Comparison of Procedures for Recovering Chloroguaiacols and Chlorocatechols From Contaminated Sediments

Abstract

Procedures for the extraction of chloroguaiacols and chlorocatechols from contaminated sediment samples were examined. Using one sample, a comparison was made of the following procedures: solvent extraction with water-miscible solvents, steam distillation, Soxhlet extraction with t-butyl methyl ether, and several more aggressive methods employing BF3/methanol, HBr/water and KOH/methanol. The recoveries of the chlorinated compounds were highly variable. Recovery of the chloroguaiacols by the nonaggressive procedures was generally low, but it was significantly greater using methanolic alkali. The efficacy of the latter procedure was confirmed by the data obtained with three other sediment samples. Qualitatively similar differences in recoverability were also observed when a high molecular weight alkali-stage chlorolignin was examined. Therefore it was not possible to determine whether the monomeric chlorinated compounds were bound to natural organic compounds in the sediment or to the chlorolignin, which is produced during the bleaching process. In an experiment using one sediment sample incubated under anaerobic conditions for nine months, no change occurred in the amount of extractable chloroguaiacols and there was an approximate 40% reduction in the corresponding chlorocatechols. It is therefore postulated that the binding mechanisms of the chloroguaiacols and chlorocatechols in the sediment phase are significantly different, and that an indeterminate fraction is not accessible to microbial transformation. There are, it is noted, inherent limitations to interpreting the results of experiments on binding and desorption in which xenobiotics are exposed to the sediment phase for only a short time.