Impact of the 2021 La Palma volcanic eruption on air quality: Insights from a multidisciplinary approach.

The La Palma 2021 volcanic eruption was the first subaerial eruption in a 50-year period in the Canary Islands (Spain), emitting ~1.8 Tg of sulphur dioxide (SO2) into the troposphere over nearly 3 months (19 September-13 December 2021), exceeding the total anthropogenic SO2 emitted from the 27 European Union countries in 2019. We conducted a comprehensive evaluation of the impact of the 2021 volcanic eruption on air quality (SO2, PM10 and PM2.5 concentrations) utilising a multidisciplinary approach, combining ground and satellite-based measurements with height-resolved aerosol and meteorological information. High concentrations of SO2, PM10 and PM2.5 were observed in La Palma (hourly mean SO2 up to ~2600 µg m-3 and also sporadically at ~140 km distance on the island of Tenerife (> 7700 µg m-3) in the free troposphere. PM10 and PM2.5 daily mean concentrations in La Palma peaked at ~380 and 60 µg m-3. Volcanic aerosols and desert dust both impacted the lower troposphere in a similar height range (~ 0-6 km) during the eruption, providing a unique opportunity to study the combined effect of both natural phenomena. The impact of the 2021 volcanic eruption on SO2 and PM concentrations was strongly influenced by the magnitude of the volcanic emissions, the injection height, the vertical stratification of the atmosphere and its seasonal dynamics. Mean daily SO2 concentrations increased during the eruption, from 38 µg m-3 (Phase I) to 92 µg m-3 (Phase II), showing an opposite temporal trend to mean daily SO2 emissions, which decreased from 34 kt (Phase I) to 7 kt (Phase II). The results of this study are relevant for emergency preparedness in all international areas at risk of volcanic eruptions; a multidisciplinary approach is key to understand the processes by which volcanic eruptions affect air quality and to mitigate and minimise impacts on the population.

Impact of Saharan dust exposure on airway inflammation in patients with ischemic heart disease.

Epidemiological studies found that increases in the concentrations of airborne particulate matter (PM) smaller than 10 microns diameter (PM10) in the ambient air due to desert dust outbreaks contribute to global burden of diseases, primarily as a result of increased risk of cardiovascular morbidity and mortality. No studies have investigated the possible association between desert dust inhalation and airway inflammation in patients with ischemic heart disease (IHD). Induced sputum was collected in 38 patients and analyzed to determine markers of airway inflammation (Transforming Growth Factor-ß1 [TGF-ß1] and hydroxyproline) concentrations. For the purpose of the investigation, PM10 and reactive gases concentrations measured in the European Air Quality Network implemented in the Canary Islands were also used. We identified Saharan desert dust using meteorology and dust models. Patients affected by smoking, chronic obstructive pulmonary disease (COPD), asthma, pulmonary abnormalities, acute bronchial or pulmonary disease were excluded. The median of age of patients was 64.71 years (56.35-71.54) and 14 (38.84%) of them were women. TGF-ß1 and hydroxyproline in sputum were highly associated to PM10 inhalation from the Saharan desert. According to a regression model, an increase of 1 µg/m3 of PM10 concentrations due to desert dust, results in an increase of 3.84 pg/gwt of TGF-ß1 (R2 adjusted = 89.69%) and of 0.80 µg/gwt of hydroxyproline (R2 adjusted = 85.28%) in the sputum of patients. The results of this study indicate that the exposure to high PM10 concentrations due to Saharan dust events are associated with intense inflammatory reaction in the airway mucosae of IHD-patients.

Monitoring of meso and microplastic debris in Playa Grande beach (Tenerife, Canary Islands, Spain) during a moon cycle.

The occurrence and composition of meso (5-25 mm) and microplastics (1-5 mm) in Playa Grande beach (Tenerife, Canary Islands, Spain) was monitored during a complete moon cycle on the different moon phases between 17th June and 16thJuly 2019. A total of 10 points were sampled each day finding an average content of mesoplastics of 18 g/m2 (0.36 g/L) and of microplastics of 13 g/m2 (1277 items/m2 or 1.6 g/L). Polypropylene and polyethylene accounted for 19% and 76% of the total, respectively. Tar was also found in the 1-5 mm fraction (2% of the total). Among the particles found, 83% were fragments, 11% pellets, 4% fibres and 2% films. The obtained results revealed that microplastic presence could not be related in this case with the tides but with the orientation and strength/speed of the wind.

Microplastic debris in beaches of Tenerife (Canary Islands, Spain).

