5
Contaminated Land
and Bioremediation
Contaminated land is another example of a widely appreciated, yet often poorly
understood, environmental problem, in much the same way as discussed for pol-
lution in the last chapter. That this should be the case is, of course, unsurprising,
since the two things are intimately linked, the one being, in essence, simply the
manifestation of the other. The importance of land remediation in cleaning up the
residual effects of previous human activities on a site lies in two spheres. Firstly,
throughout the world, environmental legislation is becoming increasingly strin-
gent and the tightening up of the entire regulatory framework has led to both a
real drive for compliance and a much greater awareness of liability issues within
industry. Secondly, as the pressure grows to redevelop old, unused or derelict so-
called ‘brown-field’ sites, rather than develop previously untouched ‘green-field’,
the need to remove any legacy of previous occupation is clear. A number of tech-
nologies are available to achieve such a clean-up, of which bioremediation, in its
many individual forms, is only one. Though it will, of course, provide the main
focus of this discussion, it is important to realise that the arguments presented
elsewhere in this book regarding the high degree of specificity which governs
technology selectionwithin biotechnological applications also appliesbetween
alternative solutions. In this way, for some instances of contamination, expressly
nonbiological methods of remediation may be indicated as the best practicable
environmental option (BPEO). It is impossible to disassociate contextual factors
from wider issues entirely. Accordingly, and to establish the relevancy of the
wider setting, alternative remediation techniques will be referred to a little later
in this chapter.
The idea of ‘contaminated land’ is something which is readily understood, yet,
like pollution, somewhat more difficult to define absolutely. Implicit is the pres-
ence of substances which, when present in sufficient quantity or concentration,
are likely to cause harm to the environment or human health. Many kinds of
sites may give rise to possible contamination concerns, such as asbestos works,
chemical works, garages and service stations, gas works, incinerators, iron and
steel works, metal fabrication shops, paper mills, tanneries, textile plants, timber
treatment plants, railway yards and waste disposal sites. This list is not, of course,
exhaustive and it has been estimated that in the UK alone something in the region