Modeling transport processes and differential accumulation of persistent toxic organic substances in groundwater systems

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6 Scopus citations


Groundwater represents the major freshwater supply in terms of potential volume for the United States. Large scale contamination by organic compounds has recently been identified in many states, especially in urbanized areas. The ability to predict the potential spread of groundwater pollution resulting from past and existing sources is of paramount interest for ensuring the potability of this important resource. Modeling groundwater movement and the transport and accumulation of conventional pollutants in groundwater systems have been successfully modeled by many investigators. Trace organic substances are, however, in general, hydrophobic and do not behave as conventional pollutants. Their potential for selective association with the particulate matter comprising the soil matrix is quite high. Since the processes of adsorption and desorption are dynamic and not completely reversible, modeling difficulties arise. Incorporating a complex sorption submodel into large scale system models results in rather complex equation systems, usually solvable only by advanced numerical techniques. The paper presents the conceptual development of several dynamic sorption models. Their relationship to the classical equilibrium partioning assumption is demonstrated. A numerical algorithm for solving time variable pollutant liquid phase and solid phase concentrations in a soil matrix in three dimensions is presented. The algorithm is formulated so as to be useful for both saturated as well as unsaturated conditions. The technique consists of segmenting the control volume into N segments for which N simultaneous, first-order, ordinary differential equations can be formulated for salute/liquid phase mass balances. Another N simultaneous ordinary differential equations can be developed for the solute/solid phase mass balances. The liquid phase/solid phase equations are coupled through the reaction term in the liquid phase equations. The resultant is a set of 2N simultaneous ordinary differential equations which can be solved by classical numerical techniques.

Original languageAmerican English
Pages (from-to)135-143
Number of pages9
JournalEcological Modelling
Issue number1-4
StatePublished - Apr 1984

ASJC Scopus subject areas

  • Ecological Modeling


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