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Microplastics (MPs) are emerging contaminants of increasing concern as they may cause adverse effects and carry other contaminants, which may potentially compromise human health. Despite occurring in aquatic ecosystems worldwide, the knowledge about MP presence in different aquaculture systems and their potential impact on seafood products is still limited. This study aimed to determine the levels of MPs in water, feed, and European seabass (Dicentrarchus labrax) from three relevant aquaculture systems and estimate human exposure to MPs and metals through seabass consumption. The recirculating aquaculture system (RAS) had the highest MP occurrence in water and feed. MP levels in seabass followed the aquaculture system's levels in water and feed, with RAS-farmed fish presenting the highest MP load, both in the fish gastrointestinal tract (GIT) and muscle, followed by pond-, and cage-farmed fish. MPs' characteristics across aquaculture systems and fish samples remained consistent, with the predominant recovered particles falling within the MP size range. The particles were visually characterized and chemically identified by micro-Fourier Transform Infrared Spectroscopy (μFTIR). Most of these particles were fibres composed of man-made cellulose and PET. MP levels in GIT were significantly higher than in muscle for pond- and RAS-farmed fish, MPs' bioconcentration factors >1 indicated bioconcentration in farmed seabass. Metal concentrations in fish muscle were below permissible limits, posing low intake risks for consumers according to the available health-based guidance values and estimated dietary scenarios., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Total-recoverable metals (Al, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in sediments from Minho estuary salt marsh were determined to evaluate possible increase in anthropogenic contamination by metals and to evaluate the possibility of this area to be considered a pristine area in terms of metals, which can be used as a reference site for other metal-contaminated national and international estuaries/salt marshes. This study revealed that the spatial distribution of metals in the salt marsh sediments was not homogeneous and that two sampling sites (sites 5 and 7) had indications of anthropogenic contamination. However, metal levels in these salt marsh sediments were lower than those observed in the wetlands of the main Portuguese estuaries. Comparison with Portuguese and international reference values used in the evaluation of the ecological quality of sediments, indicated that the sediments can be classified as "clean sediment" and that metal levels were lower or similar (only for Cu and Ni) to the values of ERL, which are the values that define the concentrations ranges that are rarely associated to adverse biologic effects in organisms. In addition, metal levels in the sediments were in chemical forms that were not easily available to organisms, indicating that these sediments probably will not have negative influences in the organisms living in the salt marsh, although no life-form ecological safety tests have been carried out. Therefore, the Minho estuary salt marsh area can probably be considered a pristine area in terms of metals and can be used as a reference for other metal-contaminated estuaries/salt marshes.

The capability of Scirpus maritimus and of Juncus maritimus to accumulate metals and the role of each plant on the physico-chemical composition of sediments, from Douro river estuary (NW Portugal), were investigated through a year of plants' life. The contents of Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were determined (by atomic absorption spectrophotometry) in sediment, rhizosediments (those in contact with each plant roots and rhizomes) and different tissues of S. maritimus and of J. maritimus. Both plants influenced the sediment composition (concentrating metals around its roots) and were able to bioaccumulate Cd, in spite of some seasonal variations in the metal levels in the system (both in rhizosediments and plants' roots). Therefore, both plants showed to have potential for Cd phytostabilization. S. maritimus could also concentrate Pb in its roots, probably by sorption on the root surface in (hydr)oxide forms, therefore, denoting capability for Pb phytostabilization.

