Development of an Analytical Procedure to Analyze Microplastics in Edible Macroalgae Using an Enzymatic-Oxidative Digestion

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] Besides being food and a refuge to marine species, macroalgae are a powerful and renewable economic resource. However, they may introduce microplastics (MPs) in the trophic chain. We developed a reliable analytical method to characterize and quantify MPs in common and edible macroalgae. Several digestion methods and filters, along with various measurement options, were studied. A new enzymatic-oxidative protocol with a unique final filtration was selected and validated with a mixture of 5 commercial macroalgae (Undaria pinnatifida spp, Porphyra spp, Ulva spp, Laminaria ochroleuca and Himanthalia elongate). Further, it was shown that washing the macroalgae to release MPs is suboptimal and the potential adhesion of MPs to macroalgae was evaluated. A filter subsampling strategy that scans 33.64 % of its surface reduced the time required to characterize <70 μm particles and fibres directly on the 47 mm diameter filter using an IR microscope (1 sample/day).This work is a part of the projects MicroplastiX (Grant PCI2020-112145, JPI Oceans Project supported by MCIN/AEI/10.13039/501100011033 and by the European Union “Next Generation EU/PRTR”) and LAnd-Based solutions for PLAStics in the Sea, LABPLAS, (Grant H2020-101003954 supported by the EU H2020 program). The Program “Consolidación e Estructuración de Unidades de Investigación Competitivas” of the Galician Government (Xunta de Galicia) is also acknowledged (Grant ED431C 2021/56). Funding for open access charge: Universidade da Coruña/CISUGXunta de Galicia; ED431C 2021/5

A Reliable Method for the Isolation and Characterization of Microplastics in Fish Gastrointestinal Tracts Using an Infrared Tunable Quantum Cascade Laser System

[Abstract] Societal and environmental concern due to frequent reports of microplastics in fish stomachs raised as they may accumulate along the trophic chain. The request for analysing microplastics in fish stresses two major analytical issues: sample treatment and final characterization. The, so far, workhorse for chemical characterization is infrared spectroscopy which is time-consuming. Here, a quantum cascade laser-based device is used to accelerate the characterization stage. Its novelty poses new challenges for sample processing and particle handling because the unknown particles must be transferred to a reflective slide. In this study, three sample digestion protocols (alkaline-oxidative with H2O2, and alkaline-oxidative with NaClO and enzymatic-oxidative) and three different procedures to transfer the filter cake to reflective slides are compared. A simplified enzymatic-oxidative digestion (validated through an interlaboratory exercise) combined with a Syncore® automatic evaporation system and a Laser Direct Infrared Imaging (LDIR) device is proposed first time as a reliable and relatively fast method to treat gastrointestinal tracts of fish. Analytical recoveries were studied using samples of Scomber scombrus and they were ca. 100% for big –i.e., >500 μm- and ca. 90% for medium –i.e., 200–300 μm- particles and ca. 75% for 10 μm thick fibres.This research was supported by the LAnd-Based Solutions for PLAstics in the Sea Project (LABPLAS Project), Grant Agreement No. 101003954, under the European Union's Horizon 2020 research and innovation programme, and the Integrated approach on the fate of MicroPlastics (MPs) towards healthy marine ecosystems Project (MicroplastiX project), Grant PCI2020-112145, supported by the JPI_Oceans Program and by MCIN/AEI/10.13039/501100011033 and the European Union “Next Generation EU/PRTR”. The Program ‘Consolidación e Estructuración de Unidades de Investigación Competitivas” of the Galician Government (Xunta de Galicia) is also acknowledged (Grant ED431C 2021/56)Xunta de Galicia; ED431C 2021/5

