Introduction to Contaminated Site Management - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 29

investigation. This study includes information on the layout of the site (the presence
of buildings, sealed surfaces, bare surfaces, vegetation, (micro)relief, the presence
of soil-foreign materials, elements that relate to former activities) and a detailed
evaluation of the history of the site (which activities might have been responsible
for which contaminants, at which spots on the site). Some sites evoke a clear sus-
picion of being contaminated, while other sites have a rather innocent appearance
with regard to soil contamination. See Fig. 1.7 , as an example, in which a suspi-
cious site, based on the presence of drums (upper photo), and a site that seems
above suspicion (lower photo), both in the Silvermines area in Tipperary county,
Ireland, contaminated with several metals due to former mining activities.
A site visit , including a so-called organoleptic investigation ('looking and
smelling'), is an essential activity at this stage of the project. The evaluation of the
history of the site might include a visit to the municipal archives and the historical
records found in the library. Moreover, interviews with former workers or inhabi-
tants might be helpful. A map of the site might also help in the interpretation, and
digital photos will support the memory of the risk assessor. This preliminary study
should result in a hypothesis about the type of contaminants and the spots where
these contaminants can be present.
Obviously, samples need to be taken and analysed in order to determine the
concentrations in soil and groundwater. If no information about the possible con-
taminants is known, the samples can be analysed for a group of 'frequently found
contaminants'. This group differs for soil and groundwater, since the more immobile
contaminants are often found in soils, while the more mobile contaminants usually
reside in the groundwater. Several countries have defined standard groups of fre-
quently found contaminants, often formalised in protocols. In the Dutch NEN 5740
protocol, for example, a standard series of contaminants has been defined that must
be determined when there is no information about the possible contaminants present
(NEN 2009 ). The selected contaminants differ for:

a

b

Fig. 1.7 A suspicious site ( a ) and a site that seems above suspicion ( b ), in the Silvermines area in
Tipperary county, Ireland, contaminated with several metals due to former mining activities (photo:
F. Swartjes)