Litter Categories Research Articles

Seasonal difference in marine litter along the coast of Dar es Salaam, Tanzania

Marine litter accumulation poses a significant threat to marine ecosystems and biodiversity. Marine litter and the influence of river discharge on marine litter accumulation during wet and dry seasons along the coast of Dar es Salaam was investigated. Litter samples collected between 2019 and 2021 from transects on beaches and by nets spanned across two rivers were counted, dried and weighed, and litter counts and weight (kg) calculated by area (litter/m2) and volume (litter/m3). Over three years, a total of 127,658 marine litter items weighing 470 kg were sampled from beaches, and 1,365 items from rivers, in nine different litter categories. Most of the litter (70 %) was produced locally and the marine litter density decreased by 61 % over the three years of the study. Litter densities at beaches and rivers were significantly greater during the wet than the dry season, attributed to the transport of litter in rivers to the ocean, especially plastics, which had a higher density than other riverine litter. It is concluded that high local plastic pro- duction and poor waste disposal systems require an intervention, and that a policy to minimize and reduce marine litter should be developed and implemented.

Benthic litter in fishing grounds of the Northern Adriatic: Role of the trawling fleet as cleaners of the seafloor

This study represents the baseline of estimation of the potential service provided by fishermen as “cleaners of the sea”. The amount, composition and depth distribution of marine litter in fishing grounds of the Northern Adriatic seafloor has been investigated through the fishing for litter (FFL) scheme. Passive FFL campaigns were carried out by trawlers from two of the most important fishing ports in the northern Adriatic, Chioggia and Goro, from May 2020 to May 2021. Over the course of 256 days of fishing, over 6 tons of litter were removed from 265 km2 of seafloor. Abandoned, lost and derelict fishing gears (ALDFG) were the most represented litter category (48 % of the total litter), and of these 67 % were plastic ALDFG (mostly mussel socks and fishing nets). Fouling on plastic waste was analyzed to determine the fraction of collected litter items that could be destinated to recycling. Only a small percentage of the plastic litter analyzed was “clean” from adherent and/or encrusting organisms. Approximately 2.4 tons of plastic were recovered, but, due to the biological colonization of surfaces, they cannot be recycled by using the technologies present in the area.

Quantification of litter in cities using a smartphone application and citizen science in conjunction with deep learning-based image processing

Cities are a major source of litter pollution. Determination of the abundance and composition of plastic litter in cities is imperative for effective pollution management, environmental protection, and sustainable urban development. Therefore, here, a multidisciplinary approach to quantify and classify the abundance of litter in urban environments is proposed. In the present study, litter data collection was integrated via the Pirika smartphone application and conducted image analysis based on deep learning. Pirika was launched in May 2018 and, to date, has collected approximately one million images. Visual classification revealed that the most common types of litter were cans, plastic bags, plastic bottles, cigarette butts, cigarette boxes, and sanitary masks, in that order. The top six categories accounted for approximately 80 % of the total, whereas the top three categories accounted for more than 60 % of the total imaged litter. A deep-learning image processing algorithm was developed to automatically identify the top six litter categories. Both precision and recall derived from the model were higher than 75 %, enabling proper litter categorization. The quantity of litter derived from automated image processing was also plotted on a map using location data acquired concurrently with the images by the smartphone application. Conclusively, this study demonstrates that citizen science supported by smartphone applications and deep learning-based image processing can enable the visualization, quantification, and characterization of street litter in cities.

Automated marine litter investigation for underwater images using a zero-shot pipeline

Accurate and automated identification of marine litter on the seafloor is crucial due to its detrimental effects on marine ecosystems. While advancements in underwater imaging have facilitated this task, the significant human involvement required in traditional approaches necessitates the development of more efficient and cost-effective solutions. This study presents an efficient zero-shot segmentation framework based on Segment-Anything (SAM) guided by Interpretable Contrastive Language–Image Pre-training (iCLIP) for identifying and segmenting eight common seafloor litter categories in realistic underwater environments without model training. The framework supports prompt input by design, which allows it to transfer its zero-shot capabilities to new types of marine litter. To further improve the framework’s performance, two additional components were incorporated: an underwater image enhancement model that addresses the degraded image quality common in underwater environments, and a mask post-processing algorithm that reduces noise masks generated by the framework. The recorded mean intersection over union (mIOU) of 69.9% on the testing dataset suggested that zero-shot approaches have the potential to become a valuable technique for automatically detecting marine litter during surveys and enabling continuous and accurate litter monitoring.

