The Fate of Dissolved Creosote Compounds in an Intact Fratured Clay Column

The fate of 16 different organics typical for creosote was studied under aerobic conditions in a large intact fractured clay column experiment. Some of the organics (benzene, toluene, o-xylene, phenol, and o-cresol) were transported at the same rate as bromide through the fractured clay, whereas naphthalene, quinoline, and 2,4-dimethylphenol were retarded significantly. The breakthrough curves indicated that phenol and o-cresol were degraded faster than benzene and toluene whereas o-xylene seemed to persist within the experimental period. A simple transport model was applied to some of the data. It was possible to model the early part of the breakthrough curves for the retarded organics (naphthalene, quinoline, and 2,4-dimethylphenol) but not the later part since the compounds were degraded. Retardation factors of 8, 9, and 8 for naphthalene, quinoline, and 2,4-dimethylphenol, respectively, were estimated. This column experiment revealed that transport of organics through fractured clay is an important process. It may in many cases cause groundwater contamination of aquifers, sofar believed to be protected by overlying clay layers.