Plastic pollution has emerged in recent decades as one of the most pressing issues of environmental concern. However, most of the regulatory and legislative initiatives aimed at curtailing this problem have centered on measures that have very limited impact on the overall prevalence of these materials in all environmental compartments. The minimal influence of these initiatives has been due to their often limited and minor effects on the overall production, use and waste management of plastics. Additionally, the onset of the 2019 global pandemic has resulted in many of these measures being put on hold or cancelled altogether, resulting in increasing levels of plastics in the environment and significantly hampering the combat against plastic pollution. This perspective focuses on microplastics, given their pervasiveness and potential ecological, environmental, and health effects. The sectors and industries contributing the most to this pollution are reviewed and assessed from a societal and environmental perspective. Effective regulatory tools are suggested to help reduce plastic emission levels into the environment.

The contamination generated by multiple antibiotics represents a general concern given its impact at the environmental level, mainly affecting the planet’s soil and water and impacting the development of numerous species. Additionally, a new problem has been triggered in terms of the development of antibiotic-resistance genes in various pathogenic microorganisms generating concern for the health sector in terms of the efficiency of antibiotics in the future. These actual problems and concerns demand efforts and actions to remove or eliminate these contaminants. Multiple alternatives to reduce the impact of antibiotics in water have been carried out, such as advanced oxidation, reverse osmosis, and membrane filtration. However, adsorption techniques have presented more favorable and viable results in which carbon-based materials are an efficient tool to remediate the environment that can take advantage of other alternatives due to their characteristics. This review presents different carbon-based absorptive materials such as biochar, carbon nanotubes, activated carbon, and graphene to remove these contaminants, given their characteristics and favorable results. However, process integration, production, and modification continue to be challenging and require more research and experimentation.

Aim: The transformation of zero-valent iron (Fe⁰) and Cu²⁺ during Cu²⁺ removal by nanoscale zero-valent iron (nZVI) has not been properly investigated using modern analytical techniques, despite its importance in environmental toxicology and surface chemistry associated with wastewater treatment/groundwater remediation. This study critically examines the phenomenon using a variety of modern instruments that characterize the physical and chemical properties of materials and provides extensive comprehension of the subject.

Methods: As-prepared nZVI was used to remove Cu²⁺ in 5 mmol/L CuSO₄. The morphological and structural characteristics of the Cu²⁺ and nZVI after removal were investigated with the aid of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectrometry (XPS).

Results: Complete removal of Cu²⁺ by the nZVI was achieved within 60 min and remained constant till 120 min. The Cu²⁺ got reduced into cuprite (Cu₂O) and copper metal (Cu⁰) (the crystals of both transformation products were cubic), while the Fe⁰ nanoparticles transformed into lath-like lepidocrocite (γ-FeOOH) and twin-rod goethite (α-FeOOH). The mechanism of Fe⁰ transformation was that the Fe²⁺ produced by Fe⁰ corrosion and oxidation by Cu²⁺ was hydrolyzed and oxidized to form hydropyrite, which was later converted into lepidocrocite and goethite with the assistance of Fe²⁺. The transformation of Cu²⁺ was due to the strong reduction property of Fe⁰. The toxicity and bioavailability of the transformed products were lower than those of Cu²⁺ and Fe⁰ nanoparticles.

Conclusion: The findings are critical in understanding the fate of Fe⁰ nanoparticles and Cu²⁺ during Cu²⁺ removal by nZVI and can provide guidance for the application of nZVI technology.

Humans are increasingly exposed to airborne plastic particles due to their widespread contamination of all parts of the environment, yet the extent of inhalation exposure is still widely unknown. Bronchoalveolar lavage (BAL) and Transbronchial needle aspiration (TBNA) are two methodologies that are routinely used to detect micron or sub-micron foreign particles lodged in the human respiratory system. However, disposable plastic sampling and collection equipment is commonly used in these procedures. In this study, the potential of sample contamination due to the migration of particles from a range of containers commonly used in BAL and TBNA sample collection was investigated. PE and PVC were detected at the highest concentrations (1.5-5.6 and 1.2-8.0 g/sample, respectively) and likely originated from the container (PE) or background contamination from the manufacture/shipping process (PVC). The results demonstrated that samples collected with BAL equipment could be confidently used for the quantification of PP, PMMA, PC and PVC. Samples collected with the TBNA equipment could be confidently used for quantification of PMMA and PC, but with further assessment of trace levels from certain pieces of equipment, PP, PET, and PS could also be quantified. The results of this study demonstrate that there is potential to analyze samples collected in plastic hospital collection equipment for certain polymers. As a recommendation, background contamination from materials to be used in sample collection should be assessed before sample collection, and if consistent, then there is the potential for the analysis of a range of target plastics, with the addition of blank subtraction.

Diclofenac (DCF) is a medication that is highly consumed and eliminated worldwide; it is constantly detected in the environment (primarily in water) and resists conventional degradation processes. It was included in the European Union watch list for the water framework. There are no regulations for this compound in Mexico. Therefore, this study evaluated the protective effect antioxidant activity of spirulina (Arthrospira maxima) against DCF-induced toxicity in Xenopus laevis at early life stages. X. laevis oocytes were exposed at the medium blastula stage for 96 h to three different mixtures: DCF+S 2 (149 µg L^-1 DCF plus 2 mg L^-1 spirulina), DCF+S 4 (149 µg L^-1 DCF plus 4 mg L^-1 spirulina), DCF+S 10 (149 µg L^-1 DCF plus 10 mg L^-1 spirulina). Other groups of oocytes were also exposed to DCF 149 µg L^-1 and a control group. The mortality and malformation rate, growth, lipid peroxidation, and antioxidant enzymatic activity (superoxide dismutase and catalase) were determined. Spirulina at 4 and 10 mg L^-1 reduced DCF-induced mortality by 80% and reduced malformations in severity and frequency. The abnormalities were malformations of the eye, tail, notochord, intestine, and rectum. All spirulina exposure groups showed an increase in total body size compared to those exposed to DCF. Regarding oxidative damage, the groups exposed to the mixture with spirulina decreased lipid peroxidation levels and diminished antioxidant activity. Spirulina reduced DCF-induced damage in X. laevis at early life stages and decreased mortality, frequency, and severity of abnormalities, growth inhibition, and oxidative damage. Further research is needed to evaluate the effects of spirulina against toxicity induced by xenobiotics in the early stages of development.