Multi-class organic pollutants in atmospheric particulate matter (PM2.5) from a Southwestern Europe industrial area: Levels, sources and human health risk.

The occurrence of 50 multi-class pollutants comprising 18 polycyclic aromatic hydrocarbons (PAHs), 12 phthalate esters (PAEs), 12 organophosphorus flame retardants (OPFRs), 6 synthetic musk compounds (SMCs) and 2 bisphenols was studied in atmospheric particulate matter (PM2.5) samples collected at an industrial area focused on automotive manufacturing located at the Southwestern Atlantic European region (Vigo city, Spain) during 1-year period. Among all quantitated pollutants in PM2.5 samples, bisphenol A (BPA) was the most predominant with an average concentration of 6180 pg m-3, followed by PAHs comprising benzo(b+j)fluoranthene (BbF + BjF) and benzo(g,h,i)perylene (BghiP), accounting for 546 pg m-3 and 413 pg m-3 respectively. In addition, two OPFRs concerning tris(chloropropyl) phosphate (TCPP) and triphenyl phosphine oxide (TPPO) were the next following the concentration order, accounting for 411 pg m-3 and 367 pg m-3 respectively; being butyl benzyl phthalate (BBP) the most profuse PAE (56.1 pg m-3 by average). High relative standard deviations (RSDs) were observed during the whole sampling period, while statistically significant differences were only observed for PAHs concentrations during cold and warm seasons. Furthermore, some water-soluble ions and metal(oid)s were analysed in PM2.5 samples to be used as PM source tracers, whose concentrations were quite below the target levels set in the current legislation. Data obtained from principal component analysis (PCA) and PAHs molecular indices suggested a pyrogenic and petrogenic origin for PAHs, whereas occurrence of the remaining compounds seems to be attributed to resources used in the automotive industrial activity settled in the sampling area. Moreover, although a substantial anthropogenic source to PM2.5 in the area was observed, marine and soil resuspension contributions were also accounted. Finally, carcinogenic and non-carcinogenic risks posed by PM2.5-bound pollutants inhalation were assessed, being both averages within the safe level considering the whole period.

Micro and Nano-Plastics in the Environment: Research Priorities for the Near Future.

Plastic litter dispersed in the different environmental compartments represents one of the most concerning problems associated with human activities. Specifically, plastic particles in the micro and nano size scale are ubiquitous and represent a threat to human health and the environment. In the last few decades, a huge amount of research has been devoted to evaluate several aspects of micro/nano-plastic contamination: origin and emissions, presence in different compartments, environmental fate, effects on human health and the environment, transfer in the food web and the role of associated chemicals and microorganisms. Nevertheless, despite the bulk of information produced, several knowledge gaps still exist. The objective of this paper is to highlight the most important of these knowledge gaps and to provide suggestions for the main research needs required to describe and understand the most controversial points to better orient the research efforts for the near future. Some of the major issues that need further efforts to improve our knowledge on the exposure, effects and risk of micro/nano-plastics are: harmonization of sampling procedures; development of more accurate, less expensive and less time-consuming analytical methods; assessment of degradation patterns and environmental fate of fragments; evaluating the capabilities for bioaccumulation and transfer to the food web; and evaluating the fate and the impact of chemicals and microorganisms associated with micro/nano-plastics. The major gaps in all sectors of our knowledge, from exposure to potentially harmful effects, refer to small size microplastics and, particularly, to the occurrence, fate and effects of nanoplastics.

A Simple Method for the Determination of Triazines from Seawater in Accordance with the Directive 2013/39/EU.

Since the Directive 2013/39/EU included terbutryn to the list of priority substances of all water bodies, a previous method based on dispersive liquid-liquid micro-extraction (DLLME) for the determination of triazines in seawater has been modified. The main change consisted on the use of tandem mass spectrometry instead of diode array as detection technique. Due to the higher sensitivity of mass detector, sample volume was reduced and extraction solvent volume was optimized. The optimum extraction conditions were 5 mL of sample, 50 µL of 1-octanol and an agitation step instead of disperser solvent. The obtained analytical recoveries (73%-101% with relative standard deviations below 4%) meeting the requirements. The limits of quantification (between 0.016 and 0.021 µg L-1) were more than 10 times lower than the limit set by the European Directive 2013/39/EU for terbutryn (0.34 µg L-1). The proposed method was applied to the determination of the target compounds in seawater samples from A Coruña (Galicia, NW of Spain).

