Chemical and geochemical characterisation of a disused red brick factory area of central Italy

Characterisation and remedial actions are proposed for a polluted site enclosed within a red brick factory, located in central Italy. Approximately 22,000 t of chromium containing tannery sludge were introduced as 'secondary raw materials' for reuse in red brick manufacture. Preliminary geo-electric tomography was carried out on the waste bank, followed by the perforation of 14 boreholes into the bottom geological stratum. Heavy metals [B, Crtot, Cr(VI), Hg, Pb, Cu, Sn, V, Zn] and polycyclic aromatic hydrocarbons [benzo(a)pyrene; phenanthrene; dibenzo(a,h)pyrene; pyrene] were determined on solid samples. Carrots were sliced to give samples from different depths in the waste bank. The following samples were determined in the waste leachate: 1,1,2trichlorethane, phenol, 2,4,6trichlorphenol, hexachlorhexane, dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethane (DDD) and dichlorodiphenyldichloroethylene (DDE). During characterisation, laboratory experiments were also carried out on lime-treated and untreated carrot sections to evaluate heavy metal release and potential migration in the subsoil. Pollutant exposure pathways were set up, based on application of the Risk-Based Corrective Action (RBCA) model, followed by the evaluation of potential environmental and sanitary targets for site-specific risk evaluation and the proposition of scientifically based restoration scenarios. Surface capping, coupled with lateral belting of the site, were selected for the site recovery operations after extensive cost-benefit evaluations.