Geochemical Fingerprinting - Application of Geochemical Tracers to Fluvial Sediment - page 13

Fig. 2.1 Eutrophication in a reservoir within the KwaZulu-Natal region of South Africa
of alluvial material) within the river. The latter is accomplished by comparing the
geochemical parameters that make up the fingerprint in the source sediments to that
of the riverine material. The use of such geochemical fingerprinting techniques has
increased dramatically since the late 1990s. In fact, many investigators now consider
geochemical fingerprinting the method of choice with respect to diffuse sediment
sources. The increased use of geochemical fingerprinting is due, in part, to recent
advances in analytical instrumentation that allow for large numbers of elements to
be analyzed in a large number of samples in a relatively short period of time. These
analytical advances have been accompanied by the enhancement of source ascrip-
tion methods that provide for a more detailed and quantitative understanding of the
uncertainty inherent in the derived results. The intent of our analysis herein is not
simply to summarize the voluminous and growing body of literature on the subject,
but to document the strengths, weaknesses, and uncertainty inherent in the approach
in general, and specific methods in particular.
2.2 Conceptual Model and Inherent Assumptions
Upstream portions of the riverine sediment-dispersal system are characterized by a
network of channels and their associated hillslopes, both of which serve as zones
of sediment production (Figs. 1.2 and 2.3 ). Hillslope areas can be geographically