Environmental Engineering Reference
In-Depth Information
The general public is only barely aware of the fact that contamination of water
resources occurs; some more interested individuals may have read about this in the
newspapers or learned about it via television. And some people then use this infor-
mation to criticise the pressure on the environment in general ('one cannot even trust
the groundwater that comes out of the tap these days').
17.2.5.2 The Groundwater Ecosystem
The ecosystem in groundwater is even more underestimated than the ecosystem in
the upper soil layer (see
Section 13.1.3
). Many humans will be surprised when they
learn that such an ecosystem in groundwater even exists. Some non-experts might
have read articles in the newspaper about the surprising abilities of organisms in the
groundwater to remove (in reality, break down) harmful organic contaminants. This
group of people generally is interested in, if not overwhelmed by, the phenomenon
of natural contaminant removal. However, they usually do not have any idea about
the magnitude of Natural Attenuation processes and the costs that are involved when
human beings have to perform these same tasks using extraction and purification
technologies.
17.2.5.3 Political
Politically, groundwater was considered to be one of the precious resources long
before contaminated sites came onto the political agenda. All developed countries
have had legislation for many decades on groundwater protection. However, origi-
nally this legislation was primarily initiated from the perspective of the protection
of drinking water resources from a quantitative point of view. During the last few
decades, water quality issues have gained in importance.
Groundwater is a means of transport (carrier) for contaminants, that is, it is a
pathway that will lead to effects at other locations. The most important aspects
of the groundwater pathway are the leaching of contaminants from the upper soil
to the deeper soil layers and subsequent groundwater flow in the water-saturated
soil layer. Both these aspects play a major role in Risk Assessment. From this
perspective, in addition to groundwater as a protection target, groundwater as a
contaminant carrier is an implicit part of most policies for contaminated sites
management.
For decision-makers and regulators, the protection of the groundwater ecosys-
tem has long been a difficult issue. Both in terms of Biodiversity as well as in
terms of Ecosystem Services, the groundwater ecosystem really is not well under-
stood. The significance of Biodiversity in the groundwater is still a matter of debate,
since the species diversity, although huge, is not as high as in the upper soil.
Moreover, these organisms are even more hidden than their terrestrial counter-
parts are. This is different vis-à-vis the significance of the Ecosystem Services of
the groundwater, mainly in terms of its 'cleaning function'. Since in situ remedia-
tion technologies offer extremely important effective solutions, Natural Attenuation
Search WWH ::
Custom Search