Modeling chlorinated solvent plumes

BIOCHLOR A natural attenuation model for chlorinated solvent plumes ... 

This chapter is focused on the natural attenuation behavior of CS at the field scale. The first part of the chapter reviews many of the physical, chemical and abiotic natural attenuation processes that attenuate CS concentrations in ground water. Some of these processes have been described in more detail in previous chapters in the handbook and are therefore only reviewed in brief In the second part of this chapter, we will review the biological processes that bring about the degradation of the most common chlorinated solvents, present conceptual models of chlorinated solvent plumes, and summarize data from field studies with chlorinated solvent contamination. 

Figure 23.1.6. Conceptual model of Type 1 environment for chlorinated solvent plumes. [From T.H. Wiedemeier, H. S. Rifai, C. J. Newell and J.T. Wilson, Natural Attenuation of Fuels and Chlorinated Solvents in the Subsurface, after reference 88. Copyright 1999 John Wiley Sons, Inc. Reprinted by permission of John Wiley Sons, Inc.]...

Anderson, M. R., Johnson, R. L., and Pankow, J. F., 1992, Dissolution of Dense Chlorinated Solvents into Groundwater. Modeling Contaminant Plumes Form Fingers and Pools of Solvent Environmental Science and Technology, Vol. 26, No. 5, pp. 901-907. 

Anderson MR, Johnson RL,PankowJF (1992) Dissolution of dense chlorinated solvents into groundwater. 3. Modeling contaminant plumes from fingers and pools of solvent. Environ Sci Technol 26 901-908... 

Two conceptual models are provided for environments in which Type 3 behavior occurs. For sources with PCE and TCE, the major natural attenuation processes are dilution and dispersion alone (no biodegradation). As shown in 23.1.7, the PCE and TCE plumes extend from the source zone and concentrations are slowly reduced by abiotic processes. Chloride concentrations and oxidation-reduction potential will not change as groundwater passes through the source zone and forms die chlorinated ethene plume. If TCA is the solvent of interest, significant abiotic hydrolysis may occur, resulting in a more rapid decrease in TCA concentrations and an increase in chloride concentrations. 

---