Misidentification of PVC Microplastics in Marine Environmental Samples

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] Poly(vinylchloride), PVC, is the third most demanded polymer in Europe although its presence in marine ecosystems, surprisingly, is scarcely observed. This does not reflect neither its production nor its widespread usage. Therefore, it is imperative to understand why this may happen. PVC is the least stable of the high-tonnage produced polymers as it has the highest sensitivity towards UV radiation and, therefore, photo-degradation is of maximum relevance. The big amount of additives included in PVC formulations, weathering and the different treatments required to isolate it from environmental samples can modify the surface of PVC microplastics, making their spectral identification/quantification an analytical challenge. All these factors can lead to large PVC underestimations in environmental studies, in which other polymers like PE, PP or PS outstand. Further, the fact that the infrared spectrum of weathered PVC can be confounded with that of PE is of most relevance and, therefore, remarkable misidentifications and/or wrong quantifications may occur. In this work some relevant factors that can explain the low percentages of PVC reported in the literature are discussed and special emphasis is made on the need for suitable spectroscopic databases that include PVC weathered standards. This has been confirmed by the results of a detailed study of PVC weathering under pilot-scale conditions, monitoring its spectroscopic and physical changes over time.This work is part of the project MicroplastiX (Grant PCI2020-112145) supported by the JPI_Oceans Program and by MCIN/AEI/10.13039/501100011033 and the European Union “Next Generation EU”/PRTR”; by the LAnd-Based solutions for PLAStics in the Sea (LABPLAS) Grant H2020- 101003954 and “ChemPlas” Project supported by the Agencia Estatal de Investigación (Grant PID2019-108857RB-C31/AEI/10.13039/501100011033). The Program ‘Consolidación e Estructuración de Unidades de Investigación Competitivas” of the Galician Government (Xunta de Galicia) is also acknowledged (Grant ED431C 2021/56). Funding for open access charge: Universidade da Coruña/CISUGXunta de Galicia; ED431C 2021/5

Polycyclic Aromatic Hydrocarbons Analysis in Tea Infusions and Tea Beverages Using Membrane Assisted Solvent Extraction

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] Membrane Assisted Solvent Extraction (MASE) was applied as an extraction and enrichment technique of polycyclic aromatic hydrocarbons (PAHs) from tea infusions and fruit/herbal-tea beverages. PAHs have been separated and detected by high performance liquid chromatography coupled to a fluorescence detector (HPLC-FLD). Variables affecting MASE comprising extraction temperature and time, stirring rate, acceptor solvent (hexane) volume, organic modifier in the donor phase (methanol) volume, aqueous donor phase pH and ionic strength were simultaneously studied by applying a Plackett–Burman design (PBD) as screening method. Results showed statistical significance for acceptor solvent volume, extraction time and stirring rate, which were optimised by an orthogonal 23 + star central composite design (CCD). Quantitative recoveries for all PAHs (within 78–116%) were obtained by using the optimized extraction conditions: 350 µL of hexane, extraction time of 70 min and stirring rate of 175 rpm. Extraction temperature, ionic strength and donor phase pH were statistically non-significant, which simplify the procedure. The MASE method has been found sensitive (LOQs < 43 ng L−1) and precise (RSDs of < 13%). Finally, the method has been applied to assess PAHs levels in several tea infusions and fruit/herbal-tea beverages in the presence of surrogate standards. The total mean Σ16PAHs in tea infusions were from 1.2 ng L−1 (white tea) to 151.7 ng L−1 (black tea), while total mean Σ16PAHs was lower than 11.5 ng L−1 regarding tea fruit/herbal beverages. Furthermore, benzo(a)pyrene (BaP) concentrations were from < 1.5 ng L−1 (white tea) to 4.6 ng L−1 (green tea). Nevertheless, BaP concentrations obtained as well as the summation of BaA, Chry, BbF and BaP concentrations (4.6 ng L−1 for tea beverages to 7.5 ng L−1 for green tea infusions) did not exceeded the maximum levels according with European Union (EU) standards. Finally, BaP carcinogenic equivalent concentration (BaPeq) and BaP mutagenic equivalent concentration (BaPMeq) were estimated, ranging from 0.01 ng L−1 to 19.8 ng L−1 and 0.23 ng L−1 to 6.9 ng L−1, respectively.This work was supported by Xunta de Galicia (Programa de Consolidación y Estructuración de Unidades de Investigación Competitivas ref: ED431C 2017/28-2017-2020) and FEDER-MINECO (UNLC15-DE-3097, financed together (80/20%) with Xunta de Galicia. Joel Sánchez-Piñero acknowledges the Xunta de Galicia and the European Union (European Social Fund - ESF) for a predoctoral grant (ED481A-2018/164)Xunta de Galicia; ED431C 2017/28-2017-2020Xunta de Galicia; ED481A-2018/16

