Despite the large research effort on reporting quantities of coastal litter, the dynamics of this litter is not yet sufficiently understood. Litter inputs in five cobble beaches located in the Mediterranean (Spain) were studied over three months during winter by biweekly litter tagging. Plastic represented the dominant material that reached the beaches (77%). In remote and narrow beaches, storms constituted the main driver in litter dynamics, favouring the accumulation of floating items such as plastic bottles and wood fragments as well as the largest but contrasting effects, increasing litter inputs and outputs from the beach, respectively. In rural beaches, beach users, mainly fisher people, but also tourists, contributed to a notable input of litter to the beach. Burial and exhumation of litter were reported as common occurring processes. Better management actions are required to improve beach environmental quality. | This research is a contribution to the Andalusia PAI Research Group "RNM-328" and to the Ibero-American Beach Management and Certification Network -PROPLAYAS. This work was supported by the Biodiversity Foundation of the Ministry for the Ecological Transition and Demographic Challenge from Spain [FBIOMARINA19-01]. Special thanks go to David Saez, Natalia Sanchez, Laura Valero and Alba Amat for their help during the sampling periods and thanks to "Puertos del Estado" for oceanographic data. Thanks are also given to the municipalities involved in this research for answering to enquires about beach cleaning modalities. Finally, special thanks to two anonymous reviewers for their useful comments and suggestions, which have been very helpful in improving the manuscript.

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.

The accumulation of human-derived debris in the oceans is a global concern and a serious threat to marine wildlife. There is a volume of evidence that points to deleterious effects of marine debris (MD) on cetaceans in terms of both entanglement and ingestion. This review suggests that about 68% of cetacean species are affected by interacting with MD with an increase in the number of species reported to have interacted with it over the past decades. Despite the growing body of evidence, there is an ongoing debate on the actual effects of plastics on cetaceans and, in particular, with reference to the ingestion of microplastics and their potential toxicological and pathogenic effects. Current knowledge suggests that the observed differences in the rate and nature of interactions with plastics are the result of substantial differences in species-specific diving and feeding strategies. Existing projections on the production, use and disposal of plastics suggest a further increase of marine plastic pollution. In this context, the contribution of the ongoing COVID-19 pandemic to marine plastic pollution appears to be substantial, with potentially serious consequences for marine life including cetaceans. Additionally, the COVID-19 pandemic offers an opportunity to investigate the direct links between industry, human behaviours and the effects of MD on cetaceans. This could help inform management, prevention efforts, describe knowledge gaps and guide advancements in research efforts. This review highlights the lack of assessments of population-level effects related to MD and suggests that these could be rather immediate for small populations already under pressure from other anthropogenic activities. Finally, we suggest that MD is not only a pollution, economic and social issue, but also a welfare concern for the species and populations involved.

Plastic pollution is one of several anthropogenic stressors putting pressure on ecosystems of the Caribbean Large Marine Ecosystem (CLME). A ‘Clean Ocean’ is one of the ambitious goals of the United Nations (UN) Decade of Ocean Science for Sustainable Development. If this is to be realized, it is imperative to build upon the work of the previous decades (1980–2020). The objectives of the present study were to assess the state of knowledge about: (i) the distribution, quantification, sources, transport and fate of marine debris/litter and microplastics in the coastal/marine environment of the CLME and, (ii) the effects of plastics on biodiversity. Snapshots, i.e., peer-reviewed studies and multi-year (1991–2020) marine debris data from International Coastal Cleanup (ICC) events, indicated that plastic debris was a persistent issue in multiple ecosystems and environmental compartments of the CLME. Collectively, a suite of approaches (debris categorization, remote sensing, particle tracking) indicated that plastic debris originated from a combination of land and marine-based sources, with the former more significant than the latter. Rivers were identified as an important means of transporting mismanaged land-based waste to the marine environment. Oceanic currents were important to the transport of plastic debris into, within and out of the region. Plastic debris posed a threat to the biodiversity of the CLME, with specific biological, physical, ecological and chemical effects being identified. Existing data can be used to inform interventions to mitigate the leakage of plastic waste to the marine environment. Given the persistent and transboundary nature of the issue, further elucidation of the problem, its causes and effects must be prioritized, while simultaneously harmonizing regional and international approaches.

Marine litter is widely distributed in marine environments and has been a severe concern worldwide, due to the disposal of waste from diverse sources. The severity of this threat has garnered increasing attention in India over the last decade, but the full consequences of this pollution are yet to be quantified. To estimate the spatiotemporal distribution, composition and beach quality of marine litter pollution, 17 beaches along the Hooghly estuary, a part of the Gangetic delta was studied. Marine litter was collected from 100 m long transects during two seasons (monsoon and post-monsoon). The OSPAR monitoring standard was applied to the 16,597 litter items collected, then grouped under 6 types and 44 categories. In terms of number, litter abundance was higher during monsoon (1.10 ± 0.39 items/m²) than that of post-monsoon (0.86 ± 0.32 items/m²). Most of the beaches were categorized as low cleanliness as computed by the general index and clean coast index and the good for the pellet pollution index. Hazardous litter constituted 6.5% of the total collected litter items. The model prediction revealed that the influence of high discharge from Hooghly, Rasulpur and Subarnarekha River carried enormous anthropogenic litter to the northeast beaches. The litter flux decreases with an increase in distance from the shore, and act as a sink to the sea-floor. The results denote that the distribution and typology of marine litter were representatives of household, tourism and fishing, which in turn highlights the need for better regional litter management measures. Suggested management practices include source reduction, mitigation, management of beach environment and change in littering behaviour through environmental education.

