Integrated characterization and risk management of marine sediments: The case study of the industrialized Bagnoli area (Naples, Italy).

The aim of the present work is to demonstrate the practical importance of a multidisciplinary approach and weighted criteria to synthesize and integrate different typologies of data (or lines of evidence, LOEs), including chemical levels in marine sediments, their bioavailability to specific indicator species, ecotoxicological effects measured through subcellular biomarkers and batteries of bioassays, and potential impacts of pollution on local benthic communities. The area of Bagnoli (Gulf of Naples, Southern Italy) was selected as a model case-study, as it is a coastal area chronically impacted by massive industrial contamination (trace metals and hydrocarbons), and dismissed decades ago without any subsequent remediation or habitat restoration. The results of each LOE were elaborated to provide specific hazard indices before their overall integration in a weight of evidence (WOE) evaluation. Levels of some trace metals and PAHs revealed a severe contamination in the entire study area. Bioavailability of hydrocarbons was evident particularly for high molecular weight PAHs, which also caused significant variations of cellular biomarkers, such as cytochrome P450 metabolization in fish, lysosomal membrane destabilization in mussels, genotoxic effects both in fish and molluscs. The results of a battery of bioassays indicated less marked responses compared to those obtained from chemical and biomarkers analyses, with acute toxicity still present in sediments close to the source of contamination. The analysis of benthic assemblages showed limited evidence of impact in the whole area, indicating a good functioning of local ecosystems at chronic contamination. Overall, the results of this study confirm the need of combining chemical and biological data, the quantitative characterization of various typologies of hazard and the importance of assessing an integrated environmental WOE risk, to orientate specific and scientifically-supported management options in industrialized areas.

Polycyclic aromatic hydrocarbons in the sediments of the Gulfs of Naples and Salerno, Southern Italy: Status, sources and ecological risk.

This study investigated the spatial distribution, potential sources, and toxic effects of polycyclic aromatic hydrocarbons (PAHs) in the sediments of the Gulfs of Naples and Salerno (NaSa Gulfs), Southern Italy. The investigation focused on the coastal sea sediments of the Bagnoli brownfield site within the Gulf of Naples. The ∑16PAHs in the sediments of the NaSa Gulfs outside of the Bagnoli brownfield site have concentrations that ranged from 9.58 to 15,818 µg/kg, with a geometric mean (Gmean) of 234 µg/kg. High-molecular weight PAHs (HMW PAHs) contributed to over 80% of the ∑16PAHs. The concentration of ∑16PAHs in the Gulf of Naples was twice as high as that in Salerno (768 µg/kg and 317 µg/kg, respectively), and the ∑16PAHs levels in the Bagnoli brownfield site exceeded that in the NaSa Gulfs by over three orders of magnitude. The molecular distributions of PAHs studies suggested biomass/coal combustion as their main sources. Based on the analysis of the toxic equivalent quantity and sediment quality guideline quotient, the contamination of PAHs in sediments may pose significant toxicity and biological risks to marine organisms.