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Programme: The four
sessions of the seminar
Session 1: “Treatment of contaminated soils and
groundwater”
The aim of this session is to review non-destructive (or less
destructive) procedures for treating contaminated soils and water. Major
research is currently being carried out into biological treatment, which in
practice entails optimisation of endogenous micro-organisms using various inputs
(nutrients, electron acceptors).
Another method involves the introduction of exogenous micro-organisms,
possibly genetically modified. This last point requires thorough debate,
both from the ethical standpoint and with regard to monitoring of the results of
biodegradation. Phyto-decontamination is another possible approach.
With regard to non-destructive (or less destructive) physical and chemical
treatment, considerable research has been done into reactive walls, which could
provide a basis for a system of passive treatment to replace the traditional
method of aquifer pumping. It is also important to review the development
of other procedures such as air sparging, stripping and venting, and
electro-decontamination, and the conditions under which they are used,
particularly electro-decontamination.
The use of such treatments – for the most part in situ – raises questions
concerning the need for monitoring of reactions and results, in order to ensure
that the objectives are achieved without causing further pollution, either
immediately or in the future (production of more toxic metabolites, physical and
chemical development of the environment, etc.).
Session 2: “Land-use planning and the problem of contaminated sites and soils”
The treatment of contaminated sites is now not only an environmental issue
but also a major problem in town planning. Plans to make use of industrial
wasteland are complicated by the financial sums at stake, the potential risks
presented by some sites and the problems of investigation. It is up to all
the actors concerned to address this issue. Partnership solutions that
anticipate problems upstream and attempt to reach mutual agreement are one
approach that has been explored by public land agencies in particular, which are
often tasked with rehabilitation and decontamination of industrial wasteland,
and with managing the sites until a new use can be found for them.
The development of urban fringe areas is an increasing problem because
land-use projects frequently include industrial wasteland and contaminated
sites. As a result, special care is needed in research, risk assessment
(health, etc.) and rehabilitation by developers (municipalities, public-private
partnerships, real estate companies, etc.).
The session will start with a presentation of the broad lines of
national policy (prevention, research, rehabilitation) and of the methods used
(infrared spectophotometry, initial analysis and basic risk assessment, and more
detailed analysis and risk assessment) in addressing the health and environment
issues (protection of populations and natural environments), followed by a
presentation of land-use planning issues. The aim of the session will be
to consider how the problem of contaminated sites and soils is dealt with in
specific land-use planning projects:
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Establishing the use to which land is to be put and identifying
rehabilitation options appropriate to that use, as part of planning projects.
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Dealing with restrictions on use of such sites in town planning
documents.
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Establishing a property-acquisition strategy in preparation for a
land-use project.
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Cost sharing among developers, owners, local communities and planners.
Session 3: “Protecting water resources and managing contaminated sites”
All countries with a problem of contaminated sites need to control the impact
on water resources. Groundwater in the bedrock is particularly vulnerable.
Groundwater is also a significant component of surface water, and contaminants
from various sources accumulate in the two environments so that it is difficult
– or even impossible in the case of certain contaminants and/or
hydro-geological contexts – and very costly to restore them sufficiently to
guarantee the quality of the drinking water supply. The sources of
pollution are remarkably consistent across all countries: localized pollution
caused by run-off, polluted sites and industrial activity; and area pollution
from agriculture, transport or contaminated sediment. The situation in
highly urbanized zones is itself comparable with area pollution, since a single
water resource may be impacted in many different ways. Sites of this kind
in urban areas are usually dealt with as a land-use management problem and not a
resource-protection issue.
The contaminants most frequently found in water resources include chlorinated
solvents, hydrocarbons, poly-cyclic aromatic hydrocarbons, and metals such as
arsenic, chrome and cadmium. However, some of these contain additives –
for example, methyl tertiary butyl ether in fuels – which, owing to their
toxicity and to physical and chemical properties that permit transport and
persistence within these environments, are bound to pose even more serious
problems, or may already do so.
As resources of high-quality water diminish, countries will face a
range of challenges in the next few years. These will be regulatory or
technical in nature and will give rise to legislative developments over the
coming months. This session will deal with various aspects of the issue:
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Comparison of European national approaches in terms of water-resource protection
as opposed to contaminated-site management
- Isolated risk (from a single site) or multiple risk (several sites impacting
on the same aquifer) ? Data ? Tools ? Substances involved
(e.g. additives) ?
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Choice of exposure point in risk assessments for water resources:
implications for resource protection;
impact on rehabilitation costs.
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Natural attenuation: a new strategy for restoring the quality of water
resources?
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Regulatory developments at the European level (European Union Water
Framework Directive and "daughter" directive on groundwater currently
in preparation, environmental liability, draft European Commission
communications on soil protection and management of contaminated sites and
soils) and their implications for management and rehabilitation of contaminated
sites (identifying pollution sources, impact management, obligation to act,
etc.).
Session 4:
“Assessment of risk to people and the environment”
The aim of this session is to review developments in knowledge and
instruments in the area of evaluation of risk to human health and to ecosystems
or components of ecosystems. Particular attention will be paid to progress
made in improving evaluations by basing them on more realistic assumptions.
Discussion will focus, on the one hand, on studies aimed at understanding the
phenomena contributing to bio-availability of soil contaminants and ways of
taking them into account in risk assessments and, on the other hand, on field
results that help in setting the values of the parameters to be taken into
account in the assessment of risk to people or components of ecosystems.
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