Mercury in fishes from Augusta Bay (southern Italy): Risk assessment and health implication

Our study reports on the total mercury (HgT) concentrations measured in the muscles and livers of several benthic, demersal and pelagic fish species caught inside and outside of Augusta Bay (southern Italy), a semi-enclosed marine area, highly contaminated by the uncontrolled (since the 1950s to 1978s) discharge of the largest European petrochemical plant. Mercury levels in fish tissues are discussed with regard to specific habitat, size and/or age of the specimens and HgT distribution in the bottom sediments. Results suggest a still active Hg release mechanism from the polluted sediments to the marine environment. Also, the high HgT concentrations measured in fishes caught in the external area of the bay imply a potential role of Augusta Bay as a pollutant source for the Mediterranean ecosystem. Finally, values of hazard target quotient (THQ) and estimated weekly intake (EWI) demonstrate that consumption of fishes caught inside the bay represents a serious risk for human health. Also, data indicate that intake of fishes caught from the external area of the bay, especially for that concern demersal and benthic species, could be represent a significant component of risk for the local population

Report relativo all'esplorazione di sismica a riflessione effettuata sul Palinuro Seamount

Le sorgenti sismiche solitamente contengono energia in un range di frequenza tra 1 e 100 Hz e man mano che si propagano l’attenuazione riduce l’energia nel terreno ; la maggior parte dei profili di sismica a riflessione commerciali è realizzato con l’utilizzo di sorgenti caratterizzati da range di frequenza fra 5 Hz e 15 kHz.Le sorgenti utilizzate differiscono se le prospezioni devono tenersi in ambiente subaereo o marino. Nel primo caso, vengono utilizzati esplosivi (piazzati alla base dello strato aerato) oppure dei Vibroseis, ossia dispositivi vibranti solidali al terreno. Le sorgenti marine più efficaci sono di tipo acustico, come ad esempio cannoni ad aria compressa che rilasciano una bolla d’aria ad alta pressione che oscilla, con un’emissione di energia che è funzione della dimensione della camera di compressione

Atomic emission spectrometry methods for determination of heavy metals (As, Cd, Co, total Cr, Cr(VI), Cu, Hg, Ni, Pb, Se, V, Zn) in marine sediments

The assessment of trace metal distribution in marine sediments allows: i) the evaluation of the current status of environmental pollution, ii) the identification of the potential sources of pollution, iii) an adequate understanding of mechanisms ruling trace metals mobility and bioavailability in order to verify the existence of a real environmental risk. Since a reliable dataset is essential to that relevant purpose, a correct procedure of sampling, storage, treatment and analysis of marine sediments plays a key role; the aim of this report is to describe in detail a protocol for preparation and analysis of sediment samples for determination of trace metals content using atomic emission spectrometry. All operating procedures were developed and checked for precision, reproducibility and accuracy in the geochemical laboratories of IAMC – CNR of Naples equipped with a VARIAN ICP-AES VISTA-MPX

Ba/Ca evolution in water masses of the Mediterranean late Neogene

A Mediterranean composite sedimentary record was analyzed for Ba/Ca ratios on carbonate shells of Orbulina universa planktonic foraminifer (Ba/Ca)carb providing the opportunity to study and assess the extent of freshwater inputs on the basin and possible impacts on its dynamics during the Tortonian to Recent period. A number of scanning electron microscope analyses and auxiliary trace element measurements (Mn, Sr, and Mg), obtained from the same samples, exclude important diagenetic effects on the studied biogenic carbonates and corroborate the reliability of (Ba/Ca)carb ratios in foraminifera calcite as indicators of seawater source components during the studied interval. A long-term trend with (Ba/Ca)carb values shifting from 7 to 3 mmol mol 1 from the base of the Tortonian to the top of the Messinian is observed. The interval of the late Messinian salinity crisis, where biogenic carbonates are missing or strongly diagenized, represents a crucial passage not monitored in our record. At the base of the Pliocene, up to about 4.7 Ma, the (Ba/Ca)carb record shows a decreasing trend from 4 mmol mol 1 stabilizing itself to an about constant value of 0.9 ± 0.3 mmol mol 1 for the whole Plio-Pleistocene interval. These results suggest a dramatic change in the continental runoff values, up to 3–16 times higher during part of the late Neogene (Tortonian–early Pliocene), with a possible profound modification in the physical dynamics of the Mediterranean basin. First-order mass balance equations used to estimate barium and salinity budgets in the Mediterranean Sea during the late Miocene–early Pliocene interval support the hypothesis of an active connection of the basin with the Paratethys region and of a definitive restriction at the base of the Pliocene after about 0.7 Ma from the well-known Messinian Lagomare phase. They also open intriguing scenarios on possible circulation shifts during the Neogene

Productivity modes in the Mediterranean Sea during Dansgaard–Oeschger (20,000–70,000 yr ago) oscillations

The study of planktonic organisms during abrupt climatic variations of the last glacial period (Dansgaard-Oeschger oscillations, D-O) may reveal important insights on climatic, oceanographic and biological interactions. Here we present planktic foraminifera and coccolithophore data collected at the Ocean Drilling Program Site 963 (Sicily Channel), with a mean sampling resolution of respectively 43.5 and 98.9. yr, over the interval between 70,000 and 20,000. yr ago. The paleoenvironmental reconstruction suggests that three different scenarios can be seen across each D-O cycle: 1. oligotrophic surface water and a deep thermocline for the early Interstadials; 2. a Deep Chlorophyll Maximum and coccolithophore winter/spring blooming in the late Interstadials; 3. reduced productivity together with the shallowing of the nutricline depth during Stadials and Heinrich events. The unique mode of productivity dynamics is corroborated by comparing our paleoecological results with those published from high-resolution cores in the Alboran Sea clearly indicating reduced trophic levels during Stadials and Heinrich events. Finally, we argue that the density contrast between the Atlantic water inflow and subsurface water may have affected productivity dynamics in such a large area. The strong vertical density gradient may have hampered the vertical convection of the water column, producing a negative effect on biological productivity, especially during Stadial phases. © 2013 Elsevier B.V