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66
Zn data and calculated enrichment factors (EF) for selected types
of environmental samples from the Seine River in and near Paris, France. Samples of suspended
particulate matter collected during low (
blue circles
) and flood flows (
purple circles
) and bed
sediment collected along a basin transect (
red squares
) plot along a mixing line composed of two
endmembers. Endmembers are represented by granitic basement rocks and an anthropogenic source
composed of plant-treatedwastewater and roof runoff (roof stream) (modified fromChen et al.
2009
)
Fig. 5.2
Relation between
ʴ
pre-smelter sediments was thought to correspond to that of the local geological mate-
rials, whereas that of the sediments corresponding to the period following smelter
operations appeared to be related to Zn in urban runoff, particularly Zn associated
with the wear of vehicle tires. Interestingly,
66
Zn values did not change during the
period of rapid urbanization and declining smelter operations characterized by peak
mass metal accumulation (
ʴ
∼
1945-1985). The limited variations in Zn isotopic val-
ues during this period were attributed to the remobilization of Zn enriched sediments
from soils that had been contaminated by smelter exhausts. A rapid shift in
66
Zn
values did, however, occur between 1979 and 1985 (Fig.
5.1
) such that the sediment
acquired a signature similar to that observed during the period of smelting. Thapalia
et al. (
2010
) argued that the alteration in
ʴ
66
Zn values was associated with the intro-
duction of Zn from urban runoff that had been stored in sediments from Hall Creek
that were eroded and transported to the lake prior to or during a remediation project.
ʴ
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