Monitorization of Polyamide Microplastics Weathering Using Attenuated Total Reflectance and Microreflectance Infrared Spectrometry

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] The EU goal to reduce marine plastic litter by ca. 30% by 2020 stressed the need to deploy analytical methods to ascertain the polymeric nature of a residue. Furthermore, as plastics age under natural conditions and usual databases do not include their weathered spectra, (micro)plastics in environmental samples may be unidentified. In this paper, polyamide (nylon) microplastics weathering was monitored because of its ubiquity in household commodities, clothes, fishery items and industry, whose residues end up frequently in the environment. Infrared spectra (ATR and microreflectance) and Scanning Electron Microscopy (SEM) images were collected periodically while exposing nylon to controlled weathering. It was seen that ATR was more sensitive than microreflectance to monitor the structural evolution of polyamide and that the spectra and the surface of weathered microplastics showed remarkable differences with the pristine material, which stresses the need for considering its evolution when identifying microplastics in environmental studies. The evolution of six band ratios related to the chemical evolution of this polymer are presented. SEM images revealed the formation of secondary microplastics at the most advanced weathering stages of polyamide.This work was supported through the JPI-Oceans BASEMAN and MicroplastiX projects, sponsored by the Spanish Ministry of Science and Innovation (Agencia Estatal de Investigación) -partially financed by the European Regional Development Fund program- (Grants: PCIN-2015-170-C02-01; PCIN- PCI2020-112145 and CTM2016-77945-C3-3-R, ARPA-ACUA). The Program ‘Consolidación e Estructuración de Unidades de Investigación Competitiva’ of the Galician Government (Xunta de Galicia) is also acknowledged (Grant: ED431C-2017/28)Xunta de Galicia; ED431C-2017/2

New Ways for the Advanced Quality Control of Liquefied Natural Gas

[Abstract] Currently, gas chromatography is the most common analytical technique for natural gas (NG) analysis as it offers very precise results, with very low limits of detection and quantification. However, it has several drawbacks, such as low turnaround times and high cost per analysis, as well as difficulties for on-line implementation. With NG applications rising, mostly thanks to its reduced gaseous emissions in comparison with other fossil fuels, the necessity for more versatile, fast, and economic analytical methods has augmented. This work summarizes the latest advances to determine the composition and physico-chemical properties of regasified liquid natural gas, focusing on infrared spectroscopy-based techniques, as well as on data processing (chemometric techniques), necessary to obtain adequate predictions of NG properties.Part of this work was performed under the EMPIR 16ENG09 project ‘Metrological support for LNG and LBG as transport fuel (LNG III)’. This project has received funding from the EMPIR programme co-financed by the Participant States and from the European Union’s Horizon 2020 Research and Innovation programme. Mestrelab, Reganosa and Naturgy are acknowledged for hiring the services of the Group of Applied Analytical Chemistry for FTIR method development. The Program “Consolidación e Estructuración de Unidades de Investigación Competitivas” of the Galician Government (Xunta de Galicia) is also acknowledged (Grant ED431C 2021/56).Xunta de Galicia; ED431C 2021/5

Development of a Fast and Efficient Method to Analyze Microplastics in Planktonic Samples

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] Microplastics (MPs) affect plankton (a basis of the trophic chain) and planktivorous fish can ingest them through food confusion or by trophic transmission. Consensus to determine MPs in plankton is lacking and, so, three digestion treatments were evaluated: Alkaline (potassium hydroxide) and enzymatic (protease plus lipase) digestions, both combined with a hydrogen peroxide stage; and an oxidative method using a surfactant (sodium dodecyl sulfate) plus hydrogen peroxide. The alkaline method using potassium hydroxide was found to damage polystyrene. MPs were identified with a stereomicroscope and characterized by reflectance infrared microscopy in semi-automatic mode (using dedicated multi-well aluminium plates). Analytical recoveries for polypropylene, polystyrene, polyethylene, polyamide, polyvinyl chloride and polyethylene terephthalate were higher than 75%, 82% and 83% for the alkaline, enzymatic and oxidative treatments, respectively. The enzymatic method was successfully validated in a European interlaboratory exercise and the oxidative method was demonstrated to be a reliable, fast and cheaper alternative.The Spanish Government (Ministerio de Economía y Competitividad and Ministerio de Ciencia e Innovación-Agencia Estatal de Investigación) and the JPI-Oceans European Program are acknowledged by the BASEMAN (PCIN-2015-170-C02-01, with FEDER/ERDF funds) and the MicroplastiX (PCIN-PCI2020-112145) projects. Thanks are given also to the Spanish Government by the CTM2016-77945-C3-3-R (ARPA-ACUA) Grant. The Galician Government (“Xunta de Galicia”) is acknowledged for its support to the QANAP group (Programa de Consolidación y Estructuración de Unidades de Investigación Competitiva. Ref. ED431C 2017/28) partially financed by FEDER/ERDF fundsXunta de Galicia; ED431C 2017/2