Validation of the analytical methodology used in obtaining the oral bioavailability of organic target pollutants in atmospheric particulate matter (PM10) applying an in-vitro method.

In recent years, scientists have started evaluating the portion of PM-bound pollutants that may be liberated (bioaccessible fraction) in human fluids and spread through the digestive system ultimately entering systemic circulation (known as the bioavailable fraction). In the current research, an analytical procedure was validated and applied to characterize the oral bioavailable fraction of PM10 samples. The approach encompassed the determination of 49 organic contaminants. The proposed method aims to biomimetic complete mouth-gastric-intestinal system basing on an adaptation of the unified bioaccessibility method (UBM) modified by the inclusion of a dialysis membrane to mimic intestinal absorption and obtain the orally bioavailable fractions. It was followed by a vortex-assisted liquid-liquid extraction (VALLE) step, using gas chromatography-tandem mass spectrometry (GC-MS/MS). Analytical procedure was effectively validated by employing selected reaction monitoring (SRM) mode in MS/MS, matrix-matched calibration, and deuterium-labelled surrogate standards. This approach ensured heightened sensitivity, minimized matrix effects, and compensated for any losses during the process. The validation process covered various aspects, including studying linearity, determining detection and quantification limits, assessing analytical recoveries at three concentration levels, and evaluating precision both within a single day and across multiple days. The validated method was applied to PM10 samples, revealing that polycyclic aromatic hydrocarbons (PAHs) were the most frequently detected, with significant seasonal variations in their concentrations. Organophosphorus flame retardants (OPFRs) like TCPP were also detected in bioavailable fractions, highlighting their potential health impact. Bisphenols, SMCs, and PAEs were not detected, suggesting low levels in the studied urban area. Further research is needed to understand the bioavailability of PM-bound pollutants in different environments.

Comparison of microplastic type, size, and composition in atmospheric and foliage samples in an urban scenario.

The rising trend of plastic production in last years and the inadequate disposal of related waste has raised concerns regarding microplastic-related environmental issues. Microplastic particles disperse by means of transport and deposition processes to different ecosystems and enter food chains. In this paper, atmospheric deposition and foliage samples of two species (i.e., Hedera helix and Photinia glabra) were collected and analysed for the quantity and identity of microplastics (MPs). A preliminary methodology to treat foliage samples and subsequently identify MPs using a quantum cascade laser IR spectrophotometer is presented. The treatment of airborne samples involved filtration, mild digestion, concentration, and transfer onto reflective slides whereas that for foliage involved washing, concentration, and transference of putative MPs onto reflective slides. Fibers and fragments were differentiated according to their physical features (size, width, height, etc.) and calculating derived characteristics (namely, circularity and solidity). The preliminary results obtained suggest a good agreement between atmospheric-deposited and foliage-retained MPs, showing the capability of leaves to act as passive samplers for environmental monitoring.

A green approach for the automatic quantitative analysis of additives in plastic samples using in-tube extraction dynamic headspace sampling technique coupled to GC-MS/MS.

BACKGROUND: Many of the chemicals frequently used as additives have been recognised as hazardous substances, and therefore their analysis is necessary to evaluate plastic contamination risk. Additives analysis in plastic samples is usually performed by methods involving high volumes of toxic solvents or having high detection limits. In this work, a novel, fast, solventless and reliable green method was developed for the automated analysis of plastic additives from plastic samples. The proposed method consists of in-tube extraction dynamic headspace sampling (ITEX-DHS) combined with gas chromatography (GC) and mass spectrometry (MS/MS) determination. RESULTS: Several parameters affecting the ITEX-DHS extraction of 47 additives in plastic samples (including phthalates, bisphenols, adipates, citrates, benzophenones, organophosphorus compounds, among others) were optimised. The use of matrix-matched calibration, together with labelled surrogate standards, minimises matrix effects, resulting in recoveries between 70 and 128%, with good quantitation limits (below 0.1 µg g-1 for most compounds) and precision (<20%). The method proposed can be applied to any type of polymer, but due to the existence of the matrix effect, calibrates with the adequate matrix should be performed for each polymer. SIGNIFICANCE: This method represents an effective improvement compared to previous methods because it is fast, solvent-free, fully automated, and provides reliable quantification of additives in plastic samples.

