Anthropogenic debris in three sympatric seal species of the Western Antarctic Peninsula.

Litter pollution is a growing concern, including for Antarctica and the species that inhabit this ecosystem. In this study, we investigated the microplastic contamination in three seal species that inhabit the Western Antarctic Peninsula: crabeater (Lobodon carcinophaga), leopard (Hydrurga leptonyx) and Weddell (Leptonychotes weddellii) seals. Given the worldwide ubiquity of this type of contaminant, including the Southern Ocean, we hypothesized that the three seal species would present anthropogenic debris in their feces. We examined 29 scat samples of crabeater (n = 5), leopard (n = 13) and Weddell (n = 11) seals. The chemical composition of the items found were identified using micro-Raman and micro-FTIR spectroscopies. All the samples of the three species presented anthropic particles (frequency of occurrence - %FO - 100 %). Fibers were the predominant debris, but fragments and filaments were also present. Particles smaller than 5 mm (micro debris) were predominant in all the samples. Leopard seals ingested significantly larger micro-debris in comparison with the other seal species. The dominant color was black followed by blue and white. Micro-Raman and micro-FTIR Spectroscopies revealed the presence of different anthropogenic pigments such as reactive blue 238, Indigo 3600 and copper phthalocyanine (blue and green). Carbon black was also detected in the samples, as well as plastic polymers such as polystyrene, polyester and polyethylene terephthalate (PET), polyamide, polypropylene and polyurethane These results confirm the presence of anthropogenic contamination in Antarctic seals and highlight the need for actions to mitigate the effects and reduce the contribution of debris in the Antarctic ecosystem.

Microplastics and anthropogenic debris in rainwater from Bahia Blanca, Argentina.

Concern about atmospheric microplastic (MP) contamination has increased in recent years. This study assessed the abundance of airborne anthropogenic particles, including MPs, deposited in rainfall in Bahia Blanca, southwest Buenos Aires, Argentina. Rainwater samples were collected monthly from March to December 2021 using an active wet-only collector consisting of a glass funnel and a PVC pipe that is only open during rain events. Results obtained show that all rain samples contained anthropogenic debris. The term "anthropogenic debris" is used to refer to the total number of particles as not all the particles found could be determined as plastic. Among all the samples, an average deposition of 77 ± 29 items (anthropogenic debris) m-2d-1 was found. The highest deposition was observed in November (148 items m-2d-1) while the lowest was found in March (46 items m-2d-1). Anthropogenic debris ranged in size from 0.1 mm to 3.87 mm with the most abundant particles being smaller than 1 mm (77.8%). The dominant form of particles found were fibers (95%), followed by fragments (3.1%). Blue color predominated (37.2%) in the total number of samples, followed by light blue (23.3%) and black (21.7%). Further, small particles (<2 mm), apparently composed of mineral material and plastic fibers, were recognized. The chemical composition of suspected MPs was examined by Raman microscopy. The analysis of µ-Raman spectra confirmed the presence of polystyrene, polyethylene terephthalate, and polyethylene vinyl acetate fibers and provided evidence of fibers containing industrial additives such as indigo dye. This is the first assessment of MP pollution in rain in Argentina.

First assessment of debris pollution in the gastrointestinal content of juvenile Magellanic penguins (Spheniscus magellanicus) stranded on the west south Atlantic coasts.

This paper provides the first evidence of debris pollution, including plastic, in juvenile Magellanic penguins (Spheniscus magellanicus) found stranded on the Atlantic coast of southern Buenos Aires Province, Argentina. Macro-, meso- and microparticles of anthropogenic origin were observed in 100 % of the studied birds, with debris abundance ranging between 33 and 200 items/bird. Microparticles represented 91 % of the total debris and 97 % of them were fibers. Black particles were the most abundant (30 %), followed by transparent (26 %), blue (14 %), yellow (10.3 %), and red (10 %). Infrared and Raman spectroscopy identified 62.7 % of the total particles as plastics, with polypropylene (27.8 %) and polyester (21.6 %) being the most abundant polymers. Semi-synthetic cellulosic fibers, metallic particles, and pigments were also found. The presence of metallic microparticles was suggested for the first time in penguins. Stranded juvenile Magellanic penguins are proposed as promising bioindicators of plastic pollution in the South Atlantic.

Beached microplastics at the Bahia Blanca Estuary (Argentina): Plastic pellets as potential vectors of environmental pollution by POPs.

