U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the Technical Meeting, Colorado Springs, Colorado, September 20-24, 1993, Water-Resources Investigations Report 94-4015

Modeling Breakthrough of Nitrogen Heterocyclic Compounds in Laboratory Columns Containing Creosote-Contaminated Aquifer Material

Abstract

Laboratory-column breakthrough curves for the nitrogen-containing heterocyclic compounds found in the water soluble fraction of creosote were modeled and compared assuming local equilibrium and nonequilibrium conditions. The aquifer material consisted of a low organic-carbon-content (0.024 percent organic carbon), low ion-exchange-capacity (2 meq/100 g) clayey sand. Retardation factors and partition coefficients for quinoline, 2(1H)-quinolinone, carbazole, and acridine, derived from breakthrough curves, were contrasted with those obtained from batch experiments. Retardation factors for quinoline and 2(1H)-quinolinone were comparable to each other, although those for carbazole and acridine were quite different despite similar chemical structures and octanol-water partition coefficients. Transport of quinoline, 2(1H)-quinolinone, and acridine is governed by organic and ionic interactions; however, transport of carbazole is controlled by organic interactions alone. In addition, although the local equilibrium assumption can be used to describe quinoline and 2(1H)-quinolinone breakthrough curves, carbazole and acridine breakthrough curves require nonequilibrium kinetics.