Introduction to Contaminated Site Management - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 21

1.3.3 Categorisation

Since hundreds of thousands of contaminants are present in the environment, it is
useful to categorise them. Several criteria can be used for this purpose, such as
'related production processes' (for example, heavy metals from zinc smelters, and
cyanide from gas works), 'type of application' (for example, pesticides) or 'chem-
ical or physical characterisation'. A systematic categorisation is given in Fig. 1.6 .
A popular policy-related categorisation is given here that is partially based on
chemical or physical characterisation and, hence, chemical properties. This results
in the following six categories:

• metals and metalloids;

• Polycyclic Aromatic Hydrocarbons (PAHs);

• monocyclic aromatic contaminants;

• persistent organic pollutants (POPs);

• volatile organic contaminants (VOCs);

• other organochlorides.

Note that some of these categories overlap. In addition, three other useful cate-
gories can be added, based on 'frequency of occurrence of contaminants in soils';
these are:

• other inorganic contaminants (other than metals);

• petrolium hydrocarbons;

• asbestos.

Inorganic Organic

Non-
chlorinated

Metal/
metalloid

Non-metal

Chlorinated

Alkenes Aliphates Alkenes Aliphates

cadmium
lead
copper
zinc
arsenic

cyanides
ammonium
sulfur

EXAMPLES : dioxines PAHs

DDT
PCBs

ethane benzene

ethyl-
benzene
xylene
toluene

Fig. 1.6 A systematic categorisation of contaminants