A comparison of the performance of the methodologies used in two distinct laboratories (Lab A and Lab B) for multi-element analysis in different wines was carried out. ICP-MS apparatus (quadrupole mass analyzers) of different brands as well as different wine pre-treatments were used. At Lab A, a pre-treatment by UV-irradiation was performed. At Lab B, a micro-concentric nebulizer was used for direct analysis of the wine. Twenty-six elements (Li, V, Co, Ni, Cu, Zn, Ga, As, Rb, Sr, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Pb) were measured in common at the two labs in three different wine samples (red and white Bordeaux table wines and Port wine) and the results were compared. The two methodologies provided similar LODs and similar precisions, with RSDs of 0.5-5%, for most of the elements. The recovery percentages were 85-120% at Lab A for the three wines, and 78-119% at Lab B for the Bordeaux wines, validating the accuracy of the methods used. Comparable results were obtained at both labs for ten elements (Li, V, Co, Ni, Cu, Zn, Rb, Sr, Ba, and Pb) in the three selected wines; the differences were lower than 10% in most cases. For REEs, the differences observed were slightly higher, but still in the acceptable range due to the sub-ppb levels involved. The results obtained for As and Ga were not comparable, due to methodological influence. A comparison through linear least-squares adjustment indicated that the results obtained by the two labs were linearly correlated (correlation coefficient =0.997) but statistically different as the slope was slightly, but significantly different from one, for a confidence level of 95% (the intercept was statistically identical to zero in any case). In the future, strictly more identical results can be achieved by using a reference wine sample.

Given the increasing pressure on water bodies, it is imperative to explore sustainable methodologies for wastewater treatment and reuse. The simultaneous presence of multiples contaminants in complex wastewater, such as the liquid effluents from biogas plants, can compromise biological treatment effectiveness for reclaiming water. Vertical subsurface flow constructed wetlands were established as low-cost decentralized wastewater treatment technologies to treat the liquid fraction of digestate from municipal organic waste with metals, antibiotics, and antibiotic resistance genes, to allow its reuse in irrigation. Twelve lab-scale planted constructed wetlands were assembled with gravel, light expanded clay aggregate and sand, testing four different treating conditions (liquid digestate spiked with oxytetracycline, sulfadiazine, or ofloxacin, at 100 µg/L, or without dosing) during 3 months. Physicochemical parameters (pH, chemical oxygen demand (COD), nutrients, metals, and antibiotics), the microbial communities dynamics (through 16S high-throughput sequencing) and antibiotic resistance genes removal (qPCR) were monitored in influents and effluents. Systems removed 85.8%-96.9% of organic matter (as COD), over 98.1% of ammonium and phosphate ions, and 69.3%-99.4% of nitrate and nitrite ions, with no significant differences between the presence or absence of antibiotics. Removal of Fe, Mn, Zn, Cu, Pb and Cr exceeded 82% in all treatment cycles. The treatment also removed oxytetracycline, sulfadiazine and ofloxacin over 99%, and decreased intl1, tetA, tetW, sul1 and qnrS gene copies. Nonetheless, after 3 months of ofloxacin dosing, qnrS gene started being detected. Removal processes relied on high HRT (14 days) and various mechanisms including sorption, biodegradation, and precipitation. Microbial community diversity in liquid digestate changed significantly after treatment in constructed wetlands with a decrease in the initial Firmicutes dominance, but with no clear effect of antibiotics on the microbial community structure. Removals above 85% and 94% were observed for Streptococcus and Clostridium, respectively. Results suggest that vertical subsurface flow constructed wetlands were a suitable technology for treating the liquid digestate to reuse it in irrigation agricultural systems, contributing to the circular bioeconomy concept. However, a more profound understanding of effective wastewater treatment strategies is needed to avoid antibiotic resistance genes dissemination. [ABSTRACT FROM AUTHOR]

