Acronym ORGALT
Category
Fisheries
Title Accumulo di composti organostannici nella catena trofica e in specie ittiche commerciali dell'alto Adriatico - Trophic magnification of organotin compounds in the marine food-web and bioaccumulation in commercial fish species in the Northern Adriatic Sea Programme National Programme
Instrument (FP6)
Contact Type (FP7)
Strand (Interreg)
NA
Theme (FP7)
Activity Area (FP6)
Regional Area (Interreg)
Action (COST)
NA
Specific Programme (FP7)
NA
Funding source National Coordinator Otello Giovanardi Coordinator email otello.giovanardi@isprambiente.it
Coordinator institution
ISPRA - Italian National Institute for Environmental Protection and Research (Italy)
Institutions involved
NA
Start year 2008 End year 2011 Funding (€) € NA Website NA Summary "Tributyltin (TBT) has been widely used as antifouling agent in marine paints for more than three decades (Strand and Jacobsen, 2005). TBT, as well as its breakdown products (dibutyltin - DBT and monobutyltin - MBT), exert chronic toxic effects on various aquatic organisms (Hoch, 2001) and on humans (Whalen et al., 2002), thus it was banned from marine paints in 2008. However, organotins are still present in the environment because of their high persistence, due to their slow degradation rates and high sorption to suspended matter and sediment (Strand and Jacobsen, 2005). The Northern Adriatic Sea (NAS) is historically subjected to intense ship traffic and consequently high TBT input. Because fishery is very developed in the area and represents an important source of food for local inhabitants, it is of major concern to study the accumulation and biomagnification of organotins along the food-web. In this project fish, invertebrates, sediment, plankton and water samples were collected between 2008 and 2010 in three areas of the NAS, located at growing distance from the coast, and organotins concentrations were determined. A wide range of species was analysed, from primary producers to top predators. Biomagnification was evaluated by regressing organisms' trophic level (TL), assessed through the measurement of the biological enrichment of nitrogen stable isotopes ('15N), against contaminants concentration. The use of '15N is a recognized method to study food-webs relationships: an increase of 3-3,8%0 characterizes the passage between subsequent TLs (Murai et al., 2008). Furthermore, '13C was determined and regressed against contaminant concentration to obtain indications of contamination sources. Indeed, '13C is a useful tracer of primary carbon sources and differences of '13C values in consumers at increasing distance from the coast is usually explained as a different influence of the terrestrial environment on the marine compartment (Lee, 2000). A positive relationship was found between TL and concentrations of TBT, DBT and MBT, confirming the existence of trophic magnification of butyltins in the NAS food web. Coherently, the Trophic Magnification Factor (TMF) (Borgå et al., 2012) was calculated to be upper than 1 for all contaminants analysed, i.e. 4,53 for TBT, 5,48 for DBT and 3,29 for MBT. A negative relationship was instead found between '13C and organotins concentration, suggesting a gradient of contamination moving from the coast. However, in most of the cases this relationship was weak and not significant, and this result may suggest that the trophic magnification is more important in determining marine species contamination than the source of food. On the other hand, it is worth noting that analysis of organotins in the biota, in the water and in surface sediments revealed differences in the three areas sampled, where fluvial and coastal areas were more contaminated than open sea ones. This study gives evidence that organotins are still present in the NAS ecosystem, although with concentrations lower than the ones observed before their ban from antifouling marine paints, and these compounds are subjected to biomagnification in the food-web. Also commercial fish species, such as Platychthys flesus (European flounder) and Sepia officinalis (common cuttlefish), resulted to be contaminated. Thus, it is necessary to intensify the monitoring of these contaminants in seafood products and to improve our knowledge on contaminants' fate in the environment and biota; for this purpose, isotope analysis revealed to be a useful tool for evaluating trophic relationships.
Keywords
Impacts;
Toxic substances;
Food web;
Marine Region
74
Northern Adriatic (GSA 17)
1
Marine Region Map
