Sludge from sewage treatment plants (STPs) is recognized as a sink of moderate to high lipophilic compounds resistant to biodegradation. Herein, we investigate the presence of emerging pollutants in ...sewage sludge combining the information provided by mass spectrometry detection, following ultra-performance liquid chromatography (UPLC), with the use of an accurate spectral database of pesticides and pharmaceuticals. In a first step, the performance of matrix solid-phase dispersion, as sample preparation technique, and two non-target data acquisition strategies (data dependent, DDA, and data independent analysis modes, DIA), used in combination with a UPLC quadrupole time-of-flight system, are assessed using a selection of deuterated compounds added either to freeze-dried sludge samples, or to sludge extracts. Possibilities and limitations of both modes are discussed. Following the DDA approach, a group of 68 micropollutants was identified in sludge from different STPs. Some of them are reported in this compartment for the first time. Finally, semi-quantitative concentration data are reported for a group of 37 pollutants in samples obtained from 16 STPs. Out of them, 10 pharmaceuticals, showing detection frequencies and median sludge residues above 50% and 100 ng g−1, respectively; are highlighted as pollutants to be monitored in sludge in order to understand their behaviour during the wastewater treatment.
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•Screening of pollutants in sludge by matrix solid-phase dispersion and UPLC-QTOF-MS•Assessment of the reliability of different acquisition modes with spiked samples•Identification of more than 60 emerging pollutants in sewage sludge•Median concentrations above 100 ng g−1 for 10 out of 37 quantified species
Ingested-derived DNA (iDNA) from insects represents a powerful tool for assessing vertebrate diversity because insects are easy to sample, have a diverse diet and are widely distributed. Because of ...these advantages, the use of iDNA for detecting mammals has gained increasing attention. Here we aimed to compare the effectiveness of mosquitoes and flies to detect mammals with a small sampling effort in a semi-controlled area, a zoo that houses native and non-native species. We compared mosquitoes and flies regarding the number of mammal species detected, the amount of mammal sequence reads recovered, and the flight distance range for detecting mammals. We also verified if the combination of two mini-barcodes (12SrRNA and 16SrRNA) would perform better than either mini-barcode alone to inform local mammal biodiversity from iDNA. To capture mosquitoes and flies, we distributed insect traps in eight sampling points during 5 days. We identified 43 Operational Taxonomic Units from 10 orders, from the iDNA of 17 mosquitoes and 46 flies. There was no difference in the number of species recovered per individual insect between mosquitoes and flies, but the number of flies captured was higher, resulting in more mammal species recovered by flies. Eight species were recorded exclusively by mosquitoes and 20 by flies, suggesting that using both samplers would allow a more comprehensive screening of the biodiversity. The maximum distance recorded was 337 m for flies and 289 m for mosquitoes, but the average range distance did not differ between insect groups. Our assay proved to be efficient for mammal detection, considering the high number of species detected with a reduced sampling effort.
End-of-life electric and electronic devices stand as one of the fastest growing wastes in the world and, therefore, a rapidly escalating global concern. A relevant fraction of these wastes ...corresponds to polymeric materials containing a plethora of chemical additives. Some of those additives fall within the category of hazardous organic compounds (HOCs). Despite the significant advances in the capabilities of analytical methods, the comprehensive characterization of WEEE plastic remains as a challenge. This research strives to identify the primary additives within WEEE polymers by implementing a non-target and suspect screening approach. Gas chromatography coupled to time-of-flight mass spectrometry (GC-QTOF-MS), using electron ionization (EI), was applied for the detection and identification of more than 300 substances in this matrix. A preliminary comparison was carried out with nominal resolution EI-MS spectra contained in the NIST17 library. BPA, flame retardants, UV-filters, PAHs, and preservatives were among the compounds detected. Fifty-one out of 300 compounds were confirmed by comparison with authentic standards. The study establishes a comprehensive database containing m/z ratios and accurate mass spectra of characteristic compounds, encompassing HOCs. Semi-quantification of the predominant additives was conducted across 48 WEEE samples collected from handling and dismantling facilities in Galicia. ABS plastic demonstrated the highest median concentrations, ranging from 0.154 to 4456 μg g−1, being brominated flame retardants and UV filters, the families presenting the highest concentrations. Internet router devices revealed the highest concentrations, containing a myriad of HOCs, such as tetrabromobisphenol A (TBBPA), tribromophenol (TBrP), triphenylphosphate (TPhP), tinuvin P and bisphenol A (BPA), most of which are restricted in Europe.
