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.
(with a signature of about 0
33
), whereas the primary source of dissolved Zn was
66
Zn value of 0
ʴ
.
Cretaceous chalk (exhibiting a
). Similarly, Chen et al. (
2009
)
suggested that Zn associated with urban runoff (particularly roof runoff) adds very
little particulate-associated Zn to the river, but is the primary anthropogenic source
of dissolved Zn.
Sivry et al. (
2008
) examined Zn contamination within the Lot River basin, France,
and found that Zn isotopes may also serve as effective tracers of Zn from industrial
ore processing within alluvial sediments. In this case, Zn isotopes within the ore
(exhibiting
90
66
Zn
) was highly fractionated duringmetallurgical processing
forming tailings materials with measurably higher
ʴ
∼
0
.
16
66
Zn values (up to
ʴ
+
1
.
49
).
66
Zn values within sediments of a
contaminated tributary (the Riou Mort) was significantly different than the isotopic
values measured in alluvial sediments located upstream of contaminant influx and
assumed to represent background materials (
In addition, they were able to demonstrate that
ʴ
66
Zn values of
ʴ
+
0
.
91
±
0
.
04
as
66
Zn values along
the river (i.e., from up- to downstream of the tributary) were consistent with the influx
of tailings materials via the Riou Mort.
Sivry et al. (
2008
) also found that systematic changes in
compared to
+
0
.
31
±
0
.
06
). The observed spatial changes in
ʴ
66
Zn values occurred
within a dated sediment core extracted from a downstream hydroelectric reservoir
(Fig.
5.3
). Sediments deposited between approximately 1952 and 1972 exhibited a
mean
ʴ
66
Zn value of
ʴ
+
0
.
95
±
0
.
08
. Sediments deposited during the late 1970s
66
Zn values until reaching a maximum value in 1986, after which
they remain relatively constant until the mid-1990s (Fig.
5.3
). The temporal shift to
exhibit increasing
ʴ
Fig. 5.3
Vertical (depth/time) variations in Zn/Sc ratios (
blue circles
), total Zn concentrations (
red
squares
), and
ʴ
66
Zn values (
brown diamonds
) measured in samples from a core extracted from the
Cajarc reservoir along the Lot River, France (from Sivry et al.
2008
); Zn and Zn/Sc variations from
Audry et al. (
2004
). The co-variation between Zn concentration and Zn isotopic data suggest that
Zn isotopes can be used to determine the source of the Zn
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