The occurrence and composition of microplastics (1-5 mm) was evaluated in six beaches of the island of Tenerife (Canary Islands, Spain). Two of them were located at the North coast (El Socorro and San Marcos) and the rest in the South littoral (Leocadio Machado, El Porís, Los Abriguitos and Playa Grande). Sampling was developed during the months of October, November and December 2018 (depending on the beach) above the high tide line. Isolated microplastics were identified by attenuated total reflection infrared spectroscopy. All the beaches showed a relatively low content of microplastics, below 3.5 g/m2, which is also below 0.069 g/L of sand, except for Playa Grande, which showed an average content of 99 g/m2 or 2.0 g/L of sand. Tar pollution (around 18%) was also found in Playa Grande. The major polymers found were polyethylene, polypropylene and polystyrene, accounting for 69%, 18% and 4%, respectively.

Developing qualitative extraction profiles of coffee aromas utilizing polymeric ionic liquid sorbent coatings in headspace solid-phase microextraction gas chromatography-mass spectrometry.

Two solid-phase microextraction (SPME) sorbent coatings based on polymeric ionic liquids (PILs) have been utilized for the analysis of complex coffee aroma samples. The PIL-based SPME coatings examined, namely, poly(1-(4-vinylbenzyl)-3-hexadecylimidazolium bis[(trifluoromethyl)sulfonyl]imide) [poly(VBHDIm(+) NTf(2)(-))], with ~14-µm thickness, and poly(1-vinyl-3-hexylimidazolium chloride) [poly(ViHIm(+)Cl(-))], with ~8-µm thickness, were employed for the headspace determination of up to 49 analytes from four different coffee beans: two French roast coffees of different brands, Sumatra coffee, and decaffeinated Sumatra coffee. The analysis was conducted using gas chromatography coupled to mass spectrometry. For comparative purposes, the commercial polyacrylate (PA, 85-µm film thickness) SPME coating was utilized under the same extraction conditions. The three SPME coatings tested behaved quite differently as a function of the families of compounds extracted. Thus, the poly(VBHDIm(+) NTf(2)(-) ) coating was extremely selective for aldehydes while also exhibiting good extraction efficiencies for acids. The poly-(ViHIm(+) Cl(-)) coating exhibited superior performance for aromatic alcohols, and the PA coating worked better for heterocyclic aromatics. Both PIL-based SPME sorbent coatings demonstrated exceptional selectivity and extraction efficiency when dealing with complex coffee aromas in spite of their small film thicknesses.

Utilization of a benzyl functionalized polymeric ionic liquid for the sensitive determination of polycyclic aromatic hydrocarbons; parabens and alkylphenols in waters using solid-phase microextraction coupled to gas chromatography-flame ionization detection.

The functionalized polymeric ionic liquid poly(1-(4-vinylbenzyl)-3-hexadecylimidazolium bis[(trifluoromethyl)sulfonyl]imide (poly(VBHDIm(+)NTf(2)(-))) has been used as successful coating in solid-phase microextraction (SPME) to determine a group of fourteen endocrine disrupting chemicals (ECDs), including polycyclic aromatic hydrocarbons (PAHs), alkylphenols, and parabens, in several water samples. The performance of the PIL fiber in direct immersion mode SPME followed by gas chromatography (GC) with flame-ionization detection (FID) is characterized with average relative recoveries higher than 96.1% from deionized waters and higher than 76.7% from drinking bottled waters, with precision values (RSD) lower than 13% for deionized waters and lower than 14% for drinking bottled waters (spiked level of 1 ng mL(-1)), when using an extraction time of 60 min with 20 mL of aqueous sample. Detection limits varied between 9 ng L(-1) and 7 ng mL(-1). A group of real water samples, including drinking waters, well waters, and swimming pool waters, have been analyzed under the optimized conditions. A comparison has also been carried out with the commercial SPME coatings: polydimethylsyloxane (PDMS) 30 µm, and polyacrylate (PA) 85 µm. The functionalized PIL fiber (∼12 µm) demonstrated to be superior to both commercial fibers for the overall group of analytes studied, in spite of its lower coating thickness. A normalized sensitivity parameter is proposed as a qualitative tool to compare among fiber materials, being higher for the poly(VBHDIm(+)NTf(2)(-)) coating. Furthermore, the partition coefficients of the studied analytes to the coating materials have been determined. A quantitative comparison among the partition coefficients also demonstrates the superior extraction capability of the functionalized PIL sorbent coating.

