Groundwater fate modeling

Soil compartment chemical fate modeling has been traditionally performed for three distinct subcompartments the land surface (or watershed) the unsaturated soil (or soil) zone and the saturated (or groundwater) zone of a region. In general, the mathematical simulation is structured around two major cycles the hydrologic cycle and the pollutant cycle, each cycle being associated with a number of physicochemical processes. Watershed models account for a third cycle sedimentation. 

Numerous examples of fate models are reviewed in other papers in this symposium. For example, single media models are covered for air by Anderson (2 ), for water by Burns ( 3), and for soil and groundwater by Bonazountas (4). 

FOCUS groundwater scenarios in the EU review of active substances" - The report of the work of the Groundwater Scenarios Workgroup of FOCUS (FOrum for the Co-ordination of pesticide fate models and their USe), Version 1 of November 2000. EC Document Reference Sanco/321/2000 rcv.2,202pp. 

The BUSES model was developed to support the risk assessment of chemicals under various regulations. BUSES is a spreadsheet-based tool that incorporates SimpleBox, a multimedia fate model, and SimpleTreat, which simulates the distribution and elimination of chemicals in sewage freafment plants. The model estimates the concentrations of a substance in air, water, soil, and sediment at local and regional scales. It simulates the steady-state transport of chemicals between media and scales, and removal of the chemical by degradation and some "disappearance processes" (e.g., leaching to the groundwater, which is not then modeled) [106,107]. 

The solubility of methyl parathion is not sufficient to pose a problem in runoff water as determined by an empirical model of Wauchope and Leonard (1980). Some recent monitoring data, however, indicate that methyl parathion has been detected in surface waters (Senseman et al. 1997). In a study to determine the residue levels of pesticides in shallow groundwater of the United States, water samples from 1,012 wells and 22 springs were analyzed for methyl parathion. No methyl parathion was detected in any of the water samples (Kolpin et al. 1998). In a study of water from near-surface aquifers in the Midwest, no methyl parathion was detected in any of the water samples from 94 wells that were analyzed for pesticide levels (Kolpin et al. 1995). Leaching to groundwater does not appear to be a significant fate process. 

PATHS (30) is mainly an analytical groundwater model, that provides a rough evaluation of the spatial and temporal status of a pollutant fate. 

Dazhi S, Xuqian L (2010) Application of Markov chain model on environmental fate of phenanthrene in soil and groundwater. Procedia Environ Sci 2 814—823... 

To construct models of this sort, we combine reaction analysis with transport modeling, the description of the movement of chemical species within flowing groundwater, as discussed in the previous chapter (Chapter 20). The combination is known as reactive transport modeling, or, in contaminant hydrology, fate and transport modeling. 

Huyakorn, P. S., Wu, Y. S., and Panday, S., 1992, A Comprehensive Three-Dimensional Numerical Model for Predicting the Transport and Fate of Petroleum Hydrocarbons in the Subsurface In Proceedings of the Petroleum Hydrocarbons and Organic Chemicals in Groundwater Conference, Water Well Journal Publishing Company, Dublin, OH, pp. 239-253. 

Development of analytical and numerical groundwater models to (1) predict the fate and transport of LNAPL and its dissolved constituents (2) provide more reliable LNAPL volume determinations and (3) enhance design for optimal groundwater cleanup strategies ... 

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