Document Type


Publication Date


Subject: LCSH

System dynamics, Cancer--Risk factors, Hazardous substances--attenuation


Civil and Environmental Engineering | Civil Engineering | Environmental Public Health | Public Health


Public health is potentially at risk after a contaminant of concern (COC) is released into the ecosphere. The extent of contamination depends on numerous factors; modeling a contaminant’s dynamic behavior is challenging, given the multitude of relevant parameters and the fluid nature of processes involved. For example, weather events (e.g., wet or dry periods) may affect the mass depletion and the fate and transport of COCs, and hence, the risk assessment of current and potential future exposures. Thus, to give realistic estimates for potential risks, a contaminant’s dynamic behavior must be taken into account in decision-making processes. In this paper, a system-dynamics framework for a dynamic-risk assessment is developed taking into consideration the mass-depletion processes in a natural attenuation environment. This framework rests on the premise that natural attenuation is a complex system involving a variety of source mass-depletion phenomena which evolve over time. Through cause-and-effect loops, a system-dynamics model connects the contaminant’s physicochemical and biological mass-depletion processes with the potential risk for exposure by water ingestion and air inhalation. The model considers an idealistic approach involving a continuous average infiltration rate, and a realistic approach incorporating weather fluctuations into the system. To test the proposed model, a conceptual example of benzene contamination in the vadose zone is analyzed. Geological site specifications, contaminant characteristics, and fate-and-transport mechanisms contributing to source mass-depletion are considered, including water infiltration, volatilization, biodegradation, and groundwater recharge. Cancer risk is assessed in two exposure routes (ingestion, inhalation) for idealistic and realistic case scenarios.


This is the authors' accepted manuscript of the article published in Environmental Processes. The final publication is available via



Publisher Citation

Kalomoiri, A., Koutsospyros, A., Braida, W., and Pavlov, J., (2017). System-Dynamics Modeling of Source Mass-Depletion and Risk-Exposure Evolution for Natural Attenuation Processes in the Vadose Zone. Environmental Processes 4(1), 207-222.



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