Environmental Engineering Reference
In-Depth Information
14.13.4 From Criterion Risk Assessment to Conventional Risk Assessment ..
669
14.13.5 Conventional Risk Assessments with SSDs: A Versatile Approach ...
669
14.14 Examples of Conventional Risk Assessment of Soil Contamination with SSDs .
671
14.14.1 Policy Framework Backgrounds - The Netherlands ............
671
14.14.2 GIS Mapping of Soil Quality ..........................
672
14.14.3 Handling Slightly Contaminated Sediments .................
675
14.14.4 Soil Quality Classes and Local Risks to Manage Local Soils .......
678
14.14.5 GIS-Mapping of Remediation Sites and Monitoring
of Remediation Policies .............................
681
14.14.6 A Contrasting Approach, the U.S. Superfund ................
683
14.15 Reflections and Conclusions ................................
684
References ................................................
686
14.1 Aims of this Chapter and Readers Guide
This chapter aims to present and illustrate the theory and practices of using
Species Sensitivity Distribution (SSD) modeling in the ecological effect and Risk
Assessment of soil contamination.
SSDs have been used since the late 1980s in various legislations to derive
environmental quality standards for water, sediment and soil. More recently, the
approach has been used for other purposes including site-specific Risk Assessments
of contaminated sites and various kinds of risk ranking. Risk ranking is needed when
quality standards are exceeded or might be exceeded. In such cases, exceedance
may occur at many sites (e.g., candidate remediation sites), they may involve dif-
ferent areas, or different risks are suspected (e.g., from pesticide uses). In such
cases, ranking of risks amongst cases in large case loads, or for alternative manage-
ment scenario's, may be of help in focusing on (cost) effective Risk Management
strategies.
SSDs are Effect Assessment models, and are never applied alone. The Risk
Assessment paradigm (Fig. 14.1 ) requires that appropriate Exposure Assessment
models be used with the SSD or other effect model. This chapter thus contains
appropriate Exposure Assessment tools when needed.
This chapter first presents the conceptual background for interpreting SSDs along
with a description of the motives for protecting living soils and a realistic example
of observed mixture effects in a soil pollution gradient. They set the scene for the
remainder of the contents and examples of the chapter. We think that the reader
should be acutely aware of the variance of realistic responses of soil ecosystems in
the field in order to understand the strengths and limitations of SSD-modeling.
Technical and practical issues in using SSDs are subsequently presented. Some
software and database references are described, to enable easy use. The practical
usefulness of SSDs is illustrated and proven with examples from current practices.
The validation studies and the practical examples may be of most interest to soil
appraisal practitioners, since the section on validation shows how SSD-output is
ground-truthed, and the section on practical uses shows the versatility and benefits
of SSD-based risk modeling. The examples of use mostly concern the Netherlands.
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