Environmental Engineering Reference
In-Depth Information
Albania
Austria
Belgium
Finland
Iceland
Norway
Bosnia
Croatia
Russia
Czech. Rep
Denmark
Hungary
Lithuania
Luxembourg
Macedonia
Montenegro
Romania
Serbia
Slovakia
Slovenia
Switzerland
Estonia
Latvia
Ireland
Belarus
U.K.
Poland
Ukraine
Kazakhstan
France
Bulgaria
Spain
Georgia
Kyrgyzstan
Italy
Armenia
Azerbaijan
Greece
Tajikistan
Portugal
Fig. 3.1 Countries with the most important mineral resources in Europe and Central Eurasia [ 13 ]
Coal extraction from quarries, a method that is almost generalised at the
moment, is presented intuitively in Fig. 3.2 .
When the soil has been stripped and the deposit uncovered (1), coal is excavated
and transported either with large vehicles or via conveyor belts. Steps (2) and
(3) represent different stages of quarry exhaustion. This technique, though very
productive, is also very polluting, especially because of slowly sedimenting PM.
Generally, studies about toxic agents and PM released during surface mining
[ 16 ] deal with the PM issue superficially; the concentration of micropollutants
under the form of nanoparticles is not specified directly, but with global indicators
of the TSP type (total suspended particulates), which are irrelevant for the subject of
this topic [ 17 - 19 ].
Recent studies [ 19 , 20 ] give more specific details about toxic agent determina-
tions in coal plants during daytime, using more precise indicators such as PM 10 or
PM 2.5 .
Figure 3.3 indicates that in the air samples collected within the perimeter of the
two quarries, the highest concentrations are those of the slowly sedimenting
particles represented by PM 10 ,orPM 2.5 which seem to follow the same specific
law of concentration variation, while coarser particles sediment immediately, so
their concentration is less relevant.
As far as the PM 2.5 variation is concerned, daily concentrations recorded in the
studied period in several places around the coal exploitations vary between 4.5 and
10.2
g/Nm 3 .
The toxic gaseous agents found in the deposits (methane, nitrogen oxides,
hydrogen sulphide, etc.) must be mentioned among the sources of nanoparticles
reformed in the atmosphere. When released, these agents cause degradation through
oxidation-reduction, hydrolysis, and neutralisation; in other words, they generate
nanoparticles with a different chemical nature than that of the initial pollutants
[ 18 - 20 ] (Table 3.2 ).
g/Nm 3 , while the average value of the whole period was about 7
μ
μ
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