Adoption and diffusion of marine litter clean-up technologies across European seas: Legal, institutional and financial drivers and barriers

An assessment of the scope and effectiveness of soft measures to handle plastic pollution in the Baltic Sea Region

As a semi-closed sea, the Baltic Sea is especially vulnerable to human activities and pressures, such as tourism, industry, and increasing population size, which is also associated with increasing levels of plastic pollution. Apart from legal frameworks and technical solutions (e.g., waste management infrastructure), one of the means to address the problem is the use of soft measures, understood as non-compulsory, non-infrastructure, low-investment and low-effort measures that can be implemented in a way that is less complicated and costly than technical solutions. Based on the perceived need to further understand this matter, this paper discusses the role of soft measures in tackling plastic pollution. This paper combines a multi-methods approach consisting of a literature review on the topic, complemented by concrete examples of soft measures from different countries across the Baltic region. Drawing from the experiences gathered, it provides some suggestions aiming to maximise the impacts of soft measures and encourage their use as one of the tools that can be deployed to handle plastic pollution in the Baltic Sea Region and beyond.

Boosting beach clean-up participation through community resilience hypothetical scenarios

Engaging coastal communities in beach clean-up initiatives is crucial for the sustainability of marine ecosystems and the support of the blue economy. This study aims to examine the influence of various resilience attributes on community willingness to participate in these activities. It uses choice experiment framework to test three distinct scenarios: (1) cultural recycling education, (2) social media task force, and (3) resilience debris recovery. The study surveyed 647 valid samples from metropolitan Bali, Indonesia to assess their preferences across these scenarios. Advanced econometric models, specifically the Random Parameter Logit (RPL) and Latent Class Model (LCM), were used to analyze the data. The results indicate that integrating cultural and digital engagement strategies can significantly enhance community participation in beach clean-ups, providing a model that can be applied in various coastal regions. Each scenario improves community engagement by aligning beach clean-up efforts with broader economic and cultural dynamics.

The hyperbenthic environment: A forgotten habitat for plastic pollution

This study investigates the abundances and composition of microplastics (MP) among the shallow layers of a coastal Mediterranean Marine Protected Area (Cabrera MPA), seafloor sediments, hyperbenthic environment, and the water column. The mid waters samples were collected mid-way between the sea surface and the seafloor and hyperbenthic samples at the water layer adjacent to the seafloor. Sampling was carried out on patchiness seafloor of Posidonia oceanica meadows. The seafloor sediments showed a mean abundance of 378,769.20 ± 508,109.11 MPs/m3, three orders of magnitude higher than the hyperbenthic (209.17 ± 117.07 MPs/m3), and the mid waters layer (106.48 ± 107.17 MPs/m3). An increasing vertical gradient in MP abundances, mainly composed of fibers was observed. Fibers were made-up mainly of polystyrene (PS, 25 %), expanded polystyrene (EPS, 18 %) and cellulose acetate (CA, 16 %). The results stress the need to increase efforts to find solutions to mitigate fiber pollution in the marine environment.

Binational survey using Mytilus galloprovincialis as a bioindicator of microplastic pollution: Insights into chemical analysis and potential risk on humans

Microplastic (MP) contamination in edible mussels has raised concerns due to their potential risk to human health. Aiming to provide valuable insights regarding the occurrence, physicochemical characteristics, and human health implications of MP contamination, in the present study, two nationwide surveys of MP contamination in mussels (Mytilus galloprovincialis) were conducted in Morocco and Tunisia. The results indicated that MP frequency ranged from 79 % to 100 % in all the analyzed samples. The highest MP density was detected in mussels from Morocco (gills "GI": 1.88 MPs/g ww^-1; digestive glands "DG": 0.92 MPs/g ww^-1) compared to mussels of Tunisia (GI: 1.47 MPs g^{- 1}; DG: 0.79 MPs g^{- 1}). No significant differences in MP density were found between the two organs (GI and DG) for both countries. MPs were predominantly blue and black fibers, and smaller than 1000 μm. Seven polymeric types were identified, of which PET, PP, and PE were the most abundant, accounting for >87 % of all samples. Scanning Electron Microscopy (SEM) coupled with Energy dispersive X-ray (EDX) showed that most MPs have noticeable signs of weathering and inorganic components on their surface. The highest MP daily intake was found in children, while the lowest was estimated in women and men. Moreover, the annual dietary exposure of MPs through mussel consumption was estimated to be 1262.17 MPs/year in Morocco and 78.18 MPs/year in Tunisia. The potential risk assessment of MPs in mussels based on the polymer hazard index (PHI) was estimated in the high-risk levels, implying that MPs may pose health risks to humans. Overall, this research suggests that the consumption of mussels represents a considerable MP exposure route for the Moroccan and Tunisian populations.

