Environmental Engineering Reference
In-Depth Information
or reprotoxic effects as well as endocrine and immune system deteriorating effects
(Chapter 2). Chemicals are able to bind to more different molecular receptor sites in
cells, organs, and organisms, thereby causing different effects such as sensitization of
the skin, metabolic failure in the liver, and developmental problems when germ cells
are exposed to these chemicals.
Environmental fate and behavior such as transport, chemical transformation, par-
tition, accumulation and magnification or effect on the biodiversity and community
structure of chemical substances may play an important role in their risk profile. The
chemical form of the contaminant is highly variable depending on the redox potential
of the environment. Lead and cadmium are completely unavailable in anoxic sediments
(PbS, CdS), but highly soluble in surface deposits in the presence of oxygen and water
(Pb 2 + ,Cd 2 + ). A low concentration of a toxic metal or a persistent pesticide may be
harmless for plants because plants contain them in a separate and inaccessible “pack-
age'' in their cells, but it may pose high risk to plant eating organisms which digest the
“package'' and become poisoned by it.
When dealing with contamination and environmental deterioration caused by con-
taminants we have to understand that every produced and used chemical substance has
the chance to get into the environment. The best prevention is to reduce the application
of chemicals as much as possible, stopping unnecessary production and consumption,
and substituting xenobiotics with natural substances whenever possible. Natural sub-
stances may also cause pollution and deterioration when they occur at the wrong time
and at the wrong place.
Once the contaminant has entered the environment, risk management is less effi-
cient and costs more. If the spatial scale of the use and emission is larger, the task
is more and more difficult with increasing uncertainties and decreasing efficiency.
The adequate use of agricultural nutrients needs calculation, planning, and careful
application, but the cleanup or remediation of a catchment such as Lake Balaton in
Hungary, takes years and incurs tremendous expenditures. Strengthening the dam
needs some effort and money, but it cannot be compared to the costs of the cleanup
after a breach/accident, such as the cyanide spill in 2001 in Baia Mare (Romania) or
the red-mud flood in 2010 in Ajka (Hungary).
Figure 1.16 shows the local, regional, and global scale environmental problems
and their management.
Management of environmental risk involves the following tasks: assessment of
the risk and its comparison with the acceptable risk level, decision-making on the best
available risk reduction measure if the risk is higher than acceptable.
The aim of many European and world-wide regulations and environmental man-
agement tools is to monitor the environment and ecosystem health and ensure its
sustainable use. The results of environmental assessment and monitoring enable the
assessment and quantification of the risk (ERA), the basis for further management
measures. On the basis of the risk scale one can decide on its reduction at local,
regional, and global levels. The necessary tools for reducing the risk are different at
local, regional, and global scales. Prevention is a general tool applicable at any spa-
tial scale. Prevention may be considered at the very beginning of the life cycle of a
chemical substance or a product either by stopping production, reducing the produced
quantities, changing materials or technologies, etc. The second very important step is
emission, which can be reduced “in pipe'' by substituting materials and technologies
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