As attention has shifted to the use of "monitored natural attenuation" to remediate sites contaminated with chlorinated solvents, optical spectroscopic methods have gained attention as a potential means to enable long-term monitoring. However, previous field research has shown that a number of geoenvironmental factors adversely influence the quality of in-situ optical spectroscopic measurements, including the presence of (non-target) fluorophores, presence of multiple chemical compounds, and the hydrogeological environment of the site.