Macroplastic accumulation in roadside ditches of New York State's Finger Lakes region (USA) across land uses and the COVID-19 pandemic

Litter in French urban areas-part 1: composition, sources, and spatio-temporal variations on urban surfaces

Urban areas concentrate on human activities that generate large amounts of waste. A small fraction is mismanaged and ends up on urban surfaces and eventually in waterways. The fraction reaching waterways is usually estimated using poorly constrained data, while litter density on urban surfaces and its subsequent transfer dynamics are also poorly documented. This study provides new insights into litter composition, sources, and spatio-temporal variations in the urban catchments of Pin Sec and Jules Verne (Nantes, France), which are dominated by industrial/commercial, collective, and individual housing areas. Regular litter collection on selected street sections was combined with visual counting of street litter (> 1 cm). In total, 50.8 kg (dry weight) of litter were collected and 232,217 items were counted, mainly smoking and food consumption-related items. Litter densities ranged between 40,000 and 452,000 items/km2 depending on local activities, item mobility, and land use as a driver of road and foot traffic. A median litter accumulation rate of 7 g/inhabitant/day was estimated, suggesting that 0.6% of the total amount of waste generated in public places is mismanaged. Results over space show that litter is strongly correlated with land use and that litter accumulation is promoted in green spaces. Results over time show that litter stock is quickly renewed and that items may have long residence time on urban surfaces.

Litter in French urban areas - Part 2: transport dynamic and fluxes in stormwater

Urban areas constitute a major hotspot of litter, including plastic litter, that stormwater can wash off towards waterways. However, few studies quantified and characterized litter densities in urban areas and fluxes transported by stormwater networks. Moreover, little information is available on litter transport dynamics in stormwater, and on the factors driving this transport. This study aims at characterizing and quantifying litter amounts transported by stormwater of two nested French urban catchments (total surface area of 105 ha). Litter densities relative to land uses and rain events were investigated in the same catchments as in a compagnon paper (Ledieu et al., 2024). The present study explores the impact of rain events on the transport of urban litter in stormwater. Litter collection and characterization combined with a capture/recapture experiment using tagged litter placed in stormwater inlets show total litter fluxes of 29 kg/year, in which 14 kg/year are plastics, exported at the stormwater outlet. These fluxes confirm that stormwater runoff is a considerable pathway from urban surfaces to waterways, especially regarding small plastic litter (< 2.5 cm). Item transport dynamic is however not linear and only 0.3% of the urban litter appear remobilized. Litter transport dynamics depends on several factors (urban litter densities, hydrometeorological parameters, item composition and morphologies, and stormwater management systems) that should be considered in global models.

Revealing the role of land-use features on macrolitter distribution in Swiss freshwaters

Macrolitter, especially macroplastics, (> 0.5 cm) negatively impact freshwater ecosystems, where they can be retained along lake shores, riverbanks, floodplains or bed sediments. Long-term and large-scale assessments of macrolitter on riverbanks and lake shores provide an understanding of litter abundance, composition, and origin in freshwater systems. Combining macrolitter quantification with hydrometeorological variables allows further study of leakage, transport, and accumulation characteristics. Several studies have explored the role of hydrometeorological factors in influencing macrolitter distribution and found that river discharge, runoff, and wind only partially explains its distribution. Other factors, such as land-use features, have not yet been thoroughly investigated. In this study, we provide a country-scale assessment of land-use influence on macrolitter abundance in freshwater systems. We analyzed the composition of the most commonly found macrolitter items (referred to as 'top items', n = 42,565) sampled across lake shores and riverbanks in Switzerland between April 2020 and May 2021. We explored the relationship between eleven land-use features and macrolitter abundance at survey locations (n = 143). The land-use features included buildings, city centers, public infrastructure, recreational areas, forests, marshlands, vineyards, orchards, other land, and rivers and canals. The majority of top items are significantly and positively correlated with land-use features related to urban coverage, notably roads and buildings. Over 60% of top items were found to be correlated with either roads or buildings. Notably, tobacco, food and beverage-related products, as well as packaging and sanitary products, showed strong associations with these urban land-use features. Other types of items, however, did not exhibit a relationship with land-use features, such as industry and construction-related items. Ultimately, this highlights the need to combine measures at the local and regional/national scales for effective litter reduction.

