Sorption Comparison Between Phenanthrene And Its Degradation Intermediates,9,10-phenanthrenequinone And9-phenanthrol In Soils/Sediments

PAHs are hydrogen compounds containing two or more benzene rings, most of the PAHs are harmful to human health, studies have shown that some PAHs could make teratogenic carcinogenic mutagenic. Speces and quantity of PAHs dramatic increase with the develpment of industry and usage of energy materials. There are Wildspread focus on PAHs beacuse the hazard of PAHs to human body. The degradation intermediates of phenanthrene may have increased health risks to organis ms than PHE. Therefore, environmental fate and risk assessment studies should take into considerations of PHE degradation products. This study compared the sorption properties of PHE and its degradation intermediates,9,10-phenanthrenequinone (PQN) and9-phenanthrol (PTR) in soils, sediments and soil components.A relationship between organic carbon content (foc) and single-point sorption coefficient (logKd) was observed for all three chemicals in10soils/sediments. Our results indicated that:1. The higher sorption of PTR may be understood from the oxygen-containing functional groups in PTR, which enabled these two chemicals to interact with soils through hydrogen bonding or electron-donor-acceptor interaction;2. The large intercept in the log foc-logKd regression for PTR indicated that inorganic fractions control PTR sorption in soils/sediments;3. No relationship between specific surface area and Kd was observed. This result indicated that determination of surface area based on gas sorption could not identify surface properties for PHE, PQN, and PTR sorption and thus provide limit information on sorption mechanisms.4. The high sorption and strong nonlinearity (low n values) of PTR in comparison to PHE suggested that the mobility of PTR could be lower than PHE.5. Increased mobility of PQN compared with PHE may be expected in soils/sediments because of PQN lower sorption.6. The varied sorption properties of the three chemicals suggested that their environmental risks should be assessed differently.PHE and its degradation intermediates, PQN and PTR, showed very different sorption properties in soils/sediments and soil components. Organic carbon contributed greatly to PHE and PQN sorption, while high sorption was observed for PTR on both organic and inorganic fractions. PTR high sorption and heterogenous properties suggested lower risks for PTR to PHE.Various mechanisms are involved in organic contaminant sorption on solid particles. But N2measurement provide SSA without differentiating surface properties, such as hydrophobic or hydrophilic surface.For these reasons, SSA may not be a generally useful parameter to understand sorption characteristics. Spectroscopy measurements, such as nuclear magnetic resonance, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy, provide detailed information on surface functional groups. But these methods give relative abundance of these functional groups without information on their contribution to the overall surface area. We thus call the readers’attention that powerful characterization technology is needed to distinguish surface area with different properties. The application of this type of instrument in environmental behavior study may greatly improve our knowledge on sorption mechanisms and tremendously facilitate the estimation of the environmental behavior and risk of organic contaminants.