Optimisation of XAD extraction methodology for the assessment of biodegradation potential of 14C-phenanthene in soil

Abstract This study investigated the use of a hydrophobic resin, amberlite XAD, as a tool for assessing the biodegradation potential of  14 C-phenanthrene in soil. The method was optimised in terms of soil/XAD ratio, shaking, extraction time and eluting solvent. The most effective method was then tested on selected XADs, and the performance compared with cyclodextrin (HP- β -CD) and dichloromethane (DCM) extractions suitability to predict phenanthrene biodegradation in soil over 100 d. Results showed that the optimum conditions for the XAD extraction technique are a 2:1 soil/XAD ratio, 100 rpm mixing for 22 h and elution using a DCM:methanol solution (1:1). Mineralisation of  14 C-phenanthrene was accurately predicted by HP- β -CD ( r 2 = 0 . 990 , slope  =  0.953, intercept  =  1.374) and XAD-4 extractions ( r 2 = 0 . 989 , slope  =  0.820, intercept  =  6.567), while DCM overestimated the bioaccessibility of 14 C-phenanthrene ( r 2 = 0 . 999 , slope  =  1.328, intercept  = − 49 . 507 ). This investigation showed that XAD extraction can be considered a suitable non-exhaustive technique for estimating biodegradability of phenanthrene in soil.