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•Non-target screening analysis for the identification of hazardous substances in WEEE.•More than 300 volatile and semi-volatile substances were identified in WEEE plastic.•Flame retardants, UV filters and PAHs exhibited the highest detection frequencies.•TBBPA and TPhP displayed the highest concentrations.
Herein, a method for the simultaneous determination of the currently prescribed sartan drugs (eprosartan, EPR; olmesartan, OLM; losartan, LOS; candesartan, CAN; telmisartan, TEL; irbesartan, IRB; and ...valsartan, VAL), and the biodegradation product valsartan acid (VALA), in water samples (raw and treated wastewater, river and tap water) was developed. Solid-phase extraction (SPE) and ultra-performance liquid chromatography (UPLC) tandem mass spectrometry (MS/MS) were employed as concentration and determination techniques, respectively. Different sorbents and elution solvents were tested for sample preparation. Under optimized conditions, samples at neutral pH (6–8 units) were concentrated using mixed-mode (reversed-phase and anionic exchange) cartridges. Thereafter, the sorbent was washed with 5 mL of a methanol: water (1:1) solution, dried under a nitrogen stream and compounds were eluted with 2 mL of methanol: NH3 (98:2). The accuracy of the method (accounting for SPE efficiency and matrix effects during electrospray ionization) was investigated using solvent-based calibration standards. Global recoveries, obtained for different water matrices (tap, river, treated and raw wastewater), ranged from 82% to 134%, with standard deviations between 2 and 18%. LOQs varied from 2 to 50 ng L−1. Analysis of un-spiked samples confirmed: (1) the incomplete removal of sartans at sewage treatment plants (STPs), (2) the formation of VALA during municipal water treatment, and (3) the presence of VALA in the processed tap water samples. Additional findings of the current study are the detection of hydroxylated derivatives of the sartan drugs IRB and LOS in wastewater, and the E-Z isomerization of EPR in environmental water samples.
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•Mixed-mode solid-phase extraction of sartan drugs and valsartan acid.•High extraction yields with reduced matrix effects for different water samples.•Presence of valsartan acid in drinking water catchments and tap water.•Isomerization of E-eprosartan to the Z-form in the aquatic environment.•Detection of hydroxylated metabolites of irbesartan and losartan in wastewater.
Premise
The diversification of island flora has been widely studied. However, the role of environmental niches in insular radiation processes has been less investigated. We combined population ...genetic analyses with species distribution modelling to clarify the genetic relationships, diversification patterns, species niche requirements, and conservation of Thesium sect. Kunkeliella, a clade of rare hemiparasitic plants endemic to the Canaries.
Methods
We studied the three extant Thesium species and a new taxon from La Palma Island. We developed 12 microsatellites and performed population genetic analysis and studied the demographic history of the group. To evaluate the role of niche conservatism in the diversification of the group, we performed species distribution modelling (ESM) with four algorithms.
Results
All species presented moderate genetic diversity values for rare endemics. Thesium canariense (Gran Canaria) showed high differentiation, whereas T. subsucculentum, T. retamoides (Tenerife), and La Palma populations are closely related. The lineage may have undergone a recent diversification with colonization proceeding east to west, with T. canariense as sister to the others. We detected a climatic niche shift, as taxa showed different distributions across the temperature gradient. There is enough evidence to describe La Palma populations as a new species.
Conclusions
We characterized the evolutionary history of Thesium sect. Kunkeliella by integrating genetic and ecological assessments. Our results indicate that this clade has undergone a recent radiation process with niche differentiation among species. The results increase our knowledge about insular radiations and will inform the conservation management of the study species.