Development of a dispersive liquid-liquid microextraction method for the determination of plastic additives in seawater.

A method using dispersive liquid-liquid microextraction (DLLME) prior to high performance liquid chromatography-diode array detection (HPLC-DAD) was developed to determine seven additives from the plastics industry (butylated hydroxytoluene, diisodecyl phthalate, irgafos 168, lawsone, quercetin, triclosan and vitamin E) in seawater samples. These compounds can reach seawater due to direct discharge from wastewater treatment plants and leaching from plastics and microplastics. The extraction was performed using 25 mL of seawater, 500 µL of 1-octanol (extraction solvent) and a stirring step instead of dispersive solvent. Additive concentrations were determined by LC-DAD on a C18 column with a mobile phase of acetonitrile and phosphoric acid aqueous solution (pH 3.5) by gradient elution. The analytical recoveries ranged from 82 to 93% for all compounds, except for lawsone (60%). Repeatability and intermediate precision were adequate with RSD < calculated values following the Horwitz equation at the concentration levels evaluated (0.06 and 0.24 mg L-1). All additives exhibited linear matrix calibration curves (R2 > 0.99). Detection limits ranged from 0.009 to 0.028 mg L-1 and quantification limits ranged from 0.027 to 0.084 mg L-1. Finally, the application of the method to real samples verified the method as accurate and applicable to seawater.

A reliable method to determine airborne microplastics using quantum cascade laser infrared spectrometry.

The number of studies dealing with airborne microplastics (MPs) is increasing but sampling and sample treatment are not standardized, yet. Here, a fast and reliable method to characterize MPs is presented. It involves the study of two passive sampling devices to collect atmospheric bulk deposition (wet and dry deposition) and three digestion methods (two alkaline-oxidative and an oxidative) to treat the samples. The alkaline-oxidative method based on KOH and NaClO was selected for a mild organic matrix digestion. In addition, some operational parameters of a high-throughput quantum cascade laser-based infrared device (LDIR) were optimized: an effective automatic tiered approach to differentiate fibres from particles (>90 % success in validation) and a criterion to establish positive matches when comparing an unknown spectrum against the spectral database (proposed match index > 0.85). The procedural analytical recoveries were very good for particles (82-90 %) and slightly lower for fibres (62-73 %). Finally, the amount and type of MPs deposited at a sub-urban area NW Spain were evaluated. Most common polymers were Polyethylene (PE), Polypropylene (PP) and Polyethylene terephthalate (PET). The deposition rates ranged 98-1220 MP/m2/day, ca. 1.7 % of the total collected particles. More than 50 % of the total MPs deposited were in the 20-50 µm size range, whereas fibres were mostly in the 50-500 µm size range.

Oxidative potential of the inhalation bioaccessible fraction of PM10 and bioaccessible concentrations of polycyclic aromatic hydrocarbons and metal(oid)s in PM10.

Atmospheric particulate matter (PM) has been related to numerous adverse health effects in humans. Nowadays, it is believed that one of the possible mechanisms of toxicity could be the oxidative stress, which involves the development of reactive oxygen species (ROS). Different assays have been proposed to characterize oxidative stress, such as dithiothreitol (DTT) and ascorbic acid (AA) acellular assays (OPDTT and OPAA), as a metric more relevant than PM mass measurement for PM toxicity. This study evaluates the OP of the bioaccessible fraction of 65 PM10 samples collected at an Atlantic Coastal European urban site using DTT and AA assays. A physiologically based extraction (PBET) using Gamble's solution (GS) as a simulated lung fluid (SLF) was used for the assessment of the bioaccessible fraction of PM10. The use of the bioaccessible fraction, instead of the fraction assessed using conventional phosphate buffer and ultrasounds assisted extraction (UAE), was compared for OP assessment. Correlations between OPDTT and OPAA, as well as total and bioaccessible concentrations of polycyclic aromatic hydrocarbons (PAHs) and metal(oid)s, were investigated to explore the association between those compounds and OP. A correlation was found between both OP (OPDTT and OPAA) and total and bioaccessible concentrations of PAHs and several metal(oid)s such as As, Bi, Cd, Cu, Ni, and V. Additionally, OPDTT was found to be related to the level of K+.