Dispersive liquid-liquid microextraction versus single-drop microextraction for the determination of several endocrine-disrupting phenols from seawaters.

Two liquid-phase microextraction procedures: single-drop microextraction (SDME) and dispersive liquid-liquid microextraction (DLLME), have been developed for the determination of several endocrine-disrupting phenols (EDPs) in seawaters, in combination with high-performance liquid chromatography (HPLC) with UV detection. The EDPs studied were bisphenol-A, 4-cumylphenol, 4-tertbutylphenol, 4-octylphenol and 4-n-nonylphenol. The optimized SDME method used 2.5 microL of decanol suspended at the tip of a micro-syringe immersed in 5 mL of seawater sample, and 60 min for the extraction time. The performance of the SDME is characterized for average relative recoveries of 102+/-11%, precision values (RSD)<9.4% (spiked level of 50 ng mL(-1)), and detection limits between 4 and 9 ng mL(-1). The optimized DLLME method used 150 microL of a mixture acetonitrile:decanol (ratio 15.7, v/v), which is quickly added to 5 mL of seawater sample, then subjected to vortex during 4 min and centrifuged at 2000 rpm for another 5 min. The performance of the DLLME is characterized for average relative recoveries of 98.7+/-3.7%, precision values (RSD)<7.2% (spiked level of 20 ng mL(-1)), and detection limits between 0.2 and 1.6 ng mL(-1). The efficiencies of both methods have also been compared with spiked real seawater samples. The DLLME method has shown to be a more efficient approach for the determination of EDPs in seawater matrices, presenting enrichment factors ranging from 123 to 275, average relative recoveries of 110+/-11%, and precision values (RSD)<14%, when using a real seawaters (spiked level of 3.5 ng mL(-1)).

Determination of water pollutants by direct-immersion solid-phase microextraction using polymeric ionic liquid coatings.

The determination of a group of eighteen pollutants in waters, including polycyclic aromatic hydrocarbons and substituted phenols, is conducted in direct-immersion solid-phase microextraction (SPME) using the polymeric ionic liquid (PIL) poly(1-vinyl-3-hexadecylimidazolium) bis[(trifluoromethyl)sulfonyl]imide as a novel coating material. The performance of the PIL fiber coating in the developed IL-SPME-gas chromatography (GC)-mass spectrometry (MS) method is characterized by average relative recoveries of 92.5% for deionized waters and 90.8% for well waters, average precision values (as relative standard deviations, RSD%) of 11% for deionized waters and 12% for well waters, using a spiked level of 5 ng mL(-1). The detection limits oscillate from 0.005 ng mL(-1) for fluoranthene to 4.4 ng mL(-1) for 4-chloro-3-methylphenol, when using an extraction time of 60 min with 20 mL of aqueous sample. The extraction capabilities of the PIL fiber have been compared with the commercial SPME coatings: polydimethylsyloxane (PDMS) 30 microm, PDMS 100 microm and polyacrylate (PA) 85 microm. The PIL fiber is superior to the PDMS 30 microm for all analytes studied. A qualitative study was also carried out to compare among the nature of the coating materials by normalizing the coating thickness. The PIL material was shown to be more efficient than the PDMS material for all analytes studied. The PIL coating was also adequate for nonpolar analytes whereas the PA material was more sensitive for polar compounds.

Micelle-mediated extractions using nonionic surfactant mixtures and HPLC-UV to determine endocrine-disrupting phenols in seawaters.

An environmentally friendly method to extract endocrine-disrupting phenols (EDPs) from seawaters was realized using nonionic surfactant mixtures and micelle-mediated extractions. The preconcentration step was achieved directly in the seawater matrix, and was followed by high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection without any clean-up steps to remove the surfactant mixture prior to injection. Various nonionic surfactant mixtures were used, and polyoxyethylene-10-laurylether (POLE) with polyoxyethylene-4-laurylether (Brij 30) was found to be the best to work with. Method optimization involved maximizing the preconcentration factor using the studied mixtures. The proposed method gave extraction recoveries ranging from 83.3 to 114.4% for an EDP spiking level of 46.7 microg L(-1), and from 63.4 to 112.4% for a spiking level of 4.7 microg L(-1) for EDPs studied in real seawater matrices, with relative standard deviations of <12.1%. The detection limits of the method varied from 0.18 microg L(-1) for bisphenol A (BPA) to 1.17 microg L(-1) for 4-cumylphenol (4-CP). The method was applied to seawaters from the Canary Islands with successful results.