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The production of silver nanoparticles has reached nowadays high levels. Bioconcentration studies, information on persistence and toxicity are fundamental to assess their global risk and thus necessary to establish legislations regarding their use. Previous studies on silver nanoparticle toxicity have determined a clear correlation between their chemical stability and toxicity. In this work, experimental conditions able to assure silver nanoparticles stability have been optimized. Then, zebrafish (Danio rerio) eleutheroembryos were exposed to ionic silver and to Ag NPs for comparison purposes. A protocol alternative to the OECD 305 technical guideline was used. To determine silver concentration in both the eleutheroembryos and the exposure media, an analytical method consisting in ultrasound assisted extraction, followed by inductively coupled plasma mass spectrometry and graphite furnace atomic absorption spectrometry, was developed. Then, bioconcentration factors were calculated. The results revealed that ionic silver was more accumulative for zebrafish eleutheroembryos than nanoparticles at the levels tested. [Copyright &y& Elsevier]

The needs for new reference materials are constantly growing and become more specific as laboratories raise their awareness. Particular emphasis is placed on how representative reference materials are.In the water analysis sector, series of “natural” water reference materials are already on the market (sea and fresh water). However, at present, there are no materials that meet the needs for quality control in the analysis of wastewaters.Recent advances were made possible within the framework of a European Commission research project, the final aim of which was to certify three wastewater reference materials for trace-element contents (BCR-713, effluent wastewater, BCR-714, influent wastewater, and BCR-715, industrial effluent wastewater). These CRMs were the result of collaborative work involving 16 European laboratories.This article describes the preparation and the certification of these three wastewater reference materials for arsenic, cadmium, copper, chromium, iron, lead, manganese, nickel, selenium and zinc. Besides information on the preparation of the CRMs, it also describes the analytical techniques used by the certifying laboratories. [Copyright &y& Elsevier]

Abstract: A new and reliable miniaturised QuEChERS-based extraction method combined with a dispersive SPE cleanup procedure for extracting triclosan and methyltriclosan from fish roe and surimi samples was proposed. The effectiveness of different extraction/partition conditions for QuEChERS method was systematically investigated, and the use of acetonitrile extraction solvent and MgSO4, PSA, C18 and Florisil as cleanup reagents was recommended in the final method. Other method based on ultrasonic extraction with ethylacetate and clean-up with SPE was also evaluated for these samples. Different polymeric and silica sorbents for clean up were tested and the combination of Florisil and PSA was finally selected. The performance of these miniaturised sample preparation methods combined with GC–MS with quadrupole detection were compared. Extraction efficiency as well as cleaning effectiveness, laboriousness and speed were taken as criteria for method evaluation. Satisfactory validation parameters, such as linearity, recovery, precision and LODs and LOQs for both developed analytical methods were obtained from fish roe and surimi samples. Finally, both methods were applied to real samples. The sensitivity of the proposed methods was good enough to ensure reliable determination of target analytes at concentration levels commonly found in this kind of samples. [Copyright &y& Elsevier]

Increasing awareness of the determination of chemical species in the environment evolves jointly with the need to control the validity of analytical measurements in a wide variety of matrices. There are few Certified Reference Materials (CRMs) available for various chemical species, and they are certified for species of one single element (e.g., species of tin and mercury). Three years of collaboration within the framework of European Commission research programmes involving more than 20 laboratories have made it possible to produce an oyster reference material for species of tin, mercury and arsenic (BCR-710) and to perform the necessary experimental work for its certification. This article summarises the feasibility study and describes the various steps in the preparation, production and characterisation of this material for its content of arsenobetaine, methylmercury, tributyltin and dibutyltin. These steps included stability and homogeneity testing as well as value assignment based on a collaborative approach involving a group of European laboratories. Further work is going on to certify total contents for a range of trace metals. [Copyright &y& Elsevier]

Pesticide uptake by seeds depends on the properties of the chemical, such as structure, stability, log kow and diffusion rate, type of water, pH, temperature, content of organic matter and composition, and on seed characteristics such as permeability of the seed coat. The efficiency with which Lupinus angustifolius seeds retain different herbicides (simazine, atrazine, isoproturon, linuron,) and insecticides (carbaryl, fenamiphos, permethrin) was evaluated using both a batch and a continuous system. Factors which affect pesticide uptake by seeds, such as flow rate, seed biomass, pesticide concentration, contact time, pH, seed saturation and also the speed of the retention process for 17 days, were tested. L. angustifolius showed a high retention capacity for the above mentioned pesticides.The extraction of pesticides from seeds using different organic solvents, such as methanol, acetonitrile, ethyl acetate and n-hexane was evaluated and no pesticide residues were detected in any of the solvents tested. This could be attributed to the capacity of the seed to degrade the pesticides. From the results obtained, L. angustifolius seems to be a promising seed to be applied for phytoremediation of industrial effluents or contaminated water. [Copyright &y& Elsevier]

