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may serve as particularly powerful tracers of particulates from vehicle emissions,
especially particulates from diesel engines (Lahd Geagea et al.
2008a
). In addition,
subsequent work by Guéguen et al. (
2012
) in the same area found that while chem-
ical waste incinerators, domestic waste incinerators, thermal power plants, and steel
plants exhibited similar Pb isotopic values and, therefore, could not be fingerprinted
using only Pb isotopes, they could be defined using a combination of Pb, Sr, and
Nd isotopes (Table
4.2
). In fact, Sr and Nd isotopes were much more effective than
Pb isotopes at differentiating the source of particulate matter from these industrial
sources.
The potential to use Sr and Nd isotopes to document changes in chemical fluxes
to aquatic systems has also been demonstrated. Kamenov et al. (
2009
), for example,
examined the vertical (depth) variations in Sr, Nd, and Pb isotopes as well as selected
trace metals and metalloids in a well-dated peat core from the Blue Cypress Marsh
of southeast Florida. Geochemical changes in the composition of the sediments with
depth were used to conclude that the flux of a number of toxic trace elements to the
marsh from atmospheric sources had increased following European settlement. In
addition, they found that significant systematic changes in both Sr concentrations
and
87
Sr/
86
Sr ratios occurred within the core (Fig.
4.5
). Changes in
87
Sr/
86
Sr values
were consistent with, and attributed to, the influx of limestone dust from quarrying
operations that were associated with urban development. Interestingly, the timing of
the Sr isotopic shift in the core did not precisely correspond to the onset of quarrying,
suggesting that Sr may have exhibited some slow downward diffusion within the
peat deposits. Nd isotopes only exhibited a minor shift in
ʵ
Nd
values with depth
in the core (at a depth of approximately 32-36 cm; Fig.
4.5
). In contrast to Sr, the
stratigraphic change in Nd isotopic values was attributed to variations in the relative
Table 4.2
Isotopic signatures of particulate matter from selected pollutant sources in the urban
environment of Strasbourg-Kehl, Germany as reported by Lahd Geagea et al. (
2008a
) and Guéguen
et al. (
2012
). Table modified from Guéguen et al.
2012
Pollutant source
87
Sr
86
Sr
143
Nd
144
Nd
206
Pb
207
Pb
/
/
/
1523
c
Domestic waste incineratorsa
0
.
70953
−
9
.
7
1
.
Chemical waste incinerator
b
1468
c
0
.
71099
−
8
.
4
1
.
Thermal power plants
a
1
.
1528
c
0
.
71241
−
11
.
9
Steel plant
a
1512
c
0
.
70904
−
17
.
5
1
.
Chimney soot
b
0
.
71428
−
11
.
2
1
.
1659
Soot—gasoline (2005)
a
1
.
0898
c
0
.
70881
−
6
.
9
Soot—diesel (2005)
a
1596
c
0
.
70871
−
6
.
0
1
.
Paper producer
b
0
.
70992
−
9
.
1
1
.
1621
Agricultural dust
b
.
−
.
.
0
72326
9
5
1
1798
Uncertainties 2
˃
0
.
00001
0
.
4
0
.
00001
0006
c
0
.
a
Lahd Geagea et al. (
2008a
)
b
Guéguen et al. (
2012
)
c
Measurements by TIMS; Other Pb isotopic measurements by MC-ICP-MS
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