We describe the initial bulk and compound specific composition of the liquid oil spilled during the Deepwater Horizon (DwH) disaster. The emphasis is on the target hydrocarbon compounds typically found in highest concentrations and on those of concern from a toxicological perspective (i.e., the target normal alkanes and isoprenoids, and PAHs on U.S. Environmental Protection Agency’s (EPA) priority list with their alkyl homolog compounds), and/or those relevant for forensic fingerprinting of spill residues (i.e., sulfur containing PAHs and biomarker compounds). Weathering changed the oil’s composition in various environmental compartments. These compositional changes and potential environmental impacts of the remaining weathered residues are presented in this paper. Biodegradation occurred in both surface and subsurface environments while photooxidation primarily modified and removed hydrocarbons in floating oil slicks. The volatile, soluble and highly labile C₁ to C₁₀ hydrocarbons were rapidly degraded in the water column and/or emitted to the atmosphere (evaporation). The semi-volatile hydrocarbons (labile C₁₀ to C₂₅) that remained in the water column and floating oil on the water’s surface were lost from oil residues during weathering. The heavy nonvolatile and insoluble hydrocarbons (recalcitrant C₂₅+) were least affected by initial weathering processes in 2010. The composition of the residual oil fraction in surface floating oil was further altered by the addition of oil soluble oxy hydrocarbons produced from photooxidation. During 2011 and 2012 the resulting highly insoluble recalcitrant C₂₅+ oily residues remained on the shorelines, bottom sediments, or bound to suspended particulates in the water column, with detectable residues mostly returning to near pre-spill levels by 2015 to 2020. Some recalcitrant oil residues can still be found at various locations, including some coastal environments (e.g., marshes), or deep-water sediments, at very low levels, ten years after the spill.

我们描述了在深水地平线 (DwH) 灾难期间泄漏的液体油的初始体积和复合特定成分。重点是通常以最高浓度发现的目标碳氢化合物以及从毒理学角度关注的那些（即目标正构烷烃和类异戊二烯，以及美国环境保护署 (EPA) 优先列表中的多环芳烃及其烷基同系物）和/或与泄漏残留物法医指纹识别相关的那些（即含硫 PAH 和生物标志物化合物）。风化改变了各种环境隔间中油的成分。本文介绍了剩余风化残留物的这些成分变化和潜在的环境影响。生物降解发生在地表和地下环境中，而光氧化主要改变和去除漂浮浮油中的碳氢化合物。挥发性、可溶性和高度不稳定的 C₁至 C ₁₀烃在水柱中迅速降解和/或排放到大气中（蒸发）。留在水柱中的半挥发性碳氢化合物（不稳定的C ₁₀至C ₂₅）和水面上的浮油在风化过程中从油渣中流失。2010 年，重质非挥发性和不溶性碳氢化合物（顽固的 C ₂₅ +）受初始风化过程的影响最小。通过添加光氧化产生的油溶性含氧烃，进一步改变了地表浮油中残油馏分的组成。在 2011 年和 2012 年期间，产生的高度不溶的顽固 C ₂₅+ 油性残留物留在海岸线、底部沉积物或与水柱中的悬浮颗粒结合，到 2015 年至 2020 年，可检测到的残留物大部分会恢复到接近溢油前的水平。一些顽固的石油残留物仍然可以在不同的位置找到，包括泄漏十年后，某些沿海环境（例如沼泽）或深水沉积物的含量非常低。