Background: Anxiety disorders are recognized as one of the most prevalent mental disorders in late-life. However, the prevalence of anxiety disorders in older Spanish people has not yet been determined. The aim was to review epidemiological studies systematically to calculate the overall prevalence of anxiety in Spanish older adults by using meta-analytic techniques.Methods: We searched relevant published studies in electronic databases up to January 2018 providing data on the prevalence of anxiety among people aged 65+  years in Spain. Overall anxiety prevalence estimates were calculated using random-effects models. Sources of heterogeneity were explored by means of univariate meta-regressions.Results: A total of 9 studies were included in the meta-analysis (N = 12,577). Pooled overall prevalence of anxiety was 11% (95% confidence interval (CI): 6%-18%) representing 1958,471 people aged 65+  (95%CI: 1068,257-3204,771). Point, 12-month and lifetime prevalence of anxiety disorders were 12%, 6% and 19%, respectively.Limitations: We detected a small publication bias effect for life-time prevalence of anxiety. The use of different diagnostic methods across the studies would have required separate analyzes.Conclusion: Some heterogeneity was found across studies, probably due to different methodological issues. Overall, the pooled prevalence of anxiety disorders in Spanish older adults was lower than that observed in other countries. Due to the negative consequences of anxiety disorders in older adults, detection and treatment should be a priority in this population. [ABSTRACT FROM AUTHOR]

The concern related to the use of nanomaterials is growing nowadays, especially the risk associated with their emission or exposure. One type of nanomaterials that has attracted much attention is quantum dots (QDs). QDs incorporation in consumer goods increases the probability of their entering in the environment and then into living organisms and human. In order to evaluate their potential to be bioconcentrated, zebrafish larvae have been exposed to SeCd/ZnS QDs, after performing an exhaustive characterization of these nanoparticles under the assay conditions. These data were compared with those obtained when zebrafish larvae were exposed to ionic cadmium. Finally, distribution of ionic Cd and QDs in exposed zebrafish larvae have been evaluated by Laser Ablation ICP-MS. [ABSTRACT FROM AUTHOR]

In this work, silver migration from commercial food containers was evaluated according to European Regulation 10/2011. Several experimental parameters affected silver release: food simulant, temperature, exposition time and sampled bag area. Results demonstrated a significant silver nanoparticle (AgNP) migration into aqueous and acidic simulants. The amount of silver migrated increased with storage time and temperature although, in general, silver showed a low tendency to migrate into food simulants (17ng/g). However, the food simulant did not seem to be a really outstanding variable for long term storage. AF4-ICP MS was used to confirm the presence of AgNPs in the simulants. The low limit of detection achieved (0.4μgL−1) allowed the identification of AgNPs and their size characterisation (40-60nm). Finally, scanning electron microscopy/energy-dispersive X-ray analysis suggested a possible transformation of the AgNPs detected in the extracts, due to association with other ligands, such as chlorine and sulphur, present in the original containers. [ABSTRACT FROM AUTHOR]

Abstract: The feasibility of a bioaccumulation test based on the use of zebrafish eleutheroembryos as an alternative to adult-individual-based approaches for REACH application has been evaluated for three test compounds, chlorpyrifos, dicofol and atrazine. Following the OECD 305 guidelines, zebrafish eleutheroembryos (72h after hatching, hpf) were separately exposed to the investigated pesticides at two nominal concentrations below 1% of its corresponding LC50. The uptake experiments lasted for 48h. Then, the exposure medium was replaced by a non-contaminated medium for depuration experiments (up to 72h). Zebrafish eleutheroembryos (larvae 144 hpf, i.e. at the end of the depuration step) and their corresponding exposure media was sampled at ten different times during each experiment and the concentration of the investigated pesticide determined in both the organisms and in the exposure medium. The experimentally determined pesticide accumulation profiles in the eleutheroembryos demonstrated that atrazine has a very fast accumulation kinetic, reaching steady sate (SS) within 24h. Chlorpyrifos and dicofol did not reach the SS within the 48-h uptake experiments although they exhibit higher accumulations than the former pesticide. Two toxicokinetic models were used to calculate the bioconcentration factor (BCF) of the studied pesticide in zebrafish eleutheroembryos. In the former, the BCF was calculated under SS conditions (BCFSS). The second was used when the compounds did not reach the SS during the uptake experiment (BCFk). Log BCF values of 3.55 and 3.84 for chlorpyrifos; 0.6 and 1.17 for atrazine, and 3.90 for dicofol were experimentally calculated at selected exposure concentrations. These values have been compared with those reported in related bioaccumulation studies and official databases. [Copyright &y& Elsevier]

Abstract: The European REACH legislation establishes the need to study the toxicity, persistence and bioaccumulation of those chemicals with an exceeding production of 100tons and/or chemicals considered PBTs substances (Persistence, Bioaccumulation and Toxicity). Currently, the OECD technical guideline 305 is the most used protocol to determine bioconcentration factors of contaminants in aquatic environments. However, this procedure implies high cost and amount of adult fishes. Zebrafish (Danio Rerio) has been selected since this animal model has several advantageous features over other vertebrates, mainly fast embryonic development and easy growth. The analytical methodology here developed has been applied to calculate the bioconcentration factors (BCFs) of two contaminants: inorganic arsenic and tributyltin (measured as arsenic and tin). The method is based on the use of an ultrasonic probe assisted extraction for accelerating the sample treatment followed by detection using graphite furnace atomic absorption spectrometry with Zeeman correction (ZGFAAS). Results obtained for the BCFs values are in good agreement with previously reported data on freshwater aquatic organisms. In the case of arsenic, after exposing larvae to concentrations of 5 and 50μgL−1, very low BCFs were observed (between 2.2 and 9.5); while for tributyltin, the BCFs observed were within the range 840–1280 after exposure to concentrations of 0.2 and 2.0μgL−1, respectively. This study shows the use of zebrafish larvae together with the proposed analytical approach as a promising alternative to the OECD 305 test to evaluate the BCFs of classical and emergent contaminants. [Copyright &y& Elsevier]