Contact with thermal printing paper is a relevant source of dermal exposure to unbonded bisphenol A (BPA). In order to limit this exposure route, the European Union has introduced a drastic reduction ...in the maximum allowed concentration of BPA in thermal paper produced after beginning of year 2020. This study investigates the suitability of direct analysis in real time (DART), combined with accurate mass spectrometry, as a faster alternative to chromatography-based methods for the quantitative determination of BPA, and three analogues species, in receipts and tickets usually printed on thermal paper. The ionization efficiency of these compounds is evaluated under different conditions, and the effect of instrumental parameters of the DART source in the observed responses is discussed. The yield of the DART desorption-ionization process was greatly improved when compounds are previously converted into their acetyl derivatives; thereafter, the temperature of electronically excited helium atoms was the most relevant of the evaluated instrumental parameters. Under optimized conditions, the reported method provided recoveries in the range from 90 to 110%, a limit of quantification of 0.004% (w:w), well below the maximum concentration established after 2020 for BPA (0.02%, w:w), and permitted to perform duplicate determinations of each sample extract with a response time around 1 min. The accuracy of BPA levels found in non-spiked samples was confirmed using GC-EI-MS as reference technique. BPA was systematically noticed in the processed samples with concentrations ranging from 0.005% to more than 6%.
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•Rapid determination of bisphenol A in thermal printing paper by DART accurate MS.•Acetylation greatly enhances the yield of DART desorption-ionization.•Procedural LOQs below limits set for bisphenol A in thermal paper.•Good correlation between DART-MS and GC-EI-MS values in thermal paper samples.
Indoor dust contains a complex mixture of anthropogenic and synthetic compounds closely related to dermal and respiratory diseases. Target methods have been developed for the quantification of ...distinct groups of substances in dust samples; however, the comprehensive characterization of the different species existing in this matrix remains a challenging issue. Herein, we assess the performance of gas chromatography (GC) time-of-flight mass spectrometry (TOF-MS), using electron ionization (EI), for the screening of compounds present in indoor dust. Samples are processed by pressurized-liquid extraction (PLE) before GC-EI-TOF-MS analysis. The study proposes a data mining workflow for the non-target identification of species contained in dust extracts, aided by preliminary comparison with nominal resolution EI-MS spectra in the NIST17 library. The possibilities, and the limitations, of the above approach are discussed and the identities of >75 compounds are confirmed by comparison with authentic standards in dust from indoor environments. Some species, such as indigo, phthalic anhydride, 2,4-toluene di-isocyanate, phthalimide, certain UV absorbers and octyl isothiazolinone, identified in this research, have not been previously considered in target methods dealing with dust analysis. The study also evaluates two different algorithms for the suspected-target screening of dust extracts using a customized library of accurate EI-MS spectra. Finally, a semi-quantitative estimation of the range of concentrations for a group of 44 pollutants in a set of 27 dust samples is provided.
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•Comprehensive screening of semi-volatile compounds in indoor dust extracts•Deconvolution of accurate electron ionization scan mass spectra•Compounds identification guided by comparison with low resolution library spectra•Novel compounds detected in dust from indoor environments•Concentration ranges estimated for a selection of 44 pollutants in dust samples
•A nitriding pretreatment increases the adhesion of AlCrN coating on 4140 steel.•The adhesive failure mode of AlCrN is changed to cohesive by the nitrides layer.•The COF of AlCrN is reduced to 50% ...due to the nitriding pretreatment.•The specific wear rate of AlCrN is greatly reduced by the nitriding pretreatment.
