The assessment of the distribution and composition of microlitter in the sea is a great challenge. Biological indicators can be an irreplaceable tool since they measure microlitter levels in their environments in a way that is virtually impossible to replicate by direct physical measurements. Furthermore, trends can provide policymakers with statistically robust analysis. We looked into the capacity of multiple fish species to describe the distribution and composition of microlitter vertically across different compartments of the water column. A total of 502 individuals from six selected species (Scomber scombrus, Oblada melanura, Spicara smaris, Boops boops, Merluccius merluccius and Mullus barbatus) were collected on the western side of Sardinia island and allocated to three compartments: surface, mid-water and bottom. The species of the surface exhibited a higher frequency of occurrence (41.89%) of microlitter ingestion, compared to those of the mid-water and bottom (19.60%; 22.58%). A significant difference in the average number of ingested microlitter was found between the surface and the bottom compartment. All the microlitter fragments found were analysed through Fourier Transform Infrared Spectroscopy (FTIR). The comparison of the expected buoyancies of the polymers identified puth faith in the allocation of the species to the respective compartments. Therefore, considering the Marine Strategy Framework Directive objective, this approach could be useful in assessing microlitter distribution and composition vertically across the water column.

While the increasing accumulation of anthropogenic litter in the marine environment has received considerable attention over the last decade, litter occurrence and distribution in rivers, the main source of marine litter, have been comparatively less investigated. Moreover, little information is available about the amount and typology of Riverine Anthropogenic Macro-litter (RAM) entering marine environments from intermittent rivers in low populated areas of the Mediterranean basin. To provide insights on this issue, we investigated density and composition of RAM accumulated over a total of 133 riverbanks, belonging to 37 river basins in the Sardinia Island (Mediterranean Sea). We report here that plastics, especially single-use items, represent the most frequent and abundant RAM category in all investigated basins. Statistical modelling revealed that occurrence of lightweight RAM (especially plastic) is mostly explained by levels of urban (12.3% of the relative contribution) and agricultural (12%) land use of the territory, whereas the proximity of bridges to the sampling point (21%) and the local population density (19.8%) are best predictors of heavy weighted RAM items (i.e., large metal items, appliances) occurrence. Our results confirm that plastics represent an important component of RAM and pinpoint that, beside plastic reduction policies and better waste management, actions aimed at abating and monitoring litter contamination should be localized on the proximity of bridges, whatever the local population density. Finally, to fill existing knowledge gaps in understanding the severity of litter discharge and accumulation in the Mediterranean Sea, land-to-sea systematic monitoring campaigns at appropriate spatial and temporal scales should be put in place.

In this work, three gastropods Patella vulgata, Osilinus turbinata, and Tahis clavigera, one echinoderm Parancetrotus lividus, one coelenterate Anemonia sulcata, and two seaweed Padina pavonica, and Cystoseira mediterranea were collected from three different marine areas of Sardinia in the Mediterranean sea and studied for heavy metals and metalloid content and accumulation trends.Inductively coupled plasma optical emission spectrometry (ICP-OES) was used for the determination of Al, AS, B, Ba, Be, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, Se, Sn, Sr, Te, Ti, V and Zn in the selected samples. The results showed that gastropods were capable of accumulating Al, Ba, Cu, Fe, Sr, and Zn; seaweeds can better concentrate Al, Fe, and Zn than all other species. At the same time, echinoderms and coelenterate had limited ability to store specific metals, showing a much more homogeneous distribution. PCA analysis allowed us to discriminate among the sites and the species. Cala Zafferano was the area with the higher values of accumulation of all metals in all species as expected, considering its proximity to industrial sites. The results of the analysis showed clearly that heavy metal and metalloid accumulation was different for each species studied. Therefore, for a correct environmental assessment of a given area, a comprehensive approach is strongly recommended by exploiting the different properties of both accumulation and concentration of the metals by different aquatic species.

Ingestion of microplastics (MPs) has been documented in several marine organisms, but their occurrence in deep-sea species remains almost unknown. In this study, MPs were investigated in two economically and ecologically key crustaceans of the Mediterranean Sea, the Norwegian lobster Nephrops norvegicus and the shrimp Aristeus antennatus. Both the species were collected from 14 sites around Sardinia Island, at depths comprised between 270 and 660 m. A total of 89 and 63 stomachs were analysed for N. norvegicus and A. antennatus respectively, and more than 2,000 MPs-like particles were extracted and sorted for identification and characterization by μFT-IR. In N. norvegicus, 83% of the specimens contained MPs, with an average abundance of 5.5 ± 0.8 MPs individual−1, while A. antennatus showed a lower frequency of ingestion (67%) and a lower mean number of MPs (1.66 ± 0.1 MPs individual−1). Composition and size of particles differed significantly between the two species. The non-selective feeding strategy of N. norvegicus could explain the 3–5 folds higher numbers of MPs in its stomach, which were mostly composed of films and fragments derived by polyethylene and polypropylene single-use plastic items. Contrarily, most MPs in the stomachs of A. antennatus were polyester filaments. The MPs abundance observed in N. norvegicus is among the highest detected in Mediterranean species considering both fish and invertebrates species, and provides novel insights on MPs bioavailability in deep-sea habitats. The overall results suggest that both N. norvegicus and A. antennatus, easily available in common fishery markets, could be valuable bioindicators and flagship species for plastic contamination in the deep-sea.