Microplastic contamination in ecosystems has emerged as an environmental issue of global significance. This research quantified microplastics in oysters from 22 sites along Taiwan coastlines. In total, 6630 microplastic items were found in 660 oysters of two genera (Crassostrea and Saccostrea). The average content of microplastics was 3.24 ± 1.02 items/g (wet weight), ranging from 0.63 ± 0.52 items/g to 37.94 ± 19.22 items/g. Over half of the microplastics were smaller than 100 μm, and the most common shape was fragments (67%), followed by fibers (29%). The dominant color was transparent (49.76%), followed by black (25.66%). Polymer types were identified using a μRaman microscope, and the major component was polyethylene terephthalate (PET) (69.54%). Microplastic contamination was higher overall in wild than in farmed oysters. In addition, the microplastic content of oysters from northeastern waters was significantly greater than that of other oysters; this result is similar to the findings of previous research on floating marine litter and beach cleaning data. The results indicated that the average content of microplastic in oysters along the Taiwan coastline was similar to that in oysters in adjacent regions. This study suggests that innovative technologies should be implemented for monitoring and removing pollution, tracking marine pollution origins, and improving accountability and that plastic limitation strategies should be strengthened.

The world's oceans are under increasing pressure from anthropogenic activities, including significant and rapidly increasing inputs of plastic pollution. Seabirds have long been considered sentinels of ocean health, providing data on physical and chemical pollutants in their marine habitats. However, long-term data that can elucidate important patterns and changes in seabird exposure to marine pollutants are relatively limited but are urgently needed to identify and support effective policy measures to reduce plastic waste. Using up to 12 years of data, we examined the benefits and challenges of different approaches to monitoring plastic in seabirds, and the relationship between plastic and body size parameters. We found the mass and number of ingested plastics per bird varied by sample type, with lavage and road-kill birds containing less plastic (9.17–9.33 pieces/bird) than beach-washed or otherwise dead birds (27.62–32.22 pieces/bird). Beached birds therefore provide data for only a particular subset of the population, mostly individuals in poorer body condition, including those severely impacted by plastics. In addition, the mass and number of plastics in beached birds were more variable, therefore the sample sizes required to detect a change in plastic over time were significantly larger than for lavaged birds. The use of lavaged birds is rare in studies of plastic ingestion due to ethical and methodological implications, and we recommend future work on ingested plastics should focus on sampling this group to ensure data are more representative of a population's overall exposure to plastics.

Entanglement of pinnipeds with plastic debris is an emerging conservation and animal welfare issue worldwide. However, the origins and long-term population level consequences of these entanglements are usually unknown. Plastic entanglement could produce a combination of wounds, asphyxiation, or inability to feed that results in the death of a certain percentage of individuals from the total population. In this research, we report on the consequent effect of plastic entanglement on population growth demographics in a South American fur seal (Arctocephalus australis australis) colony on Guafo Island, southern Chile. Using a stochastic matrix population model structured according to age and sex, and assuming an otherwise stable population, we explored population growth rates under five scenarios with differing rates of entanglement: A) a zero rate of plastic entanglement, B) entanglement rates (number of entangled individuals as a proportion of the total number of individuals) as observed in our study population (overall entanglement ratio of 1.2 × 10⁻³); and for the other scenarios, entanglement ratios as reported in the literature for other pinniped colonies around the world: C) 3.04 × 10⁻³, D) 4.42 × 10⁻², and E) 8.39 × 10⁻². Over the 30 years forecasting period and starting with a population size of ∼2950 individuals, the population growth rate was lower under all scenarios with rates of entanglement greater than zero (scenarios B-E). In comparison with scenario A, at the end of the 30-year period forecasted, we calculated a projected decrease in population size of between 20.34% (scenario B) and 91.38% (scenario E). These results suggest that even the lowest levels of entanglement in pinnipeds as reported in the literature might have significant effects over time on population-level dynamics. Our research offers potential insight when devising policy for the management and limitation of plastic pollution in the oceans, and indeed for the conservation and management policy of affected marine species. Furthermore, whilst there are some limitations to our methodology, it offers a straightforward and potentially useful approach for the standardized prediction of impacts at a population level of different rates of plastic pollution and entanglement and could be applied in distinct populations of the same species around the world.

Microplastics in commercially important seafood species is an emerging area of food safety concern. While there have been reports of plastic particles in the gastrointestinal tract of several species, presence of microplastics in edible fish tissues has not yet been reported from India. This study examined the presence of microplastics in the edible (muscle and skin) and inedible (gill and viscera) tissues of nine commercially important pelagic fish species from Kerala, India. A total of 163 particles consisting mainly of fragments (58%) were isolated. Out of 270 fishes analysed (n = 30 per species), 41.1% of the fishes had microplastics in their inedible tissues while only 7% of fishes had microplastics in their edible tissues. The quantity of microplastics in inedible tissue was significantly larger in filter feeders than, that in visual predators (p < 0.05). The average abundance of microplastics in edible tissues was 0.07 ± 0.26 items/fish (i.e., 0.005 ± 0.02 items/g) and was 0.53 ± 0.77 items/fish (i.e., 0.054 ± 0.098 items/g) in inedible tissues. The results suggest the possibility of human intake of microplastics by the consumption of pelagic fishes from this region, albeit in small quantities.