Environmental monitoring on the basis of benthic foraminifers response and geochemical characterization in the coastal area surrounding the Industrial Complex of Portovesme (South-Western Sardinia, Italy)

Samples of surface sediments were collected in 2005 and 2006 from a polluted coastal zone shorefront to the Industrial Complex of Portoscuso-Portovesme (Sulcis, South-Western Sardinia) in order to study the benthic foraminifers response to heavy metals pollution, and to analyze the geochemical parameters (BOLTOVOSKOY et alii, 1991; SHARIFI et alii, 1991; ALVE, 1991, 1995; YANKO et alii, 1994, 2002; MURRAY, 2000; ARMYNOT DU CHÂTELETE et alii, 2004; COCCIONI et alii, 2005; SCOTT et alii, 2005). Samples came from the upper 1-2 cm of the undisturbed sediments in water less than 2 m deep, along coastline (about 8.5 Km length) proximal to emerged alluvial plain. The whole examined marine area represents a shallow inner shelf, physiographically fairly protected and characterized by low turbulence, but subjected to southward littoral drift. Geochemical analyses of seawater, sediments and foraminiferal tests, correlated to biotic indexes (Dominance, Shannon-Weaver, Simpson, Eveness, Menhinick, Margalef, Equitability, Fisher-α, Berger-Parker and Q-mode Cluster Analyses – Ward Method) provide data on the environmental stress (SCOTT & MEDIOLI, 1980; PILSON, 1998; CHESTER, 2000; HAMMER & HARPER, 2005). A total of 31 benthic foraminiferal species were identified (CIMERMAN & LANGER, 1981; HOTTINGER et alii, 1983; LANGER, 1988). Increasing pollution results in low species diversity, low population density and more frequent abnormal specimens (YANKO et alii, 1998; SAMIR et alii, 2001; GESLIN et alii, 2002). Results from ESEM images allowed to recognize a strong infestation on the calcareous foraminiferal tests by microbial communities developed in the polluted environment (CAMPBELL, 1982; HALLOCK et alii, 1996; HALLOCK, 2000).