Abstract
This study presents an evaluation of three screening-level models, namely the Dilution Factor (DF) model from 1996, the update version from 2005, as well as the Johnson and Ettinger model (JEM) from 1997, that are applied within the frameworks for contaminated land management (CLM) in Sweden. This evaluation applies, besides a deterministic approach (point estimate), a probabilistic assessment plus sensitivity analysis. The latter approach allows the models to be ranked according to conservatism, accuracy and parsimony by contrasting predicted and observed soil and indoor air concentrations for two contaminants (benzene and ethylbenzene), as to determine their suitability for application within CLM. The results and conclusions from this study suggest that the most accurately model for predicting the soil and indoor concentration is the JEM followed by the DF 2005 and 1996. Predictions of the soil air concentration are primarily driven by variation in physico-chemical parameters. The variation in indoor air concentration by physico-chemical and/or soil parameters for the DF models, while for the JEM soil parameters dominate. The deterministic analysis showed that default parameter values could be revised as to increase the conservatism, and be closer to the probabilistic 95-percentile predicted indoor air concentration. The DF 1996 model includes a limited number of parameters, and this analysis shows that a model with more parameters is more accurate, and less conservative. The DF 2005 seems to be the most parsimonious model as it is accurate, sufficiently conservative, and has 14 parameters, whereas the DF 1996 with 9 parameters is the most conservative and the JEM with 27 parameters the most accurate with an increased probability to produce false negative predictions. For the latter some of the dominant parameters cannot easily be measured on site.
Highlights
In Sweden contaminated soils are regulated by the Sweden Environmental Protection Agency (S-EPA), who issued guideline values in 1996 as part of their assessment framework for contaminated land management (CLM), which was expanded in 1998 to include petrol stations (S-EPA, 1996; 1998)
This study presents an evaluation of three screening-level models, namely the Dilution Factor (DF) model from 1996, the update version from 2005, as well as the Johnson and Ettinger model (JEM) from 1997, that are applied within the frameworks for contaminated land management (CLM) in Sweden
A deterministic and probabilistic approach was applied to provide insight in the accuracy, conservatism and parsimony of three vapour intrusion (VI) models used in Sweden for human health risk assessment within the framework of CLM
Summary
In Sweden contaminated soils are regulated by the Sweden Environmental Protection Agency (S-EPA), who issued guideline values in 1996 as part of their assessment framework for contaminated land management (CLM), which was expanded in 1998 to include petrol stations (S-EPA, 1996; 1998). The generic exposure model as described in S-EPA (1996) and resulting guideline values are applicable for typical Swedish land-use and are sufficiently conservative based on the precautionary principle. For consistency reasons a model for the prediction of site specific concentrations and exposure (S-EPA, 2005a) was issued, and includes lists of typical parameter values (physical and chemical, bioconcentration factors, (eco)toxicological reference values), as well as background concentrations and exposure. The S-EPA published a supplementary guidance to risk assessment of contaminated areas (S-EPA, 2005b; 2009) that advises on how to adapt the model to site specific conditions. Additional information on the approach in Sweden can be found in Carlon et al (2007), and its progress on managing contaminated land in van Liedekerke et al (2014)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
