Safety of 0.5% hydrogen peroxide mist used in the disinfection gateway for COVID-19

The effect of hypochlorous acid inhalation on the activity of antioxidant system enzymes in rats of different ages

Hypochlorous acid HOCl is an effective disinfectant with a broad spectrum and high rate of microbicidal action. Its use for air treatment can be an effective tool for the prevention and therapy of infectious diseases. In this work, the in vivo study was conducted on 110 Wistar Han rats (12 and 72 weeks old) on the effect of a single inhalation of air containing gaseous HOCl on the activity of antioxidant system enzymes. For this, a special installation was designed to uniformly maintain the concentration of HOCl in the air and regulate it over a wide range. Inhalation exposure was carried out for 4 h at total chlorine concentrations in the air of approximately 2.0 mg/m3 and 5.0 mg/m3, after which the animals were observed for 14 days. The effect of inhalation on the antioxidant system activity varied significantly in animals of different ages. Catalase activity in young rats increased approximately 2-fold on days 1-2 after inhalation, regardless of the HOCl concentration, while in old animals a sharp dose-dependent decrease was initially observed. The glutathione peroxidase activity in animals of both ages increased upon inhalation of air with 5.0 mg/m3 HOCl, and in old animals this was more pronounced; when the HOCl concentration decreased to 2.0 mg/m3, this indicator increased slightly in old rats and remained virtually unchanged in young ones. The glutathione reductase activity when exposed to 2.0 mg/m3 HOCl did not change for both age groups, and with increasing HOCl concentration it increased by 1.5-2.0 times in all animals.

The Efficient Disposal of Biomedical Waste Is Critical to Public Health: Insights from the Central Pollution Control Board Guidelines in India

Biomedical waste (BMW), encompassing hazardous medical materials, poses environmental and public health risks if not correctly managed. The Central Pollution Control Board (CPCB) in India is a statutory organization that oversees BMW disposal standards, aimed at mitigating these hazards. BMW mismanagement is a major problem and potentially poses threats to the environment as well as public health. During the coronavirus disease 2019 (COVID-19) pandemic, increased use of personal protective equipment (PPE) and other medical equipment was witnessed which led to a marked raised BMW generation. To ensure proper and optimized BMW management, CPCB established guidelines and rules to be followed by the medical facilities as well as the common BMW treatment facilities (CBWTFs). The challenges in implementing proper waste management practices were lack of awareness and inadequate infrastructure. Strategies for better BMW management were proposed, including color-coded bins, improved infrastructure, advanced technology, and awareness campaigns. Highlighting CPCB's vital role, this emphasizes healthcare facilities' proactive role in implementing and evolving regulations for sustainable BMW disposal, ensuring both public health and environmental well-being through compliance and responsible waste management partnerships.

Thiophene-Containing Covalent Organic Frameworks for Overall Photocatalytic H2 O2 Synthesis in Water and Seawater

H2 O2 is a significant chemical widely utilized in the environmental and industrial fields, with growing global demand. Without sacrificial agents, simultaneous photocatalyzed H2 O2 synthesis through the oxygen reduction reaction (ORR) and water oxidation reaction (WOR) dual channels from seawater is green and sustainable but still challenging. Herein, two novel thiophene-containing covalent organic frameworks (TD-COF and TT-COF) were first constructed and served as catalysts for H2 O2 synthesis via indirect 2e- ORR and direct 2e- WOR channels. The photocatalytic H2 O2 production performance can be regulated by adjusting the N-heterocycle modules (pyridine and triazine) in COFs. Notably, with no sacrificial agents, just using air and water as raw materials, TD-COF exhibited high H2 O2 production yields of 4060 μmol h-1  g-1 and 3364 μmol h-1  g-1 in deionized water and natural seawater, respectively. Further computational mechanism studies revealed that the thiophene was the primary photoreduction unit for ORR, while the benzene ring (linked to the thiophene by the imine bond) was the central photooxidation unit for WOR. The current work exploits thiophene-containing COFs for overall photocatalytic H2 O2 synthesis via ORR and WOR dual channels and provides fresh insight into creating innovative catalysts for photocatalyzing H2 O2 synthesis.

Resolving the "health vs environment" dilemma with sustainable disinfection during the COVID-19 pandemic

The overuse of disinfection during the COVID-19 pandemic leads to an emerging "health versus environment" dilemma that humans have to face. Irresponsible and unnecessary disinfection should be avoided, while comprehensive evaluation of the health and environmental impacts of different disinfectants is urgently needed. From this discussion, we reach a tentative conclusion that hydrogen peroxide is a green disinfectant. Its on-demand production enables a circular economy model to solve the storage issues. Water, oxygen, and electrons are the only feedstock to generate H2O2. Upon completion of disinfection, H2O2 is rapidly converted back into water and oxygen. This model adopts several principles of green chemistry to ensure overall sustainability along the three stages of its whole life cycle, i.e., production, disinfection, and decomposition. Physical methods, particularly UV irradiation, also provide sustainable disinfection with minimal health and environmental impacts.

Environmental impacts of the widespread use of chlorine-based disinfectants during the COVID-19 pandemic

Chlorinated disinfectants are widely used in hospitals, COVID-19 quarantine facilities, households, institutes, and public areas to combat the spread of the novel coronavirus as they are effective against viruses on various surfaces. Medical facilities have enhanced their routine disinfection of indoors, premises, and in-house sewage. Besides questioning the efficiency of these compounds in combating coronavirus, the impacts of these excessive disinfection efforts have not been discussed anywhere. The impacts of chlorine-based disinfectants on both environment and human health are reviewed in this paper. Chlorine in molecular and in compound forms is known to pose many health hazards. Hypochlorite addition to soil can increase chlorine/chloride concentration, which can be fatal to plant species if exposed. When chlorine compounds reach the sewer/drainage system and are exposed to aqueous media such as wastewater, many disinfection by-products (DBPs) can be formed depending on the concentrations of natural organic matter, inorganics, and anthropogenic pollutants present. Chlorination of hospital wastewater can also produce toxic drug-derived disinfection by-products. Many DBPs are carcinogenic to humans, and some of them are cytotoxic, genotoxic, and mutagenic. DBPs can be harmful to the flora and fauna of the receiving water body and may have adverse effects on microorganisms and plankton present in these ecosystems.

Biomedical waste generation and management during COVID-19 pandemic in India: challenges and possible management strategies

The COVID-19 pandemic has resulted in the massive generation of biomedical waste (BMW) and plastic waste (PW). This sudden spike in BMW and PW has created challenges to the existing waste management infrastructure, especially in developing countries. Safe disposal of PW and BMW is essential; otherwise, this virus will lead to a waste pandemic. This paper reviews the generation of BMW and PW before and during the COVID-19 pandemic, the regulatory framework for BMW management, policy interventions for COVID-19-based BMW (C-BMW), the capacity of BMW treatment and disposal facilities to cope with the challenges, possible management strategies, and perspectives in the Indian context. This study indicated that policy intervention helped minimize the general waste treated as C-BMW, especially during the second pandemic. Inadequacy of common BMW treatment facilities' (CBMWTFs) capacity to cope with the BMW daily generation was observed in some states resulting in compromised treatment conditions. Suggestions for better management of BMW and PW include decontamination of used personal protective equipment (PPEs) and recycling, alternate materials for PPEs, segregation strategies, and use of BMW for co-processing in cement kilns. All upcoming CBMWTFs should be equipped with higher capacity and efficient incinerators for the sound management of BMW. Post-pandemic monitoring of environmental compartments is imperative to assess the possible impacts of pandemic waste.