Levels and spatial distribution of polychlorinated biphenyls (PCBs) in superficial sediment from 15 Italian Marine Protected Areas (MPA)

Abstract

Human activities such as industry, sewage, coastal sprawl, intensive agriculture and oil spills have a high impact on the Mediterranean marine environment. In Italy, growing awareness of how man is threatening marine ecosystems has prompted conservation measures, including the designation of Marine Protected Areas (MPAs). MPAs are essential for conservation, providing protection for critical areas and refuges for overexploited species. They can also act as buffers against management miscelation (Allison et al., 1998). Italy has instituted a number of MPAs that are proving effective in protecting wildlife. Most of them contain one or more no-entry zones which coincide with the areas of greatest natural value (Boero et al., 1999). However, MPAs cannot protect populations or assemblages from transboundary movements of chemicals (I.U.C.N, 1981), a phenomenon observed mostly in MPAs located near human activities such as harbours. MPAs can be useful for monitoring release of contaminants. For instance, Terlizzi et al. (2004) reported the effects of organotin compounds such as tributyltin (TBT) and its transboundary movements in species of marine snails living in Italian MPAs. Persistent organic pollutants (POPs) are semivolatile organic compounds of special concern because of their toxicity, persistence, long-range transport and bioaccumulation potential (UNEP, 2001). POPs such as polychlorinated biphenyls (PCBs) have been widely used in industry and are characterized by low vapour pressure, low water solubility and environmental persistence (Mackay et al., 1992). Since they are hydrophobic they bind readily to particulate in water and are transported/deposited with sediment into rivers, lakes and oceans (Bergamaschi et al., 2001). The Stockholm Convention on POPs, coordinated through the United Nations Environment Programme (UNEP), aims to reduce or eliminate the use, discharge and emission of these compounds to the benefit of the environment, reducing risks to humans and wildlife (UNEP, 2001). Initially, 12 chemicals were identified as priority POPs: nine organochlorine pesticides (OCPs), one industrial chemical class, polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-pdioxins/dibenzofurans (PCDD/Fs) associated with various industrial/combustion emissions (UNEP, 2001). Several countries in Europe are parties to the Convention; Italy signed the Stockholm Convention in May 2001, but has not yet ratified it. PCBs were widely used as insulating fluids in electrical equipment, such as transformers and capacitors, and for many other uses. Italian production of PCBs began in 1958. PCB mixtures were