Vinyl chloride (VC) groundwater contamination around Ferrara city seems widespread and has created a serious environmental problem in a highly urbanized region. The paper discusses recent data derived from a geochemical and isotopic fingerprinting study carried out at the Pandora site which is characterized by the existence of long VC plume and the Caretti site where high concentrations of chlorinated compounds, including VC occur. Data was also collected in an unconfined aquifer underneath a major petrochemical plant. The isotope data showed than the unusual negative δ13C values observed in the VC at both sites (Pandora –43 and –65‰; Caretti: -62 and –72‰) could not be associated to reductive dechlorination of manufactured primary PCE or TCE. The isotope data showed also unusual negativeδ13C values for PCE and TCE in the impacted aquifer beneath the petrochemical plant and the Caretti site. Based on the industrial history in the region that included production of PVC and chloromethanes (ClM), it is postulated that the contamination in the Ferrara region is linked to wastes originating from the production of chloromethanes. The primary organic compound used in ClM production is methane, which is strongly depleted in 13C similar to the values observed in VC, PCE and TCE at the investigated sites. It is also postulated that the contamination is linked to dumping of industrial waste in the abandoned old lagoons used by the sugar industry and in clay pits associated to the clay industry.
Use of hydrogeological and geochemical methods to investigate the origin and fate of vinyl chloride in groundwater in an urban environment, Ferrara, Italy
PASINI, Monica;GARGINI, Alessandro;
2008
Abstract
Vinyl chloride (VC) groundwater contamination around Ferrara city seems widespread and has created a serious environmental problem in a highly urbanized region. The paper discusses recent data derived from a geochemical and isotopic fingerprinting study carried out at the Pandora site which is characterized by the existence of long VC plume and the Caretti site where high concentrations of chlorinated compounds, including VC occur. Data was also collected in an unconfined aquifer underneath a major petrochemical plant. The isotope data showed than the unusual negative δ13C values observed in the VC at both sites (Pandora –43 and –65‰; Caretti: -62 and –72‰) could not be associated to reductive dechlorination of manufactured primary PCE or TCE. The isotope data showed also unusual negativeδ13C values for PCE and TCE in the impacted aquifer beneath the petrochemical plant and the Caretti site. Based on the industrial history in the region that included production of PVC and chloromethanes (ClM), it is postulated that the contamination in the Ferrara region is linked to wastes originating from the production of chloromethanes. The primary organic compound used in ClM production is methane, which is strongly depleted in 13C similar to the values observed in VC, PCE and TCE at the investigated sites. It is also postulated that the contamination is linked to dumping of industrial waste in the abandoned old lagoons used by the sugar industry and in clay pits associated to the clay industry.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
