Ecological Risk Assessment of Diffuse and Local Soil Contamination Using Species Sensitivity Distributions - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 681

set local soil quality standards, using the Risk Toolbox. In that case, the local soil
quality standards are selected so that they do not pose harm to the current or planned
future use of the soil, while solving practical and urgent soil transfer problems as in
the sediment management example. In this way, competent authorities are supported
in local Management assessments.
For both Conventional and Management assessments (and in the future,
Outcome Assessments), the Risk Toolbox has been used since mid-2008 as an
instrument tailored to the Dutch policy framework. Many authorities apply the soil
classification approach, whereby one determines whether soils are generally fit for
particular uses. Evaluation of local toxic pressures, which is available as an option,
can be used more widely.
As yet, there are no management or Outcome Assessment results. The Risk
Toolbox is now being widely used by competent authorities to refine the Risk
Assessments that were so far based on national, protective soil quality standards and
remediation trigger values. Often, this refinement has suggested that a current soil
use does not pose risks, despite the “warning signal” provided by the exceedance of
the generic standards. The tiered system, with the Risk Toolbox being the refined
tier as compared to the generic standards, appears to be of help in solving many
local slight soil contamination problems.
14.14.5 GIS-Mapping of Remediation Sites and Monitoring
of Remediation Policies
14.14.5.1 Problem Setting
In the Netherlands, a national inventory of cases of “serious soil contamination”
resulted in a large number of sites for which (a) the Intervention Value was exceeded,
and (b) a minimum-volume criterion was exceeded (Fig. 14.18 , left). The Dutch
government has asked for a cost-benefit analysis of various remediation policy
options. The immediate regulatory problem is to select those cases where risks are
highest. Another trigger to consider remediation is of course a practical trigger, like
the fact that an area will be restructured for other reasons.
14.14.5.2 Approach
The analysis of costs and benefits of remediation options was explored using toxic
pressure analyses and human health risks (not treated in this chapter), to assess
costs and benefits of alternative remediation scenarios. The results were reported
by Rutgers et al. ( 2006 ). The focus was on the contaminants that pose the highest
hazards, so as to explore the need for specific remediation techniques.
14.14.5.3 Conventional Risk Assessment Results
An assessment of the contaminants posing the highest risks resulted in the graph
of Fig. 14.18 (right). Apparently, PAH contamination in the inventory list relates