The deadlock in the plastics treaty negotiations has exposed the weight of petrochemical interests, yet a second constraint on plastics regulation has drawn little scholarly attention. Some 3,300 international investment agreements allow foreign investors, petrochemical and plastics manufacturers among them, to sue states directly before arbitral tribunals when regulation reduces the value of their assets. Evidence from climate, tobacco and pesticide policy indicates that the threat of such claims can delay or dilute public-interest measures, a phenomenon known as regulatory chill. This article maps the exposure of plastics regulation to investment law, to our knowledge the first mapping of its kind, and sets it beside the public numbers on both sides. Drawing on production statistics for 1950–2023, UNCTAD arbitration data to end-2024 and OECD projections to 2060, we extrapolate two trends: primary plastics production reaches about 1,235 million tonnes by 2060, and the known arbitration caseload passes two thousand in the mid-2030s. We identify the measures most exposed: production caps, polymer and additive bans, producer-responsibility levies and waste-trade restrictions, consider how arbitration risk may shape bargaining inside the negotiations and assess reform pathways from express carve-outs to interpretive tools that preserve host-state regulatory autonomy.

Extended Producer Responsibility (EPR) requires quantitative tools to identify responsibility concentration and prioritize interventions. This study introduces an inequality-based framework combining Lorenz curves, Gini coefficients, and concentration ratios to assess producer responsibility in marine plastic pollution. We analyzed 232 producer-attributable items from 830 macrolitter items collected on Isla Arena, an uninhabited Colombian Caribbean island, identifying 48 producers, 72 brands, and 95 products. A Corporate Environmental Impact (CEI) index assessed whether abundance-based dominance corresponded to potential environmental impact. Producer responsibility was highly concentrated (Gini = 0.690; bootstrap 95% CI: 0.629–0.698), with the five and ten leading producers accounting for 65.5% and 80.6% of attributable litter, respectively. Beverage companies dominated, while Pony Malta alone represented 27.2% of attributable items. Impact-based inequality was nearly identical (Gini = 0.692). Sensitivity analysis addressing the 72.0% unattributed fraction showed that category-specific attribution corrections increased inequality (Gini = 0.714), supporting the robustness of observed concentration. These findings establish responsibility inequality as a measurable property of pollution assemblages and provide a transferable framework for targeting EPR interventions, assessing governance feasibility, and monitoring corporate environmental performance across pollution systems.

Over the past two decades, research on (micro)plastics has expanded rapidly, with a dominant focus on identifying where plastics are found in the environment, which polymer types are present and what chemicals are associated with them. Although leading scholars increasingly emphasise the urgent need for interdisciplinary approaches that integrate human behaviour, policy, health, socio-economic and socio-ecological systems, it remains unclear whether scientific activity is evolving in line with these calls. The MICRO conference series – one of the largest recurring international meetings on plastic pollution – offers a unique perspective through which to assess research priorities and emerging trends in plastic research. This study analyses all abstracts submitted to the MICRO conferences between 2018 and 2024 (n = 1,794) to examine whether research activity reflects the growing need for interdisciplinary, social, behavioural, health and governance-oriented approaches to plastic pollution. Following stop-word removal, 276 meaningful lemmas were identified (i.e., words for which different spellings were collapsed) and inductively grouped into 12 themes. Four themes – One Health, Human Dimensions, Policy and Governance, and Lifecycle and Waste Management – were selected for in-depth analysis, including their prevalence over time and the qualitative context in which high-frequency terms were used. Across all conference years, research remained strongly dominated by natural science-oriented themes. Engagement with socio-economic, behavioural, educational and policy dimensions was comparatively limited, and contributions from the Global South remained underrepresented, with little evidence of change over time. Together, these findings point to a persistent gap between the direction that plastic research is widely encouraged to take and the research that is currently being presented in this key international forum. We discuss implications for conference design, abstract selection criteria, funding priorities and global inclusion, and argue for a stronger emphasis on socio-economic, behavioural, cultural and educational perspectives to better support effective and equitable action on plastic pollution.