Marine Macro- and Micro Plastic Litter on Beach Sediment of Northern Peninsular Malaysia

This paper investigates the spatial distribution of small plastic litter on the beach of Kuala Perlis and Pulau Langkawi in the northern region of Peninsular Malaysia. The objectives are to ascertain the categories of macro marine litter and macroplastic types, the amount of microplastic in the sediment layer, and the relationship between macroplastic and microplastic. Macro marine litter was collected in 100-meter transects at six different locations. Sediment samples for microplastic identification were collected using a quadrat measuring 0.5 m × 0.5 m with a depth of 0.05 m. Plastic accounts up most of the macro marine litter collected (73.8%), followed by glass (12%), fabric (7.8%), rubber (4.4%), wood (2%), and metal (0.07%). Between 2018 and 2020, the overall weight of macroplastic (>5 mm) litter and the amount of microplastic (<5 mm) litter on northern beaches were 80.371 g/m2 and 11.094 g/m3, respectively. In this investigation, macroplastic collected on the beach surface ranged from 0.02 g to 14.09 g/m2, while microplastic in the beach sediment ranged from 0 to 1.192 g/m3. The packaging category seems to have the highest percentage of collected macroplastic. At the 95% confidence level, the calculated R2 of 0.7444 indicates a substantial association between macroplastic and microplastic. The linear regression equation is y = 0.1927x + 0.0226, with y representing microplastic (g/m3) and x being macroplastic (g/m2). This strong link demonstrates that the presence of microplastic in sediment is strongly related to the abundance of macroplastic on the beach. This finding provides a good approximation of actual microplastic occurrence to macroplastic abundance, which will be useful in environmental evaluation and management approaches.

Spatial and Temporal Deposition Rate of Beach Litter in Cadiz Bay (Southwest Spain)

This study explores the spatial and temporal distribution of beach litter accumulation rates at seven sites in Cadiz Bay, Southwest Spain, during October 2022 (i.e., autumn) and March 2023 (i.e., spring). Beach litter was collected during low tide conditions at the strandline during two series of 10 consecutive daily surveys. The main aim of this paper is to comprehensively analyze the influence of seasonality and hydrodynamic and wind patterns on litter abundance and composition. In October, 4199 items (22.58 kg) were recorded, increasing to 4634 items (22.68 kg) in March. Overall, the average litter abundance remained relatively consistent but notable variations were observed at different beach locations. Plastic litter was the most abundant in the total litter amount with 71.13% and 88.39% in October and March, respectively. Litter categories increased from 90 to 107 from October to March and the top 10 litter categories included cigarette butts (1746 in autumn and 514 in spring), plastic fragments (985 and 339) and plastic packaging (297 and 211). Statistical analyses showed no significant seasonal impact on litter quantities but confirmed seasonal variations in litter types. For instance, cigarette butts were more abundant in October, i.e., in autumn, as they are linked to the intensive use of beaches during the summer period (June–September), while wet wipes were prevalent in March, i.e., in spring, because they are associated with an increase in wastewater and river discharges recorded during the late autumn and winter months (November–February). No clear correlations were found between litter quantity and wave height, but specific patterns emerged at exposed and sheltered beaches. The findings provide valuable insights for optimizing coastal clean-up efforts with customized strategies. Further investigations are needed to fully understand the relationships between litter and environmental factors.