Predicted concentrations of antineoplastic drugs in the aquatic environment: The case of Ría de Vigo (NW, Spain).

The European Medicines Agency (EMA) mandates Environmental Risk Assessments (ERAs) since 2006 to determine potential risks of new marketed medicines. Drugs with a Predicted Environmental Concentration (PEC) in inland surface waters exceeding 0.01 µg L-1 require further environmental risk assessment. PEC may be refined based on prevalence data and/or based on the treatment regimen. In this study, based on EMA regulations, refined PEC of 108 antineoplastic drugs in coastal waters were determined based on the consumption in a coastal health area during 2021, identifying six drugs with potential environmental risk in surface waters (hydroxyurea, capecitabine, abiraterone, ibrutinib, imatinib and 5-fluorouracil) and two in marine ecosystem (hydroxyurea and capecitabine). Comparison of these refined PECs with data from marketing laboratories revealed significant disparities, suggesting the need for regular updates, especially with changes in drug indications or financing. Notably, the identified drugs are not yet on the main reference lists of emerging contaminants.

Bioaccumulation of trace metals in the plastisphere: Awareness of environmental risk from a European perspective.

The term "Plastisphere" refers to the biofilm layer naturally formed by microorganisms attaching to plastic surfaces. This layer possesses the capability to adsorb persistent organic and inorganic pollutants, particularly trace metals, which are the focus of this research study. Immersion experiments were concurrently conducted in five locations spanning four European countries (France, Ireland, Spain, and Italy) utilising eight distinct polymers. These immersions, repeated every three months over a one-year period, aimed to evaluate the baseline bioaccumulation of 12 trace metals. The study underscores the intricate nature of metal bioaccumulation, influenced by both micro-scale factors (such as polymer composition) and macro-scale factors (including geographical site and seasonal variations). Villefranche Bay in France exhibited the lowest metals bioaccumulation, whereas Naples in Italy emerged as the site where bioaccumulation was often the highest for the considered metals. Environmental risk assessment was also conducted in the study. The lightweight nature of certain plastics allows them to be transported across significant distances in the ocean. Consequently, evaluating trace metal concentrations in the plastisphere is imperative for assessing potential environmental repercussions that plastics, along with their associated biota, may exert even in locations distant from their point of emission.

Determination of chlorobenzenes in water samples based on fully automated microextraction by packed sorbent coupled with programmed temperature vaporization-gas chromatography-mass spectrometry.

A fully automated method consisting of microextraction by packed sorbent (MEPS) coupled directly to programmed temperature vaporizer-gas chromatography-mass spectrometry (PTV-GC-MS) has been developed to determine the 12 chlorobenzene congeners (chlorobenzene; 1,2-, 1,3-, and 1,4-dichlorobenzene; 1,2,3-, 1,2,4-, and 1,3,5-trichlorobenzene; 1,2,3,4-, 1,2,3,5-, and 1,2,4,5-tetrachlorobenzene; pentachlorobenzene; and hexachlorobenzene) in water samples. The effects of the variables on MEPS extraction, using a C18 sorbent, and the instrumental PTV conditions were studied. The internal standard 1,4-dichlorobenzene d4 was used as a surrogate. The proposed method afforded good reproducibility, with relative standard deviations (RSD %) lower than 12%. The limits of detection varied between 0.0003 µg L(-1) for 1,2,3,4-tetrachlorobenzene and 0.07 µg L(-1) for 1,3- and 1,4-dichlorobenzene, while those of quantification varied between 0.001 µg L(-1) and 0.2 µg L(-1) for the same compounds. Accuracy of the proposed method was confirmed by applying it to the determination of chlorobenzenes in different spiked water samples, including river, reservoir, and effluent wastewater.

Application of a developed method for the extraction of triazines in surface waters and storage prior to analysis to seawaters of Galicia (northwest Spain).

