Division of Environmental Science and Ecological Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea.
Division of Environmental Science and Ecological Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea.
Chemosphere. 2019 May;222:656-664. doi: 10.1016/j.chemosphere.2019.01.153. Epub 2019 Jan 29.
Crude oil released into the environment contains many polycyclic aromatic hydrocarbons (PAHs). Alkylated PAHs are more abundant than unsubstituted PAHs and their toxicity is also of serious concern. Among the various physical, chemical, and biological weathering processes of crude oils, photodegradation is one of the most important for determining the environmental fate of oil residues. In this study, the photodegradation rate constants of naphthalene and alkylated naphthalenes were determined under simulated laboratory conditions at different temperature. Changes in the luminescence inhibition of Aliivibrio fischeri, as an indicator of the baseline toxicity, were observed in photodegradation mixtures. The major transformation products were also identified by gas chromatography-mass spectrometry. The photodegradation of naphthalene and the eight alkylated naphthalenes was described well by pseudo-first-order kinetics regardless of experimental temperature. The measured toxicity of the reaction mixtures obtained by photodegradative weathering slightly increased initially and then decreased with further weathering. In all cases, the observed toxicity was greater than accounted for by the parent compounds, indicating that the photodegradation products also contributed significantly to the overall toxicity of the mixtures. The identified photodegradation products were mostly oxygenated compounds such as alcohols, aldehydes, ketones, and quinones, which warrant further investigation.
环境中石油释放出许多多环芳烃（PAHs）。取代和未取代的多环芳烃相比，烷基取代的多环芳烃更为丰富，其毒性也引起了严重关注。在原油的各种物理、化学和生物风化过程中，光降解是决定油残留物环境命运的最重要过程之一。在这项研究中，在不同温度下的模拟实验室条件下，测定了萘和烷基萘的光降解速率常数。在光降解混合物中观察到 Aliivibrio fischeri 发光抑制作为基线毒性的指示剂的变化。通过气相色谱-质谱联用仪也鉴定了主要的转化产物。萘和八种烷基萘的光降解很好地符合假一级动力学，无论实验温度如何。通过光降解风化获得的反应混合物的测量毒性最初略有增加，然后随着进一步风化而降低。在所有情况下，观察到的毒性都大于母体化合物的解释，表明光降解产物也对混合物的整体毒性有显著贡献。鉴定出的光降解产物主要是含氧化合物，如醇、醛、酮和醌，这值得进一步研究。
