Assessment of sediment quality in the Mediterranean Sea–Boughrara lagoon exchange areas (southeastern Tunisia): GIS approach-based chemometric methods Adel Kharroubi & Dorra Gargouri & Houda Baati & Chafai Azri Received: 11 March 2011 /Accepted: 15 July 2011 /Published online: 28 July 2011 # Springer Science+Business Media B.V. 2011 Abstract Concentrations of selected heavy metals (Cd, Pb, Zn, Cu, Mn, and Fe) in surface sediments from 66 sites in both northern and eastern Mediterra- nean Sea–Boughrara lagoon exchange areas (south- eastern Tunisia) were studied in order to understand current metal contamination due to the urbanization and economic development of nearby several coastal regions of the Gulf of Gabès. Multiple approaches were applied for the sediment quality assessment. These approaches were based on GIS coupled with chemometric methods (enrichment factors, geoaccu- mulation index, principal component analysis, and cluster analysis). Enrichment factors and principal component analysis revealed two distinct groups of metals. The first group corresponded to Fe and Mn derived from natural sources, and the second group contained Cd, Pb, Zn, and Cu originated from man- made sources. For these latter metals, cluster analysis showed two distinct distributions in the selected areas. They were attributed to temporal and spatial varia- tions of contaminant sources input. The geoaccumu- lation index (I geo ) values explained that only Cd, Pb, and Cu can be considered as moderate to extreme pollutants in the studied sediments. Keywords Boughrara lagoon . Southern Tunisia . Heavy metals . GIS . Chemometric methods Introduction Coastal lagoons are common environments in the transitional zone located between terrestrial ecosystems and adjacent seas. These ecosystems are controlled by complex interactions between land, ocean, and atmo- sphere, resulting in high changeable and vulnerable environments (Viaroli et al. 2007). The hydrological balance of these coastal lagoons dictates their charac- teristic salinity, which may vary between freshwater and hypersaline conditions (Kjerfve 1994). Lagoons are economically and ecologically important because of intensive recreational and fishing activities. When menaced by man-made source effects, the biogeo- chemical processes of these ecosystems can alter the Environ Monit Assess (2012) 184:4001–4014 DOI 10.1007/s10661-011-2239-8 A. Kharroubi Université de Gabès, Institut Supérieur des Sciences et Techniques des Eaux de Gabès, Campus Universitaire, Cité Erriadh, 6072 Zrig Gabès, Tunisia D. Gargouri : C. Azri (*) Université de Sfax, Faculté des Sciences de Sfax, Département des Sciences de la Terre, Route Soukra, km 3,5, PB 1171, 3000 Sfax, Tunisia e-mail: chafai_azri@yahoo.fr H. Baati Université de Sfax, Ecole Nationale d’Ingénieurs de Sfax—LARSEN, UR Etude et Gestion des Environnements Côtiers et Urbains, BP 1173-3038, Sfax, Tunisia