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J.Health Sci., 50(1), 66-74, 2004
Formation of 1,3-, 2,4-, 1,2-, 1,6-, 1,8- and
1,7-Dinitropyrenes in Metallic Oxides as Soil Components in the Presence of Indoor Air
with 1-Nitropyrene and Sodium Chloride
Under Xenon Lamp Irradiation
Hidetoshi Sugiyama,*, a Tetsushi
Watanabe,b Tsuyoshi
Murahashi,b and Teruhisa
Hirayamab
aKanagawa Environmental Research Center, 1-3-39 Shinomiya, Hiratsuka-shi, Kanagawa 254-0014, Japan and
bKyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8411, Japan
The reaction products obtained from the mixture of 1-nitropyrene (1-NP) and sodium chloride were
investigated on three metallic oxides as soil components under xenon lamp irradiation in the presence of indoor air.
These chemicals including 1-NP were extracted with benzene/ethanol (4/1, v/v) and analyzed by gas
chromatography/mass spectrometry (GC/MS). The amounts of 1-NP gradually decreased as irradiation time elapsed on all
three metallic oxides (TiO2: titanium dioxide, anatase form;
SiO2: silicon dioxide, silicic anhydride form; and
Al2O3: aluminum oxide). In
TiO2 in particular, 1-NP showed a greater decrease than the other two metallic
oxides for all irradiation times. Six types of dinitropyrenes (DNPs) were detected from the reaction products
(1,3-, 2,4-, 1,2-, 1,6-, 1,8- and 1,7-DNP). In both
TiO2 and Al2O3, all 6 DNPs were detected, while in
SiO2, 5 DNPs were confirmed except for 2,4-DNP. In
TiO2, 1,7-DNP was formed in especially rich amounts for all
irradiation times in comparison with the other metallic oxides. We presumed that 4- and 2-NPs were generated
from 1-NP by the photochemical reaction of OH radical, and that 2,4-, 1,2- and 1,7-DNPs were formed
continuously by the nitration of these isomers. The formation of 2,4-, 1,2- and 1,7-DNPs was confirmed for the first time
on the metallic oxides by the photochemical reaction system of the 1-NP-NOx-Cl ion. NOx in the indoor air was
shown to be a source of nitrogen used in forming DNPs in these metallic oxides. The yields and formation
patterns of DNPs differed in the 3 metallic oxides as the irradiation time was extended. Hence, the nature of the
photochemical reaction in the formation of DNPs differed depending on the type of metallic oxide in question.
In SiO2, mutagenicity increased gradually up to 6hr of irradiation when mutagenic potency showed 2.6 million
revertants/sample, and then decreased to 1.5 million revertants/sample at 12hr. In
Al2O3, mutagenicity increased
gradually as irradiation time elapsed to a maximum of 1.64 million revertants/sample. In
TiO2, mutagenicity decreased rapidly to 60% at 10min and thereafter decreased gradually to 22% at 12hr.
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