Microplastics (MPs) from the coastal areas of a highly anthropised estuary were sampled to assess their distribution in coastal sediments and their role as potential vectors of pollution. The average MP density was 1693 ± 2315 MPs/kg, which mainly accumulated in the high tide and storm berm areas of the beach. The Microplastic Pollution Index (MPPI), Microplastic Impact Coefficient (CMPI), Hierarchical Cluster Analysis and Principal Component Analysis revealed spatial variation in MPs pollution. High-density polyethylene plastic pellets were abundant at two beaches (192 ± 218 MPs/kg sediment). Furthermore, the presence of sorbed chemicals on pellets was assessed through GC-MS, showing 0.95 ± 0.09 ng/g of ∑7OCPs, 4.03 ± 0.89 ng/g of ∑7PCBs, 108.76 ± 12.88 ng/g of ∑16 PAHs and 122.79 ± 11.13 g/g of ∑29 PAHs. The sorption capacity of plastics, combined with their abundance, poses an environmental concern and also highlights their suitability as indicators of chemical exposure.

Stamplike flexible SERS substrate for in-situ rapid detection of thiram residues in fruits and vegetables.

A simple and sensitive Surface-Enhanced Raman Spectroscopy (SERS) method for the detection of thiram residues in fruit and vegetable peels is reported. A flexible SERS substrate based on silver nanoparticles in an agar gel has been developed and characterised. Peels of different fruits and vegetables were intentionally contaminated with different amounts of thiram. The analyte was then extracted within few seconds by gentle rubbing the surface with the agar substrate using it as a stamp. The optimum experimental conditions of the developed method were explored. The limit of detection of thiram in the peels of tomato and green pepper was 140 pg/cm2. The values achieved for apple was 2 pg/cm2. The method presented could be extensively used for the detection of traces of other contaminants on food surfaces and for other relevant applications.

Color Source for the First Argentinian Flags.

In this work, a historical controversy of more than 200 years is settled by the study of the oldest preserved Argentinian flag. The results of the present work reinforce the hypothesis of a number of historians who consider it to be the first flag that was originally hoisted on February 27, 1812, on the banks of the Paraná River. The work consists of a study of the original textile. Through chemical analysis and implementation of different types of analyses, techniques, and spectroscopies such as UV-vis, UV-vis diffuse reflectance spectroscopy, attenuated total reflectance Fourier transform infrared spectroscopy, scanning electron microscopy-energy-dispersive X-ray spectroscopy, and resonance Raman, the original characteristics of the flag of Macha were determined. The flag was colored with indigotin from Europe (from Isatis tinctoria) and made of silk; it is white, blue, and white in a horizontal arrangement. It was not treated with tin, and its blue color was subsequently adopted by the Central American Confederation and later by various states of Central America. According to related contemporaneous stories, its preservation was due to the watchfulness of the patriots.

Photodegradation of methyl thioglycolate particles as a proxy for organosulphur containing droplets.

Understanding the formation and transformation of sulphur-rich particles is of prime importance since they contribute to the global atmospheric sulphur budget. In this work, we performed a series of experiments on a photoactive organosulphur compound namely, methyl thioglycolate, as a model of an organosulphur species of marine origin. By investigating the photoproducts within levitated droplets, we showed that elemental sulphur (α-S8) and sulphate (SO42-) can be photochemically generated at the gas-liquid interface by heterogeneous interaction with gaseous O2 and H2O. These results demonstrate that the surface of levitated droplets facilitate the oxidation of methyl thioglycolate in the dark, while illumination is necessary to produce the oxidation in bulk experiments.

Structural Analysis of Perfluoropropanoyl Fluoride in the Gas, Liquid, and Solid Phases.

The coexistence of two conformers in perfluoropropanoyl fluoride, CF3CF2C(O)F, differing in the CC-CF dihedral angle (gauche 85(10)% and anti 15(10)%), has been determined by means of gas-phase electron diffraction (GED). Quantum-chemical calculations performed at the MP2 and B3LYP approximations and cc-pVTZ basis sets reproduce the experimental values with confidence. By contrast, FTIR spectra give no clear evidence for the anti-conformer in the gas phase. Information on this less abundant but stable rotamer is obtained from matrix-isolation/FTIR spectroscopy and liquid Raman spectroscopy. In situ crystallization and single-crystal X-ray diffraction (XRD) data reveal the presence of solely the gauche-conformation in the solid state. A set of intermolecular interactions including C═O···C═O, C-F···F-C, and F···C═O is detected. The nature of bonding and the relative stabilities of gauche- and anti-conformers are explored using natural bond orbitals.

