A Practical Approach for Site Investigation - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 141

in the site specific design of an investigation. In the translation from the standardized
approach towards a site specific approach, the investigator has to cope with the local
complexity. Often there are no “easy results”.

3.3 Objectives for the Investigation of Soil Quality

Before discussing different approaches for the investigation of potentially contami-
nated sites, it is important to focus on objectives for site investigations. Early in the
process of recognizing that soil contamination was an important issue, in the 1980s,
the simple suspicion that a site might be contaminated was sufficient to start a soil
investigation and subsequent remediation. And indeed, to some extent this is still a
relevant motive. However, as through the years more and more contaminated sites
were discovered, it became obvious that all these sites cannot be investigated and
remediated within a short period of time. Therefore, it became necessary to priori-
tise among sites. Moreover, other motives began to play a role in the investigation
of potentially contaminated sites. Today, the investigation of (potentially) contam-
inated sites is often initiated when sites are to be redeveloped, while other sites,
although contaminated, will have to wait. Of course, when there are serious threats
to humans or the environment, even derelict sites might need urgent remediation,
but as long as there is no secondary incentive, it might be hard to find sufficient
funding for the investigation and potential subsequent remediation of a site.
In case of secondary incentives, such as for example the redevelopment of a
former industrial site as a residential area, the overall site investigation should not
only focus on obtaining data on the contaminants in soil and groundwater. It should
also take account of the site's future use as well as the method of remediation that
will be applied, where this is known. The investigation has to provide data relevant
to the site's future use, as well as data for the intermediate period of remediation.
Imagine a site where old building waste, containing relatively high concentra-
tions of heavy metals, has been used to raise the level of the ground. It is obvious
that contact with that layer of building waste has to be prevented if this site is to
be reused as a residential area. This might be done by removing the contaminated
waste. However, apart from the fact that removal of all the waste would be costly,
it implies that a large quantity of new soil material would be necessary to keep the
soil surface at the desired level. A better solution might be, when the contamination
is immobile, to cover the contaminated building waste with clean soil and thus pre-
vent exposure of humans to the contamination. Identifying in advance two different
ways to deal with the contamination on the site in this simple example, either remov-
ing all of the building waste or covering it, will influence the type of investigation
necessary. In summary:

• When removing building waste:

◦ The environmental quality of the building waste has to be determined - prob-

ably an estimate of the mean concentrations of quantities of several hundred
tonnes might be sufficient.