Inhalation Bioaccessibility of Multi-Class Organic Pollutants Associated to Atmospheric PM2.5: Correlation with PM2.5 Properties and Health Risk Assessment

[Abstract] Inhalation exposure to fine particulate matter (PM2.5) represents a global concern due to the adverse effects in human health. In the last years, scientific community has been adopted the assessment of the PM2.5-bound pollutant fraction that could be released (bioaccessible fraction) in simulated lung fluids (SLFs) to achieve a better understanding of PM risk assessment and toxicological studies. Thus, bioaccessibility of 49 organic pollutants, including 18 polycyclic aromatic hydrocarbons (PAHs), 12 phthalate esters (PAEs), 11 organophosphorus flame retardants (OPFRs), 6 synthetic musk compounds (SMCs) and 2 bisphenols in PM2.5 samples was evaluated. The proposed method consists of a physiologically based extraction test (PBET) by using artificial lysosomal fluid (ALF) to obtain bioaccessible fractions, followed by a vortex-assisted liquid-liquid microextraction (VALLME) and a final analysis by programmed temperature vaporization-gas chromatography-tandem mass spectrometry (PTV-GC-MS/MS). The highest inhalation bioaccessibility ratio was found for bisphenol A (BPA) with an average of 83%, followed by OPFRs, PAEs and PAHs (with average bioaccessibilities of 68%, 41% and 34%, respectively). Correlations between PM2.5 composition (major ions, trace metals, equivalent black carbon (eBC) and UV-absorbing particulate matter (UVPM)) and bioaccessibility ratios were also assessed. Principal Component Analysis (PCA) suggested that PAHs, PAES and OPFRs bioaccessibility ratios could be positively correlated with PM2.5 carbonaceous content. Furthermore, both inverse and positive correlations on PAHs, PAEs and OPFRs bioaccessibilites could be accounted for some major ions and metal (oid)s associated to PM2.5, whereas no correlations comprising considered PM2.5 major ions and metal (oid)s contents and BPA bioaccessibility was observed. In addition, health risk assessment of target PM2.5-associated PAHs via inhalation was assessed in the study area considering both total and bioaccessible concentrations, being averaged human health risks within the safe carcinogenic and non-carcinogenic levels.This work was supported by the Ministerio de Ciencia, Innovación y Universidades (MCIU), the Agencia Estatal de Investigación (AEI) and the Fondo Europeo de Desarrollo Regional (FEDER)501100008530 (Programa Estatal de I + D + i Orientada a los Retos de la Sociedad, ref: RTI 2018-101116-B-I00), the Xunta de Galicia (Programa de Consolidación y Estructuración de Unidades de Investigación Competitivas, refs: ED431C 2017/28 (2017–2020) and ED431C 2021/56 (2021–2024)) and FEDER501100008530-MINECO (UNLC15-DE-3097, financed together (80/20%) with the Xunta de Galicia). Joel Sánchez-Piñero acknowledges the Xunta de Galicia and the European Union (European Social Fund - ESF) for a predoctoral grant (ED481A-2018/164). Natalia Novo-Quiza acknowledges the Ministerio de Ciencia e Innovación and the European Union (European Social Fund - ESF) for a predoctoral grant (PRE 2019-088744). The Laboratorio de Medio Ambiente de Galicia (LMAG) of the Subdirección Xeral de Meteoroloxía e Cambio Climático (Xunta de Galicia) is also acknowledged for providing the samples used in the present research workXunta de Galicia; ED431C 2017/28Xunta de Galicia; ED431C 2021/56Xunta de Galicia; ED481A-2018/16