Introduction - Application of Geochemical Tracers to Fluvial Sediment - page 4

Fig. 1.2 Leading causes of river impairment in the U.S. as determined by the National Water
Quality Inventory. Data reported for 2010-2012 (depending on state). Note that sediment is the
second leading cause of impairment (data from USEPA 2013 )
observed differences between dissolved and particulate concentrations. This led to the
argument that within rivers exhibiting typically observed pH and Eh conditions more
than 90%of the tracemetal load is transported as part of the sediment load (Table 1.1 ).
The potential for sediment and sediment-associated contaminants to negatively
impact aquatic ecosystems has led to the general evolution in the application of envi-
ronmental tracers from a state in which they were primarily used in academic studies
to their use as a management and regulatory tool. While this evolution in tracer uti-
lization has been slower with regards to rivers than it has been for, say, groundwater,
it is likely to progress in the future. It is also likely to be closely linked to the devel-
oping field of Environmental Forensics . Haddad ( 2004 ) described Environmental
Forensics as “that part of the Venn Diagramwhere environmental technical questions
overlap legal issues”. Amore detailed definition, put forth byWenning and Simmons
( 2000 ), is the “systematic examination of environmental information to determine
sources of chemical contamination, the timing of releases to the environment, the spa-
tial distribution of contamination, and the potential responsible party(ies)”. It seems