Linking desorption kinetics to phenanthrene biodegradation in soil.
The desorption of polycyclic aromatic hydrocarbons (PAHs) often exhibits a biphasic profile similar to that observed for biodegradation whereby an initial rapid phase of degradation or desorption is followed by a phase of much slower transformation or release. Most investigations to-date have utilised a polymeric sorbent, such as Tenax, to characterise desorption, which is methodologically unsuitable for the analysis of soil. In this study, desorption kinetics of (14)C-phenanthrene were measured by consecutive extraction using aqueous solutions of hydroxypropyl-beta-cyclodextrin (HPCD). The data indicate that the fraction extracted after 24 h generally approximated the linearly sorbed, rapidly desorbing fraction (F(rap)), calculated using a three-compartment model. A good linear correlation between phenanthrene mineralised and F(rap) was observed (r(2) = 0.89; gradient = 0.85; intercept = 8.20). Hence HPCD extraction (24 h) and first-order three-compartment modelling appear to provide an operationally straightforward tool for estimating mass-transfer limited biodegradation in soil.
Rhodes
Angela H
AH
Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, United Kingdom.
McAllister
Laura E
LE
Semple
Kirk T
KT
D000327:Adsorption; D007700:Kinetics; D010616:Phenanthrenes / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry*
D010616:Phenanthrenes; D012989:Soil Pollutants; C031181:phenanthrene