Evaluatie van de met CSOIL berekende blootstelling, middels een op Monte Carlo-technieken gebaseerde gevoeligheids- en onzekerheidsanalyse

Abstract

The distribution of calculated potential exposure due to soil contamination is quantified to gain insight into the reliability of the human exposure calculated with the CSOIL model. The study is focused on the distribution of exposure due to uncertainty in the input parameters caused by spatial variability and lack of information. A Monte Carlo-based sensitivity and uncertainty analysis is performed for this purpose using the UNCSAM computer package. Also investigated is the chance of occurrence of the deterministically calculated potential exposure underlying the intervention values, using the probability density function of the calculated potential exposure. Finally, the most important input parameters for the exposure distribution are derived for both potential and actual exposure. The study is focused on five contaminants, differing widely in their contaminant characteristics. The exposure via separate exposure routes is also evaluated so as to indicate the distribution of the exposure and contribution of the input parameters to exposure to other contaminants. To achieve this, other contaminants have to be characterised according to the contribution of these separate exposure routes to the total exposure. Because of large uncertainties in the calculation of the contents in the contact media (indoor air, plant content), for some contaminants one should consider performing measurements in these contact media. On the basis of probalistically derived exposure, Maximal Permissable Risk (MPR) for intake and ecotoxicological serious soil-contamination concentration (ECOTOX EBVC), it is recommended in the future to consider deriving probalistically based guidelines (e.g. intervention values) or other environmental quality objectives (e.g. final contaminant level after remediation).<br>