Interactive effects of palladium (Pd) and microplastics (MPs) on metal bioaccumulation and biological responses in the Mediterranean mussel, Mytilus galloprovincialis.

This study investigates the potential of MPs as carriers of pollutants as they can strengthen bioaccumulation of toxic metals on marine organisms. For the first time, the interaction of the metal palladium (Pd) with the widespread MPs, both with increasing concentrations in water environments from anthropogenic sources, was tested. Mytilus galloprovincialis, an important seafood product, was exposed to Pd (24 h) in two ways: water-dissolved and MPs-adsorbed, with depuration followed for 144 h. Quantification of Pd in tissues shown an accumulation 2-3 times higher (59 % of initial Pd) for mussels exposed to MPs-adsorbed Pd and higher in digestive gland than when exposed to water-dissolved Pd (25 %; higher in gills). Additionally, it was demonstrated that Pd induced oxidative stress and altered the feeding behavior of mussels. Therefore, this work support MPs as being vectors of metals (i.e. Pd) to enhance their bioaccumulation on marine organisms which highlights ecological risk of these emerging pollutants.

Metal(oid)s in plastic debris, with distinct features, from Spanish Mediterranean beaches with different anthropogenic pressure: Are these particles potential monitors for metal pollution?

Metal(oid)s concentrations have been quantified in plastic pieces collected from four beaches located in the Mediterranean coast of Spain with different characteristics (i.e. anthropogenic pressure, zone). Metal(oid)s content was also related to selected plastic criteria (i.e. color, degradation status, polymer). The selected elements were quantified with mean concentrations in the sampled plastics with the following order: Fe > Mg > Zn > Mn > Pb > Sr > As > Cu > Cr > Ni > Cd > Co. Moreover, black, brown, PUR, PS, and coastal line plastics concentrated the higher metal(oid)s levels. Local of sampling (influence of mining exploitation) and severe degradation were key factors for uptake of metal(oid)s from water by plastics as modification of surfaces strengths their adsorption capacity. Determined high levels of Fe, Pb and Zn in plastics reflected the pollution degree of the marine areas. Therefore, this study is a contribution for the potential use of plastics as pollution monitors.

Functional traits of a native and an invasive clam of the genus Ruditapes occurring in sympatry in a coastal lagoon.

The main objective of this study was to evaluate the functional traits regarding bioturbation activity and its influence in the nutrient cycling of the native clam species Ruditapes decussatus and the invasive species Ruditapes philippinarum in Ria de Aveiro lagoon. Presently, these species live in sympatry and the impact of the invasive species was evaluated under controlled microcosmos setting, through combined/manipulated ratios of both species, including monospecific scenarios and a control without bivalves. Bioturbation intensity was measured by maximum, median and mean mix depth of particle redistribution, as well as by Surface Boundary Roughness (SBR), using time-lapse fluorescent sediment profile imaging (f-SPI) analysis, through the use of luminophores. Water nutrient concentrations (NH4-N, NOx-N and PO4-P) were also evaluated. This study showed that there were no significant differences in the maximum, median and mean mix depth of particle redistribution, SBR and water nutrient concentrations between the different ratios of clam species tested. Significant differences were only recorded between the control treatment (no bivalves) and those with bivalves. Thus, according to the present work, in a scenario of potential replacement of the native species by the invasive species, no significant differences are anticipated in short- and long-term regarding the tested functional traits.