Monitoring microplastics in coastal waters of a biosphere reserve: a case study in Menorca (Spain)

This study provides with evidence of the presence of sea surface microplastics in a UNESCO marine biosphere reserve: the island of Menorca in the north-western Mediterranean Sea. From a total of 90 samples, in 100% of the samples, microplastics were observed with a mean value of 0.18 ± 0.01 items/m2. According to data, no significant differences were observed for sampling period with very similar values between 2021 (0.17 ± 0.02 items/m2) and 2022 (0.18 ± 0.02 items/m2). However, significant differences were observed regarding sampling area (both site and locality) suggesting that sea surface plastics in the study area might be more dependent of the spatial scale rather than on the temporal scale. Fibre type microplastics predominated over fragments, films, pellets, and foams, but in the commercial Port de Maó, almost 50% of the identified items were foams which could be related to the transportation of packed goods to this port. Results from the model applied to study the relation between waste management indicators and microplastic abundance indicate that when considering all marine litter categories, the explanatory variables are plastic waste generated by residents population (tonnes/year/km2) and waste collection rate (%), whereas if only plastics are considered, the indicator regarding waste per capita (kg/hab/year) is also included. Data in this study is obtained through a harmonized protocol which can be used to define baseline and threshold values to evaluate good environmental status regarding descriptor 10 of the Marine Strategy Framework Directive.

What, where, and when: Spatial-temporal distribution of macro-litter on the seafloor of the western and central Mediterranean sea

The progressive increase of marine macro-litter on the bottom of the Mediterranean Sea is an urgent problem that needs accurate information and guidance to identify those areas most at risk of accumulation. In the absence of dedicated monitoring programs, an important source of opportunistic data is fishery-independent monitoring campaigns of demersal resources. These data have long been used but not yet extensively. In this paper, MEDiterranean International Trawl Survey (MEDITS) data was supplemented with 18 layers of information related to major environmental (e.g. depth, sea water and wind velocity, sea waves) and anthropogenic (e.g. river inputs, shipping lanes, urban areas and ports, fishing effort) forcings that influence seafloor macro-litter distribution. The Random Forest (RF), a machine learning approach, was applied to: i) model the distribution of several litter categories at a high spatial resolution (i.e. 1 km2); ii) identify major accumulation hot spots and their temporal trends. Results indicate that RF is a very effective approach to model the distribution of marine macro-litter and provides a consistent picture of the heterogeneous distribution of different macro-litter categories. The most critical situation in the study area was observed in the north-eastern part of the western basin. In addition, the combined analysis of weight and density data identified a tendency for lighter items to accumulate in areas (such as the northern part of the Tyrrhenian Sea) with more stagnant currents. This approach, based on georeferenced information widely available in public databases, seems a natural candidate to be applied in other basins as a support and complement tool to field monitoring activities and strategies for protection and remediation of the most impacted areas.

Macroplastic deposition and flushing in the Meuse river following the July 2021 European floods

Rivers play an important role in the macroplastics transport and retention dynamics in the environment. Therefore, gaining an understanding of these processes is vital in order to help determine the fate of macroplastic in the environment. During flood events the transport of floating macroplastic is known to increase. We compared plastic accumulation and flushing on sixteen riverbanks along the Dutch Meuse river during the period that includes the July 2021 extreme flood to plastic accumulation on the same riverbanks as during normal discharge conditions between 2018 and 2021. Here we show that following the flood small macroplastic categories ( cm) were flushed from the riverbanks, while larger soft plastic fragments (2.5–50 cm) and wet tissues were deposited. We found that for all plastic categories and for all riverbanks averaged, the plastic accumulation rate during the July 2021 flood was higher than that which would be expected for that time of year. However, the average accumulation rate for all locations during the period that included the flood was lower than the average accumulation rate over the Dutch winter (Oct/Nov–Feb/Mar). Our results show that litter category composition following the July 2021 flood differed from normal conditions. This indicates that plastic deposition and remobilization processes on riverbanks differ between extreme flood and annually average conditions. These observations contribute to a better understanding of the fate of macroplastic in the environment in terms of the drivers of both its transport and deposition.

Polymer Characterization of Submerged Plastic Litter from Lake Tahoe, United States.

