Plastisphere on microplastics: In situ assays in an estuarine environment.

In this study, the influence of the plastisphere on metals accumulation and weathering processes of polystyrene (PSMPs) and nylon microplastics (NyMPs) in polluted waters during a 129 day-assay were studied. MPs were characterized through scanning electron microscopy (SEM) with Energy dispersive X-ray (EDX), X-ray diffraction (XRD), attenuated total reflectance Fourier transformed infrared (ATR-FTIR) spectroscopy, contact angle, and thermogravimetric analysis (TGA). Also Cr, Mn, Zn, Cd, Pb, and Cu in the plastisphere on MPs were analyzed during the assay. Potentially pathogenic Vibrio, Escherichia coli, and Pseudomonas spp. were abundant in both MPs. Ascomycota fungi (Phona s.l., Alternaria sp., Penicillium sp., and Cladosporium sp.), and yeast, were also identified. NyMPs and PSMPs exhibited a decrease in the contact angle and increased their weights. SEM/EDX showed weathering signs, like surface cracks and pits, and leaching TiO2 pigments from NyMPs after 42 days. XRD displayed a notorious decrease in NyMPs crystallinity, which could alter its interaction with external contaminants. Heavy metal accumulation on the plastisphere formed on each type of MPs increased over the exposure time. After 129 days of immersion, metals concentrations in the plastisphere on MPs were in the following order Cr ˃ Mn ˃ Zn ˃ Cu ˃ Pb ˃ Cd, demonstrating how the biofilm facilitates metal mobilization. The results of this study lead to a better understanding of the impact of marine plastic debris as vectors of pathogens and heavy metals in coastal environments.

Tracking synthetic microdebris contamination in a highly urbanized estuary through crabs as sentinel species: An ecological trait-based approach.

Synthetic microdebris (particles of <5 mm) are a worldwide concern because they can affect the community structure of the aquatic ecosystems, organisms, and even food webs. For the biomonitoring of synthetic microdebris (especially microplastics, MPs), mainly benthic invertebrates are used, but crabs have been less studied in the literature. We studied the synthetic microdebris contamination in water, sediments, and three representative intertidal crabs (Neohelice granulata, Cyrtograpsus angulatus and Leptuca uruguayensis) with different lifestyles from the Bahía Blanca estuary, Argentina. The results obtained show the presence of cotton-polyamide (PA), polyethylene (PE), and polyethylene terephthalate (PET) in surface waters. In sediments, we identified cellulose modified (CE), polyester (PES), polyethylene (PE), and alkyd resin, while in crabs, cotton-PA and CE were the predominant ones. The MPs abundance ranged from 8 to 68 items L-1 in surface water, from 971 to 2840 items Kg-1 in sediments, and from 0 to 2.58 items g-1 ww for the three species of crabs. Besides, paint sheets ranged from 0 to 17 in the total samples, with Cr, Mo, Ti, Pb, Cu, Al, S, Ba and Fe on their surface. There were significant differences between the microdebris abundances in the abiotic matrices but not among crabs species. The ecological traits of the different crabs helped to understand the accumulation of synthetic microdebris, an important characteristic when determining the choice of a good biomonitor.

Microplastics in bivalves, water and sediments from a touristic sandy beach of Argentina.

This study assesses for the first time the concentrations of microplastics (MPs) in sediments, water and two human-consumed mussels with different ecological traits (Amarilladesma mactroides and Brachidontes rodriguezii) in a touristic sandy beach of Argentina. MPs were characterized through FTIR and SEM/EDX techniques. All the samples presented MPs with similar concentrations as other human-impacted coastal areas of the world, being black and blue fibers of < 0.5 and 0.5-1 mm the most abundant. SEM images exhibited cracks and fractures with clay minerals and microorganisms adhered to MPs surface. EDX spectrums showed potentially toxic elements, such as Cr, Ti, and Mo. FTIR identified polymers such as cellulose, polyamides, and polyacrylates in most of the samples analyzed. Our study demonstrates that microplastic pollution is a common threat to sandy beaches in Argentina, worsened by plastic particles carrying metal ions with potential toxic effects to the biota, including A. mactroides, an endangered species.

COVID-19 pandemic repercussions on plastic and antiviral polymeric textile causing pollution on beaches and coasts of South America.

The propagation of the COVID-19 pandemic worldwide has been alarming in the last months. According to recommendations of the World Health Organization (WHO), the use of face masks is essential for slowing down the transmission rate of COVID-19 in human beings. This pandemic has generated a substantial increase in the use, as well as in the production, of face masks and other elements (gloves, face protectors, protective suits, safety shoes) manufactured with polymeric materials, including antiviral textiles most of which will end as microplastic pools. Focusing on South America, the use and mismanagement of this type of personal protective equipment (PPE) represents an environmental problem. Added to this issue are the increase in the use of single-use plastic, and the reduction of plastic recycling due to the curfew generated by the pandemic, further aggravating plastic pollution on coasts and beaches. Recently, researchers have developed antiviral polymeric textile technology composed of Ag and Cu nanoparticles for PPE to reduce the contagion and spread of COVID-19. Antiviral polymeric textile wastes could also have long-term negative repercussions on aquatic environments, as they are an important emerging class of contaminants. For this reason, this work provides reflections and perspectives on how the COVID-19 pandemic can aggravate plastic pollution on beaches and coastal environments, consequently increasing the damage to marine species in the coming years. In addition, the potential impact of the pandemic on waste management systems is discussed here, as well as future research directions to improve integrated coastal management strategies.

Evaluación comparativa de dispositivos para pruebas epicutáneas de diagnóstico en Alergia / Comparative evaluation of devices for diagnostic skin testing in Allergy

Antecedentes. Las pruebas epicutáneas pueden realizarse utilizando diferentes técnicas y dispositivos. Objetivos: evaluar lancetas disponibles en Argentina: Diater (por prick test y puntura) y Greer-Pick (por rotación), compararlos con dispositivos internacionales (ALK y Allergy Therapeutics, por prick y puntura) y uno inespecífico (aguja 30G, por prick). Material y métodos Lugar de realización: Rosario, Argentina. Diseño: descriptivo, doble ciego. Población: 22 estudiantes, 50% mujeres, entre 18 y 65 años. Método: un operador realizó pruebas utilizando histamina y fisiológico en antebrazos por duplicado. Otro realizó lectura midiendo diámetros mayor y ortogonal. Otro interrogó grado molestia. Con EPI INFO se calcularon promedio diámetro pápula y DE para control positivo y negativo, índice histamina (IH), tamaño pápula para especificidad 99%, coeficiente variación (CV), sensibilidad y especificidad. Falso negativo si histamina < 3 mm. Falsos positivos (fisiológico) según: a) valor arbitrario, b) pápulas superiores al tamaño especificidad 99%. Resultados. Existieron diferencias en tamaño pápula histamina, fisiológico, IH y variancia entre todos los dispositivos-técnicas. Sensibilidad dispositivos específicos: >88% y menor para aguja. Especificidad de todos: >97%. CV >30% sólo para aguja y ALK prick test. Tamaño pápula para especificidad 99%: diferente para cada dispositivo-técnica, llegando Greer-Pick a 7 mm (único con IH >0,5 y alto grado molestia). Al tomar tamaño para especificidad 99%, sólo 4 pápulas resultaron falsos positivos. Greer-Pick y AT puntura: sin falsos negativos. Más falsos negativos: aguja. Conclusiones. Dispositivos específicos presentaron superior desempeño que aguja. Se deben conocer virtudes y desventajas del dispositivo elegido, incluyendo el valor que otorgue 99% de especificidad.(AU)