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COSOLVENT EFFECTS ON PHENANTHRENE SORPTION-DESORPTION ON A FRESH-WATER SEDIMENT
Citation:
Bouchard, D C. COSOLVENT EFFECTS ON PHENANTHRENE SORPTION-DESORPTION ON A FRESH-WATER SEDIMENT. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 22(4):736-740, (2003).
Impact/Purpose:
The primary objectives of this research task are to measure the magnitude and kinetics of organic contaminant sorption and transport in soils and sediments, to apply and compare the utility of bicontinuum and distributed parameter models for describing contaminant release from soils and sediments, and to use the measured and estimated sorption/desorption kinetic descriptors developed for assessing long-term contaminant release from soils and sediments. Miscible displacement techniques with soil and sediment columns (with some supporting batch equilibration treatments) will be used in these studies, with analyses by high performance liquid chromatography (HPLC)and gas chromatography (GC). Liquid scintillation counting will be used to quantify 14C-labelled HOCs and the 3H2O used as a conservative tracer to characterize column hydrodynamics.
Description:
This study evaluated the effects of the water-miscible cosolvent methanol on the sorption-desorption of phenanthrene by the natural organic matter (NOM) of a fresh-water sediment. A biphasic pattern was observed in the relationship between the log of the carbon-normalized sorption distribution coefficient (Koc) and the volumetric fraction of methanol (fc) that was accounted for with phenanthrene solubility data. Results also indicated that methanol elicited additional effects on phenanthrene sorption beyond the solution phase effects. The level of fc was observed to have a significant effect on sorption-desorption hysteresis, with hysteresis being greater for treatments where phenanthrene and sediment were equilibrated with methanol-phenanthene solutions, but desorbed with aqueous solutions. These results are discussed in light of the deformable pore network of the rubbery-glassy NOM polymer construct.