In this work, a gas nitriding pretreatment (iron nitrides layer) formed on the surface of 4140 steel is proposed to improve the adhesion and wear resistance of the AlCrN coatings deposited by arc cathodic PVD. AlCrN, FexN and AlCrN/FexN (duplex) systems were formed with total thicknesses of 3, 10 and 13 µm, respectively. Using spherical instrumented indentation, hardness more than 22 GPa were determined for the AlCrN-based coatings, meanwhile 10 GPa for the iron nitrides. The adhesion of the coatings were evaluated by progressive load scratch tests (PLST) where the duplex coating reduced the CoF and changed the failure mode from adhesive to cohesive for the AlCrN coating. The AlCrN/FexN coating exhibited the lowest specific wear rate and the severity of damage was reduced in multipass scratch wear tests (MPST). The duplex system presented the best adhesion and wear resistance.
In this study the mechanical behavior of FeB and Fe2B layers formed at the surface of AISI D2 steels was estimated by the Berkovich nanoindentation technique. The boriding of AISI D2 steels was ...developed by the powder-pack method at temperatures of 1223, 1273 and 1323K with exposure times of 3–7h for each temperature. The mechanical characterization was performed to determine the effect of the set of experimental parameters of the boriding process with three experimental procedures: first, nanoindentation was performed along the depth of the surface layers at a constant load of 250mN to determine the hardness gradient and the state of the thermal residual stresses in the boride layers; then, loads in the range of 10 to 300mN were applied to the “pure” zone of the FeB layer at a distance of 10μm from the surface, and in the “pure” zone of the Fe2B layer (40μm), respectively. Finally, the fracture toughness, compressive residual stresses, and brittleness of the boride layers were evaluated using the length of the cracks that originated from the corners of the Berkovich nanoindentation site after the application of loads ranging from 300 to 500mN.
For a constant load of 250mN, the results showed that the state of thermal residual stresses and the hardness of both the FeB and Fe2B layers were a function of the temperature and exposure time of the process. Moreover, the presence of the indentation size effect (ISE) in the FeB and Fe2B layers was verified in the range of applied loads (10–300mN), in which the apparent or real hardness was estimated by the elastic recovery (ER) model according to the boriding experimental parameters. Finally, the estimated values of the fracture resistance and brittleness of the boride layers fell within the range of 1.48–3.02MPam and 2.01–4.65MPam, with the presence of compressive stresses in the range of 428 to 1604MPa for the FeB and Fe2B layers, respectively.
► Mechanical properties of the FeB and Fe2B layers were evaluated by nanoindentation. ► The thermal residual stresses across the boride layers were compressive. ► The presence of the indentation size effect was verified in both FeB and Fe2B layers. ► The FeB layer showed low fracture resistance with high brittleness.
New results about the scratch adhesion resistance of nickel boride layer on Inconel 718 superalloy were estimated in the present study. The nickel boride layer was developed on the surface of Inconel ...718 superalloy by means of the powder-pack boriding process conducted at 1173K with 2, 4, and 6h of exposure. The microstructure of the nickel boride layer was analyzed from optical microscopy, X-ray diffraction and energy dispersive spectroscopy (EDS). Furthermore, and before the scratch tests, indentation properties of the nickel boride layers such as hardness, Young's modulus, and the distribution of residual stresses were evaluated using Berkovich nanoidentation tests applying a constant load (50mN) across the diffusion layers. The scratch tests were performed over the surface of the nickel boride layer-substrate systems using a Rockwell-C diamond indenter with a continuously increasing normal force from 1 to 80N, whereas the behavior of the coefficient of friction and the residual depth as a function of the scratch length were monitored during the tests. For the determination of the critical loads, the combination of acoustic emission signal with microscopic observations of the worn tracks were used; the critical loads were estimated at which the layer cracks (cohesive failure) or is detached (adhesive failure) and they explained according to the mechanical properties of the nickel boride layer-substrate system. For all the set of experimental conditions, the presence of three types of failure mechanisms over the worn tracks were detected, while the results showed that the critical loads increase with enhancing nickel boride layer thickness.
•New results about the adhesion resistance of nickel boride layer were obtained.•From scratch test, the critical loads of the layer-substrate system were estimated.•Tensile residual stresses decrease the practical adhesion resistance of the layer.•The adhesion resistance increases as a function of the boride layer thickness.•Hertzian cracking, chipping and spalling were observed over the scratch tracks.
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