SARS-CoV-2 and other main pathogenic microorganisms in the environment: Situation in Galicia and Spain

Unfolding of the SARS-CoV-2 spike protein through infrared and ultraviolet-C radiation based disinfection

The spreading of coronavirus from contacting surfaces and aerosols created a pandemic around the world. To prevent the transmission of SARS-CoV-2 virus and other contagious microbes, disinfection of contacting surfaces is necessary. In this study, a disinfection box equipped with infrared (IR) radiation heating and ultraviolet-C (UV-C) radiation is designed and tested for its disinfection ability against pathogenic bacteria and SARS-CoV-2 spike protein. The killing of a Gram-positive, namely, S. aureus and a Gram-negative namely, S. typhi bacteria was studied followed by the inactivation of the spike protein. The experimental parameters were optimized using a statistical tool. For the broad-spectrum antibacterial activity, the optimum condition was holding at 65.61 °C for 13.54 min. The killing of the bacterial pathogen occurred via rupturing the cell walls as depicted by electron microscopy. Further, the unfolding of SARS-CoV-2 spike protein and RNase was studied under IR and UV-C irradiations at the aforesaid optimized condition. The unfolding of both the proteins was confirmed by changes in the secondary structure, particularly an increase in β-sheets and a decrease in α-helixes. Remarkably, the higher penetration depth of IR waves up to subcutaneous tissue resulted in lower optimum disinfection temperature, <70 °C in vogue. Thus, the combined UV-C and IR radiation is effective in killing the pathogenic bacteria and denaturing the glycoproteins.

A critical review on diverse technologies for advanced wastewater treatment during SARS-CoV-2 pandemic: What do we know?

Advanced wastewater treatment technologies are effective methods and currently attract growing attention, especially in arid and semi-arid areas, for reusing water, reducing water pollution, and explicitly declining, inactivating, or removing SARS-CoV-2. Overall, removing organic matter and micropollutants prior to wastewater reuse is critical, considering that water reclamation can help provide a crop irrigation system and domestic purified water. Advanced wastewater treatment processes are highly recommended for contaminants such as monovalent ions from an abiotic source and SARS-CoV-2 from an abiotic source. This work introduces the fundamental knowledge of various methods in advanced water treatment, including membranes, filtration, Ultraviolet (UV) irradiation, ozonation, chlorination, advanced oxidation processes, activated carbon (AC), and algae. Following that, an analysis of each process for organic matter removal and mitigation or prevention of SARS-CoV-2 contamination is discussed. Next, a comprehensive overview of recent advances and breakthroughs is provided for each technology. Finally, the advantages and disadvantages of each method are discussed.

The COVID-19 pandemic and its implications on the environment

The emerging threat posed by COVID-19 pandemic has strongly modified our lifestyle, making urgent to re-consider the humans-environment relationships and stimulating towards more sustainable choices in our daily behavior. Scientific evidences showed that the onset of new viral pathogens with a high epidemic-pandemic potential is often the result of complex interactions between animals, humans and environment. In this context, the interest of the scientific community has also been attracted towards the potential interactions of SARS-CoV-2 with environmental compartments. Many issues, ranging from the epidemiology and persistence of SARS-CoV-2 in water bodies to the potential implications of lockdown measures on environmental quality status are here reviewed, with a special reference to marine ecosystems. Due to current sanitary emergence, the relevance of pilot studies regarding the interactions between SARS-CoV-2 spread and the direct and indirect environmental impacts of the COVID-19 pandemic, that are still a matter of scientific debate, is underlined.

Performance study of a sterilization box using a combination of heat and ultraviolet light irradiation for the prevention of COVID-19

SARS-CoV-2 virus and other pathogenic microbes are transmitted to the environment through contacting surfaces, which need to be sterilized for the prevention of COVID-19 and related diseases. In this study, a prototype of a cost-effective sterilization box is developed to disinfect small items. The box utilizes ultra violet (UV) radiation with heat. For performance assessment, two studies were performed. First, IgG (glycoprotein, a model protein similar to that of spike glycoprotein of SARS-COV-2) was incubated under UV and heat sterilization. An incubation with UV at 70 °C for 15 min was found to be effective in unfolding and aggregation of the protein. At optimized condition, the hydrodynamic size of the protein increased to ~171 nm from ~5 nm of the native protein. Similarly, the OD₂₈₀ values also increased from 0.17 to 0.78 indicating the exposure of more aromatic moieties and unfolding of the protein. The unfolding and aggregation of the protein were further confirmed by the intrinsic fluorescence measurement and FTIR studies, showing a 70% increase in the β-sheets and a 22% decrease in the α-helixes of the protein. The designed box was effective in damaging the protein's native structure indicating the effective inactivation of the SARS-COV-2. Furthermore, the incubation at 70 °C for 15 min inside the chamber resulted in 100% antibacterial efficacy for the clinically relevant E.coli bacteria as well as for bacteria collected from daily use items. It is the first detailed performance study on the efficacy of using UV irradiation and heat together for disinfection from virus and bacteria.

SARS-CoV-2 and other viruses in soil: An environmental outlook

In the present review, the authors shed light on the SARS-CoV-2 impact, persistence, and monitoring in the soil environment. With this purpose, several aspects have been deepened: i) viruses in soil ecosystems; ii) direct and indirect impact on the soil before and after the pandemic, and iii) methods for quantification of viruses and SARS-CoV-2 monitoring in soil. Viruses are present in soil (i.e. up to 417 × 10⁷ viruses per g TS^-1 in wetlands) and can affect the behavior and ecology of other life forms (e.g. bacteria), which are remarkably important for maintaining environmental equilibrium. Also, SARS-CoV-2 can be found in soil (i.e. up to 550 copies·g^-1). Considering that the SARS-CoV-2 is very recent, poor knowledge is available in the literature on persistence in the soil and reference has been made to coronaviruses and other families of viruses. For instance, the survival of enveloped viruses (e.g. SARS-CoV) can reach 90 days in soils with 10% of moisture content at ambient. In such a context, the possible spread of the SARS-CoV-2 in the soil was evaluated by analyzing the possible contamination routes.

Emerging contaminants, SARS-COV-2 and wastewater treatment plants, new challenges to confront: A short review

The current pandemic caused by SARS-CoV-2 has put public health at risk, being wastewater-based epidemiology (WBE) a potential tool in the detection, prevention, and treatment of present and possible future outbreaks, since this virus enters wastewater through various sources such as feces, vomit, and sputum. Thus, advanced technologies such as advanced oxidation processes (AOP), membrane technology (MT) are identified through a systematic literature review as an alternative option for the destruction and removal of emerging contaminants (drugs and personal care products) released mainly by infected patients. The objectives of this review are to know the implications that the new COVID-19 outbreak is generating and will generate in water compartments, as well as the new challenges faced by wastewater treatment plants due to the change in a load of contaminants and the solutions proposed based on the aforementioned technologies to be applied to preserve public health and the environment.