Microplastics in seawater and marine organisms: Site-specific variations over two-year study in Giglio Island (North Tyrrhenian Sea).

Geographical and temporal differences of microplastic occurrence were documented in water and fish collected in 2017 and 2019 from the Giglio Island (North Tyrrhenian Sea) close to the area where the Costa Concordia sank in January 2012. Results on water samples showed a site-dependent difference, suggesting the role of surface current dynamics in the microplastic local distribution, while tested Neuston nets (200 µm and 330 µm mesh size) did not influence microplastic retention efficiency. Fish exhibited in 2019 a higher frequency of specimens positive to microplastic ingestion with respect to 2017, with an occurrence higher than those typically observed in other Mediterranean areas. Both in water and fish, fragments were the dominating shape, polypropylene and polyethylene were the prevalent polymers, without particular difference between sites and years. This study highlights the importance of applying microplastic investigation in biotic and abiotic matrices for an effective monitoring of this pollution in the marine environment.

[Perfluoroalchilic food contamination in the PFAS high-risk area of the Veneto Region (Northern Italy)]. / Sostanze perfluoroalchiliche (PFAS) negli alimenti dell'area rossa del Veneto.

In a wide area among the provinces of Vicenza, Verona, and Padua (Veneto Region, Northern Italy), one of the larger known massive contamination of the environment by per- and polyfluoroalkyl substances (PFASs) occurred since the year 1965. The most important source of human exposure was through aquiferous and contaminated water supplies (the regional authorities distinguished red zone A - aquiferous - and red zone B - water supply) for a total of slightly less than two hundred thousand exposed people. Food contamination and food contribution to total human exposure were assessed by a food monitoring campaign on the years 2016-2017 by the National Health Institute sponsored by Veneto Region.Thanks to the availability of the individual records of the monitoring campaign, we evaluated the spatial distribution of PFAS contamination by food matrix. Generally speaking, PFAS contamination was widespread over the entire red zone (either A or B). Some zones appeared to be higher contaminated consistently with the water plume. Other higher contaminated zones were less consistent and such result raises questions about routes of environmental pollution.

Behavioural responses of the supralittoral amphipod Talitrus saltator (Montagu) to trace metals contamination.

We investigated behavioural responses (locomotor activity and substrate selection) of the amphipod Talitrus saltator after laboratory exposure to different concentrations of Hg, Cu and Cd. Locomotor activity, measured with a microwave radar device, was assessed in animals exposed to contaminated sand and in sandhoppers previously kept for 48 h in contaminated seawater and tested in clean sand. The contents of Hg, Cu and Cd in T. saltator tissues were measured at the end of pre-exposure to contaminated seawater and after 7 days of exposure to contaminated sand. Substrate selection tests were carried out in a binary choice arena. Tests in contaminated sand showed that sandhopper locomotor activity varied in a dose-dependent manner in the presence of Cu and Hg (at lower Hg concentration they were more active during daytime) but did not show significant changes in Cd-exposed animals except for disappearance of the typical circadian activity pattern. Pre-exposure to trace metals in seawater induced a significant decrease of movements for all metals, although the effects varied according to the toxicity of the metal. Trace metals analyses showed that tissue concentrations of Hg, Cu and Cd were related to their concentrations in the test medium. Substrate selection tests showed avoidance of contaminated sand only when sandhoppers were tested in the presence of both concentrations of Hg and at the higher concentration of Cu. In conclusion, locomotor activity and avoidance behaviour of T. saltator could be used as behavioural biomarkers of trace metals exposure.

Trace metal contamination of Tuscan and eastern Corsican coastal supralittoral zones: The sandhopper Talitrus saltator (Montagu) as a biomonitor.

The aim of this study was to determine trace metal concentrations (Hg, Cd, Cu, Zn, Al, Fe, Mn, Cr and Pb) in samples of Talitrus saltator collected at 14 localities along the Tuscan and eastern Corsican coasts. This talitrid amphipod is a well-known biomonitor of trace metal contaminations of the supralittoral zone of European sandy beaches. The results show the ability of T. saltator to accumulate Cu, Cd, Zn, Hg, Al, Fe and Mn, but not Cr or Pb. Moreover, the sites can be distinguished on the basis of the accumulated metals. Finally, comparison with literature data regarding the same species and the same sampling sites shows a general decrease in Cd, Zn and Hg contamination. In conclusion, this study confirms that T. saltator can be used as an indicator of the spatial distribution of trace metals contamination.

Seawater Ca2+ concentration influences solar orientation in Talitrus saltator (Crustacea, Amphipoda).

The role of salinity in the ecophysiology of many intertidal invertebrates has been extensively investigated. Calcium (Ca(2+)), magnesium (Mg(2+)), potassium (K(+)) and sodium (Na(+)) are the major constituents of seawater and it has been demonstrated that sandhoppers tested under the sun in diluted seawater (3.5 per thousand) head seaward, instead of going landward as expected. Therefore, the variation in seawater salinity (from 35 per thousand to 3.5 per thousand) influences their directional choice. This paper investigates the contribution of different cations to the sea-land directional choice of Talitrus saltator (Crustacea, Amphipoda) by the sun compass orientation mechanism. Results of releases carried out in basic seawater selectively deprived of Ca(2+), Mg(2+) or K(+) and containing the same concentration of Na(+) indicate that only the reduction in Ca(2+) concentration affects the capacity of solar orientation. The pH does not influence the directional choice of sandhoppers and nor do small variations in salinity in the range 32-39 per thousand. Moreover, the clear photopositive tendency registered in experiments of phototaxis in Ca(2+)-deprived seawater indicates that the absence of Ca(2+) does not affect the normal functioning of the visual cells. Therefore, our results show that Ca(2+) seawater concentration is important for the correct functioning of one of the principal mechanisms of orientation in supralittoral amphipods and it could affect their survival in the field.

Sandhopper solar orientation as a behavioural biomarker of trace metals contamination.

Although many studies have focused on trace metals accumulation, investigations of talitrid amphipods as biomarkers are rare. This study explores the possibility of using the solar orientation capacity of Talitrus saltator as a behavioural marker of exposure to two essential (Cu and Zn) and two non-essential (Cd and Hg) metals. LC(50) analyses performed before the solar orientation tests showed that the 72 h LC(50) for Hg was 0.02 ppm while the 96 h LC(50) values for Cu, Cd and Zn were 13.28 ppm, 27.66 ppm, and 62.74 ppm, respectively. The presence of metals in seawater affects the solar orientation capacity of T. saltator in a concentration-dependent manner and according to the toxicity ranking of the metals (Hg > Cu > Cd > Zn). Therefore, the solar orientation capacity of T. saltator seems to be a promising behavioural marker for exposure to trace metals.

The amphipod Talitrus saltator as a bioindicator of human trampling on sandy beaches.

The present paper assesses the use of the supralittoral amphipod Talitrus saltator as a bioindicator of the effects of human trampling on the supralittoral sandy band. Samplings in delimited areas were carried out at sites subjected to different human impact. The results showed a strong negative correlation between the number of swimmers and the sandhopper population density, while there was no clear relationship between sandhopper abundance and the other factors considered: granulometry, compactness and organic carbon content of the sand, and trace metal contents in the sand and sandhoppers. A field test of trampling conducted in a confined space showed its direct negative effect on sandhopper survival. However, trace metal analysis confirmed the ability of T. saltator to bioaccumulate some elements (Hg, Zn, Cu, Cd). Our study demonstrates that T. saltator is a good bioindicator of human impact in the supralittoral zone of sandy shores.