Management of COVID-19 healthcare waste based on the circular economy hierarchy: A critical review

The overall objective of this work was to conduct a critical literature review on the application of the circular economy (CE) hierarchy for the management of COVID-19 healthcare waste (HCW). To describe the problem created by COVID-19 HCW, first, the subsystems of the overall management system, including generation, segregation, classification, storage, collection, transport, treatment and disposal, were reviewed and briefly described. Then, the CE hierarchy using the 10R typology was adapted to the management of COVID-19 HCW and included the strategies Refuse, Reduce, Resell/Reuse, Repair, Reprocess, Refurbish, Remanufacture, Repurpose, Recycle and Recover (energy). Disposal was added as a sink of residues from the CE strategies. Using the detailed 10R CE hierarchy for COVID-19 HCW management is the novelty of this review. It was concluded that R-strategy selection depends on its position in the CE hierarchy and medical item criticality and value. Indicative HCW components, which can be managed by each R-strategy, were compiled, but creating value by recovering infectious downgraded materials contaminated with body fluids and tissues is not currently possible. Therefore, after applying the circular solutions, the end of pipe treatment and disposal would be necessary to close material cycles at the end of their life cycles. Addressing the risks, knowledge gaps and policy recommendations of this article may help to combat COVID-19 and future pandemics without creating environmental crises.

Tracing macroplastics redistribution and fragmentation by tillage translocation

Soil is polluted with plastic waste from macro to submicron level. Our understanding of macroplastics (> 5 mm) occurrence and behavior has remained comparatively elusive, mainly due to a lack of a tracing mechanism. This study set up a methodology to trace macroplastic displacement, which combined magnetic iron oxide-tagged soil and macroplastic pieces tagged by an adhesive passive radiofrequency identification transponder. By utilizing these techniques, a field study was carried out to analyze the effect of tillage implement and plastic sizes on plastic displacement, to understand the fate of macroplastics in arable land. Results indicated that the displacement of macroplastics did not depend upon plastic sizes but did depend upon the tillage implement used. The mean macroplastics displacement per tillage pass was 0.36 ± 0.25 m with non-inversion chisel tillage and 0.15 ± 0.13 m with inversion disk tillage, which was similar to bulk soil displacement. However, only inversion disk tillage caused fragmentation (41 %) of macroplastics and generated microplastics (< 5 mm). In contrast, both tillage implements drove to similar burial of surface macroplastics into the tilled layer (74 % on average). These results highlight that tillage is a major process for macroplastics fate in arable soils, being one of the first studies to investigate it.

After the sun: a nanoscale comparison of the surface chemical composition of UV and soil weathered plastics

Once emitted into the environment, macro- (MaP), micro- (MP) and nanoplastics (NP) are exposed to environmental weathering. Yet, the effects of biogeochemical weathering factors occurring in the soil environment are unknown. As the transport, fate, and toxicity of MP and NP depend directly on their surface properties, it is crucial to characterize their transformation in soils to better predict their impact and interactions in this environment. Here, we used scanning transmission x-ray micro spectroscopy to characterize depth profiles of the surface alteration of environmental plastic debris retrieved from soil samples. Controlled weathering experiments in soil and with UV radiation were also performed to investigate the individual effect of these weathering factors on polymer surface alteration. The results revealed a weathered surface on a depth varying between 1 µm and 100 nm in PS, PET and PP environmental plastic fragments naturally weathered in soil. Moreover, the initial step of surface fragmentation was observed on a PS fragment, providing an insight on the factors and processes leading to the release of MP and NP in soils. The comparison of environmental, soil incubated (for 1 year) and UV weathered samples showed that the treatments led to different surface chemical modifications. While the environmental samples showed evidence of alteration involving oxidation processes, the UV weathered samples did not reveal oxidation signs at the surface but only decrease in peak intensities (indicating decrease of the number of chemical C bonds). After a one-year incubation of samples in soil no clear aging effects were observed, indicating that the aging of polymers can be slow in soils.

