Microplastics (<5 mm) are ubiquitous contaminants of growing concern. These have been found in multiple environmental compartments, including remote sites where anthropogenic activity is null. Once ...released, microplastics interact with multiple chemicals in the environment, many of which are classified as organic contaminants or heavy metals. Some contaminants have an affinity for microplastics, attributed to certain sorption mechanisms, and thus become vectors of hazardous chemicals. Here, we focused on the sorption behavior of degradable and non-degradable microplastics, including field and laboratory experiments. We reviewed the sorption mechanisms, namely hydrophobic interactions, electrostatic interactions, pore-filling, Van der Waals forces, hydrogen bonding, and π-π interactions, and the factors strengthening or weakening these mechanisms. Then, we analyzed the literature investigating the sorption behavior of a wide range of chemicals contaminants on microplastics, and the current knowledge regarding the occurrence of organic contaminants and heavy metals on microplastics extracted from the environment. The future perspectives and research priorities were discussed. It is apparent that degradable microplastics, such as polylactic acid or polybutylene succinate, have a greater affinity for hydrophobic contaminants than conventional synthetic non-degradable microplastics according to recent studies. However, studies assessing degradable microplastics are scarce and much research is required to further prove this point. We stated several knowledge gaps in this new line of research and suggest the future studies to follow an integrative approach, allowing to comprehend the multiple factors involved, such as ecotoxicity, bioaccumulation, and fate of the chemical contaminants.
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•Microplastics (MPs) serve as vectors of chemical contaminants.•The sorption capacity of MPs depends on mechanisms and factors.•The sorption capacity of degradable MPs is similar or higher than nondegradable MPs.•Future research must focus on elucidating the full potential of degradable MPs.
In the present contribution, two nationwide surveys of personal protective equipment (PPE) pollution were conducted in Peru and Argentina aiming to provide valuable information regarding the ...abundance and distribution of PPE in coastal sites. Additionally, PPE items were recovered from the environment and analyzed by Fourier transformed infrared (FTIR) spectroscopy, Scanning electron microscopy (SEM) with Energy dispersive X-ray (EDX), and X-ray diffraction (XRD), and compared to brand-new PPE in order to investigate the chemical and structural degradation of PPE in the environment. PPE density (PPE m−2) found in both countries were comparable to previous studies. FTIR analysis revealed multiple polymer types comprising common PPE, mainly polypropylene, polyamide, polyethylene terephthalate, and polyester. SEM micrographs showed clear weathering signs, such as cracks, cavities, and rough surfaces in face masks and gloves. EDX elemental mapping revealed the presence of elemental additives, such as Ca in gloves and face masks and AgNPs as an antimicrobial agent. Other metals found on the surface of PPE were Mo, P, Ti, and Zn. XRD patterns displayed a notorious decrease in the crystallinity of polypropylene face masks, which could alter its interaction with external contaminants and stability. The next steps in this line of research were discussed.
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•Mean PPE density was 6.6 × 10−4 and 7.2 × 10−4 PPE m−2 in Peru and Argentina.•FTIR revealed that PP, PA, PET, and polyester were the main polymer types.•SEM micrographs showed signs of structural degradation in face masks and gloves.•XRD showed decreased crystallinity in PP face masks.•PPE aging could promote MPs and contaminant release into the environment.
Marine litter, such as plastic bags, bottles, fabrics, or fishing gear, serve as a shelter for many marine organisms that are likely to colonize artificial substrata. Such assemblages can potentially ...turn marine litter into vectors of alien invasive species (AIS). Here, we report the abundance and diversity of macroinvertebrates inhabiting marine litter in Peruvian beaches. Results indicate that most of the fouled items found came from land-based sources (81.5%) and Bivalvia was the most abundant class (53.5%), mainly composed of the mussel Semimytilus algosus. No significant differences were found in the abundance and diversity of macroinvertebrates (class level) among sampling sites or sources of litter. Polypropylene and low-density polyethylene items were most frequently found with fouled biota. Although none of the identified species were non-native to the coast of Peru, we discuss marine litter as a potential source of AIS in this region.
•Marine macroinvertebrates were found fouling or inhabiting stranded plastic litter.•None of the organisms found were considered non-native to the Peruvian coast.•Class abundance and diversity did not differ significantly among sites and sources.•Polypropylene and high-density polyethylene were the most frequent items.•Fouling organisms in Peru may become a source of AIS for other regions.
Tuberculosis esofágica: informe de un caso Manrique Martínez, Camilo Andrés; Salinas G, Diana Carolina; Martínez Marín, Julián David ...
Revista colombiana de gastroenterología,
12/2014, Letnik:
29, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Informamos el caso de un hombre inmunocompetente que consultó por cuadro de sangrado digestivo alto secundario a una úlcera esofágica de origen tuberculoso. El compromiso gastrointestinal por el ...Mycobacterium tuberculosis es raro aun en pacientes con altas prevalencias de enfermedad pulmonar y extrapulmonar; los sitios de mayor afectación son íleon terminal y el peritoneo, la enfermedad esofágica es exótica y generalmente es secundaria a la extensión proveniente de órganos vecinos infectados, como ganglios mediastinales y/o bronquios.
La clínica, las imágenes endoscópicas y radiológicas de la enfermedad esofágica suele simular una neoplasia maligna. La quimioterapia antituberculosa es la base del tratamiento, rara vez se requiere manejo quirúrgico.
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