To assess the possible effect that surfactants commonly found in the aquatic environment may have on the remediation potential of the salt marsh plant Halimione portulacoides, a non-ionic (Triton X-100) and an anionic (sodium dodecyl sulfate, SDS) surfactants were used. Experiments were carried out in the laboratory, either in hydroponics (sediment elutriate) or in sediment soaked in elutriate, using sediment and water from an estuarine salt marsh (Cávado River, NW Portugal). Groups of H. portulacoides (grown in a greenhouse) were exposed for 6d to media with 0.16mM added Cu(II) in the absence and in the presence of each one of the two selected surfactants, at concentrations lower than the respective micellar critical concentration. Cu was determined in solutions, sediments and in different plant tissues before and after experiments. Plant photosynthetic efficiency did not indicate deletory effects of the exposure to the added pollutants. The non-ionic surfactant Triton X-100 and, to a lesser extent, the anionic surfactant SDS too, favored Cu accumulation in the plant roots but not Cu translocation, indicating that surfactants may favor Cu adsorption to the roots (phytostabilization). On the other hand, both surfactants favored Cu solubility from the sediment. Therefore, the presence of surfactants, which are frequently found in estuarine areas, as a result of urban and industrial effluent discharges, may condition metal distribution in those environments. [Copyright &y& Elsevier]

Influence of Halimione portulacoides, commonly found in temperate salt marshes, on sediment metal contents, speciation and potential mobility in case of sediment re-suspension was evaluated. Both colonized and non-colonized sediments were studied for total Cd, Cu, Pb and Zn contents and metal fraction exchangeable to water collected in situ. Sediment elutriates, prepared with water collected from each site, were used to simulate a sediment re-suspension phenomenon. As the characteristics and degree of contamination of sediments may influence system behaviour, salt marshes of two Portuguese estuaries, Cavado (NW coast) and Sado (SW coast), were studied. Cu, Pb and Zn contents higher than ERL (quality guideline, effect range-low) were observed, indicating potential risks for living organisms. Strong Cu-complexing organic ligands, also determined in both water and elutriates, were higher in rhizosediment elutriates, at concentrations similar, or even higher, to those of Cu. Such ligands condition metals speciation in the water column and probably also metal bioavailability. From rhizosediment significant amounts of Cu and Zn were transferred to the aqueous phase, concentrations 2–8 times higher than concentrations present in water. In contrast, elutriates of non-colonized sediment removed metals from water, Cu and Zn levels in elutriates being 2–6 times lower than initial ones. Cd and Pb levels in water and elutriates were not measurable in most cases. Results clearly indicate that metals potential solubility in the rhizosphere of plants was markedly higher than that in the surrounding sediment. The obtained results indicated that H. portulacoides presence (and probably other salt marsh plants) may cause a marked increase in metals concentrations in dissolved phase (pore water or even water column if rhizosediment is re-suspended). As salt marsh plants may be abundant in temperate and subtropical estuaries and costal lagoons, this phenomenon should not be disregard in future studies towards the sustainable management of such environments. [Copyright &y& Elsevier]

Abstract: A relatively cheap and accessible way to analyze difficult samples without loss of analyte was optimized for determination of Cd, Cr, Cu, Hg, Ni, Pb, V and Zn in animal material. Reference materials with suitable matrix were used: Dorm-2 (Dogfish Muscle), Tort-2 (Lobster Hepatopancreas), and SRM 2976 (Mussel Tissue). The analytical procedure included digestion of the sample in Parr reactor bombs combined with a commercial microwave oven and metals analysis by atomic absorption spectrometry. A weak digestion procedure was optimized to prevent metal losses: a two-step digestion with an aqueous solution of HNO3, each step carried at a microwave power of 340W during 4min. With the optimized procedure, metals concentrations in all reference materials matched certified ones (for a 95% level of confidence) with the exception of Cd in Tort-2 and Hg in SRM 2976. The present work reinforces the need to use matrix-matched reference materials and that any digestion protocol needs to be modified to maximize recoveries. [Copyright &y& Elsevier]

