Mobilization potential of hydrophobic organic compounds (HOCs) in contaminated soils and waste materials. Part 2. Mobilization potentials of PAHs, PCBs, and phenols by natural waters.
To evaluate the hazard potential of org. pollutants in a soil, the mobilization potential of polycyclic arom. hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and phenol derivs. in different waters was ascertained by elution expts. and compared to common elution procedures. Furthermore, dissolved org. matter from different sources was examd. with regard to its influence on soly. Depending on the compn. of the water sample, the leaching behavior of the PAHs and PCBs was very different and was detd. not only by the concn. of the dissolved org. C (DOC) but particularly by its quality. The sepn. of DOC-assocd. and free dissolved pollutants with the solid-phase extn. on C18-reversed phases revealed the responsibility of the sorption of the pollutants to the DOC for their soly. and mobilization. Moreover, an increase of assocn. of pollutants to the DOC was obsd. with growing hydrophobicity corresponding to their octanol/water partition coeff. KOW. The comparison of the elutions showed that the exclusively used S4-elution (German std. DIN 38414 part 4) was not appropriate to evaluate the mobilization of hydrophobic org. pollutants realistically. The eluted PAHs (PCBs) of the S4-elution were exceeded in landfill leachate by a factor of 7, in the pond water by a factor of 9, and in the compost satn. ext. even by a factor of 35. In contrast, a realistic \"worst-case\" leaching could be simulated with a SDS-soln. corresponding to an elution process evaluating the mobilization of org. pollutants. The DOC of real waters and surfactants has little influence on the mobilization of the comparatively polar phenols. Concerning a \"worst-case\" evaluation of mobilization, the S4-elution under alk. conditions is doubtlessly useful for water-sol. phenols.
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