Monitoring plastic litter in the environment is critical to understanding the amount, sources, transport, fate, and environmental impact of this pollutant. However, few studies have monitored plastic litter on lakebeds which are potentially important environments for determining the fate and transport of plastic litter in freshwater basins. In this study, a self-contained underwater breathing apparatus was used for litter collection at the lakebed along five transects in Lake Tahoe, United States. Litter was brought to the surface and characterized by litter type. Plastic litter was subsampled, and polymer composition was determined using attenuated total reflection Fourier transform infrared spectroscopy. The average plastic litter from the lakebed for the five dive transects was 83 ± 49 items per kilometer. The top plastic litter categories were other plastic litter (plastic litter that did not fall in another category), followed by food containers, bottles <2 L, plastic bags, and toys. These results are in line with prior studies on submerged litter, and intervention approaches or ongoing education are needed. The six polymers most frequently detected in the subsamples were polyvinyl chloride, polystyrene/expanded polystyrene, polyethylene terephthalate/polyester, polyethylene, polypropylene, and polyamide. These observations reflect global plastic production and microplastic studies from lake surface water and sediments. We found that some litter subcategories were primarily comprised of a single polymer type, therefore, in studies where the polymer type cannot be measured but litter is categorized, these results could provide an estimate of the total polymer composition for select litter categories.

Assessment of plastic pollution in coastal areas of Karachi: Case study of West Warf, Kemari Jetty, and Manora

This study focused on marine pollution in coastal areas of Karachi, particularly West Warf, Kemari Jetty, and Manora. The research examined the sources and quantities of waste, from boat manufacturing, export units, and local commercial activities. Stakeholder interviews were conducted to understand waste management practices and identify the key contributors to ocean litter. The results indicated that restaurants, export units, boat construction, and tourist and commuter activities were the primary sources of marine pollution. Plastic was found to be the most prevalent litter category, with LDPE (e.g., single-use bags) and polystyrene (e.g., material in floating docks) being the most common types. Additionally, multi-layer packaging, such as chip wrappers, was frequently observed in the surveyed areas. Overall, this research highlights the urgent need for improved waste management and compliance measures in coastal regions to mitigate marine pollution.

Psammophytes as traps for beach litter in the Strait of Messina (Mediterranean Sea)

In the present paper, for the first time, the presence of beach litter in dunal plants has been verified in a Strait area in an island. The aims of the present study were to evaluate if the psammophytes can act as a trap for the beached litter, to compare beach litter in plants located in beaches with different anthropogenic impacts, and to describe a new approach (namely clean patch index, CPI) to evaluated the cleanliness of dunal plants. In total 738 macro litter items, belonging to 7 litter categories were found in the study area. The main litter category collected was plastic, followed by ceramic, glass, paper/cardboard, metal, sanitary waste, and medical waste. Our results showed that psammophytes acted as a sink for the beach litter by trapping it. The CPI was higher in the dunal plants than in the relative control patches. The average dissimilarity between “Montorsoli” and “Pylon” beaches was 88.7%. The highest contribution to the dissimilarity between the two beaches was the construction material, followed by polystyrene and plastic pieces. Our data could be important for the implementation of the monitoring program within the Marine Strategy Framework Directive, and may also contribute to the development of specific management of the clean-up measures as well as implement National and Regional action plans.

Socio-economic factors affecting the distribution of marine litter: The Portuguese case study

Marine litter is a growing global problem with serious environmental, economic, social, and health threats. Understanding the socio-economic factors that influence the types and amounts of litter is of utmost importance. In this study, an integrative analysis of the socio-economic factors that characterize the beach litter distribution in continental Portugal and the Azores archipelago was conducted via a cluster analysis, implementing a novel technique to support the difficult task of marine litter characterization. The results highlighted that the most abundant beach litter material is plastic (92.9 %), followed by paper (2.2 %), wood (1.5 %), and metal (1.3 %). The majority of the items could not be attributed to a specific source (46.5 %). The remaining were attributed to public litter (34.5 % of total aggregated items), fishing (9.8 %), sewage-related debris (6.4 %) and shipping (2.2 %). The top-three beach litter categories were small plastic pieces (0–2.5 cm, 43.5 %), cigarette butts (30.1 %), and medium plastic pieces (2.5–50 cm, 26.4 %). A positive relation between both municipality environment expenditures and population density and the quantity and typology of litter was found. Beach litter quantity and categories were also associated with specific economic sectors, as well as with geographical/hydrodynamic conditions, demonstrating the utility of the technique and its applicability to other regions.

