 4 倍。我们证明，天然存在的溶解有机物不会影响膜采样方法的结果，并且可以通过对构建和天然水中的 NA 异构体类分布进行主成分分析，区分 DB 和 CC 污染的水。最后，我们描述了通过控制膜的渗透选择性和质谱的电离模式，在同一水样中同时分析痕量 NAs 和 PAHs 的首次演示。这里用于水中石油衍生化合物痕量分析的技术可用于快速筛选和实时监测污染和修复过程。
