Abstract

The National Institute for Public Health and the Environment has formulated a proposal for accurate decision making about the necessity of remediation of contaminated sites. The ecosystem risks will be based on the mixture of contaminants. The current methodology only addresses remediation urgency by taking into account one substance at a time. The proposal fits in the Remediation Criterion which is a system for authorities to decide on the necessity of remediation in order to prevent negative consequences of soil contamination.
The proposed methodology operates with the same input data, but equations are more accurate. It is possible that another decision will become evident, in cases where concentrations of contaminants are fluctuating around the decision criteria. Decision criteria mark the border between remediation or no remediation. The Ministry of Spatial Planning, Housing and the Environment can choose this decision criterion in a way that an equal number of contaminated sites have to be remediated. This will result in equal overall costs for remediation of contaminated sites, but with a net gain for the environment.
The Toxic Pressure (TP) of the mixture will be calculated from the total concentration of contaminants determined in the standard protocol for Extended Soil Analysis (Nader Bodemonderzoek). The TP will be expressed in an msPAF (multi-substance Potentially Affected Fraction). The TP value gives an estimate for the ecological effect of the mixture in a sample of the contaminated site and can be used for the ecological risk assessment.