A loosely aligned, informal grouping of developing states is pressing for a strong plastics treaty. This article evaluates the past influence and future prospects of this “quasi-bloc” of high-ambition developing countries (HADCs). We argue that the HADC quasi-bloc is driving demands for stringent controls across the full life cycle of plastics, including on oil and gas feedstock, petrochemical processing and product design. It is also energizing calls for robust financing to support just transitions to low-plastic economies, while amplifying the demands of Indigenous peoples and civil society to address the injustices of plastic pollution. Notably, during treaty talks in Busan in 2024 and Geneva in 2025, the HADC quasi-bloc stood firm against petrostates and industry interests seeking to weaken the treaty. HADCs share much in common, including histories of subjugation and disproportionate vulnerability to plastic pollution. Yet the cohesion and power of the HADC quasi-bloc should not be overstated. This is not a formal coalition, but rather an ad hoc, fluid grouping of states with shared interests and concerns. Looking ahead, the HADC quasi-bloc, alongside high-ambition states in the Global North, appears to have enough power to block a weak treaty, but achieving strong obligations presents a far greater political challenge.

Despite substantial research into policy interventions, harm reduction and alternative materials, plastic pollution is a worsening environmental and waste management crisis for countless governments and ecosystems. In response, the recent Global Plastics Treaty negotiations have highlighted urgent actions, including the “prevention and reduction of waste” and elimination of “unnecessary plastics.” Non-functional slack filling (or packaging that is intentionally underfilled) is a poorly documented tactic used by manufacturers to increase profits while maintaining consumer confidence. Here we describe the amount of slack fill and non-functional slack fill (excess packaging) for 17 and 366 products, respectively, that were sampled by citizen scientists based in 24 countries. On average, the material associated with the non-functional slack filling space equated to 38% of the total packaging, with >60% of the packaging for 39 products considered to be surplus. Confectionery (e.g., candy, cookies) and cleaning/sanitary products (e.g., laundry soap) had the highest amounts of non-functional slack filling (42 and 40% respectively), followed by pet food and human food (39% and 37% respectively). Our results highlight the prevalence of excess, non-functional packaging across multiple countries and product categories. This problem presents an important opportunity to reduce excessive and largely avoidable amounts of unnecessary plastic production and waste, thereby improving transport efficiency, but this can likely only be achieved with international standards, binding agreements and industry innovation.

The accumulation of plastic in the oceans is a global environmental problem that requires international solutions. In 2022, the UN Environment Assembly launched negotiations for a Global Plastics Treaty (GPT). In four years of negotiations, an Intergovernmental Negotiations Committee has promoted seven meetings to reach an agreement. This research analyzes the GPT negotiation process through the lens of the two-level game theory, seeking to understand how domestic and international constraints influence Brazil’s position during the agreement formation. We analyzed negotiation documents as well as public hearings from Brazilian representatives and non-state actors as well as surveys. Regarding analysis procedures, the research is qualitative and relies on content analysis. We observe the country’s material challenges in consolidating, at the international level, a policy that tries to balance proposals promoted domestically around the bioeconomy and the green development agenda without compromising economic interests.

Plastic pollution is a diffuse, cumulative and value chain-generated environmental problem that remains insufficiently addressed by existing product, waste and market regulations. This article examines the potential of the EU Corporate Sustainability Due Diligence Directive (CSDDD) to function as a horizontal governance mechanism capable of embedding plastics-related risk management within corporate decision-making. Using a doctrinal and governance-oriented analytical framework, the article assesses whether plastic pollution qualifies as an “adverse environmental impact” under the Directive, how its risk-based obligations may apply across upstream and downstream stages of plastics value chains, and how its enforcement architecture shapes corporate accountability. The analysis demonstrates that, although the CSDDD does not directly regulate plastics, it can procedurally operationalise existing EU plastics and circular economy objectives by integrating environmental risk management into corporate governance systems. At the same time, its effectiveness is constrained by structural limitations, including the exclusion of post-consumer stages, challenges of causation in diffuse pollution contexts and variations in enforcement across Member States. The article contributes a systems-oriented assessment of regulatory coherence at the intersection of plastics governance and corporate due diligence, while critically evaluating the limits of procedural regulatory approaches in addressing systemic environmental harm.

Since publishing its first article in May 2023, Cambridge Prisms: Plastics has established itself as a leading platform for interdisciplinary, policy-relevant scholarship addressing the global plastics crisis. The journal has published research spanning political economy, activism, waste management, chemical safety, life-cycle assessment and environmental justice, united by a commitment to societal relevance and actionable insights. Its contributions have informed policy debates, supported international negotiations, strengthened civil society advocacy and fostered collaborations across disciplines, sectors and regions. A notable achievement was the 2025 collection of open letters from more than 60 experts calling for ambitious measures within the global plastics treaty negotiations. The journal has now received its first Impact Factor (5.3) and CiteScore (4.2), placing it in the top quartile of Environmental Studies journals. While these metrics signal strong early visibility and scholarly engagement, they should be interpreted cautiously as partial and short-term indicators. More significant is the journal’s growing influence in connecting research, policy and practice to drive meaningful change.

