Groundwater risk assessment of PCE at contaminated sites

Human risk assessment of a former industrial plant situated in the South of Italy is analyzed. Risk is estimated by simulating tetrachloroethylene (PCE) degradation and the formation of breakdown products. Transport of PCE, tri-chloroethylene (TCE), di-chloroethylene (DCE) and vinyl-chloride (VC) in groundwater is modelled accounting for sorption, dispersion and kinetics degradation within a time horizon of 90 years. Since reliable values of sorption parti-tioning coefficients and degradation kinetics are rarely avail-able at contaminated sites, risk is evaluated in several sce-narios in which the physical-chemical parameters values are varied according to literature values. The risk results are highly influenced by different but feasible scenarios, em-phasizing that reliable site specific field data are necessary to accurately assess the risk. Moreover, naturally occurring PCE degradation does not always result in a decreasing cancer risk with time and the human health risk can increase because of the formation of more toxic substances and, only after a really long time, attenuated by further degradation.