A local-to-global emissions inventory of macroplastic pollution

Global patterns of lake microplastic pollution: Insights from regional human development levels

Microplastics have emerged as a pervasive pollutant across various environmental media. Nevertheless, our understanding of their occurrence, sources, and drivers in global lakes still needs to be completed due to limited data. This study compiled data from 117 studies (2016-May 2024) on microplastic contamination in lake surface water and sediment, encompassing surface water samples in 351 lakes and lake sediment samples in 200 lakes across 43 countries. Using meta-analysis and statistical methods, the study reveals significant regional variability in microplastic pollution, with concentrations ranging from 0.09 to 130,000 items/m3 in surface water and from 5.41 to 18,100 items/kg in sediment. Most microplastics were under 1 mm in particle size, accounting for approximately 79 % of lake surface water and 76 % of sediment. Transparent and blue microplastics were the most common, constituting 34 % and 21 % of lake surface water and 28 % and 18 % of sediment, respectively. Fibers were the dominant shape, representing 47 % of lake surface water and 48 % of sediment. The primary identified polymer types were polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). Countries like India, Pakistan, and China had higher contamination levels. Positive correlations were found between microplastic abundance in surface water and factors like human footprint index (r = 0.29, p < 0.01), precipitation (r = 0.21, p < 0.05), and net surface solar radiation (r = 0.43, p < 0.001). In contrast, negative correlations were observed with the human development index (r = -0.61, p < 0.01) and wind speed (r = -0.42, p < 0.001). In sediment, microplastics abundance correlated positively with the human footprint index (r = 0.45, p < 0.001). This study underscores the variability in microplastic pollution in global lakes and the role of human activities and environmental factors, offering a valuable reference for future research.

Inventories of plastic pollution sources, flows and hotspots as a baseline for national action plans: The experience of Mexico

This article explores the development of Mexico's National Inventory of Plastic Pollution Sources (NIPPS), designed to establish a baseline for the country's National Action Plan. The study employed a multifaceted approach, combining material flow analysis tools, literature reviews, and stakeholder workshops. This methodology successfully identified critical leakage points within the waste management system, such as deficiencies in collection and the prevalence of uncontrolled disposal sites. It also recognized priority geographic regions and fostered engagement with relevant stakeholders. However, a comprehensive assessment was hampered by data limitations, including a lack of information on waste composition, inconsistent recycling data, and the use of varied methodologies in field studies of plastic pollution. By highlighting the strengths and limitations of the process, this article underscores the critical role of standardized data collection and analysis in creating robust national plastic pollution inventories. Such inventories serve as a cornerstone for effective National Action Plans and contribute significantly to broader efforts tackling the global plastic pollution crisis. The valuable lessons from Mexico's experience offer insights for other countries facing similar challenges.

Pathways to reduce global plastic waste mismanagement and greenhouse gas emissions by 2050

Plastic production and plastic pollution negatively affect our environment, environmental justice, and climate change. Using detailed global and regional plastics datasets coupled with socio-economic data, we employ machine learning to predict that, without intervention, annual mismanaged plastic waste will nearly double to 121 Mt (100 - 139 Mt 95% CI) by 2050. Annual greenhouse gas emissions from the plastic system are projected to grow by 37% to 3.35 Gt CO2 equivalent (3.09 - 3.54 CO2e) over the same period. The United Nations plastic pollution treaty presents a unique opportunity to reshape these outcomes. We simulate eight candidate treaty policies and find that just four could together reduce mismanaged plastic waste by 91% (86% - 98%) and gross plastic-related greenhouse gas emissions by one third.

Biotechnology for the degradation and upcycling of traditional plastics

Traditional plastics, predominantly derived from petrochemicals, are extensively utilized in modern industry and daily life. However, inadequate management and disposal practices have resulted in widespread environmental contamination, with polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, and polystyrene being the most prevalent pollutants. Biological methods for plastic degradation have garnered significant attention due to their cost-effectiveness and potential for resource recovery, positioning them as promising strategies for sustainable plastic waste management. While polyethylene terephthalate, characterized by its relatively less stable C-O bonds, has been extensively studied and demonstrates significant potential for biodegradation. In contrast, the biodegradation of other plastics remains a significant challenge due to the inherent stability of their C-C backbone structures. This review comprehensively examines the state-of-the-art biotechnology for treating these traditional plastics, focusing on: (1) the roles of specific microorganisms and enzymes, their taxonomic classifications, and the metabolic pathways involved in plastic biodegradation; and (2) a proposed two-stage hybrid approach integrating physicochemical and biological processes to enhance the biodegradation or upcycling of these traditional plastics. Additionally, the review highlights the critical role of multi-omics approaches and tailored strategies in enhancing the efficiency of plastic biodegradation while examining the impact of plastic molecular structures and additives on their degradation potential. It also addresses key challenges and delineates future research directions to foster the development of innovative biological methods for the effective and sustainable management of plastic waste.