The anthropogenic contamination of water bodies with metals via fertilizer, industrial sewage and urban wastewater has resulted in widespread problems in aquatic organisms, but also poses a risk to consumer health. Shellfish from coastal and estuarine environments bioaccumulate toxic metals in their tissues due to their ability to concentrate inorganic contaminants several orders of magnitude above ambient levels. The aim of this study was to evaluate the presence of trace elements in adult specimens of indigenous clams (Ruditapes decussatus). To this end, wild clams were collected from four different brackish areas of Sardinia (Western Mediterranean Sea, Italy) devoted to extensive aquacultural practices. The concentration of 16 trace elements (Al, Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Sn, Tl and Zn) in the tissues of the clams was quantified. The legal limits set by European Regulations for cadmium; mercury and lead were never exceeded. However, unexpectedly high values for aluminium and iron (mean 207 mg kg⁻¹ and 113 mg kg⁻¹ wet weight) were found in Santa Gilla lagoon, which is close to industrial settlements and had the highest values for the majority of chemical elements investigated. The highest values of the metalloid arsenic (As) were reported in the Porto Pozzo and San Teodoro lagoons (9.6 and 6.8 mg kg⁻¹ w.w., respectively). The clam R. decussatus confirmed the capacity of bivalves as suitable bioindicators of trace elements pollution. Further investigations are necessary for constant monitoring of clams, 32 which constitute an important traditional resource for the fishing activity in Sardinia.

Concern about microplastic pollution little is known about levels in deep-sea species; to fill this knowledge gap, levels of microplastics in the gastrointestinal (GI) tracts of 34 fish from eight different deep–sea by–catches: blackmouth catshark, lesser spotted dogfish, and velvet belly, armless snake eel, hollowsnout grenadier, phaeton dragonet, royal flagfin, and slender snipe eel were measured. All were collected at the same site (east Sardinia, Mediterranean Sea; 40°10′12.49″N, 9°44′12.31″E) using a bottom gillnet at depths between −820/250 and −1148 ft./350 m. Microplastics (MPs) were retrieved in 16 out of 34 fish. At least one microplastic item was found in 48% (33%, E. spinax - 75%, G. melastomus) of the samples. The most frequent was polyethylene (PE), with nine items (filaments, films, fragments) found in five specimens. This preliminary study of by–catches adds new data on MPs ingestion by species inhabiting a deep–sea environment of the Mediterranean.

This paper describes the results of a two-year monitoring study examining the pollution of the sea urchin Paracentrotus lividus by polycyclic aromatic hydrocarbons (PAHs) in Sardinia. GC–ITMS analysis of sea urchin gonads showed the presence of 11 and 12 PAHs in the samples of Capo Pecora, and Capitana, respectively. Fluorene, naphthalene and its two degradation products, 1-methyl-naphthalene, and 2-methyl-naphthalene, were detected in all samples analyzed. The ΣPAH residues showed a similar trend over the two-year sampling period. Furthermore, the residues in the first year were slightly higher than in the second year. The information obtained by the multivariate statistical analysis PLS-DA allowed for the determination of samples based on field site and varying habitat types (rocky reef, and Posidonia seabed). The results of this study showed that Posidonia sea urchins are contaminated by high molecular weight PAHs and that Capitana samples are more contaminated due to a higher level of human activity in the area.

Aqueous concentrations of individual polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were determined in coastal sites of two marine protected areas (MPAs), that is, Asinara and the La Maddalena Archipelago, in Sardinia (Western Mediterranean Sea). The use of semi-permeable membrane devices (SPMDs) enabled the detection of dissolved PAHs and PCBs, even in very low concentrations of (pgL−1), in seawater. The results reveal significant differences between the two sampling areas relative to the concentration of the individual PAHs, which provide information concerning the pollution sources affecting relatively pristine environments. The PCBs were generally observed at levels below the detection limits of the utilised method.

Intensive exploitation of base metal deposits in the Sulcis-Iglesiente district (Sardinia, Italy), lasted from the 1850s to the 1990s, determined a high environmental impact on the coastal area, but the effects on marine environment have never been investigated. A marine sediment core, dated with 14C, was characterized for grain size, chemical and mineralogical composition, in order to reconstruct the sedimentary history of the area and to assess the environmental impact of mining. The comparison of chemical and mineralogical characteristics of recent sediments with those of pre-industrial age allowed discriminating the real anthropogenic impact from the natural metal enrichment. The correspondence, in the upper core, of anthropogenic trace metal enrichment with the presence of mine waste minerals is attributed to the exploiting over industrial scale; the still high metal enrichment in sediment surface levels suggests a still existing impact due to mine dumps and tailings weathering.

The presence of microcystin-LR (MC-LR) was monitored in Tapes decussatus harvested in two Sardinian ponds (Cabras and Tortolì, Italy) in spring and summer. After solid phase extraction, samples were analyzed using a screening enzyme-linked immunosorbent assay (ELISA) followed by a liquid chromatographic coupled to tandem mass spectrometer (LC–MS/MS) analysis. Results obtained through the ELISA test showed the presence of microcystins with a maximum concentration in August for Cabras pond (0.55ng/g) and in September for Tortolì pond (0.85ng/g). The LC–MS/MS analysis did not confirm the presence of MC-LR suggesting that results obtained with the ELISA technique could be due to the presence of other microcystins. According to the tolerable daily intake suggested by the World Health Organization, these results hint that clams harvested in these ponds are safe for human health. These data can contribute to enrich the knowledge about the healthiness of Sardinian ponds and of their products.