2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Environmental Chemistry & Technology
Table I
G-factor values, ΔH pp and spin concentrations
Sample g-factor ΔHpp [mT]
Spin concentration
[spin mg –1 ]
TSP 2.070 34.6 3.84 × 10 18
TSP 2.015 40.0 3.68 × 10 17
TSP 2.020 40.0 1.64 × 10 18
TSP 2.010 40.0 2.22 × 10 18
PM10 2.093 472 2.01 × 10 18
PM10 2.080 554.9 2.02 × 10 17
PM10 2.055 410.8 2.06 × 10 17
PM10 2.070 345.65 1.09 × 10 19
The signals on EPR spectra recorded on the particulate
samples were identified as a superposition of signals arising
from various paramagnetic species. It is mainly the presence
of transition metal ions in a low oxidation state, typically
iron, which have to be regard as a possible cause of toxicity.
In accordance with results obtained in paper 4 , the appearance
of Fe 2+ on the surface of the dust particles and its subsequent
oxidation to Fe 3+ in octaedric configuration leads to production
of free radicals at solid-liquid interphase by direct
reduction of atmospheric molecular oxygen. These sites may
be implicated in the formation of dangerous active oxygen
species in vivo.
The total surface spin concentrations of particulate samples
were determined in range from 3.68 × 10 17 to 3.84 ×10 18
spin.g -1 for total suspended particulate matter and from
2.02 ×10 17 to 1.09 ×10 19 spin g –1 for PM 10 . The significant
difference between spin concentrations values of total
s475
suspended particulate matter and PM 10 was not found. The
determined spin concentrations values are approximately 10 2
times higher than spin concentrations values of mechanically
activated quartz and silicon powders 5 .
Conclusions
The determined surface spin concentrations obtained
from EPR spectra were high. But based on these experimental
results of paramagnetic centres occurrence study explicitly,
it cannot be expressily considered particulate matter to have
toxic properties. The paramagnetic ions testing in special
chemical reactions 6 used for this purpose may more accurately
indicate potential risk of particulate matter toxicity.
Acknowledgement: This work has been supported by
Grant Agency of Slovak Republic (project No. 1/3342/06).
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4. Volante M., Giamello E. et al: Proceeding of the 1 st
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