Abstract: Metal accumulation by Juncus maritimus and the effect this plant might have on the physico-chemical composition of sediments, from Douro river estuary (NW Portugal), were investigated through one year of plant’s life. The contents of Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were determined (by atomic absorption spectrophotometry) in sediments, rhizosediments (those among plant roots and rhizomes) and different tissues of J. maritimus. Two estuarine sites with different characteristics were studied, one a sandy sediment with relatively low organic matter content, the other a muddy site. The role of the plant seemed to be markedly dependent on the sediment composition. At the sandy site, significant variations throughout the year (a decrease from winter to summer and an increase in autumn) either in rhizosediment and sediment or in J. maritimus roots were only observed in Cd and Cu levels. These variations were the same in both compartments, probably caused by tidal water movements and the activity of the plant. At the muddy site, variations throughout the year were observed for all studied elements but Pb. Changes in the Cd and Zn contents of roots were opposite to those in the rhizosediment (uptake of Cd and Zn by J. maritimus roots in summer may have caused a decrease in rhizosediment levels). Fe and Mn showed similar patterns of variation in both roots and rhizosediment (contents significantly increasing in summer). Higher contents of Fe and Mn in roots in summer could be related to changes in mass, higher availability of the elements, or accumulation at the surface of the root in (hydr)oxides forms. For the remaining elements no significant correlations between rhizosediment and roots variations were observed, indicating that their uptake and release by roots were not based on single exchanges with the sediment. J. maritimus showed capacity to accumulate Cu, Zn and particularly Cd, thus appearing to be useful for the phytostabilization of these metals. [Copyright &y& Elsevier]

The article presents information on the role of salt marsh plant on trace metal bioavailability in sediments. It says that Results and Discussion. Plants could concentrate metals around its roots and rhizomes. In addition, they were capable of oxidizing the anaerobic medium surrounding their roots in muddy sediment. As sulphide oxidation renders metals like Cadmium, Copper, Nickel and Lead into more soluble forms, according to the proposed model, metals from muddy sites would be more available in rhizosediment than in sediment.

• Effect of polyethylene microspheres (mPE) on metal phytoremediation investigated. • P. australis accumulated identical amounts of Cu and Cd with or without PE MPs. • Polyethylene microbeads did not affect the plant capacity to phytoremediate Cu or Cd. The negative impacts of microplastics (MPs) in aquatic organisms have been stressed out, but investigation on MPs impacts in plants is scarce. This study aimed to investigate possible interferences of polyethylene microbeads (mPE) (intentionally produced MPs) in the phytoremediation of metals. For that, the plant Phragmites australis , a salt marsh plant with known capability for metals phytoremediation, was exposed for seven days to media contaminated with Cu or Cd and mPE. Elutriate solution, with or without sediment, was used to simulate interactions between estuarine water, plants and sediments. Metal contents on plants tissues and media were measured afterwards. Results showed that plants accumulated significant amounts (up to 70 times more than in non-exposed plants) of both metals in their belowground tissues (reaching ca. 1 mg/g of Cu and ca. 70 μg/g of Cd in roots). Metal accumulation occurred either in absence or in presence of sediments, denoting plants capability to phytoremediate Cu and Cd. No significant metal translocation to the upper ground tissues was observed, metals levels being identical to those of non-exposed plants. The accumulation of both metals in plants belowground tissues was identical in the presence and absence of mPE, indicating that mPE did not interfered with plants capacity to phytoremediate Cu or Cd contaminated medium. This study further our scientific understanding of MPs impacts in saltmarsh plants and on their phytoremediation potential. [ABSTRACT FROM AUTHOR]

This study aimed to investigate if microplastics (MPs) type (polyethylene microspheres (mPE), fishing line fibers, film plastic bags MPs and bottle cap particles) and aging affect MPs capacity to sorb Cd or Cu in estuarine salt marsh medium. Tests were carried out in elutriate solution, a simple medium obtained by mixing rhizosediment (sediment in contact with plants roots) with the respective estuarine water, that can be used to simulate water-sediment exchanges in estuarine salt marsh environments. After 7 days of exposure, metals adsorption was only detected for film MPs. No differences were observed between virgin and aged MPs. Salinity also did not influence metal adsorption to mPE. Present results indicate that in estuarine salt marsh areas some types of MPs might adsorb metals, which could affect metals availability. • MPs type and aging effect on metal adsorption not significant for most MPs tested. • Both Cu and Cd were slightly adsorbed by film MPs and no other tested MPs. • Tested MPs may not reduce metal availability in estuarine salt marsh medium. [ABSTRACT FROM AUTHOR]

