ENVR 9 |
| The nonhydrolyzable carbon (NHC) and black carbon (BC) in three contaminated soils and seven sediments from the Pearl River Delta and Estuary, China, were isolated upon treatments with an acid hydrolysis method and with a combustion method at 375 oC, respectively, and their sorption isotherms for phenanthrene (Phen) were established. It was found that NHC is chemically and structurally different from biopolymer and humic substances and consists mainly of aliphatic and aromatic carbon using elemental analysis, 13C unclear magnetic resonance spectroscopy (13C-NMR) and Fourier transformed infrared spectroscopy (FTIR). All the sorption isotherms are nonlinear and are well fitted by the Freundlich model. The single-point organic carbon-normalized distribution coefficient (Koc) measured for the isolated NHC is 1.3~7.7 times higher than that for the bulk samples at the same aqueous concentration of Phen. The NHC fractions play a dominant role to the overall sorption isotherms in the bulk samples. The bulk soils and their NHC fractions have lower sorption capacity than the bulk sediments and their NHC fractions, relating to the different source of organic matter between the soils and the sediments. The Phen sorption capacity in the NHC samples is related significantly to H/C ratios and aliphatic carbon (p<0.01), but negatively to aromatic carbon(p<0.01), demonstrating the important role of aliphatic carbon to the Phen sorption and fate in the investigated soils and sediments. |
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Fate of Persistent Organic Pollutants in Urban Systems
8:30 AM-11:30 AM, Sunday, August 19, 2007 Boston Park Plaza -- Beacon Hill Rm, Oral
Division of Environmental Chemistry |