Rossella Di Leonardo

Distribution of REEs in box-core sediments offshore an industrial area in SE Sicily, Ionian Sea: evidence of anomalous sedimentary inputs.

The distribution of rare earth elements and yttrium (REEs+Y) has been investigated in box-core sediments recovered from four stations in the Sicilian coastal zone seawards of Augusta, one of the most industrialized and contaminated areas in the Mediterranean region. Shale-like REE patterns and low Y/Ho ratios (close to the chondritic ratio) suggest a dominant terrigenous (geogenic) source for REE. Slight enrichment of LREE over the HREE is interpreted as due to preferential adsorptive transfer of LREE from seawater to sediment particles. Samples from offshore cores exhibit slightly positive Gd and negative Ce anomalies. It is here hypothesized that main drivers of anthropogenic Gd flux towards the offshore are dredged contaminated materials that, recovered from the Augusta Bay, have been repeatedly discharged offshore. Consistent with the redox-chemistry of Ce, these anomalous sedimentary inputs induce a decrease of O(2) concentration in the sediment, which in turn triggers Ce regeneration.

Premature aging in bone of fish from a highly polluted marine area

Fish species have attracted considerable interest in studies assessing biological responses to environmental contaminants. In this study, the attention has been focussed on fishbone of selected fish species from a highly polluted marine area, Augusta Bay (Italy, Central Mediterranean) to evaluate if toxicant elements had an effect on the mineralogical structure of bones, although macroscopic deformations were not evident. In particular, an attempt was made to evaluate if bone mineral features, such as crystallinity, mineral maturity and carbonate/phosphate mineral content, determined by XR-Diffraction and FT-IR Spectroscopy, suffered negative effects due to trace element levels in fishbone, detected by ICP-OES. Results confirmed the reliability of the use of diffractometric and spectroscopic techniques to assess the degree of crystallinity and the mineral maturity in fishbone. In addition, in highly polluted areas, Hg and Cr contamination induced a process of premature aging of fishbone, altering its biochemical and mineral contents.

Granulometry, mineralogy and trace elements of marine sediments from the Gulf of Milazzo (NE Sicily): evaluation of anthropogenic impact

Granulometry, mineralogy, and trace element concentrations are determined in marine sediments from thirty-six sampling sites in the littoral environment of the Gulf of Milazzo (NE Sicily). Sediment samples were collected in August 2008, along 18 seaward transects, at water depths of ‐10, ‐20 and ‐30 m, by using a Van Veen grab. Grain-size analysis shows predominance of sand (56%) and silt (35%) fractions with respect to clay (7%) and gravel (2%) fractions. Bulk mineralogical analysis documents the presence of quartz, micas, feldspars, calcite, and chlorite, which reflect erosion processes affecting the Kabilian-Calabrian Units. Concentrations of most trace elements in the deeper sediments were notably higher than shallower ones, due to the gradual increase of the fine fraction (<63 mm). Concentrations of Cr, Ni, Pb and, at lesser extent, Zn and Cu in the <63 mm fraction appear to be potentially hazardous, exceeding national and international regulatory guidelines, both close to the Milazzo industrial area and at Capo Rasocolmo. Trace element mean values from the Gulf of Milazzo are comparable with those measured in polluted sediments collected in the Gulf of Palermo and Augusta Bay with a moderate enrichment in Zn. Differ ent sources of trace elements and different geochemical mechanisms are probably responsible of this distribution. Among these sources and mechanisms, local anthropogenic inputs, different contents of organic matter, and surface water circulation may be invoked.

Trace element storage capacity of sediments in dead Posidonia oceanica mat from a chronically contaminated marine ecosystem

Posidonia oceanica mat is considered a long-term bioindicator of contamination. Storage and sequestration of trace elements and organic carbon (Corg ) were assessed in dead P. oceanica mat and bare sediments from a highly polluted coastal marine area (Augusta Bay, central Mediterranean). Sediment elemental composition and sources of organic matter have been altered since the 1950s. Dead P. oceanica mat displayed a greater ability to bury and store trace elements and Corg than nearby bare sediments, acting as a long-term contaminant sink over the past 120 yr. Trace elements, probably associated with the mineral fraction, were stabilized and trapped despite die-off of the overlying P. oceanica meadow. Mat deposits registered historic contamination phases well, confirming their role as natural archives for recording trace element trends in marine coastal environments. This sediment typology is enriched with seagrass-derived refractory organic matter, which acts mainly as a diluent of trace elements. Bare sediments showed evidence of inwash of contaminated sediments via reworking; more rapid and irregular sediment accumulation; and, because of the high proportions of labile organic matter, a greater capacity to store trace elements. Through different processes, both sediment typologies represent a repository for chemicals and may pose a risk to the marine ecosystem as a secondary source of contaminants in the case of sediment dredging or erosion. Environ Toxicol Chem 2017;36:49-58.

Element-specific behaviour and sediment properties modulate transfer and bioaccumulation of trace elements in a highly-contaminated area (Augusta Bay, Central Mediterranean Sea)

High sediment contamination in the coastal area of Priolo Bay, adjacent to the highly-polluted Augusta Harbour, poses serious risks for the benthic communities inhabiting the area. Nevertheless, the transfer of trace elements and consequent bioaccumulation in the biota is an overlooked issue. This study aimed to assess the transfer and bioaccumulation patterns of As, Cd, Ni and Hg to the dominant macroalgae and benthic invertebrates of Priolo Bay. Results revealed different patterns among trace elements (TEs), not driven by sediment contamination but rather by element-specific behaviour coupled with sediment physicochemical properties. Specifically, As accumulated in macroalgae but not in invertebrates, indicating bioavailability of dissolved As only, and a lack of effective trophic transfer. Ni was confined to surface sediment and transfer to biota was not highlighted. Cd and Hg showed the highest concentrations in invertebrates and bioaccumulated especially in filter feeders and carnivores, revealing the importance of suspended particulate and diet as transfer pathways. Total organic carbon (TOC), fine-grained sediments and redox potential were the most important sediment features in shaping the sediment contamination spatial patterns as well as those of TE transfer and bioaccumulation. In particular, As and Cd transfer to macroalgae, and especially Hg bioaccumulation in benthic invertebrates was controlled by sediment properties, resulting in limited transfer and accumulation in the most contaminated stations.