Public preferences for marine plastic litter management across Europe

Plastic pollution is one of the most challenging problems affecting the marine environment of our time. Based on a unique dataset covering four European seas and eight European countries, this paper adds to the limited empirical evidence base related to the societal welfare effects of marine litter management. We use a discrete choice experiment to elicit public willingness-to-pay (WTP) for macro and micro plastic removal to achieve Good Environmental Status across European seas as required by the European Marine Strategy Framework Directive. Using a common valuation design and following best-practice guidelines, we draw comparisons between countries, seas and policy contexts. European citizens have strong preferences to improve the environmental status of the marine environment by removing and reducing both micro and macro plastic litter and implementing preventive measures favouring a pan-European approach. However, public WTP estimates differ significantly across European countries and seas. We explain why and discuss implications for policymaking.

Sources, sinks and transformations of plastics in our oceans: Review, management strategies and modelling

Currently, 60-80 % of litter is plastic, and almost 10 % ends up in the ocean directly or indirectly. Plastics often suffer from photooxidation producing microplastics and these microplastics derived from the breakdown of larger plastics are called secondary microplastics. These compounds simply cannot be extracted from the oceans, and once mixed, they enter the food chain and may have toxic effects. This work reviews the current existing information on the topic in the scientific literature. Then, the current plastic management strategies in the marine environment are analysed, with the objective of identifying possible needs and improvements from a sustainable point of view, and to define new approaches. Simultaneously, a material flows analysis in different media of the marine environment is carried out using system dynamics. A preliminary model of plastics mobilization into the ocean to other media of the marine environment (like sediments and biota) is developed and validated with the existing data from the previous steps of the work. This work expands the current knowledge on the plastics management, their transformations and accumulation in the marine environment and the harmful effects on it. Likewise, preliminary dynamic model of mobilization of plastics in the ocean is implemented, run, and validated. The developed model can be used to predict trends in the distribution of the plastics in the ocean with time. In addition, the most important reservoirs of plastics in the ocean can be observed. Although plastics undergo transformations in the marine environment, it is not a means of disposal since most of them are non-biodegradable. Most plastics accumulate on the seabed. The proportion of microplastics found in sediments is higher than that of macroplastics.

Temporal changes of plastic litter and associated encrusting biota: Evidence from Central Italy (Mediterranean Sea)

We investigated the temporal changes from spring to summer of the stranded litter and the composition of plastic encrusting biota along an Italian beach. Our findings highlight a higher quantity of litter (average value 1510.67 ± 581.27 items) in spring, particularly plastic material with a composition driven by currents, winds and waves transported from rivers to sea. During summer the source was caused by anti-social behaviours (e.g. cigarettes). Regarding the plastic size, the most is macroplastic (85.96 %), followed by mesoplastic (13.74 %) and megaplastic (0.30 %) overall, and no seasonal trend was observed. Concerning the encrusting biota, Mollusca was the most frequent phylum found on plastic beach litter, whereas Porifera the most abundant overall. During spring a greater abundance of individuals was recorded compared to summer. The trend of taxa richness was decreasing from spring to summer. Arthropoda, Porifera and Mollusca phyla were significantly more abundant in spring, while Algae in summer.

