University of Ottawa, Ottawa, Ontario, Canada; York University, Toronto, Ontario, Canada.
Emergencies Science and Technology Section, Environment and Climate Change Canada, Ottawa, Ontario, Canada.
Environ Pollut. 2021 Oct 1;286:117286. doi: 10.1016/j.envpol.2021.117286. Epub 2021 May 3.
The Peace-Athabasca Delta (PAD) receives a mixture of hydrocarbons from biogenic, pyrogenic, and petrogenic processes. Source apportionment in the PAD has focussed on polycyclic aromatic compounds (PACs), which are ubiquitous in the environment and susceptible to weathering. In contrast, petroleum biomarkers of terpanes, hopanes, and steranes are degradation-resistant organic compounds found uniquely in petroleum products that can identify the input and origin of petrogenic hydrocarbons (PHCs). We provide an analysis of environmentally-relevant PHCs (including n-alkanes, PACs, and petroleum biomarkers) in surficial sediments of strategically selected lakes in the Athabasca and Peace deltas and adjacent boreal uplands. Alkanes were found to be predominately biogenic in all lakes. PAC sources were identified as wood combustion in the upland boreal lakes, a mixture of petrogenic and pyrogenic combustion in two closed-drainage lakes in the Peace Delta, and predominately petrogenic in two flood-prone Athabasca Delta lakes. Using multivariate analyses, raw Alberta oil sands were identified as a potential source of PHCs to the two flood-prone lakes in the Athabasca Delta. Biomarkers of terpanes and hopanes were identified in the Peace Delta and boreal uplands, likely from bitumen and transported atmospherically. These findings validate the use of petroleum biomarkers as tracers for bituminous sands in surficial lake sediments and their potential use in paleolimnological investigations at the PAD to improve understanding of relative roles of natural and industrial processes on far-field deposition of PHCs.
和平-阿萨巴斯卡三角洲（PAD）接收来自生物成因、热成因和石油成因过程的碳氢化合物混合物。在 PAD 中的源分配主要集中在多环芳烃（PACs）上，这些化合物在环境中无处不在，容易风化。相比之下，萜烷、藿烷和甾烷等石油生物标志物是在石油产品中发现的具有抗降解性的有机化合物，可用于识别石油成因烃类（PHC）的输入和来源。我们对阿萨巴斯卡和和平三角洲以及相邻的北方旱地中具有战略意义的选定湖泊的表层沉积物中的环境相关 PHC（包括正构烷烃、PAC 和石油生物标志物）进行了分析。在所有湖泊中，烷烃均被认为主要是生物成因的。PAC 来源被确定为北方旱地内陆湖泊的木材燃烧，和平三角洲两个封闭排水湖中混合了石油成因和热成因燃烧，而两个易受洪水影响的阿萨巴斯卡三角洲湖中则主要是石油成因。使用多元分析，艾伯塔省油砂被确定为两个易受洪水影响的阿萨巴斯卡三角洲湖泊中 PHC 的潜在来源。萜烷和藿烷的生物标志物在和平三角洲和北方旱地中被发现，可能来自沥青并通过大气传输。这些发现验证了使用石油生物标志物作为表层湖泊沉积物中沥青砂的示踪剂的有效性，以及它们在 PAD 古湖泊学研究中的潜在用途，以提高对自然和工业过程在远场 PHC 沉积中的相对作用的理解。