Reusing reclaimed wastewater is needed to fight water scarcity, reduce freshwater consumption and conserve water resources, but one must ensure that hazardous substances are fully removed/eliminate before that reuse. The potential of lab-scale constructed wetlands (CWs) for the removal of chemical and biological contaminants from livestock wastewater, while maintaining nutrient levels for fertilization, was assessed, evaluating changes in microbial communities, with particular focus on potential pathogens. CW microcosms with two different substrates (lava rock or light expanded clay aggregate), both planted with Phragmites australis , were tested. After 15 days of treatment, removal rates were higher than 80% for Cd, Cr, Cu, Fe, Pb and Zn, in general with no significant differences between the two different substrates. Organic matter and nutrients were also removed but their levels still allowed the used of the treated wastewater as a fertilizer Removal of bacterial contamination was estimated through enumeration of cultivable bacteria. High removal rates of fecal indicator bacteria were observed, reaching >95% for enterococci and >98% for enterobacteria after 15 days of treatment, decreasing hazardous biological contaminants initially present in the wastewater. In addition, the microbial communities in the initial and treated wastewater, and in the plant roots bed substrate, were characterized by using 16SrRNA gene amplicon sequencing. Microbial communities in the CW systems showed a clear shift comparatively with the initial wastewater showing system adaptation and removal potentialities. This also revealed an important removal of the most represented potential pathogenic genus, Clostridium , which relative abundance decreased from 33% to 1% through the treatment. Overall, CWs showed potential to be efficient in removing chemical and biological contaminants, while maintaining moderated levels of nutrients, allowing the reuse of reclaimed water in agriculture, namely as fertilizer. Current results will contribute for the optimization and use of CWs for a sustainable treatment of liquid wastes, promoting the circular economy. • Removal rates >80% for Cd, Cr, Cu, Fe, Pb and Zn in livestock wastewater treatment CWs. • Fecal indicator bacteria removal >95% for enterococci and >98% for enterobacteria after CW treatment. • CW systems microbial communities clearly shifted comparatively with the initial wastewater. • CW systems microbial communities showed system adaptation and removal potentialities. • CW treatment maintain moderated levels of nutrients, allowing reclaimed water reuse in agriculture. [ABSTRACT FROM AUTHOR]

The recovery of estuarine environments is in need. Phytoremediation could be a valid option to reduce pollution while preserving natural biodiversity. In this work, estuarine sediments colonized by Juncus maritimus or Phragmites australis were spiked with cadmium in the absence and in the presence of an autochthonous microbial consortium resistant to the metal. The aim of this study was to increase the potential for cadmium phytoremediation that these two halophyte plants have shown. Experiments were carried out in greenhouses with an automatic irrigation system that simulated estuarine tidal cycles. After 2 months, Cd concentration in P. australis stems increased up to 7 times when the rhizosphere was inoculated with the microbial consortium. So, P. australis phytoextraction potential was increased through autochthonous bioaugmentation. As for J. maritimus, up to 48% more Cd (total amount) was observed in its belowground tissues after being subjected to autochthonous bioaugmentation. Therefore, the phytostabilization potential of this plant was promoted. For both plants this increase in cadmium uptake did not cause significant signs of toxicity. Therefore, the addition of autochthonous microorganisms resistant to cadmium seems to be a valuable strategy to potentiate phytoremediation of this metal in saltmarshes, being useful for the recovery of moderately impacted estuaries. This will contribute for an effective management of these areas. Research on this topic regarding estuarine ecosystems, especially saltmarshes, is, to our knowledge, inexistent. [Copyright &y& Elsevier]