Integrated approach to sediment pollution: a case study in the Gulf of Trieste.

The Gulf of Trieste is located at the northernmost part of the Adriatic Sea (Italy), and is a shallow embayment with an average depth of 17 m. The gulf is an interesting site for studies on anthropic impacts because it has been populated for at least the last 2000 years and activities such as marble quarrying and oyster culture have been practised for centuries; today, it houses several ports and an industrial zone which generate noticeable anthropogenic pressures. The gulf’s peculiar geomorphologic and hydrologic conditions make it prone to the accumulation of pollutants, since it is an elongated, sheltered bay with reduced hydrodynamism (SolisWeiss et al., 2004). The Servola sewage disposal plant is the most important sewage plant of the city, serving up to 270,000 inhabitants. Its primary treatment has been based on chemical precipitation since 1992. The treated water is discharged via two adjacent submarine ducts (6.5 and 7.5 km) ending at 23 m depth with several diffusers (Novelli, 1996). In many marine environments, benthic communities constitute the most effective tool for assessing environmental variations of any given habitat. This is because benthos, in contrast to nekton and plankton, remain in place and are thus subjected to different environmental stresses, and react to these synergetically without any escape possibility. The resulting composition of species, replacements, eliminations, diversity or abundance changes, can indicate the recent history of events affecting the area (Solis-Weiss et al., 2001). The aim of this study was to assess the sediment quality near the outlet of the main wastewater pipeline of the city, applying