Supplementary Information

The online version contains supplementary material available at 10.1186/s43591-023-00066-2.

Land use and COVID-19 lockdowns influence debris composition and abundance in stormwater drains

Stormwater drains act as a pathway for anthropogenic debris from land to sea, particularly in urbanised estuaries where impervious surfaces expedite the process. Debris type and abundance in stormwater drains may vary due to land use and human activity, and knowledge of this variation is necessary to manage the growing threat of debris. Surveys of stormwater debris can inform targeted reduction and remediation efforts by intercepting and identifying pollutants near their source. We surveyed replicate stormwater gross pollutant traps across four land use zones (city centre, shopping centre, transportation hub, industrial precinct) before and during COVID-19 measures to assess the effects of changing human activities. Gross pollutant traps were installed in 120 drains in Greater Melbourne, Australia, and citizen scientists trained by Tangaroa Blue Foundation weighed and classified debris at 6-week intervals between October 2019 and October 2020. Four survey cycles were conducted before lockdowns were implemented, then another four during lockdowns. COVID-19 lockdowns and patterns of debris type and abundance across land use revealed how changes in human activity might impact the flow of debris. Cigarette butts were the most abundant macro debris (>5 mm) item in every survey cycle, regardless of lockdowns. Industrial land use zones had the lowest macro debris counts but contained over 90 % of the micro debris (1-5 mm). The amount of total macro debris decreased during lockdowns, however the most abundant and problematic debris items such as cigarettes and single-use plastics did not decrease as much as might be expected from the concomitant reductions in human activity. Occupational health and safety items, such as masks and gloves, increased (144 %) during COVID-19 lockdowns. Micro debris counts did not change in industrial zones during lockdowns, suggesting that workplace interventions may be necessary to reduce this debris leakage. Tracing the pathway of debris from source to sea can inform reduction and long-term management strategies.

Assessing human and physical drivers of macro-plastic debris spatially across Queensland, Australia

Plastic pollution poses environmental and socio-economic risks, requiring policy and management interventions. The evidence-base for informing management and evaluation of their effectiveness is limited. Partnerships with citizen scientists provide opportunities to increase the spatio-temporal scale of monitoring programs, where training and standardised protocols provides opportunities for the use of data in addressing multiple hypotheses. Here, we provide a baseline of debris trends and infer debris drivers of abundance across 18° of latitude, using 168 surveys from 17 beaches across Queensland, Australia through the ReefClean project. Plastics were the dominant material (87% of total debris, with hard, soft and foam plastics aggregated), although linking recovered debris to sources was limited, as 67% of items were fragmented. We tested potential drivers of specific debris types (i.e., plastics, commercial fishing items, items dumped at-sea, and single-use items) and identified significant relationships between debris accumulation with distance from the nearest population centre and site characteristics (modal beach state, beach orientation and across-beach section). Management efforts should consider beach type and orientation within site selection, as an opportunity to maximise the amount recovered, alongside other criteria such as the risks posed by debris on environmental, economic, and social values. This study demonstrates the utility of citizen science to provide baselines and infer drivers of debris, through data gathered at scales that are infeasible to most formal monitoring programs. The identified drivers of debris may also differ from regional and global studies, where monitoring at relevant scales is needed for effective management.

