FIGURE 3-1 Effect of soil–water partitioning coefficient (Kd ) on maximum soil residue for RDX. SOURCE: Phelan et al. (2003).
(unless one is fortunate enough to collect a core sample that contains DNAPL in its pores, something that is unusual due to the highly inhomogeneous DNAPL distribution). Furthermore, solids can interfere with the extractability of certain components. Historical records may be able to provide some information on the age and identity of the compounds and how they were used on the site. Yet, short of collecting actual chemical samples such as a DNAPL sample, it may not be possible to fully understand the nature of the source material (in terms of the key physical and chemical parameters mentioned above).
Table 3-3 lists the likelihood of a source zone being present at a site, given the occurrence of certain events. For example, if there was a known or probable historic release of a DNAPL, then there is high certainty that there is a source.