Boll, Esther Sørensen4; Johnsen, Anders R.3; Christensen, Jan H.5
1 Section for Environmental Chemistry and Physics, Department of Plant and Environmental Sciences, Faculty of Science, Københavns Universitet2 Parks and urban landscapes, Forest & Landscape Denmark, Faculty of Life Sciences, Københavns Universitet3 Geological Survey of Denmark and Greenland (GEUS)4 Parks and urban landscapes, Forest & Landscape Denmark, Faculty of Life Sciences, Københavns Universitet5 Section for Environmental Chemistry and Physics, Department of Plant and Environmental Sciences, Faculty of Science, Københavns Universitet
This study investigated the sorption to soil of water-soluble metabolites from polycyclic aromatic compounds (PACs). The soil fungus Cunninghamella elegans was used to produce PAC metabolites from two un-substituted PACs (phenanthrene, pyrene), three alkyl-substituted PACs (2-methylnaphthalene, 1-methylphenanthrene, 1-methylpyrene), and one sulfur-containing heterocyclic PAC (dibenzothiophene). Fifty-eight metabolites were tentatively identified; metabolites from the un-substituted PACs were hydroxylated and sulfate conjugated, whereas metabolites from alkyl-substituted PACs were sulfate conjugated and either hydroxylated or oxidized to carboxylic acids at the methyl group. The metabolism of the sulfur-containing heterocyclic PAC resulted in sulfate conjugates. The sorption of the PAC metabolites to three soils was determined using a batch equilibrium method, and partition coefficients (Kd's) were calculated for fourteen representative metabolites. Sulfate conjugated metabolites displayed Kd's below 70 whereas the metabolites with both a sulfate and a carboxylic acid group had Kd's below 2.8. The low Kd's of water-soluble PAC metabolites indicate high mobility in soil and a potential for leaching to surface- and groundwaters.