A multi-criteria assessment of policies to achieve the objectives of the EU marine litter strategy

This paper proposes and assesses policy options to achieve the objectives of the EU marine litter strategy, based on the existing EU legislation. A group of experts and stakeholders was involved through a multi-staged workshop organized to generate the information to assess the contribution of the policies to the set of objectives, as well as the relative importance of the objectives, on qualitative scales. The ELECTRE TRI multi-criteria decision analysis method was used to rate the policies, which were subsequently ranked. Per the results, all policies deserve to be considered, even when the more pessimistic assessments (33rd percentile) are used. Revising the Urban Wastewater Treatment Directive, setting legislative targets on marine litter and ensure they are fully monitored, and funding proven clean-up technologies were deemed to be the most potentially impactful policies. The remaining policies assessed can nevertheless play an important role in complementing the higher-ranked policies.

Achieving greater policy coherence and harmonisation for marine litter management in the North-East Atlantic and Wider Caribbean Region

The effects of marine litter pose ecological, economic and optional value threats to the countries and territories on the margins of the Atlantic Basin. As the abundance of transboundary marine litter increases, this in turn has triggered the development of marine litter policy action plans and inter-regional collaboration. The OSPAR Commission and Cartagena Convention of North-East Atlantic (NEA) and the Wider Caribbean Region (WCR) respectively, have established a memorandum of understanding to facilitate collaboration for enhanced marine litter management. In light of this development, this paper conducts a scoping review of management measures of marine litter within these regions as well as a coherence analysis between their regional action plans (RAPs). The analysis uses a proactive framework based on a modified categorization by Chen (2015) and Williams and Rangel-Buitrago (2019) for comparatively analyse management measures. The analytical categorizations include legislation and enforcement measures, prevention, removal, monitoring, research, information management and exchange and education and outreach. Although specific approaches differed among the regions depending upon geographical and individual situations, each categorization included detailed management activities except for prevention in NEA and removal in the WCR. The comparative analysis demonstrates that there are opportunities for inter-regional cooperation, knowledge sharing and overall enhanced and informed marine litter management.

Characterization of anthropogenic marine macro-debris affecting coral habitat in the highly urbanized seascape of Mumbai megacity

Marine debris has become a major form of pollution and a serious ecosystem health concern. The present study evaluates the accumulation, origin, and fate of debris in intertidal coral habitats of Mumbai-one of the world's highly populated coastal cities on the west coast of India. Predominantly, seven hermatypic coral species belonging to seven genera and five families were identified and mainly represented by Pseudosidastrea, Porites, and Bernardpora. In terms of number, the mean density of marine debris was 1.60 ± 0.13 SE items/m², which is higher than the global average. The mean density of plastic debris was 1.46 ± 0.14 SE items/m². Approximately 9% of total coral colonies were in physical contact with debris, and 22% of these colonies showed visible signs of partial bleaching. Single use plastic bags and wrappers were dominant plastic debris. The study area was characterized as 'very poor cleanliness' according to the Beach Quality Indexes, which include the Clean Coast Index, General Index, and Hazardous Items Index. The numerical model indicates the influence of river discharge and probable areas of plastic accumulation with high tidal currents in this region, maneuvering the spatial advection of litter in the nearshore areas. Combined analysis of ground-truthing and model simulation implies that the possible contributing sources of litter were representatives of land-based and sea-originated. The overall results point to increasing anthropogenic stressors threatening coastal coral communities, including marine debris pollution. It is advocated to adopt an integrated coastal zone management approach supported by coordinated policy frameworks could guide the mitigation of the debris footprint in coastal environments.

Macro problems from microplastics: Toward a sustainable policy framework for managing microplastic waste in Africa

Microplastic pollution is a ubiquitous and emerging environmental and public health concern in Africa due to increased plastic production, product and waste importation, and usage. While studies on the environmental monitoring and characterization of microplastics demonstrated the urgent need for a drastic reduction in plastic waste generation, the effectiveness of the various regulatory and policy interventions implemented or proposed in Africa countries remains poorly understood. We critically examined policies, legislations, and regulations enacted to control microplastic pollution in Africa to develop a sustainable, harmonized framework for the coordinated reduction of plastic waste generation across Africa. Analysis of the interventions revealed most African countries employed traditional perspective (i.e., command-and-control) approaches, whereby state instruments such as plastic ban, production and importation levies, and consumer taxes were enacted. However, the continued increase in microplastic waste generation suggests traditional perspective approaches might not be effective in Africa. Although rarely used in Africa, market-oriented approaches such as private-public waste management are often effective in controlling plastic pollution. Hence, we proposed a bottom-up hybrid regulatory approach for managing microplastics pollution in Africa, involving price-based, right-base, legislation and behavioral frameworks based on best practices in microplastic waste management.

