CYCLODEXTRINS: A CHEMICAL MIMIC OF PAH BIOAVAILABILITY IN SOILS?

摘要

Traditionally, soil extraction techniques have been concerned with the determination of “total” organic contaminant concentrations, following an “exhaustive” extraction. However, in light of the increasing body of knowledge relating to organic contaminant availability and ageing, such methods have little relevance to the amount of contaminant which may be available to soil biota, I.e. the “bioavailable” portion. Lessexhaustive techniques have been investigated, in that they may access the “labile” or bioavailable pool. This paper describes the use of an aqueous based extraction technique, utilising hydroxypropyl-β-cyclodextrin (HPCD), to extract organic contaminants from soil. In the first experiment, the amount of phenanthrene extracted by HPCD was compared to that mineralised by catabolically active microorganisms. In the second experiment, soil from a former coke works was extracted by HPCD and compared to the biodegradation of organic contaminants over a 6-week biodegradation assay. In both cases, the HPCD extraction compared strongly with the biodegradation of the organic contaminants, suggesting that HPCD mimicked the processes controlling biodegradation and represented a direct measure of microbial availability.