Page 4 - Orecchio_alii_2008

Author's personal copy
ARTICLE IN PRESS

374 S. Orecchio et al. / Environmental Research 107 (2008) 371–379

Table 2 Table 4
Sites of sampling and characteristics of the sample sites List of groups of PAHs formed for analysis, the deuterated standards employed
(underlined), the quantification ion and confirmation ion for SIM GC– MS mode
No Sample site Characteristics of the sample site
Group Chemical Quantification ion Confirmation ions
1 Indipendenza Large square frequented by very heavy and slow traffic. The area
1 is exposed to airflows that readily disperse pollutants. 1 Acenaphthylene 152 76, 151
2 Indipendenza Large square frequented by very heavy and slow traffic. The area Acenaphthene 154 152, 76
2 is exposed to airflows that readily disperse pollutants. The tree Fluorene 166 164,165
is located near a petrol pump. Acenaphthene d 10 164
3 Harbour Located in a busy road near Palermo harbour and near the
historical centre of the city.
2 Phenanthrene 178 188, 89
4 Oreto sx Road that connects the freeways to the city centre, frequented
Anthracene 178 188, 89
by traffic, both cars and commercial vehicles. 2 methyl anthracene 192 96, 82
5 Oreto dx Road that connects the freeways to the city centre, frequented
9 methyl anthracene 192 96, 82
by traffic, both cars and commercial vehicles. Fluoranthene 202 101, 200
6 Erice Distant from any known major anthropogenic sources, chosen
Pyrene 202 101, 200
as control 1 methyl pyrene 216 108, 94
7 Favignana Favignana is a small island located to the west of Sicily
Benzo(a)anthracene 228 114,226
frequented mainly during bathing season. The station is situated
Phenanthrene d 10 188
in a rural area 800 m away from the nearest trafficked urban
area. The area is periodically is affected by agricultural practices
(combustion of grass and other agricultural residues). 3 Chrysene 228 114,226
8 A29 Located inside a large service area of the Palermo-Trapani Benzo(b)fluoranthene 252 126,250
motorway with high traffic. The area is open and exposed to Benzo(k)fluoranthene 252 126,250
wind. Benzo(a)pyrene 252 126,250
9 Botanical Inside a green area 200 m away from traffic and 200– 300 m Chrysene d 12 240
Garden away from a plant for gas production (inactive during the
previous four years). The area is peridiodically affected by 4 Perylene 252 126,250
agricultural practices (combustion of grass and other Indeno(1,2,3-cd)pyrene 276 277,138
agricultural residues). Dibenzo(a,h)anthracene 278 279,139
10 University The station is inside the university campus, 100– 200 m away Benzo(g,h,i)perylene 276 277,138
from a busy road that connects the ring road to the city center. 264
Perylene d 12
11 Papireto Inside a the garden of a school 300 m away from a busy road and
protected by buildings.
12 Lennon Near traffic lights on a road frequented by very high traffic, both
cars and commercial vehicles. Part of the area is used for bus
parking.
13 Industrial Industrial area characterized by modest industrial emissions, same experimental conditions. Identification was confirmed by
area where traffic is almost absent, 500 m away from a petrol depot comparing the spectra of the single components with those stored
14 V.le Francia Located in a busy road in a residential area near a railroad. in the acquisition system library. The identification of PAHs in the
15 Castellana A small agricultural village about 100 km. from Palermo and in a
mountainous area at an altitude of 765 m above sea level. solutions extracted from sediment was carried out on the basis of
Heating of the houses is by means of fireplaces in which previously determined retention times, and it was confirmed
firewood is burned. The area is periodically affected by using mass spectra. The PAH content in each sample was
agricultural practices. quantified relative to perdeuterated PAH added to the dry residue.
16 A-19 PA-CT Located in a little-used parking area 150 m away from the
Palermo-Catania motorway subject to high traffic The response factors of different compounds were measured by
injecting a mixture containing 19 standard compounds and
having the same concentration of perdeuterated PAHs as that
used for spiking the sample.
Table 3
Results of recovery tests
4. Results and discussion
Extraction method solvent Recovery % a Standard deviation
Soxhlet CH 2 Cl 2 88 12 In general, the more volatile 2- and 3-ring polycyclic aromatic
65 14
Ultrasound CH 2 Cl 2 compounds exist primarily in the gas phase of the atmosphere,
Ultrasound CH 2 Cl 2 -pentane 69 12 and will tend to be deposited upon the plants via dry gaseous and/
or wet deposition. The less volatile 5- and 6-ring PAHs are more
a
Mean of three analysis
likely deposited on the plant surface bound to particles in wet and
dry deposition. For compounds of intermediate vapour pressure
(4-ring PAHs, for example), a temperature-dependent gas/particle
extracted fractions from samples and standard solutions (1 ml) was partitioning of PAHs will occur, so that they are subject to both
performed by hand. The injector temperature was maintained at wet and dry deposition in gaseous and particle-bound form
280 1C. The GC temperature programme was: from 40 1C (2 min) to (McVeety and Hites, 1967; Bidleman, 1988; Lane, 1988). Particle-
100 1Cat40 1C/min, to 200 1Cat10 1C/min, to 325 1C (8 min) at bound PAHs can be moved to very long distances and are removed
30 1C/min. The carrier gas was helium (flow rate 1.6 ml/min). The from the atmosphere through precipitation and dry deposition.
use of an Equity-5 column allowed complete separation within a PAHs are accumulated in terrestrial and aquatic organisms.
shorter time (about 25 min) compared to previous research The PAHs uptake by plants from soil and the subsequent
(Culotta et al., 2002, 2005). The interface temperature was biomagnification is generally quite low (Gao and Zhu, 2004). In a
325 1C. The analysis was operated in selected ion monitoring study of PAH uptake from cropland soils, high concentrations of
(SIM) mode. The selected ions are reported in Table 4. The PAHs in soils were not correlated with concentrations in plant
identification of the components of the standard mixture was tissues. The PAH amount found in the plants at ground level was
carried out by comparing the retention times of each mixture not related to the soil PAH concentration but was attributed to
component with those of pure components, analysed under the atmospheric deposition (Wild and Jones, 1992).