Amount, composition and sources of macrolitter from a highly frequented roadway

Many researches mention the need to identify the land-based sources of riverine macrolitter but few field data on litter amount, composition and sources are available in the scientific literature. Describing macrolitter hotspot dynamics would actually allow a better estimation of fluxes in the receiving environments and a better identification of the more appropriate mitigation strategies. This study provides new insights in roadway macrolitter production rates, typologies and input sources (i.e. deliberate or accidental). The macrolitter from an 800 m portion of a highly frequented roadway (around 90,000 vehicles per day) was collected during almost one year. Typologies were defined using the OSPAR/TGML classification. Results show high annual loads of macrolitter (42.8 kg/yr/ha), suggesting significant contributions of the road runoff to the litter fluxes in urban stormwater. Over the course of a year, 88.5 kg of debris were collected, including 53.2 kg (60%) of plastic debris. In total, 36,439 items were characterized, of which 84% were plastics. The macrodebris collected present a low diversity of components with Top 10 items accounting for 92% by count and a majority of small and lightweight items like plastic fragments (31%) or cigarette butts (18%). Input sources were estimated for 43% of the mass collected in which 37.2% were deliberately littered and 62.8% were accidental leaks, illustrating a major contribution of uncovered trucks and unsecured loads. The accumulation rates show a linear correlation with the road traffic. Such data are of prime interest since they enable to determine the potential contribution of road traffic to plastic fluxes to the environment.

Macrolitter dataset from a highly frequented roadway in Nantes, France

Land-based sources of riverine macrolitter are now recognized as a major concern, but few field data on litter amount, composition and sources are available. This is especially the case for macrolitter hotspots like high frequented roadways that could generate large amount of macrolitter potentially reaching rivers. This dataset provides macrolitter amount and composition over one year from a retention pond collecting stormwater and carried macrolitter from a 800 m portion of a highly frequented roadway (around 90,000 vehicles per day). The typology of macrolitter was defined using the TSG-ML/OSPAR classifications. A total of 36,439 items in which 84% of plastics were individually counted, classified and weighted by category for a total mass of 88.5 kg (60% of plastics). Raw data are available in Mendeley Data (DOI:10.17632/t6ryv6crjd.4). Top 10 items represent 92% by count of the total with plastic fragments (31%), cigarette butts (18%), EPS fragments (17%) or foam packaging (11%) as most common items. Top 10 items represent 72% by mass of the total with plastic fragments (24%) and Cardboard (13%) as most common items, followed by foam packaging (6%), wood fragments (6%), industrial plastic sheets (5%), rubber fragments (4%) and EPS fragments (4%). More than 94% of plastic items are below 1.9 g/item. This dataset is related to the research paper Amount, composition and sources of macrolitter from a highly frequented roadway.

Towards a Circular Economy of Plastics: An Evaluation of the Systematic Transition to a New Generation of Bioplastics

Plastics have become an essential part of the modern world thanks to their appealing physical and chemical properties as well as their low production cost. The most common type of polymers used for plastic account for 90% of the total production and are made from petroleum-based nonrenewable resources. Concerns over the sustainability of the current production model and the environmental implications of traditional plastics have fueled the demand for greener formulations and alternatives. In the last decade, new plastics manufactured from renewable sources and biological processes have emerged from research and have been established as a commercially viable solution with less adverse effects. Nevertheless, economic and legislative challenges for biobased plastics hinder their widespread implementation. This review summarizes the history of plastics over the last century, including the most relevant bioplastics and production methods, the environmental impact and mitigation of the adverse effects of conventional and emerging plastics, and the regulatory landscape that renewable and recyclable bioplastics face to reach a sustainable future.

Roadside ditch macroplastic and other litter dataset in the Finger lakes region across land uses and COVID-19 pandemic

Litter was collected from 12 roadside ditches in the Finger lakes Region of New York State over two sampling periods: pre-COVID-19 pandemic and during COVID-19 pandemic. Litter pieces were washed in DI water, oven dried, massed and plastic-type visually determined. Macroplastic data was analysed to assess the impact of land use, traffic, and COVID-19 variables on macroplastic accumulation on a piece, mass, and plastic-type basis. These data are all litter pieces collected, including both plastics categorized as 1 through 7 in the RIC resin classification codes as well as non-plastic litter. These data have wide-ranging reuse potential, as terrestrial microplastic accumulation is not well documented. These data could be compared with other litter accumulation across regions, specifically to assess total environmental macroplastic loading and enable contaminant mitigation strategies. These data also have direct application to modelling and transport of macroplastics into surface water bodies as a result of road ditch sampling locations. Macroplastic accumulation data across varying land uses, traffic, and COVID-19 conditions has been published [1].