Difference between invasive alien and native vegetation in trapping beach litter: A focus on a typical sandy beach of W-Mediterranean Basin

Beach litter is one of the most pervasive pollution issues in coastal environments worldwide. In this study, we aim to assess the amount and distribution of beach litter on Porto Paglia beach, its entrapment across psammophilous habitats, and whether the invasive Carpobrotus acinaciformis (L.) L.Bolus plays a different role in trapping litter than native vegetation. To this end, two seasonal samplings (in spring and autumn) were conducted using a paired sampling method that considers plots in all coastal habitats with and without C. acinaciformis. Our results confirm that the main beach litter category is plastic, and that its distribution varies across habitats: the white dune seems to play a greater role in trapping and filtering beach litter, reducing its amount in the backdune. A correlation was found between the Naturalness index (N) and the beach litter amount, supporting the finding that invaded habitats trap beach litter better than native ones.

Sample size requirements for riverbank macrolitter characterization

Anthropogenic litter is omnipresent in terrestrial and freshwater systems, and can have major economic and ecological impacts. Monitoring and modeling of anthropogenic litter comes with large uncertainties due to the wide variety of litter characteristics, including size, mass, and item type. It is unclear as to what the effect of sample set size is on the reliability and representativeness of litter item statistics. Reliable item statistics are needed to (1) improve monitoring strategies, (2) parameterize litter in transport models, and (3) convert litter counts to mass for stock and flux calculations. In this paper, we quantify sample set size requirement for riverbank litter characterization, using a database of more than 14,000 macrolitter items (&amp;gt;0.5 cm), sampled for 1 year at eight riverbank locations along the Dutch Rhine, IJssel, and Meuse rivers. We use this database to perform a Monte Carlo based bootstrap analysis on the item statistics, to determine the relation between sample size and variability in the mean and median values. Based on this, we present sample set size requirements, corresponding to selected uncertainty and confidence levels. Optima between sampling effort and information gain is suggested (depending on the acceptable uncertainty level), which is a function of litter type heterogeneity. We found that the heterogeneity of the characteristics of litter items varies between different litter categories, and demonstrate that the minimum required sample set size depends on the heterogeneity of the litter category. This implies that more items of heterogeneous litter categories need to be sampled than of heterogeneous item categories to reach the same uncertainty level in item statistics. For example, to describe the mean mass the heterogeneous category soft fragments (&amp;gt;2.5 cm) with 90% confidence, 990 items were needed, while only 39 items were needed for the uniform category metal bottle caps. Finally, we use the heterogeneity within litter categories to assess the sample size requirements for each river system. All data collected for this study are freely available, and may form the basis of an open access global database which can be used by scientists, practitioners, and policymakers to improve future monitoring strategies and modeling efforts.

Macroplastics in Lakes: An Underrepresented Ecological Problem?

Lakes are the greatest reserve of available superficial inland fresh water and concurrently one of the most threatened ecosystems. Among the many pollutants, plastics contaminate lakes worldwide; notwithstanding that, little is known on the impacts of macroplastics. The aim of this work is to provide the first global overview of scientific articles researching macroplastic pollution in lakes. Articles were selected from Web of Science and Scopus databases. We performed a bibliometric analysis of the results on the publication trend, geographical distribution of study areas, investigated matrix (i.e., water, sediment, biota), as well as abundance and type (i.e., shape, litter category, polymer) of lacustrine macroplastics. We also compared the articles’ methodologies. Fourteen articles were collected (the publication trend is increasing in recent years), showing a diffuse contamination by macroplastics. Research efforts are mostly focused on shoreline assessments. There is a lack of information and methodological standardisation (i.e., macroplastic size definition, sampling protocol, shape, litter categories), which limits the comparison of article outputs. We propose the definition of lacustrine macroplastics as plastics &gt;5 mm and the adoption of the UNEP/IOC protocol to sample lake shoreline. We suggest focusing future investigations on (1) testing the methodological standardisation, (2) understanding the factors influencing macroplastic dispersal, and (3) assessing the impacts on biota.

