Vis-NIR Reflectance Spectroscopy and PLSR to Predict PCB Content in Severely Contaminated Soils: A Perspective Approach

: Soil reclamation from polychlorinated biphenyls (PCBs) requires careful analysis in termsof their concentrations and spatial distribution. Conventional laboratory analysis, even if providingthe careful evaluation of PCBs, is costly and time-consuming. Therefore, rapid and cost-effectivetechniques to replace traditional analytical approaches are required. The utility of visible-near infrared (vis-NIR) reflectance spectroscopy in conjunction with partial least square regression (PLSR)analysis was evaluated in this study. Spectral reflectance was measured in the laboratory on 28 soilsamples collected in a highly contaminated area of southern Italy and chemically analysed to determine eighteen PCB congeners, their sum (PCBs18), and extractable organic halogen content (EOX).Spectroscopic data were pre-processed prior to data analysis by combining different methods. UsingPLSR analysis, significant relationships were observed between the predicted and the measuredcontent of PCBs18, EOX, and the percentage of several isomeric classes of PCBs. Although rigorousmodels could not be calibrated, due to the limited number of samples, the preliminary results of thisstudy demonstrated that vis-NIR reflectance spectroscopy, coupled with PLSR, can be considered apromising method for a rapid and cost-effective prediction of PCBs.