SOIL AND SEDIMENT TRACING USING COMPOUND-SPECIFIC STABLE ISOTOPE (CSSIS): THE IMPORTANCE OF UNDERSTANDING SOURCES OF PHYSIOLOGICAL, ENVIRONMENTAL AND ANALYTICAL VARIABILITY

The use of stable isotopes (e.g. ¹⁵N/¹⁴N, ¹³C/¹²C, etc) in ecology, such as food web studies and microbial probing, has been in existence for several decades. The use of compound-specific stable isotopes (e.g. ¹³C/¹²C in specific fatty acids) for the purpose of soil and sediment tracing is a relatively new approach to dealing with soil erosion and water quality issues. Indeed, CSSIs have the potential to complement and enhance current techniques, such as geochemical analyses and the use of fallout radio nuclides. The CSSI method is perhaps more complex in its application than other current methods; however, CSSIs may be able to resolve sediment sources in deposition zones based on land use on source soils and its associated vegetation. The implications of more precisely determining the source of sediments include addressing soil erosion issues more specifically and improving field management, thereby targeting resources to problem areas rather than using a general, broad approach for an entire watershed.