Two-photon absorption properties and (1)O2 generation ability of Ir complexes: an unexpected large cross section of [Ir(CO)2Cl(4-(para-di-n-butylaminostyryl)pyridine)].

The new complexes cis-[Ir(CO)2Cl(4-(para-di-n-butylaminostyryl)pyridine)] () and [Ir(cyclometallated-2-phenylpyridine)2(4,4'-(para-di-n-butylaminostyryl)-2,2'-bipyridine)][PF6] () were synthesized and fully characterized along with the known complex Ir(cyclometallated-2-phenylpyridine)2(5-Me-1,10-phenanthroline)][PF6] (). Remarkably, complex , with an Ir(i) centre, displays fluorescence - as opposed to the phosphorescence typical of many Ir(iii) complexes - with a modestly high quantum yield in solution, opening a new route for the design of iridium-based emitters which should not be limited to the +3 oxidation state. It is also characterized by an unexpectedly large two-photon absorption (TPA) cross section, an order of magnitude higher than that previously reported for Ir(iii) or Pt(ii) complexes. The great potential of cyclometallated Ir(iii) complexes for photodynamic therapy was confirmed, with and showing a good singlet oxygen generation ability, coupled with a modest TPA activity for .

Experimental and theoretical characterization of molecular complexes formed between OCS and XY molecules (X, Y = F, Cl and Br) and their role in photochemical matrix reactions.

Molecular complexes between OCS and ClF, Cl(2), Br(2), or BrCl have for the first time been isolated in solid matrixes at low temperature, and characterized by their IR spectra. 1 : 1 adducts between OCS and ClF, Cl(2), or BrCl were formed by broad-band UV-visible photolysis of matrix-isolated FC(O)SCl, ClC(O)SCl or BrC(O)SCl, respectively. Co-deposition of gaseous mixtures of OCS and ClF or Br(2) diluted with Ar on a CsI window cooled to approximately 15 K led to the identification of 1 : 1 complexes, while similar mixtures of OCS and Cl(2) gave rise mainly to 1 : 2 species. The differences in the structures and stoichiometries of the molecular complexes may well be responsible for the different reaction channels observed for the photochemical matrix reactions between OCS and Cl(2) or Br(2). The structures, energy differences, vibrational spectra, and bonding properties of all the possible complexes formed between OCS and XY (XY = ClF, Cl(2), Br(2), or BrCl) have been studied with different theoretical approximations.

Early barriers in the matrix photochemical formation of syn-anti randomized FC(O)SeF from the OCSe:F(2) complex.

The photochemically induced reaction of OCSe and F(2), isolated together in an Ar matrix at about 15 K, leads to formation of the hitherto-unknown fluorocarbonylselenyl fluoride FC(O)SeF. The reaction occurs via a van der Waals complex O=C=Se...F-F that favors very early formation of the anti conformer. The presence and subsequent decay of a band assigned to the F-F vibration correlated with perturbed OCSe bands seems to confirm this hypothesis. Subsequent irradiation of the matrix leads to randomized FC(O)SeF by a photochemically induced conformational equilibrium between syn and anti forms. Another photochemical reaction channel is the formation of CO and SeF(2) molecules, which are produced in the same matrix cage and then form a loose complex. The changes were monitored and the products characterized experimentally by their IR spectra, and the spectra analyzed in the light of the results of theoretical calculations.

Matrix-isolated van der Waals complexes formed between CS2 and dihalogen molecules XY, Where XY = Cl2, Br2, BrCl, ICl, or IBr.

Weakly bound 1:1 complexes formed between CS2 and a dihalogen molecule XY = Cl2, Br2, BrCl, ICl, or IBr have each been trapped in an Ar matrix and hence investigated experimentally by their IR spectra as well as theoretically by MP2 and density functional calculations. A planar structure, with an intermolecular angle close to 90 degrees , is expected for such a S=C=S...XY molecular complex. Moreover, for each system involving a heteronuclear dihalogen, two possible complexes exist, viz., S=C=S...XY and S=C=S...YX. The calculated structures, vibrational properties, and binding energetics of the complexes are analyzed, and the NBO formalism is used to interpret their bonding properties. The IR spectra of the complexes thus simulated provided vital guidance for the interpretation of the matrix spectra. For example, complexation was predicted and observed (i) to induce red shifts of the principal absorptions associated with both the CS2 and XY components and (ii) to result, through the change in symmetry, in activation of some modes that are IR-silent for the free components.