A simple method based on solid-phase extraction combined with liquid chromatography for simultaneous determination of nine triazine herbicides (ametryn, atrazine, cyanazine, prometryn, propazine, simazine, simetryn, terbuthylazine, and terbutryn) in surface water samples was developed and validated. Under optimized conditions, 50 mL of water sample was pumped through the Oasis HLB cartridge, and triazines were eluted with 3 mL acetone. Finally the extract was concentrated to dryness, reconstituted with 1 mL methanol : water (1 : 1) and injected into the HPLC-DAD system. The stability of the herbicides on the cartridges at -18 and 4°C was also evaluated, and the recoveries obtained after three weeks of storage were satisfactory for all compounds. The analytical features of the proposed method were satisfactory: repeatability and intermediate precision were <10% and recoveries in spiked river water and seawater samples were higher than 93% for all compounds studied. Limits of quantification (varied from 0.46 to 0.98 µg L⁻¹) were adequately allowing the determination of these compounds at the levels requested by the 2008/105/EC Directive. Finally, this method was applied to the analysis of 50 seawater samples from Galicia (northwest Spain).

Mixed-mode chromatography of mixed functionalized analytes as the homologues of benzalkonium chloride. Application to pharmaceutical formulations.

In this work, a retention behavior based on mixed-mode reversed-phase (RP)/hydrophilic interaction liquid chromatography (HILIC) was observed for benzalkonium chloride (BAK) using a core-shell column functionalized with biphenyl groups. Although in the literature, the U-shaped retention was reported for polar compounds in mixed functionalized phases, in the present work, the behavior was dependent upon the chemical structure of the analyte with mixed functionality (ammonium group, a benzyl group and an alkyl chain) and on the high selectivity of the chromatographic column. The bimodal retention was observed for the four BAK homologues using a content of acetonitrile from 65 to 95% in the mobile phase. The data were adjusted to polynomial equations which allow for modeling and predicting the U-shaped retention. The salt concentration (50 and 100 mM), anion (formate and acetate) and cation (ammonium and triethylammonium) of the salt, pH (4 and 5) in the mobile phase were studied in order to understand their influence on the two retention modes. Significant electrostatic interactions were involved in the two retention modes, especially with a content of acetonitrile higher that 90%. Linear relationships between the retention factors of the four homologues were found in a wide range of %acetonitrile when the salt and triethylamine concentration, pH and nature of salt were changed. The differences found on the retention of the homologues, when increasing the alkyl chain length, were more significant in the RP mode due to predominant hydrophobic interactions. A pH decrease and a salt concentration increase caused a retention decrease for both modes. A decrease on of the retention was observed when acetate anion was replaced by formate anion. The different order of the polynomial equations according to the used mobile phase confirmed its relevant role in the interactions with the analytes and stationary phase. A mobile phase was selected (85% acetonitrile, pH 4 and 100 mM ammonium formate) for the BAK determination in cutaneous, otic and ophthalmic formulations with different active pharmaceutical ingredients and excipients. Low sample volume (500 µL) and short analysis time (<5 min) were some of the advantages of the proposed method. In addition, good analytical performance (R2 > 0.999, % RSD <4.5% for intra-day precision and <5.8% for inter-day precision, and recoveries in the 92-105% range) was obtained.

Filtration of biopolymer PHB particles loaded with synthetic musks does not cause significant bioaccumulation in marine mussels.

The role of the biopolymer polyhydroxybutyrate (PHB, <250 µm) as a vehicle of a synthetic musks mixture (celestolide, galaxolide, tonalide, musk xylene, musk moskene and musk ketone) to Mytilus galloprovincialis was investigated. For 30 days, virgin PHB, virgin PHB+musks (6.82 µg g-1) and weathered PHB+musks, were daily spiked into tanks containing mussels, followed by a 10-day depuration period. Water and tissues samples were collected to measure exposure concentrations and accumulation in tissues. Mussels were able to actively filter microplastics in suspension but the concentration of the musks found in tissues (celestolide, galaxolide, tonalide) were markedly lower than the spiked concentration. Estimated Trophic Transfer Factors suggest that PHB will only play a minor role on musks accumulation in marine mussels, even if our results suggest a slightly extended persistence in tissues of musks loaded to weathered PHB.

