Site-Specific Ecological Risk Assessment - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 694

15.6.1 An Example of a General Framework from the Netherlands .........

710

15.6.2 Examples of the Lines of Evidence in the Dutch Remediation Criterion .. 711

15.6.3 Outline of ERA in Other Countries ........................ 715

15.7 Outlook ............................................. 716

References ................................................

717

15.1 The Soil Ecosystem and Site-Specific Risk Assessment

Site-specific Ecological Risk Assessment (ERA) is a process aiming at the sup-
port of site management decisions with respect to contamination (Suter et al. 2000 ).
Typically, site-specific ERA focuses on a specific site. A broad spectrum of deci-
sions can be considered, such as adaptive land management, changes in land use,
and tailoring the site remediation objectives. In order to arrive at these decision
points, data have to be collected, organized and analyzed to estimate the risk of con-
tamination for ecosystems. ERA encompasses a complex procedure as many issues
have to be addressed. A comprehensive ERA requires various contributions from
stakeholders, authorities, managers and experts at different stages of the process
before it can be fully accomplished.
Site-specific ERA ranges from rather simple or small situations to very com-
plicated processes with many experts involved and numerous data evaluations
conducted, often leading to tailored decisions. The commonality of different ERAs
arises from a persuasive notion of adverse ecological effects, irrespective of the
complexity or dimensions of the site. Any ERA should start with the applica-
tion of generic and conservative principles for optimum protection (first tier Risk
Assessment). This may be accomplished, for instance, by comparing contami-
nant concentrations at the site with national Soil Quality Standards, which may
be adjusted for differences in soil characteristics and background concentrations (a
common practice in the Netherlands, see Chapter 1 by Swartjes, this topic). For the
majority of sites such a generic Risk Assessment is sufficient to exclude unaccept-
able risks. However for a number of sites the uncertainty in this kind of generic
and general assessment may be too high, e.g. when the Soil Quality Standards
do not provide the right insight or the Soil Quality Standards are exceeded. This
will often trigger more site-specific and less-generic actions, in higher tier Risk
Assessment. In this stage, divergence between experts may occur, because different
investigations/disciplines may not provide similar conclusions. Divergence between
authorities and stakeholders may also reveal as a result of soil - or rather land -
being treated as real estate with fixed boundaries, while contamination and eco-
logical damage typically cross such site boundaries. Therefore, ERA should be
embedded in structured frameworks allowing complex paradigms to be developed
and the outcomes to be transparent, uniform and applicable for contaminated site
management decisions (Barnthouse 2008 ; Hope 2006 ; Linkov et al. 2006 ).
For ERA in terrestrial systems, lessons can be learned from aquatic and sediment
systems (Chapman and Anderson 2005 ; Rutgers and Den Besten 2005 ). Terrestrial
systems, however, differ because they are generally more heterogeneous, have much