Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 425624
Title Sensitivity analysis on parameters and processes affecting vapor intrusion risk
Author(s) Picone, S.; Valstar, J.R.; Gaans, P. van; Grotenhuis, J.T.C.; Rijnaarts, H.H.M.
Source Environmental Toxicology and Chemistry 31 (2012)5. - ISSN 0730-7268 - p. 1042 - 1052.
DOI https://doi.org/10.1002/etc.1798
Department(s) Sub-department of Environmental Technology
WIMEK
Publication type Refereed Article in a scientific journal
Publication year 2012
Keyword(s) unsaturated porous-media - capillary-fringe - indoor-air - organic-compounds - gas-transport - vadose zone - soil - groundwater - biodegradation - buildings
Abstract A one-dimensional numerical model was developed and used to identify the key processes controlling vapor intrusion risks by means of a sensitivity analysis. The model simulates the fate of a dissolved volatile organic compound present below the ventilated crawl space of a house. In contrast to the vast majority of previous studies, this model accounts for vertical variation of soil water saturation and includes aerobic biodegradation. The attenuation factor (ratio between concentration in the crawl space and source concentration) and the characteristic time to approach maximum concentrations were calculated and compared for a variety of scenarios. These concepts allow an understanding of controlling mechanisms and aid in the identification of critical parameters to be collected for field situations. The relative distance of the source to the nearest gas-filled pores of the unsaturated zone is the most critical parameter because diffusive contaminant transport is significantly slower in water-filled pores than in gas-filled pores. Therefore, attenuation factors decrease and characteristic times increase with increasing relative distance of the contaminant dissolved source to the nearest gas diffusion front. Aerobic biodegradation may decrease the attenuation factor by up to three orders of magnitude. Moreover, the occurrence of water table oscillations is of importance. Dynamic processes leading to a retreating water table increase the attenuation factor by two orders of magnitude because of the enhanced gas phase diffusion
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