A multi-residue method for the analysis of organic pollutants released from atmospheric PM2.5 in simulated biological fluids: Inhalation bioaccessibility and bioavailability estimation.

BACKGROUND: In recent decades, there has been a growing interest within the scientific community regarding the study of the fraction that could be released in simulated biological fluids to estimate in vitro bioaccessibility and bioavailability of compounds. Concerning particulate matter (PM), studies were essentially focused on metal (oid)s probably due to more complex methodologies needed for organic compounds, requiring extraction and pre-concentration steps from simulated fluids, followed by chromatographic analysis. Thus, the development of a simple and sensitive methodology for the analysis of multi-class organic compounds released in different inhalation simulated fluids would represent a great contribution to the field. RESULTS: In this work, a methodology for the analysis 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 released in simulated fluids from PM2.5 samples was developed. After a physiologically based extraction test (PBET) by using artificial lysosomal fluid (ALF) and a simulated body fluid (SBF, filling a dialysis membrane) to obtain in vitro inhalation bioaccessible and bioavailable fractions, respectively; compounds were determined by a vortex-assisted liquid-liquid extraction (VALLE) and a subsequent analysis by programmed temperature vaporization-gas chromatography-tandem mass spectrometry (PTV-GC-MS/MS). Experimental conditions concerning VALLE extraction (extraction time and amount of NaCl (g)) were optimized by using a central composite design (CCD), best MS/MS transitions were selected and matrix-matched calibration combined with use of labelled subrogate standards provided high sensitivity, minimization of matrix effects and recovering losses compensation. SIGNIFICANCE: The successful validation results obtained for most of the compounds demonstrated the effectiveness of the proposed methodology for the analysis of multi-class organic pollutants released in ALF and SBF for inhalation bioaccessibility and bioavailability assessment, respectively. Furthermore, applicability of the method was proved by analysing 20 p.m.2.5 samples, being the proposed in vitro PBET dialyzability approach for assessing organic pollutant's inhalation bioavailability applied to PM2.5 samples for the first time.

Organotin compounds in seafood by ultrasonic assisted extraction and gas chromatography-triple quadrupole tandem mass spectrometry.

Although restricting environmental quality values for organotin compounds (OTs) are set by Directive 2013/39/EU of the European Parliament, marine environment remains being affected due to maritime circulation at global scale. Fish and seafood accumulate OTs, making fish and seafood consumption the main source of OTs in humans. Because of the fish and seafood matrices complexity and the required low limits of detection, a robust and fast procedure for the quantification of OTs in fish and seafood, using ultrasound-assisted extraction and gas chromatography-tandem mass spectrometry, was validated and applied. Detection (2.7 µg Sn kg-1) and quantification (8.0 µg Sn kg-1) limits, repeatability and intermediate precision (<10%), accuracy by analysing ERM®-CE477 Mussel Tissue and analytical recoveries (65-122%) were assessed. Multivariate analysis shown that the matrix effect for some OTs displayed good negative correlation with the fat and protein content. Health risk assessment of OTs intake revealed no serious risk for human consumption.

In-vitro inhalation bioavailability estimation of Metal(oid)s in atmospheric particulate matter (PM2.5) using simulated alveolar lysosomal fluid: A dialyzability approach.

A novel in-vitro method, by using synthetic body fluids, human physiological conditions and a simulated air-blood barrier (by using a dialysis membrane) has been developed and applied to assess in-vitro inhalation bioavailability of metal(oid)s associated to particulate matter (PM2,5) samples collected from an industrial site of the Northwest of Spain. A validated analytical methodology based on inductively coupled plasma mass spectrometry (ICP-MS) was used to analyse metal(oid)s concentrations in bioavailable fractions. This approach would be a more realistic human health risk assessment since considering processes that occur in human body in contrast the overestimation derived from current models (which consider environmental concentrations). Metal(oid)s such as Cu and Mo seemed to be the most bioavailable (mean in-vitro bioavailability ratios higher than 70%); Ba, Cd, Mn, Pb, Rb, Sb, Sn, V and Zn shown mean ratios between 20 and 60%, while low in-vitro bioavailability ratios (less than 20%) were observed for metal(oid)s such as Al, Co, Cr, Fe, Ni, Ti, and Tl. Health risk assessment via inhalation based on hazard carcinogenic and non-carcinogenic indexes (HIc and HInc, respectively) were performed considering three exposure scenarios using both inhalation bioavailable and total metal(oid)s concentrations in PM2.5 samples, suggesting no risk to human health. The influence of chemical composition on in-vitro bioavailability ratios was obtained, pointing out that inhalation ratios of Al, Ba, Cr, Cu, Fe, Ni, Pb and V seem to be affected by sea salt and/or crustal and/or biogenic and/or anthropogenic content of PM2.5.