To inform decision making for the sustainable use of plastic, policymakers require accounts of all short-term and long-term use of plastic at a national level. However, the underlying data used for plastics accounting require extensive time and effort for collation or estimation. Generative AI has recently demonstrated promise in research tools due to its use of extensive knowledge bases. In this study, we tested whether GPT, the model behind Open Artificial Intelligence’s ChatGPT, could produce estimates for plastic accounting tasks that are comparable to experts. Fine-tuned GPT-3.5 turbo models were used for two tasks: (i) estimating the material composition of imported products by plastic type and (ii) estimating the volumes tested whether the training dataset size and modifying model hyper-parameters improved performance. Increasing the training dataset size was found to improve the performance of models trained for the first task, while increasing the number of training rounds improved the precision and accuracy of models trained for the second task. However, in both tasks models did not provide estimates comparable to those provided by experts. Although future generative AI models that are specifically trained for accounting tasks may increasingly become useful tools for reducing manual work, currently they do not provide reliable estimates.

Bioluminescence is a predominant phenomenon in marine environments, the production of light by living organisms through enzyme-mediated chemical reactions involving luciferin, the light-emitting substrate and luciferase, the enzyme that catalyses its oxidation. In the deep sea, bioluminescence is not merely a visual trait but a critical ecological function supporting prey capture, mate recognition, communication and other species interactions. Recent evidence indicates that plastic exposure can alter bioluminescent responses through ingestion, tissue stress, oxidative damage and interference with chemical signalling pathways. This is of growing concern because plastic debris and microplastics are increasingly detected from surface waters to abyssal environments, making them bioavailable to deep-sea organisms. Since many deep-sea organisms depend on bioluminescence for survival and reproduction, any impairment of light production mechanisms can influence not only individual fitness but also prey–predator interactions, trophic transfer and ecosystem functioning. This letter highlights plastic pollution as an emerging threat to deep-sea bioluminescence and calls for long-term monitoring and policy attention to protect biological light-mediated ecological processes in the deep ocean.

Floods have a large impact on the mobilization, distribution and retention of macroplastic in rivers. Some of the transported plastic is deposited on riverbanks and floodplains. However, the specific deposition patterns, that is, where precisely macroplastics are deposited across the floodplains, are poorly investigated. We sampled 25 floodplain sites along the Meuse following the 2021 summer flood (>100 year$ {}^{-1} $), and 23 floodplain sites along the IJssel following the 2024 winter flood (4 year$ {}^{-1} $). For each found item, we recorded the landcover element (such as grass, herbaceous, bushes, tree and debris pile) in which it was deposited. Along the IJssel, debris piles contained plastic concentrations of 12.7 #/m2 and 58% of plastic by count, despite covering only 2% of the sampled area. We found that plastic concentrations vary between landcover elements, but also plastic characteristics. Out of the macroplastics deposited in riparian vegetation along the Meuse, 84% were soft plastics or textiles, compared to 53% of items deposited on the ground. This article sheds additional light on the role of vegetation and debris piles on plastic retention caused by floods. Our results can be used to help improve the monitoring, mitigation and reduction of river scale plastic pollution.

Microplastic (MP) pollution in terrestrial ecosystems is attracting global attention. The transfer of MPs in terrestrial food chains remains poorly understood, particularly in poultry systems. This study investigates polystyrene (PS) MP transfer and surface weathering characteristics in an “earthworm-chicken” food chain by feeding chickens earthworms that had been previously exposed to PS MPs and by oral gavage. The results showed that MP concentrations decreased from soil (10.06 ± 0.03 mg/g) to earthworm casts (6.39 ± 1.05 mg/g) to chicken faeces (3.76 ± 0.39 mg/g), and the transfer process of MPs in the “earthworm-chicken” food chains is characterized by continuous fragmentation. MPs were distributed throughout different parts of the chickens’ digestive tract after 3 h oral gavage and were only detected in the faeces after 24 h. Scanning electron microscopy and Fourier transform infrared spectroscopy revealed that MPs underwent varying degrees of weathering in the earthworm casts, chicken faeces and gastrointestinal tract, exhibiting surface holes and cracks. Compared with pristine MPs, the significantly higher carbonyl index of MPs in the gizzard demonstrates the key role of the gizzard in MP fragmentation. This study contributes to understanding the trophic transfer and fragmentation processes of MPs in chickens, and provides a basis for future research on the environmental processes of MPs in terrestrial food chains.