A Practical Approach for Site Investigation - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 143

• To determine the environmental quality of contaminated soil, or waste materials

excavated from the soil, to ensure safe handling and subsequent treatment or
disposal of these materials.

• To provide information for assessing legal liabilities associated with the contam-

ination history of the site.

• To determine any immediate actions necessary to protect currently exposed

receptors on the site.

This list of technical goals is just an example, but even based on this list, it
can be concluded that the technical goals have a much wider meaning than solely
identifying the concentration of contaminants in soil or groundwater.
Additional technical goals can and should be formulated for each site that is to
be investigated. Based on these technical goals, the investigator has to determine the
type and intensity of the investigation that is necessary for the site.

3.5 Three Investigation Phases

For the investigation of (potentially) contaminated sites prior to remediation, three
different investigation phases are recognised:

• The Preliminary Investigation - see Section 3.6 .

• The Exploratory Investigation - see Section 3.7 .

• The Main Investigation - see Section 3.8 .

The terminology used for these investigation phases might vary when going
through the international literature on site investigations. But independent of the
terminology, the distinction in three phases and the characteristics of these three
phases are internationally well recognised. The main questions and actions that are
addressed in these three phases are depicted in Fig. 3.1 .
The Preliminary Investigation is a desk study, combined with a site visit. No
samples are taken in this phase. Nevertheless, it is without doubt the most essen-
tial phase of the whole investigation. A Preliminary Investigation can be performed
both for sites where contamination is expected and for sites that are probably
uncontaminated. The latter sites might, for example, be future residential areas
where confirmation is necessary of the fact that there is indeed no contamination
present, and consequently that there are no objections from this perspective to use
of the site as a residential area without further protective measures. But the inves-
tigation of sites that are expected to be uncontaminated might also be relevant
for industrial sites in relation to present or future legal liabilities. As the normal
exploratory investigation for industrial sites will focus on the parts thought to be
contaminated, no information will be obtained for the rest of the site. To ensure that
no contamination is present at the non-suspected parts of the site, an exploratory
investigation of areas believed to be uncontaminated will be a valuable addition to
the exploratory investigation for the suspected parts of the site.