Sublethal effects induced by morphine to the freshwater biological model Dreissena polymorpha

Opioids are considered as emerging contaminants in aquatic ecosystems, mainly due to their large illicit consume worldwide. Morphine (MOR) is the main opiate and it was commonly found at measurable concentrations in freshwaters. Even though its occurrence is well documented, just limited information is available regarding its hazard to nontarget organisms. The aim of this study was of the evaluation of sublethal effects induced by MOR to the freshwater bivalve Dreissena polymorpha. We exposed mussels to two MOR concentrations (0.05 \ub5g/L and 0.5 \ub5g/L) for 14 days and we investigated the sublethal effects by a suite of biomarkers. The Neutral Red Retention Assay (NRRA) was used as a test of cytotoxicity, while the oxidative stress was evaluated by the activity of antioxidant and detoxifying enzymes, namely catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione-S-transferase (GST), and by measuring the levels of lipid peroxidation (LPO) and protein carbonylation (PCC). The genetic damage was assessed by the Single Cell Gel Electrophoresis (SCGE) assay, the DNA diffusion assay and the micronucleus test (MN test). Finally, the filtration rate of D. polymorpha was evaluated in order to investigate possible physiological effects. Both tested concentrations reduced the lysosome membrane stability of bivalves, but only the highest MOR concentration induced significant changes in the activity of antioxidant enzymes (SOD, CAT, and GPx) and increase in lipid peroxidation levels. Slight increase in primary DNA fragmentation was noticed, while no fixed genetic damage and alterations of the filtering rate were found

Microplastics in deep water : a combined GC-MS e FT-IR approach

Microplastics are water-insoluble, solid polymer particles that are 645\u202fmm in size. A lower size boundary has not been defined, but particles below 1\u202f\u3bcm are usually referred to as nanoplastics rather than microplastics. The ubiquity of microplastics of all sizes in surface water, groundwater and wastewater has raised the question if pollution of drinking water occurs and to date, few studies indeed described the presence of this new contaminant in tap and bottled water. Toxicity it is not yet known, they might cause local inflammations in the gut, but a transport into organs might occur. As a final problem in this field, microplastics in the environment are difficult to sample, to identify and standardized methods do not exist. For this reason, we have been involved in a research project finalized to the definition of a protocol strategy for sampling and analysis of microplastics in drinking waters, coming from deep water wells, in the networks of three large cities in the Northern part of Italy. The project is on going and presently two groups of deep water samples have been collected in the city of Milano and Brescia, before and after the treatment stages used for the urban network. Great attention has been paid to sampling and extraction steps as microplastic contamination, in this kind of samples, is expected to be very low and contamination during sampling might occur through air or materials. Analytical methods have been defined for the detection of main microplastic contamination, like PE/PP, PS, PA, PVC e PET residues > 1 \ub5m. Samples have been analysed first by a non-destructive approach using a Spotlight 200i microscope equipped with a \ub5ATR probe and coupled to an FT-IR spectrophotometer, followed by a mass spectrometric characterization of the polymers by a solid phase microextration (SPME) GC-MS of thermal decomposition products (TED) of microplastic residues. Results will be presented and critically discussed

Removal of metallic elements from real wastewater using zebra mussel bio-filtration process

The metallic element pollution is a serious environmental problem but still unsolved since these contaminants are released mainly by human activity, reaching all the environmental compartments. Traditional wastewater treatment plants are very efficient in removing metallic elements only when their concentration is in the order of mg/L, but are not able to remove them until \u3bcg/L, as it would be needed to cope with the water quality standards in low flow receptors. Therefore, the aim of our study was to evaluate the potential removal of some recalcitrant metallic elements to the classical treatments, by the natural process of bio-filtration performed by the invasive zebra mussel (Dreissena polymorpha). For this purpose we built a pilot-plant at the Milano-Nosedo wastewater treatment plant, where we placed about 40,000 D. polymorpha specimens appointed to the wastewater bio-filtration. The metallic element removal due to zebra mussel activity was evaluated in the treated wastewater with a plasma optical emission spectrometry (ICP-OES). Data obtained in these experiments showed an encouraging metallic element removal due to D. polymorpha activity; in particular, the total abatement (100%) of Cr after one day of bio-filtration exposure is remarkable. Therefore, this study encourages further research related with the use of bivalves as a new tool for the wastewater depuration process; in this regard, the contaminated mollusks used in the bio-filtration could be incinerated or stored in special landfills, as is also the case of traditional sewage sludge

