Actual decay of tetrachloroethene (PCE) and trichloroethene (TCE) in a highly contaminated shallow groundwater system

Novel Oxidation Strategies for the In Situ Remediation of Chlorinated Solvents from Groundwater—A Bench-Scale Study

“…The attenuation of DCE (89%) and TCE (87%) was greater than that of PCE (59%). Our results agree with the experiments [8,9] that observed that, in the remediation of contaminated GW under flow-through conditions by S-nZVI and Fe(VI) treatments, higher efficiencies were achieved when employing S-nZVI rather than Fe(VI) under similar conditions. Because of the acidic media, Fe(VI) was more strongly retained in the soil column than S-nZVI particles.…”

“…Moreover, this observation could signify a shift in the industrial spill of solvents or an enhanced remediation of chlorinated solvents in the spill area, possibly due to the higher presence of organic matter and TSSs. In relation to the concentration ratio between TCE and PCE, a review of the literature [9] indicates that PCE has a high potential for dichlorination, leading to the production of more TCE, in concordance with our results. It is noteworthy that industrial activities ceased in the area three years ago, eliminating the expectation of further inputs of chlorinated solvents from this specific industry.…”

“…This can be explained by the fact that the TCE concentration was reduced from 100 to 10 µg/L, but also by the addition of DCE and PCE to the reactor. Additionally, it is pertinent to note that, owing to the reported dichlorination of PCE primarily into TCE [9] and DCE [6,14], the removal of TCE may have decreased. However, it is reported that those TCE by-products normally account for less than 5% of the total degradation products [25].…”

“…Even though they are well-known contaminants, chlorinated solvents are still a real environmental issue, as they are a large family of compounds and one of the most prevalent organic contaminants found in GW [7]. Some of these chlorinated solvents are known to be potential human carcinogens: trichloroethylene (TCE; a metallurgic-industry solvent) [6,8], tetrachloroethylene (perchloroethylene, PCE; a metallurgic-industry solvent) [9], and cis-1,2-dichloroethylene (DCE; a petrol-industry solvent) [7,10]. As a consequence, chlorinated solvents have been classified as persistent, mobile, and toxic (PMT) and very persistent and very mobile (vPvM) substances, as dictated by REACH [11].…”