Evaluation of mercury biogeochemical cycling at the sediment–water interface in anthropogenically modified lagoon environments

The Marano and Grado Lagoon is well known for being contaminated by mercury(Hg) from the Idrija mine(Slovenia) and the decommissioned chlor-alkali plant of Torviscosa(Italy).Experimental activities were conducted in a local fish farm to understand Hg cycling at the sediment–water interface. Both diffusive and benthic fluxes were estimated in terms of chemical and physical features. Mercury concentration in sediments(up to 6.81 μg/g)showed a slight variability with depth, whereas the highest methylmercury(MeHg) values(up to 10 ng/g) were detected in the first centimetres. MeHg seems to be produced and stored in the 2–3 cm below the sediment–water interface, where sulphate reducing bacteria activity occurs and hypoxic–anoxic conditions become persistent for days. DMeHg in porewaters varied seasonally(from 0.1 and 17% of dissolved Hg(DHg)) with the highest concentrations in summer. DHg diffusive effluxes higher(up to 444 ng/m~2/day) than those reported in the open lagoon(~ 95 ng/m~2/day), whereas DMeHg showed influxes in the fish farm(up to-156 ng/m~2/day). The diurnal DHg and DMeHg benthic fluxes were found to be higher than the highest summer values previously reported for the natural lagoon environment. Bottom sediments, especially in anoxic conditions, seem to be a significant source of MeHg in the water column where it eventually accumulates. However, net fluxes considering the daily trend of DHg and DMeHg, indicated possible DMeHg degradation processes. Enhancing water dynamics in the fish farm could mitigate environmental conditions suitable for Hg methylation.     

Role of the second-trimester ‘genetic sonogram’ for Down syndrome screen in the era of first-trimester screening and noninvasive prenatal testing

Ultrasonography for the screening of Down syndrome was first introduced about 25 years ago. Different combinations of markers detectable at second-trimester ultrasonography have been proposed under the banner of ‘genetic sonogram’. In recent years, several developments in first-trimester screening and the recent introduction of noninvasive prenatal testing for aneuploidy screening have had important implications for the prevalence of these conditions in the second-trimester and the screening performance of a genetic sonogram. Several second-trimester sonographic markers for Down syndrome have been reported; meta-analysis has shown that the most powerful predictors are mild ventriculomegaly, increased nuchal fold, hyperechoic bowel, and absent or hypoplastic nasal bone. Whereas use of individual markers should be discouraged and scoring systems of multiple markers are now obsolete, use of combined likelihood ratio and logistic regression analysis formulae provides better accuracy. However, there is significant heterogeneity in results among studies. Despite such limitations, the genetic sonogram will continue to have a place in prenatal screening, particularly in twin and higher-order multiple pregnancies, in countries with limited access to the most recent genetic screening tests, in cases with borderline results at maternal serum screening tests, and as noninvasive supplementary test for high-risk women reluctant to undergo invasive diagnostic testing. © 2014 John Wiley & Sons, Ltd.     

Prehibernating aggregations of Polistes dominulus: an occasion to study early dominance assessment in social insects

At a very early age several mammals establish a first dominance hierarchy, which often persists into adulthood. Social wasps offer an excellent opportunity to study such a phenomenon in insects. Indeed, foundresses of several paper wasps meet in clusters to hibernate from September to March. In spring, wasps found new associative nests where linear hierarchies occur. In the first phase of hibernation, clustering Polistes dominulus wasps show most of the social interactions occurring on the nest 6 months later. At the emergence from diapause, some females already show some behavioral and physiological traits typical of dominant individuals. Here, we investigated the significance of the interactions in the autumnal clusters. We demonstrated that in a given pair, it is more likely that the dominant wasp in autumn becomes the alpha female in spring after the nest foundation phase occurred. Moreover, we showed that dominant females in clusters have both larger body size and ovaries. As ovarian development mainly depends on the social context, our findings seem to indicate that social factors affect the tendency to dominate in aggregations. Furthermore, we suggest that some females may reinforce their physiological status by dominating in clusters, thus increasing the probability to become dominant in spring.     

Survey on fluoride, bromide and chloride contents in public drinking water supplies in Sicily (Italy)

Six hundred and sixty-seven water samples were collected from public drinking water supplies in Sicily and analysed for electric conductivity and for their Cl(-), Br(-) and F(-) contents. The samples were, as far as possible, collected evenly over the entire territory with an average sampling density of about one sample for every 7,600 inhabitants. The contents of Cl(-) and Br(-), ranging between 5.53 and 1,302 mg/l and between <0.025 and 4.76 mg/l respectively, correlated well with the electric conductivity, a parameter used as a proxy for water salinity. The highest values were found both along the NW and SE coasts, which we attributed to seawater contamination, and in the central part of Sicily, which we attributed to evaporitic rock dissolution. The fluoride concentrations ranged from 0.023 to 3.28 mg/l, while the highest values (only three exceeding the maximum admissible concentration of 1.5 mg/l) generally correlated either with the presence in the area of crystalline (volcanic or metamorphic) or evaporitic rocks or with contamination from hydrothermal activity. Apart from these limited cases of exceeding F(-) levels, the waters of public drinking water supplies in Sicily can be considered safe for human consumption for the analysed parameters. Some limited concern could arise from the intake of bromide-rich waters (about 3% exceeding 1 mg/l) because of the potential formation of dangerous disinfection by-products.     

Influence of weight on the content of trace metals in tissues of Mytilus galloprovincialis (Lamarck, 1819): a forecast model

Fifty seven samples of Mytilus galloprovincialis (Lamarck, 1819) collected along the breakwater barriers of Fano (station 1) and Pesaro (station 2), Adriatic Sea, Marche Region, central Italy, were analyzed by atomic absorption spectrometry and Cd, Cu, Pb and Zn concentrations in the soft tissues were measured. The aims of this work were the statistical analysis of Cd-weight, Cu-weight, Pb-weight, Zn-weight relationships, and the building of a tendency function that allows assessing with a good approximation the concentrations of a metal in different weight organisms. In Mytilus galloprovincialis the content of Cd proportionally grew with the weight and therefore its concentration was independent from this factor; while the concentration of Pb decreased as the weight increased. In both cases the accuracy of multiple regression models improved considering the variable ‘site’, while the same approach appeared not reliable for Cu and Zn, that were two essential metals. Our results showed that a tendency function was reliable, solid and able to predict to a very satisfying extent the concentration of non-physiological metals, like Cd and Pb; while it did not show a good approximation with real Cu and Zn contents.     

Aluminium flows in vehicles: enhancing the recovery at end-of-life

The transportation sector constitutes the major end-use market for aluminium-containing products and expectations for the future do indicate that aluminium will increase at 140 kg per vehicle. Moreover, up to 75 % aluminium recycled in Europe is used in transportation: thus, metal scrap recovered from ELVs is a key lever to act for closing material cycles. However, although the management chain of ELVs has an established procedure and aluminium scrap is usually recovered in shredding plants, a considerable fraction of the metal particles ends up in the light fraction called car fluff and is then landfilled. In this study we investigated potential of enhancing the recovery of aluminium scrap from the light fluff treatment. With this goal, the quantity of aluminium embedded in the Italian transport sector in the last 62 years was estimated, and a campaign of characterization in size and shape distribution of aluminium particles in the light fluff output has been carried out. The results estimated up to about 560,000 tons of metal are potentially recoverable from the treatment of light fluff at current operating conditions, but relevant improvements may be achieve when size and shape distribution criteria are adopt to implement eddy currents separation for a quantitative metal recovery.