Organic Chemicals in Groundwater: Modeling Fate and Transport

Abstract

Hazardous organic chemical waste that has been placed in landfills or recycled for use as highway construction and repair materials has the potential of leaching through the vadose zone into the groundwater. The groundwater may then serve as a pathway to transport these chemical contaminants to human and environmental receptors. Thus, it is important that we understand how processes that occur in groundwater affect the fate and transport of these organic chemicals. Groundwater fate and transport models are available to help us to gain this understanding, as well as to quantify the concentrations at which these organic chemicals reach receptors, so that we may be able to quantify risk.

In this chapter, we first present the physical, chemical, and biological processes that affect organic chemical fate and transport in groundwater. We also present models of these individual processes. In the second part of the chapter, we examine models that combine the individual processes, so as to comprehensively simulate how organic chemical concentrations in a contaminated groundwater system vary over space and time. Finally, we present case studies that demonstrate the utility of fate and transport modeling in helping us to understand the behavior of organic contaminants in groundwater.