Introduction to Contaminated Site Management - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 41

lead through soil ingestion is avoided or reduced. A popular option, mainly effi-
cient for immobile contaminants, is covering contaminated hotspots with pavement,
grass or any other vegetation, also reducing the possibilities for hand-mouth contact
and, hence, exposure through soil ingestion. Another example is found in Arienzo
et al. ( 2004 ), who revegitated a soil at a former ferrous metallurgical plant in Naples,
Italy, for the purpose (among others) of preventing dispersion of metal-contaminated
particles by water or wind erosion. Fencing off highly contaminated parts of a con-
taminated site, as, for example, described in Louekari et al. ( 2004 ), for the purpose
of avoiding practically any lead exposure near a former lead smelter in Finland,
would be a good example of rather drastic measures in regard to adapting the
site use.
The disadvantage of changing land use or the layout of the site with the same
land use is that concessions often have to be made in regard to the ideal way the site
is used.
Moreover, risks for other protection targets should also be investigated.
Therefore, this solution often offers limited possibilities.
1.6.4 Remediation Technologies
1.6.4.1 Scope
Remediation is a hard-to-protocollise activity. It is often not feasible to follow a
cookbook-type recipe for the design of a remediation plan. The reasons for this
are that for every combination of contaminant, site, soil properties and land use,
a different remediation technology may be appropriate. Moreover, the execution
of one specific remediation technology can be carried out in many different ways.
Therefore, the development of the remediation plan typically must be done on a
site-by-site basis. Remediation experts often lobby against rigid remediation plans.
Instead, they would prefer a remediation approach in which the proceedings develop
during the remediation activities.
The basic distinction in remediation technologies is in situ (at the site) and ex
situ (off the site) technologies. In situ technologies, mainly applicable to organic
contaminants, have the advantage that no transport of soil material is needed. The
huge advantage of ex situ technologies is that the physical-chemical treatment of
soil is generally more efficient in a factory than on site. In Fig. 1.8 , an illustration
of an excavation in Bilthoven, the Netherlands is given, as an example of an ex situ
remediation.
Bardos et al. ( Chapter 20 of this topic) give a detailed description of innovative,
sustainable remediation technologies.
1.6.4.2 In Situ Remediation Technologies
The US Environmental Protection Agency includes 12 different in situ remedi-
ation technologies in their Annual Status report on contaminated sites treatment