Contaminated Land and Bio-Remediation - Environmental Biotechnology: Theory and Application - page 101

consists of the contaminants themselves and actual origin of the contamination,
which clearly have a major bearing on the overall picture. However, edaphic
factors such as the soil type, depth, porosity, texture, moisture content,
water-holding capacity, humus content and biological activity may all interact
with the primary influences, and/or with each other, to modify the contamination
effect, for better or worse. Figure 5.3 is a simplified illustration of this
relationship, but as recent work on the ecohydrologic separation of soil water
has shown, the inter-functional reality is often vastly more complex (Brooks
et al ., 2010).
Hence, it is not enough simply to consider these elements in isolation; the
functional outcome of the same contaminant may vary markedly, dependent on
such site specific differences.
After consideration of the generalised issues of suitability, the decision remains
as to which technique is the most appropriate. This is a site-specific issue, for all
of the reasons discussed, and must be made on the basis of the edaphic matters
mentioned previously, together with proper risk-assessment and site surveys. At
the end of all these studies and assessments, the site has been investigated by
desk top and practical means, empirical data has been obtained, the resident con-
tamination has been characterised and quantified, its extent determined, relevant
risk factors identified and risk assessment has been performed. The next stage
is the formulation of a remediation action plan, making use of the data obtained
to design a response to the contamination which is appropriate, responsible and
safe. At this point, having obtained the clearest possible overview, technology
selection forms a major part of this process.
When this has been done, and approval has been gained from the relevant statu-
tory, regulatory or licensing bodies, as applicable, the last phase is to implement
the remediation work itself.
Figure5.3 Modificationofeffectbyedaphicfactors