Generation and consequence of nano/microplastics from medical waste and household plastic during the COVID-19 pandemic.

Since the end of 2019, the world has faced a major crisis because of the outbreak of COVID-19 disease which has created a severe threat to humanity. To control this pandemic, the World Health Organization gave some guidelines like wearing PPE (personal protective equipment) (e.g., face masks, overshoes, gloves), social distancing, hand hygiene and shutting down all modes of public transport services. During this pandemic, plastic products (e.g., household plastics, PPE and sanitizer bottles) have substantially prevented the spread of this virus. Since the outbreak, approximately 1.6 million tons of plastic waste have been generated daily. However, single-use PPE like face masks (N95), surgical masks and hand gloves contain many non-biodegradable plastics materials. These abandoned products have created a huge number of plastic debris which ended up as microplastics (MPs) followed by nanoplastics (NPs) in nature that are hazardous to the eco-system. These MPs and NPs also act as vectors for the various pathogenic contaminants. The goal of this review is to offer an extensive discussion on the formation of NPs and MPs from all of these abandoned plastics and their long-term impact on the environment as well as human health. This review paper also attempts to assess the present global scenario and the main challenge of waste management to reduce the potential NP/MPs pollution to improve the eco-systems.

White spill: Life cycle assessment approach to managing marine EPS litter from flood-released pontoons.

Expanded polystyrene (EPS) pollution in the marine environment is a pressing issue in Queensland, Australia due to a recent flood that scattered hundreds of EPS-containing pontoons along the coastline, causing severe ecological damage. To assist in the clean-up effort and provide crucial data for developing management guidelines, this study investigates the environmental performance of different end-of-life (EoL) disposal/recycling methods, including (i) landfill; (ii) on-site mechanical re-processing using a thermal densifier (MR); and (iii) on-site dissolution/precipitation using d-limonene (DP). Applying the life cycle assessment framework, the results showed that DP was the most environmentally favourable option. Its impacts in climate change (GWP), acidification (TAP), and fossil fuel depletion (FFD) were 612 kg CO2 eq, 4.3 kg SO2 eq, and 184.7 kg oil eq, respectively. For comparison, the impacts of landfilling EPS in these categories were found to be 700 kg CO2 eq, 3.5 kg SO2 eq, and 282 kg oil eq, respectively. Landfill also contributed considerably to eutrophication potential (MEP), at 3.77 kg N eq. Impacts from MR were most significant due to the need to transport the densifier unit to the site. The analysis also revealed that the transportation of personnel and heavy machinery to the site, was the biggest contributor to impacts in the EoL stage. Its impacts in GWP, TAP, MEP, and FFD were 1369.8 kg CO2 eq, 6.5 kg SO2 eq, 0.2189 kg N eq, and 497.7 kg oil eq, respectively. Monte Carlo analysis showed that the conclusions made from these results were stable and reliable. Limitations of this model and recommendations for future investigations were also discussed in this work.

Nano/microplastics: Fragmentation, interaction with co-existing pollutants and their removal from wastewater using membrane processes.

NANO: and microplastic (NP/MP) is one of the most challenging types of micropollutants, coming from either direct release or degradation of plastic items into ecosystems. NP/MP can adsorb hazardous pollutants (such as heavy metals and pharmaceutical compounds) and pathogens onto their surface that are consumed by humans, animals, and aquatic living organisms. This paper presents the interaction of NP/MP with other pollutants in the water environment and mechanisms involved to enable the ultimate fate of NP/MP as well as the effectiveness of metal-organic frame (MOF)-based membrane over conventional membrane processes for NP/MP removal. It is found that conventional membranes could remove MPs when their size is usually more than 1000 nm, but they are ineffective in removing NPs. These NPs have potentially greater health impacts due to their greater surface area. MOF-based membrane could effectively remove both NP and MP due to its large porous structure, high adsorption capacity, and low density. This paper also discusses some challenges associated with MOF-based membranes for NP/MP removal. Finally, we conclude a specific MOF-based ultrafiltration membrane (ED-MIL-101 (Cr)) that can potentially remove both negative and positive charged NP/MP from wastewater by electrostatic attraction and repulsion force with efficient water permeability.

Understanding the fate of nano-plastics in wastewater treatment plants and their removal using membrane processes.

Nanoplastics (NPs) have become a major environmental issue due to their adverse effect on the water environment. Wastewater treatment plant (WWTP) is considered as one of the main sources for breaking down of larger-sized plastic debris and microplastics (MPs) into NPs. This study aims to provide a comprehensive understanding of NPs generation in the WWTPs, their physiochemical characteristics and interaction with the WWTPs. It is found that cracking is the major mechanism of plastics fragmentation in the WWTPs. This review also discusses the current membrane process used for NPs removal. It is found that conventional membrane processes are ineffective as they are not designed for NPs removal and fouling is a major obstacle for its application. Therefore, this study concludes by providing an outlook of developing a bio-nanofiltration process that can be used as a tertiary treatment for removing NPs and other components present in water. Such a process can produce NPs-free water for non-potable use or safe discharge into open waterways.