Natural polluted waters in Calabria Region (Italy): preliminary data on arsenic contamination and treatment

In the water systems, potentially harmful elements such as arsenic (As), can reach high concentrations, becoming extremely dangerous for environment and human health. To limit the proved negative effects on the human health of this element, the World Health Organization (WHO, 2001) has set the drinking water guideline values of As to 10 ?g/?. The abundance of dangerous elements in water systems mainly depends on their availability into bedrocks and on geochemical conditions during water-rock interaction process. In water systems, As can occur mainly as oxyanions of trivalent (As3+) and pentavalent (As5+) inorganic forms (Smedley & Kinniburgh, 2002) as the result of water-arsenic minerals interaction. These minerals are mainly sulphides: arsenopyrite (FeAsS), orpiment (As2S3), realgar (As2S2) and arsenian (As-rich) pyrite (Fe(As,S)2). In this regard, a thorough bibliographic research has been performed to create a database of all the waters of Calabria Region and some anomalies have been identiied. In response to these preliminary data it was planned a geochemical prospection in the areas where anomalies were found and many springs, river waters and wells were sampled and analyzed. New data have shown high concentration of As in the southern Sila Massif where Hercynian and pre- Hercynian gneiss, granite and metapelite belonging to Calabride complex, outcrop. Subsequently, preliminary tests of treatment on As contaminated groundwater were performed using membranes technology (Figoli et al., 2016). Four types of membrane modules named HL (polyamide), DK (proprietary thin-ilm), CK (cellulose acetate) and ?P0?0P (polyethersulfone) were used through a nanoiltration (NF) laboratory pilot unit. The results have shown that all the membranes, except NP030P, are able to reject As very well and As concentrations after the treatment were below 10 ?g/? (WH? limit). The application of this technique could allow the use of water resource in the studied contaminated area.