This study represents the first quantitative global prediction of the mass distribution of six widespread polymers, plus plastic fibers and rubber across four environmental compartments and 11 sub-compartments. The approach used probabilistic material flow analysis for 2015, with model input values and transfer coefficients between compartments taken from literature. We estimated that 3.2 ± 1.8 Mt/year of polyethylene, 1.3 ± 0.8 Mt/year of polypropylene, 0.5 ± 0.3 Mt/year of polystyrene, 0.3 ± 0.15 Mt/year of polyvinyl chloride, 1.6 ± 0.9 Mt/year of polyethylene terephthalate and 2.4 ± 1.2 Mt/year of plastic fibers enter the environment. Combining all plastic, including rubber, 4.9 ± 1.3, 4.8 ± 1.9 and 1.8 ± 1.2 Mt/year accumulated in the soil, ocean, and freshwater, respectively. Urban soils and ocean shorelines were predicted as hotspots for plastic accumulation, accounting for 33% and 25% of total plastic, respectively. The floor of freshwater systems and the ocean were predicted as hotspots for high density plastic such as polyethylene terephthalate, polyvinyl chloride and plastic fibers. Furthermore, 59% of environmental rubber was predicted to accumulate in soil. The findings of this study provide baseline data for quantifying plastic transport and accumulation, which can inform future ecotoxicity studies and risk assessments, as well as targeting efforts to mitigate plastic pollution.

Brominated flame retardants (BFRs) are an important group of additives in plastics that increase resistance to ignition and slow down the rate of burning. Because of concerns about their environmental and human health impacts, however, some of the most widely employed BFRs, including hexabromocyclododecane (HBCD) and commercial mixtures of penta-, octa- and deca- (poly)bromodiphenyl ethers (PBDEs), have been restricted or phased out. In this review, the oceanic sources and pathways of PBDEs, the most widely used BFRs, are evaluated and quantified, with particular focus on emissions due to migration from plastics into the atmosphere versus emissions associated with the input of retarded or contaminated plastics themselves. Calculations based on available measurements of PBDEs in the environment suggest that 3.5 and 135 tonnes of PBDEs are annually deposited in the ocean when scavenged by aerosols and through air-water gas exchange, respectively, with rivers contributing a further ∼40 tonnes. Calculations based on PBDE migration from plastic products in use or awaiting or undergoing disposal yield similar net inputs to the ocean but indicate a relatively rapid decline over the next two decades in association with the reduction in the production and recycling of these chemicals. Estimates associated with the input of PBDEs to the ocean when “bound” to marine plastics and microplastics range from about 360 to 950 tonnes per year based on the annual production of plastics and PBDEs over the past decade, and from about 20 to 50 tonnes per annum based on the abundance and distribution of PBDEs in marine plastic litter. Because of the persistence and pervasiveness of plastics in the ocean and diffusion coefficients for PBDEs on the order of 10⁻²⁰ to 10⁻²⁷ m² s⁻¹, microplastics are likely to act as a long-term source of these chemicals though gradual migration. Locally, however, and more important from an ecotoxicological perspective, PBDE migration may be significantly enhanced when physically and chemically weathered microplastics are exposed to the oily digestive fluids conditions of fish and seabirds.

Microplastic debris is ubiquitous and yet sampling, classifying and enumerating this prolific pollutant in marine waters has proven challenging. Typically, waterborne microplastic sampling is undertaken using nets with a 333 μm mesh, which cannot account for smaller debris. In this study, we provide an estimate of the extent to which microplastic concentrations are underestimated with traditional sampling. Our efforts focus on coastal waters, where microplastics are predicted to have the greatest influence on marine life, on both sides of the North Atlantic Ocean. Microplastic debris was collected via surface trawls using 100, 333 and 500 μm nets. Our findings show that sampling using nets with a 100 μm mesh resulted in the collection of 2.5-fold and 10-fold greater microplastic concentrations compared with using 333 and 500 μm meshes respectively (P < 0.01). Based on the relationship between microplastic concentrations identified and extrapolation of our data using a power law, we estimate that microplastic concentrations could exceed 3700 microplastics m⁻³ if a net with a 1 μm mesh size is used. We further identified that use of finer nets resulted in the collection of significantly thinner and shorter microplastic fibres (P < 0.05). These results elucidate that estimates of marine microplastic concentrations could currently be underestimated.

