Radiogenic Isotopes - Application of Geochemical Tracers to Fluvial Sediment - page 94

(a) (b)

Fig. 4.4 a Map of the primary tributaries to the Nile River; b Relative sediment budget based on Sr
and Nd isotopic provenance data. Relative sediment contributions were calculated using a inverse
(mixing) model and the available isotopic data (modified from Padoan et al. 2011 )

of contamination has thus far been limited, particularly with regards to rivers. At
issue is whether Sr and Nd isotopic ratios vary to the extent needed to form an effec-
tive fingerprint. Nonetheless, a number of recent studies unrelated to rivers suggest
that both isotopes can be used to discriminate between contaminated source mate-
rials and may therefore prove to be effective tracers of contaminated sediments in
river systems (Lahd Geagea et al. 2007 , 2008a , b ; Kamenov et al. 2009 ; Guéguen
et al. 2012 ). Lahd Geagea et al. ( 2008a ), for example, demonstrated that particulate
matter associated with urban pollutants within the area of Starsbourg-Kehl, Germany
could be fingerprinted on the basis of Sr, Nd, and Pb isotopes (Table 4.2 ). Partic-
ularly large differences were found between the ʵ Nd values of various industrial

sources (e.g., waste incinerators and steel plants) and car soot, suggesting that they