Environmental Engineering Reference
In-Depth Information
3.
it can be used in the tripartite approach introduced in Rutgers and Jensen
(
Chapter 15
of this topic); in which all three techniques focus on net mixture
effects (msPAF, next to toxicity tests of site soils and field observations).
Detailed examples of the use of toxic pressure estimates in Conventional Risk
Assessments and management of contaminated sites are specified in the next
Section. Here, we first list some examples (partly on aquatic assessments),
to
elicit further thought and creativity
. They are meant to illustrate how soil policy
formulation and soil Risk Management can profit from the SSD concept.
Toxic pressure estimation has been used as follows:
1. Focus on
Which Contaminant
? An exploration was made of the net mixture
impacts of upstream production of High Production Volume Chemicals or pes-
ticides in downstream mixing zones (the sea), see Harbers et al. (
2006
) and
Henning-de Jong et al. (
2008
); the net risks in the sea appeared to be relatively
low, and they appeared mainly attributable to only a few contaminants.
2. Focus on
Which Contaminant
? An exploration was made of the spatio-temporal
net potential impacts of pesticide use (> 100 compounds) in a region with water
bodies adjoining the croplands; this resulted in identification of the seven most
hazardous contaminants on a landscape scale, which appeared linked to only two
crops of key interest, potatoes and flower bulbs (De Zwart
2005
).
3. Focus on
Where?
A GIS-mapping of soil, water and sediment quality in terms
of toxic pressure, was used to explore the locations of sites or areas of con-
cern, and to discriminate them from areas where (mixture) risks are unlikely
to occur. This helps to focus management actions where they are needed most
(cost-effectiveness), as promoted by Verdonck et al. (
2003
).
4. Focus on
Which Stressors, including mixtures
? An exploration was made to diag-
nose the relative role of environmental mixtures as compared to the impacts of
other stressors in species loss in natural systems based on Biomonitoring data
(De Zwart et al.
2006
; Mulder et al.
2005
). This is a very relevant use of SSDs,
since current policies not only have looked at exceedances of soil quality stan-
dards for selected contaminants, but also have introduced a
Good Ecological
Status
as a “holistic” policy target as in the EU-Water Framework Directive
(European Commission
2000
).
5. Focus on
Industrial Product safety by Life Cycle Assessment.
SSDs may be
used to derive toxic effects metrics when assessing environmental impacts in
the Life Cycle Assessment of, e.g., industrial products (Huijbregts et al.
2002
)
or pesticides (Van Zelm et al.
2009
), to support the design of products with low
environmental impacts during their
production - use - waste
life cycle.
6. Focus on
Decision Support in repetitive, complex situations
. Scenario-based Risk
Assessments can support Risk Management after a natural disaster when the
disaster may cause or has caused the release of large amounts of chemicals (Van
Dijk et al.
2009
). In this case, SSDs based on EC50-data are used to estimate the
perimeter that would show 50% of species loss after a major chemical accident,
which is a relevant measure for addressing likely impacts on human food sources
(e.g., fish in lakes) and biodiversity.
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