the!Scienceofthe -maI-t AmUlmW,-*-II- Im.!h?hviremem~Lll-“mMm The Science of the Total Environment 204 (1997) 49-56 ELSEVIER Santa Gilla lagoon (Italy) : a mercury sediment pollution case study. Contamination assessment and restoration of the site S. Degettoa, M. Schintubp*, A. Contub, G. Sbrignadello” “ICTIMA-CNR, Cso Stati Uniti 4,3.5127 Padova, Italy bDipartimento di Igiene e Sanitci Pubblica, Universit5 di Cagliari, Vii Porcell4, 09100 Cagliuri, Italy Received 22 February 1997; accepted 5 June 1997 -. Abstract The SantaGilla lagoon,on the southerncoastof the islandof Sardinia(Italy), hasreceived industrial discharge of mercury, lead and zinc compounds, as well asmunicipaluntreated sewage for several decades from the urban areaof Cagliari (about 400000 inhabitants). The lagoon, which covers an area of 15 km2 of shallowwaters, has always represented an important source of quality fish and shellfish for the island.Pollution sources were brought under control only in the mid-198Os, when a costly restoration program, which is still in progress, wasstarted. About 26 tons of mercury, discharged from a chlor-alkali plant, havebeen estimated to havebeen deposited in the lagoonsince the mid-1960’s, mostly confined in an area of about 2 km2 in front of the industrial area. According to the restoration project this area has been isolated with proper dykes and used to discharge sediments dredged from the most polluted sectors of the lagoon. It wasfinally coveredup with sediments dredged from cleanerareas of the lagoon with the aim of usingit for aquaculture.This work reviewsseveralinvestigations carried out on the sediments of the S. Gilla lagoon to monitor and control the real extent and hazard of the mercury pollution. Recent data on the mercury concentration in the sediments of the lagoon after remediationwere compared with previous data on the same area and the effectiveness of the clean-upplan wasevaluated. 0 1997 Elsevier Science B.V. Keywords: Sardinia,Italy; SantaGilla lagoon; Mercury pollution; Sediment;Clean-up * Corresponding author. Tel. + 39 70 6758364; fax: + 39 70 668661; e-mail: schintu@vaxcal.unica.it 004%9697/97/$17.00 0 1997 Elsevier Science B.V. All rights reserved. PII SOO48-9697(97) 00165-4