Laboratory Column Measurement of VOC Retardation Factors and Comparison with Field Values

Abstract

A laboratory column technique was developed to measure retardation factors (Rf) of volatile organic compounds (VOC) using geological material obtained from an outwash aquifer. The site is a former solvent disposal pit near Ottawa, Canada. The experimental column was designed as a closed system from introduction of the sample to the collection and analysis of effluent samples to prevent loss through volatilization of the VOCs. The retardation of the volatile compounds 1,4‐dioxane, tetrahydrofuran, diethyl ether, 1,2‐dichloroethane, chloroform, 1,1‐dichloroethene, and benzene was measured. The centers of mass of both the contaminant and conservative tracer breakthrough curves were compared to determine Rf. The measured Rf values ranged from 1.1 (1,4‐dioxane) to 14.3 (benzene) compared with values of 1.6 and 8.8 derived from contaminant plume lengths. Considering the uncertainty of the disposal history at the site, the values are of reasonable agreement in comparison.

Analysis of benzene transport in a two-dimensional aquifer model

“…In the same manner, R at 16 h (Figure 3b) was found to be 1Ð20. These values are considerably different from the results of Priddle and Jackson (1991), who reported from a laboratory column experiment that benzene was retarded 14Ð3 times relative to a conservative tracer. However, they were slightly overestimated compared to the results of Baek et al (2003), who found that no benzene retardation occurred during transport through sandy aquifer materials.…”

“…Sorption plays a prominent role in the fate and transport of contaminants in soils and groundwater, resulting in retardation and reduction of contaminant concentration through reversible and irreversible sorption respectively. Many researchers have investigated the reversible sorption of organic contaminants in porous media and determined the sorption-related parameters, such as retardation factor, using various laboratory and field methods (Roberts et al, 1986;Mehran et al, 1987;MacIntyre et al, 1991;Priddle and Jackson, 1991;Rogers, 1992;Benker et al, 1998).…”

Biodegradation of Ether Pollutants by Pseudonocardia sp. Strain ENV478

“…Very recently, the solvent stabilizer 1,4-dioxane has emerged as an important groundwater contaminant throughout the United States and elsewhere (26). Like many ethers, this compound is miscible in water, has a low dimensionless Henry's Law constant (2.0 ϫ 10 Ϫ4 ), and has a low octanol/water partitioning coefficient (1.23); thus, it is poorly retarded in aquifers and has the potential to create large contaminant plumes that threaten drinking water supplies that are distant from the original release sites (14,23,29).…”

Joint Improvised Explosive Device Defeat Organization: Anomaly or Future Roadmap

“…Because of its miscibility in water, its low Henry's Law constant (4.9 x 10 -6 atm m 3 /mol), and low octanol/water partitioning coefficient (K oc 1.23), it is poorly retarded in aquifers. As a result, this compound has the potential to create large contaminant plumes and to threaten drinking water supplies distant from the original release sites (Jackson and Dwarakanath, 1999;Priddle and Jackson, 1991). It has only recently been added to the list of pollutants that must be regularly monitored in several states.…”

“…Most recently, the solvent stabilizer 1,4-dioxane has emerged as an important groundwater contaminant throughout the United States and elsewhere (Mohr, 2001). Typical of many ethers, it is miscible in water, has a low dimensionless Henry's Law constant (2.0 x 10 -4 ), and low octanol/water partitioning coefficient (K oc 1.23), resulting in it being poorly retarded in aquifers resulting in the potential to create large contaminant plumes that threaten drinking water supplies distant from the original release sites (Priddle and Jackson, 1991;Jackson and Dwarakanath, 1999;Lesage et al, 1990).…”