Microplastics in surface water of the Bay of Asunción, Paraguay.

This study identified and quantified microplastics in the Bay of Asunción, Paraguay, and its main tributaries. Surface water samples were sieved in duplicate at six locations using stainless-steel sieves (0.3-4.75 mm range), digested employing the Fenton's reaction (Fe-catalysed H2O2 digestion), and floated using NaCl and NaI. Particles were inspected using a microscope and characterized by IR spectrometry. Microplastics were found in all samples; more abundant (p < 0.05) in water from the bay (13.2 ± 13.4 items·m-3) than from the tributaries (1.0 ± 0.5 items·m-3). Most microplastics were common polymers and their abundance was in the order polypropylene > high-density polyethylene > low-density polyethylene, transparent and white. The results were similar to other regional studies and suggested that their main source was single-use packaging, disposed inadequately due to poor garbage collection.

Source apportionment of PM10 and health risk assessment related in a narrow tropical valley. Study case: Metropolitan area of Aburrá Valley (Colombia).

This study investigates spatio-temporal variations of PM10 mass concentrations and associated metal(oid)s, δ13C carbon isotope ratios, polycyclic aromatic hydrocarbons (PAHs), total organic carbon (TOC) and equivalent black carbon (eBC) concentrations over a half year period (from March 2017 to October 2017) in two residential areas of Medellín (MED-1 and MED-2) and Itagüí municipality (ITA-1 and ITA-2) at a tropical narrow valley (Aburrá Valley, Colombia), where few data are available. A total of 104 samples were analysed by using validated analytical methodologies, providing valuable data for PM10 chemical characterisation. Metal(oid)s concentrations were measured by inductively coupled plasma mass spectrometry (ICP-MS) after acid digestion, and PAHs concentrations were measured by Gas Chromatography-Mass Spectrometry (GC-MS) after Pressurised Hot Water Extraction (PHWE) and Membrane Assisted Solvent Extraction (MASE). Mean PM10 mass concentration ranged from 37.0 µg m-3 to 45.7 µg m-3 in ITA-2 and MED-2 sites, respectively. Al, Ca, Mg and Na (from 6249 ng m-3 for Mg at MED-1 site to 10,506 ng m-3 for Ca at MED-2 site) were the major elements in PM10 samples, whilst As, Be, Bi, Co, Cs, Li, Ni, Sb, Se, Tl and V were found at trace levels (< 5.4 ng m-3). Benzo[g,h,i] perylene (BghiP), benzo[b + j]fluoranthene (BbjF) and indene(1,2,3-c,d)pyrene (IcdP) were the most profuse PAHs in PM10 samples, with average concentrations of 0.82-0.86, 0.60-0.78 and 0.47-0.58 ng m-3, respectively. Results observed in the four sampling sites showed a similar dispersion pattern of pollutants, with temporal fluctuations which seems to be associated to the meteorology of the valley. A PM source apportionment study were carried out by using the positive matrix factorization (PMF) model, pointing to re-suspended dust, combustion processes, quarry activity and secondary aerosols as PM10 sources in the study area. Among them, combustion was the major PM10 contribution (accounting from 32.1 to 32.9% in ITA-1 and ITA-2, respectively), followed by secondary aerosols (accounting for 13.2% and 23.3% ITA-1 and MED-1, respectively). Finally, a moderate carcinogenic risk was observed for PM10-bound PAHs exposure via inhalation, whereas significant carcinogenic risk was estimated for carcinogenic metal(oid)s exposure in the area during the sampling period.