Yang Zeyu, Zhang Gong, Hollebone Bruce P, Brown Carl E, Yang Chun, Lambert Patrick, Wang Zhendi, Landriault Mike, Shah Keval
Emergencies Science and Technology Section, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, ON, K1A0H3, Canada.
Emergencies Science and Technology Section, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, ON, K1A0H3, Canada.
Environ Pollut. 2017 Dec;231(Pt 1):622-634. doi: 10.1016/j.envpol.2017.08.043. Epub 2017 Aug 29.
Two types of diluted bitumen (dilbit) and a light crude oil spiked onto the surface of saltwater were irradiated with natural solar light in Ottawa to assess the impact of sunlight to the fate of oxygenated intermediates. Oxygenated components, including carbonyl polycyclic aromatic hydrocarbons (PAHs) and acidic polar fractions (naphthenic acid fraction compounds, NAFCs), were identified after periods of solar exposure under both winter and summer conditions. Carbonyl PAHs and NAFCs were formed in both seasons; however, light crude and summer irradiation produced higher abundance of them than dilbits and winter exposure. The formed NAFCs were abundant with the congeners containing a heteroatom of oxygen only (O species), accompanied by the minor amounts of sulfur- and nitrogen-containing acids. The produced O species were predominant with the congeners with light molecular weight, high degree of saturation and heavy oxygen numbers. For both carbonyl PAHs and NAFCs, their abundance continually increased throughout the period of winter exposure. In the summer, some carbonyl PAHs and all O species increased during the early exposure period; then they decreased with continued exposure for most oils, illustrating their transitional nature. Oxygenated intermediates thus appear to have been created through the photo-oxidation of non-to medium-polar petroleum hydrocarbons or the intermediates of aldehydes or ketones (O). Oil properties, the duration of exposure, exposure season and the chemical structure of these intermediates are critical factors controlling their fate through photo-oxidation. The observed chemical changes highlight the effects of sunlight on the potential behavior, fate and impact of spilled oil, with the creation of new resin group compounds and the reduction of aromatics and saturates. These results also imply that the ecological effects of spilled oil, after ageing in sunlight, depend on the specific oil involved and the environmental conditions.
在渥太华，将两种稀释沥青（稀释原油）和一种轻质原油添加到盐水表面，并用自然太阳光照射，以评估阳光对含氧中间体归宿的影响。在冬季和夏季条件下经过一段时间的阳光照射后，鉴定出了含氧成分，包括羰基多环芳烃（PAHs）和酸性极性馏分（环烷酸馏分化合物，NAFCs）。两个季节均形成了羰基PAHs和NAFCs；然而，轻质原油和夏季照射产生的这些物质的丰度高于稀释沥青和冬季照射。所形成的NAFCs中，仅含一个氧杂原子的同系物（O类）含量丰富，同时伴有少量含硫和含氮酸。所产生的O类以分子量轻、饱和度高和氧原子数多的同系物为主。对于羰基PAHs和NAFCs，它们的丰度在整个冬季照射期间持续增加。在夏季，一些羰基PAHs和所有O类在照射初期增加；然后，对于大多数油而言，随着照射的持续，它们减少，这说明了它们的过渡性质。因此，含氧中间体似乎是通过非极性至中极性石油烃或醛或酮（O）中间体的光氧化作用产生的。油的性质、照射持续时间、照射季节以及这些中间体的化学结构是通过光氧化作用控制其归宿的关键因素。观察到的化学变化突出了阳光对溢油潜在行为、归宿和影响的作用，产生了新的树脂类化合物，并减少了芳烃和饱和烃。这些结果还意味着，溢油在阳光下老化后的生态影响取决于所涉及的特定油类和环境条件。
