Environmental Engineering Reference
In-Depth Information
whereas the spatial planners position often leads to a fitness-for-current-use only
approach, which may become a burden for future users of the site in case of a land
use change.
The major conclusion concerning policy development identified in this discus-
sion is to address environmental and spatial planning issues simultaneously. This
became evident in the current holistic approach in urban development at con-
taminated sites. The holistic approach made it easier to link contaminated site
remediation to economic issues, such as changes to land values and use of the market
to drive environmental improvements.
23.4.2 Generic Soil “Numbers” Versus Site Specific Risk
Assessment
The various approaches used to assess the significance of soil contamination and
to set remediation goals in a number of industrialized countries has been heavily
debated in the past. A review by Siegrist of this discussion was published as early as
1990. This report was the first comparison of different national policy approaches
for contaminated sites and was followed up with reviews by Visser (
1993
), Ferguson
(
1999
) and Carlon (
2007
). Siegrist noted that sometimes the actual remediation goal
is not stated explicitly, but a decision on some acceptable course of action is reached
on an ad hoc basis. If remediation goals are stated explicitly they are set by:
•
Ad hoc site by site negotiation and decision-making.
•
In reference to background levels.
•
Application of predetermined Soil Quality Standards, guidelines and criteria.
•
Site specific mathematical modelling, Risk Assessment and Risk Management
decisions.
•
Some combination of the options given above.
When only a few sites have to be dealt with, ad hoc approaches based on expert
judgment and site-by-site negotiation and decision-making are appropriate. If the
number of sites is larger, a programmatic approach was generally recommended.
One should note, however, that within a programmatic approach, site-by-site
negotiation and decision-making may still play an important role. The third gen-
eration policies as described earlier strengthen local decision making within flexible
programmatic frameworks at the national level.
Visser (
1993
) gave the first detailed overview of policies in industrialized
countries. This international comparison of approaches stimulated an intensive dis-
cussion of whether a programmatic approach should consist of predetermined Soil
Quality Standards or more versatile site-specific modelling and Risk Assessment
methods. Of course simple testing of measured concentrations in soil and ground-
water against predetermined Soil Quality Standards is rather straightforward and
by consequence less expensive than more elaborate Risk Assessment methods.
However, remediation of contaminated sites is very expensive, especially for larger
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