This paper aims to find mechanisms to align commercial interests with underwater noise reductions from commercial shipping. Through a survey and a series of interviews with representative stakeholders, we find that while acknowledging the wide variations in ports' specificities, port actions could support the reduction in underwater noise emissions from commercial shipping through changes in hull, propeller and engine design, and through operational measures associated with reduced speed, change of route and travel in convoy. Though the impact of underwater noise emissions on marine fauna is increasingly shown to be serious and wide-spread, there is uncertainty in the mechanisms, the contexts, and the levels which should lead to action, requiring precautionary management. Vessels owners are already dealing with significant investment and operating costs to comply with fuel, ballast water, NOx and CO2 requirements. To be successful, underwater noise programs should align with these factors. Based on a multiple criteria decision making (MCDM) approach, we find a set of compromise solutions for a wide range of stakeholders. Ports could propose actions such as discounted port fees and reduced ship waiting times at ports, both depending on underwater noise performance. Cooperation between ports to scale up actions through environmental indexes and classification societies' notations, and integration with other ports' actions could help support this. However, few vessels know their underwater noise baseline as there are very few hydrophone stations, and measurement methodologies are not standardized. Costs increase and availability decreases dramatically if the vessel buyer wants to improve the noise profile. Local demands regarding airborne noise close to airports boosted global pressure on the aviation industry to adopt existing quieting technology. This experience of the aviation noise control could inform the underwater noise process.

The Anthropocene, defined by human-induced environmental transformations, presents a critical challenge: plastic pollution. This complex problem, particularly prominent in coastal and marine environments, requires integrated and adaptive responses. This opinion paper examines global efforts across policy interventions, scientific innovations, and public education, highlighting both advancements and hurdles in managing this problem. These include enforcement limitations in policy implementation, scalability and cost issues in scientific innovations, and challenges in effecting large-scale behavioral change through public education. The complexities inherent in managing plastic litter in coastal and marine environments are further discussed, emphasizing the necessity for an integrated approach. This approach involves interdisciplinary collaboration, adaptive management, stakeholder engagement, policy integration, sustainable financing, resilience building, capacity enhancement, technological innovation, policy reform, ecosystem-based management, disaster risk reduction, and advocacy. The management of plastic pollution in the Anthropocene requires strategic planning, innovative thinking, and unified global efforts, ultimately providing an opportunity to redefine our relationship with the planet and steer toward a more sustainable future.

Municipal wastewater treatment plants (WWTPs) are conduits through which microplastics (MPs) are released into aquatic environments. However, the technical challenges in working with wastewater sample matrices have precluded reliable particle count budget calculations. We applied newly-adapted methods for MP collection and analysis to a study of a major WWTP serving a population of 1.3 million people near Vancouver, Canada. Suspected MP particles, including fibres, were counted and categorized using light microscopy in influent, primary effluent, secondary effluent, primary sludge and secondary sludge. Fourier Transform Infrared Spectroscopy (FT-IR) confirmed that just 32.4% of the suspected MPs were plastic polymers. Using FT-IR corrected data, we estimate that 1.76 ± 0.31 trillion MPs enter the WWTP annually, with 1.28 ± 0.54 trillion MPs settling into primary sludge, 0.36 ± 0.22 into secondary sludge, and 0.03 ± 0.01 trillion MPs released into the receiving environment. This corresponds to a retention of microplastics of up to 99% in the WWTP.

This work presents preliminary results about abundance, distribution, characteristics, sources, and fate of microplastics (MPs) in the Central Atlantic Ocean (CAO) of Morocco. The investigation was conducted into three subsections, each characterized by different types of human activities and covering rural, village, and urban areas. MPs were detected in 100 % of the sampling sites. The abundances varied from 0.048 to 3.305 items/m³, with a mean abundance of 0.987 ± 1.081 items/m³. MPs abundance was higher in surface seawater linked to urban areas compared to village and rural areas. The dominant polymer type was polyester (PET-53.8 %) followed by polypropylene (PP-24.36 %), polyamide (PA-7.56 %), polystyrene (PS-6.88 %), polyvinyl chloride (PVC-2.64 %), ethylene vinyl acetate (EVA-2.60 %), polyetherurethane (PUR-1.36 %), and acrylic (AC-0.8 %). Fibers were the most dominant shapes accounting for over 50 %. MPs were mainly smaller than 2 mm in size (71 %) and characterized by colorful aspects. These findings suggested that wastewater treatment plant (WWTP) effluents and anthropogenic activities (industry, tourism, sanitation, and fishing) are the major pollution sources of MPs in the study area. SEM/EDX micrographs showed different weathering degrees and chemical elements adhered to the MPs surface.