Scattered accumulation hotspots of macro-litter on the seafloor: Insights for mitigation actions

Marine litter is an ever-increasing problem that demands immediate reduction plans and mitigation actions that should act synergically to efficiently meet ambitious goals. Since the seafloor has been recognized as the major sink for marine debris, the study of litter accumulation dynamics represent a fundamental tool to evaluate possible removal actions. We analysed a 7 years (2013-2019) standardized data series collected along Sardinian fishing grounds through MEDiterranean International Trawl Survey, for which estimates of density and weight of seafloor macro-litter were calculated for over 707 hauls. Results show the absence of any temporal trend in seafloor macro-litter density and weight, but rather indicate a spatial and bathymetric segregation of different litter categories. Our data showed how different sources and physical features of macro-litter items (i.e., plastic and fishing gear, rubber, glass, metals, and cloth) led to spatially segregated accumulation hotspots. We also point out here how the identification of seafloor macro-litter hotspots using aggregated data that include plastic items could obscure the identification of other segregated but yet relevant hotspots of other macro-litter categories accumulated in the marine environment. These hotspots often occurred at shallower depths and closer to coastlines, thus representing potential spots where eventual future litter removal action could be prioritized.

Scattered accumulation hotspots of macro-litter on the seafloor: Insights for mitigation actions

Marine litter is an ever-increasing problem that demands immediate reduction plans and mitigation actions that should act synergically to efficiently meet ambitious goals. Since the seafloor has been recognized as the major sink for marine debris, the study of litter accumulation dynamics represents a fundamental tool to evaluate future removal actions. We analysed a 7 years (2013-2019) standardized data series collected along Sardinian fishing grounds through MEDiterranean International Trawl Survey, for which estimates of density and weight of seafloor macro-litter were calculated over 707 hauls. Results show the absence of any temporal trend in seafloor macro-litter density and weight, but rather indicate a spatial and bathymetric segregation of different litter categories. Our data showed how different sources and physical features of macro-litter items (i.e., plastic and fishing gears, rubber, glass, metal and textile) led to spatially segregated accumulation hotspots. These hotspots often occurred at shallower depths and closer to coastlines, representing spots where future litter removal action could be prioritized. We also point out here how the identification of seafloor macro-litter hotspots using aggregated data that include plastic items could indeed hide the identification of hotspots of other less abundant but yet detrimental macro-litter categories accumulated in the marine environment.

Preserving Community’s Environmental Interests in a Meta-Ocean Governance Framework towards Sustainable Development Goal 14: A Mechanism of Promoting Coordination between Institutions Responsible for Curbing Marine Pollution

The United Nations has recently recognised the global community’s environmental interests in ocean governance through the Sustainable Development Goal 14. The marine environmental protection targets stand in need of rejuvenating international environmental law, which fosters interconnection between oceans, climate, and terrestrial ecosystems. The existing literature on this aspect of ocean governance, however, is segregated and lacks an ecosystem-based approach. Therefore, a comprehensive review of the literature on ocean governance with an ecosystem-based approach becomes essential and is conducted through this research. This research has proposed that ocean governance programmes and plans need to be re-arranged under established legal frameworks at national and regional levels. Such a challenge can be addressed by taking the elements of governance provided by the list of targets of sustainable development goals. This research has facilitated the given hypothesis via a meta-ocean-governance framework that incorporates a deliberate regional monitoring system, intergovernmental review, capacity building techniques, national action through strong institutions, scientific decision making, and policy coherence. The idea is to fit the conceptualisation of ocean governance under international environmental law in the existing initiatives within a box of institutions to coordinate and encourage an ecosystem-based approach.