Sustainability and Remediation - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 933

Table 20.6 Indicative examples of possible impacts of climate change on the mobility of
contaminants (not an exhaustive listing)

Impact on contaminant
mobility Process

Increased leaching/erosion Increase

Increased soil drying Increase

Increased evaporation Increase

Change in redox condition Increase/Decrease

Enhanced biodegradation Decrease

Affecting mineral capping
(bentonite)

Increase

Increased flooding risk Increase

20.5 Case Studies

The case studies following are either examples of remediation carried out with
additional sustainable development “gain” in mind, or examples of the use of
sustainability appraisal tools in decision making.

20.5.1 Soil Redevelopment in the Volgermeerpolder, Amsterdam,
the Netherlands

In the 19th and 20th century peat was an important fuel in the Netherlands. North
of Amsterdam peat layers with a thickness of up to 8 m were excavated. In the
Volgermeerpolder a 100 ha wetland remaining after this peat extraction was used
as a chemical and domestic waste dump for the municipality of Amsterdam until
1980. Residues from chlorinated pesticide production were also deposited in the
Volgermeerpolder, which resulted in contamination of the surrounding waterways
with dioxins. Groundwater on the site is severely contaminated with aromatic and
chlorinated compounds, mainly benzene and chlorobenzene, both biodegradation
products of the pesticides. However, the residual peat in the subsurface strongly
sorbs organic solutes and allows limited migration of the contaminants, resulting in
a fragile but stable situation without off-site migration of contaminants.
A large scale remediation project for this area was initiated in 2003. From the
beginning of the project planning it was clear that a remediation of the site by
removal of the waste would not be feasible. A remediation concept was developed
centred on the reclamation of the area as a constructed wetland with bog develop-
ment. The waste deposit will be capped, using a low permeable layer (PE-liner).
This cover layer will prevent infiltration of rain water, and reduce the contaminant
flux into the surrounding subsurface. The wetland system will be constructed on
top of this cover layer (see Fig. 20.9 for an aerial view of the Volgermeerpolder). It
consists of 60 individual wetland cells (“paddy fields”), separated by dykes with an
integral water management system similar to the construction of rice fields in Asia.