Environmental Engineering Reference
In-Depth Information
5.4 Management is more than assessing and reducing risk
Contaminated land management is a complex and dynamic activity, in close relation
with spatial planning and other land management (natural heritage, urbanization,
water management, etc.) activities. It is linked to water and air contaminations and
vice versa. Contaminated land management should deal with long-term care and sus-
tainability to promote the utilization of brownfields and keep green fields as green as
possible.
The risks of point and diffuse sources, human and ecological risks of other contam-
inants than chemicals, i.e., microorganisms, GMOs (genetically modified organisms),
invasive species should be taken into consideration. The terrestrial ecosystem as a com-
plex and dynamic system should be better recognized and should be managed in a soft
manner. Mammals, arthropods, earthworms, plants and microorganisms are equally
important.
Management of contaminated sites needs an integrating approach and versatile
knowledge. It requires the cooperation of professionals in the fields of geology, geotech-
nics, physics, chemistry, biology, toxicology, ecotoxicology, ecology, engineering,
economy and social sciences, mathematics and information technology, etc. Man-
agement methodologies are not uniform throughout Europe, but some tool boxes for
site assessment and software for transport and fate modeling and risk assessment are
used widely, making the comparison possible. Harmonization is spontaneously done
through EU networking. Many professionals agree that the European Guidelines for
tiering risk assessment, jointly developed tool boxes, human health and ecological
screening levels as well as a European technology verification system would help in
making contaminated land management more efficient.
Risk-based management and risk-based decision-making has been for many years
the goal of both theoretical and practical environmental professionals, knowing
that the correct risk value is the stable corner point of environmental risk manage-
ment and decisions. But we have experienced the instability of this pillar due to
uncertainties in the environment and, sometimes, ill-defined concepts. Very com-
mon problems are the identification of the contaminants (if all the contaminants and
their derivatives have been taken into consideration, if we know the environmental
fate of chemicals properly), the time scale (short- or long-term risk) and the spa-
tial extent (local, regional or global scale risk) of the problem. The risk value can
be significantly different depending on the chemicals present, the time frame and
spatial extension considered. But to make a good decision, the scale of risk is not
enough. We know from practice that other circumstances such as resources (availabil-
ity of materials, time, finances, professionals and workers) and expected economic
and social benefits, ethical or cultural aspects may overwrite the acceptable level
of risk. Of course, it is not possible to compare all these factors because they can-
not be expressed in the same units: the soil's microbiota cannot be compared with
starving children, eutrophication and the ozone hole. Nevertheless, developing meth-
ods and increasing knowledge will enable experts to aggregate and weight different
risks and socio-economic aspects and to provide good information for decision mak-
ers. What is still lacking is public awareness, social responsibility and true guiding
principles.
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