Environmental Engineering Reference
In-Depth Information
deemed a success. However, as we have previously highlighted, there is a question
as to where this point should lie. Is the aim to return an environment to its pre-
contaminated conditions, or alternatively should the target be a particular com-
munity composition, such as the presence of a rare species, or more generally a
sustainable water resource? It appears that returning a particular habitat to its
pre-industrial conditions is an unrealistic goal for two main reasons. The first of
these is a lack of good quality data that provide a detailed characterisation of the
abiotic and biotic components of any environment. Although there has been some
attempt to use palaeoecological data (
Chapter 8
), this is limited in many environ-
ments due to preservation, and the lack of consistency in methods and data
analysis has been highlighted (
Chapter 6
). The second is that, even where more
recent data are available, it is evident that the community does not return to its
previous state even when given sufficient time. Tibbett, Williams et al., Langford
et al., Batty et al. and Purvis (
Chapters 15
,
14
,
13
,
4
and
3
, respectively) all report
that, despite improvements in the physico-chemical environment, either through
a decline in industry or active remediation activities, the community does not
return to its pre-contaminated state (or other target condition). This constraint to
recovery is probably due to the lack of sources of colonising organisms, lack of
physical habitat (although chemical conditionsmay improve), the impact of other
pollutants in the environment (other than those directly targeted by remediation)
and transfer of industrial pollutants from long-term sources (such as sediments)
not tackled by remediation. In addition, ecological function may continue to
be impaired as a result of the changes in community structure, although there
is little information on the causes of ecological dysfunction in recovering commu-
nities (
Chapter 15
).
The presence of adapted organisms on industrially contaminated sites provides
a potential opportunity to exploit these organisms for either the stabilisation of
such sites or active remediation. The potential for using metallophyte plants in
the remediation of metalliferous soils has been postulated for a number of years
and successfully applied in some cases; however, this potential is rather under-
exploited due to a lack of knowledge of the mechanisms of adaptation and
metabolic and genetic responses to pollutants (
Chapter 2
). Rather more progress
has been made in the use of bacteria in remediation activities, particularly where
the land is contaminated by organic pollutants or radionuclides (
Chapters 12
and
11
, respectively). Advances in knowledge of the genetics involved in adapta-
tion of microorganisms and mechanisms of action in remediation processes
(
Chapter 10
) provides great potential for these organisms to be applied in many
situations, particularly where there are problems of mixed contaminants.
Conclusions
This volume provides an overview of the impacts of industrial pollution, ways
of monitoring and remediation and recovery of such systems. It is clear that,