First evidence of protein modulation by polystyrene microplastics in a freshwater biological model

Microplastics (MPs)are now one of the major environmental problems due to the large amount released in aquatic and terrestrial ecosystems, as well as their diffuse sources and potential impacts on organisms and human health. Still the molecular and cellular targets of microplastics\u2019 toxicity have not yet been identified and their mechanism of actions in aquatic organisms are largely unknown. In order to partially fill this gap, we used a mass spectrometry based functional proteomics to evaluate the modulation of protein profiling in zebra mussel (Dreissena polymorpha), one of the most useful freshwater biological model. Mussels were exposed for 6 days in static conditions to two different microplastic mixtures, composed by two types of virgin polystyrene microbeads (size = 1 and 10 \u3bcm)each one. The mixture at the lowest concentration contained 5 7 105 MP/L of 1 \u3bcm and 5 7 105 MP/L of 10 \u3bcm, while the higher one was arranged with 2 7 106 MP/L of 1 \u3bcm and 2 7 106 MP/L of 10 \u3bcm. Proteomics\u2019 analyses of gills showed the complete lack of proteins\u2019 modulation after the exposure to the low-concentrated mixture, while even 78 proteins were differentially modulated after the exposure to the high-concentrated one, suggesting the presence of an effect-threshold. The modulated proteins belong to 5 different classes mainly involved in the structure and function of ribosomes, energy metabolism, cellular trafficking, RNA-binding and cytoskeleton, all related to the response against the oxidative stress

Hazard evaluation of plastic mixtures from four Italian subalpine great lakes on the basis of laboratory exposures of zebra mussels

Studies related to the evaluation of plastics in freshwaters have been increasing in recent years because approximately 80% of plastic items found in the sea are from inland waters. Despite the ecological relevance of these surveys, no information has been available until now about the hazard related to plastic mixtures in freshwaters. To fill this knowledge gap, we carried out a study aimed to assess the environmental risk associated with the \u201ccocktail\u201d of plastics and environmental pollutants adsorbed on their surface in one of the larger European freshwater basins. Plastic debris was collected by a manta trawl along one transect each in four of the Italian subalpine great lakes (Lake Maggiore, Como, Iseo and Garda) and administered to zebra mussels (Dreissena polymorpha), a useful freshwater biological model present in all these lakes. We estimated a plastic density from 4908 MPs/km2 (Lake Iseo) to 272,261 MPs/km2 (Lake Maggiore), while the most common polymers found were polyethylene and polypropylene, with percentages varying between 73% and 100%. A biomarkers suite consisting of 10 different endpoints was performed after 7 days of exposure to investigate the molecular and cellular effects of plastics and related adsorbed pollutants. The main results highlighted a diffuse but different toxicity due to plastics for each lake, and there were significant changes in the antioxidant and detoxifying enzyme activities in Lake Maggiore, Iseo and Garda, an increase in protein carbonylation in L. Como, and a cellular viability decrease of approximately 30% for zebra mussels from L. Iseo and Garda. Despite this variability in the endpoints' responses, the application of the biomarker response index showed a similar environmental hazard due to plastics for all the sampled lakes

Removal of enteric viruses and Escherichia coli from municipal treated effluent by zebra mussels

Dreissena polymorpha is a widespread filter-feeder species, resistant to a broad range of environmental conditions and different types of pollutants, which has recently colonized Italian freshwaters. Although widely used to monitor pollution in freshwater environments, this species is also an important food source for some fish and water birds. It can also be used to concentrate or remove particulate organic matter to interrupt avian-to-human transmission of pollutants and control health risks for animals and humans. In this study, the accumulation/inactivation in D. polymorpha of human health-related spiked enteric viruses was described. The removal of endogenous Escherichia coli, the classical indicator of fecal contamination, was tested as well. Our preliminary lab-scale results demonstrate that zebra mussels can reduce significantly poliovirus titer after 24 h and rotavirus titer after 8 h. E. coli counts were also reduced in the presence of zebra mussels by about 1.5 log after 4 h and nearly completely after 24 h. The fate of the two enteric viruses after concentration by zebra mussels was also investigated after mechanical disruption of the tissues. To our knowledge, the accumulation from water and inactivation of human health-related enteric viruses by zebra mussels has never been reported