Linking marine litter accumulation and beach user perceptions on pocket beaches of Northern Sardinia (Italy)

Marine litter is a global issue, and one way to face this problem is to increase citizen knowledge and awareness. In our study, we analyzed and quantified the abundance of marine litter on 5 pocket beaches located in North Sardinia. From the 7975 collected items, plastic was the most important litter category. Regarding the MLs' sources, no-sourced and public litter were the most abundant. Waste density is quite high and characterized by great variability, due to two site-specific factors: geomorphological control and human influences. Those key aspects underlying the importance of further understanding marine debris fate and transport and human behaviors because they denote a crucial role to achieve effective marine debris management.In addition, social surveys were performed to assess users' perceptions and knowledge of marine litter. The results of the interviews show that people are aware of the negative impacts that may arise from the presence of waste, and recognized that the presence of litter on the beach is mainly due to human behavior. However, the comparison of beach users’ perceptions and the marine litter collected reveals that users only have partial knowledge of the waste composition, requiring further actions involving different targets.

Plastic pollution on Durance riverbank: First quantification and possible environmental measures to reduce it

Plastic pollution is one of the most pressing issues of our time, with negative impacts on natural ecosystems, human health, and the climate system. The identification of top litter items discarded in the environment is essential to prioritize environmental policies to prevent plastic leakage and promote a circular economy. Here, we present the first quantification of macrolitter on three sites along Durance riverbank and one site on Lake Serre-Ponçon's beach, in the Région SUD–Provence-Alpes-Côte d'Azur, southeastern France. Data were collected through citizen science between 2019 and 2020 in three sampling occasions (autumn, winter, spring) on Durance riverbank and in 22 occasions on Lake Serre-Ponçon. A total of 25'423 litter items were categorized, of which 82% were plastics. Single-use plastic items correspond to 8.13% of total, while single-use plastic bottles are among the top 10 litter items at each site. Median litter abundance across all samples is 2,081 items/100 m survey, two orders of magnitude higher than European precautionary threshold value for marine litter (20 items/100 m survey). The majority of items (74.83%) were small and non-identifiable. Pieces of polystyrene, soft plastics and rigid plastics represented the majority of litter items in total (56.63%) and at S1 (89.28%), S2 (58.95%) and S3 (79.60%). Glass pieces corresponded to 15.83% of total litter items. Soft plastic pieces are the most abundant litter category overall and correspond to 58.85% of litter items at sampling site along Durance riverbank located in an agricultural zone, suggesting their source from agricultural plastic mulch films. Among the identifiable items, the most abundant were plastic biomedia used in waste water treatment plants and single-use beverage bottles in plastic and in glass. The development of extended producer responsibility schemes for plastic mulch films and plastic biomedia and of deposit return schemes for single-use beverage bottles is suggested as a way to prevent leakage in the environment. This work confirms the opportunity to use citizen science to gather relevant data on macrolitter items and to monitor the effectiveness of environmental regulations to reduce plastic pollution.

Spatio-temporal variations of litter on Qingdao tourist beaches in China

Beaches are an integral part of coastal tourism, but they are deteriorated by the beachgoers and recreational activities due to lack of adequate beach environmental awareness and management. Litter is widely distributed in marine and coastal environment and has been considered a severe concern. In China investigations to determine the beach litter abundance and pollution level are limited. The aim of this study is to estimate spatio-temporal distribution and composition of litter on 10 well-known Qingdao tourist beaches, involving pollution level by beach quality indexes. Beach litter was collected within an area of 25 × 25 m2 in both summer (May, June and July) and winter (Nov, Dec and Jan) seasons, and was classified into eight categories. The abundance of beach litter was found higher in summer (0.13 ± 0.04 items/m2) than in winter (0.04 ± 0.01 items/m2). Overall, the percentage of plastics were higher in both summer (23.48%) and winter (24.04%) than that of other litter categories. Based on Clean Coast Index, 70% of beaches were very clean, 25% clean, and 5% moderately clean. Beach Grade Index showed that 15% beaches were very good, 5% good, 55% fair, and 25% poor. 85% beaches constituted some quantity of hazardous litter and 15% had no hazardous litter for Hazardous Items index. The findings suggest that the sources of beach litter along Qingdao beaches mainly come from the recreational and tourist activities. The substantial quantity of litter is also being transported by ocean (tides or current), which are finally deposited along beachfront. Despite regular cleaning operation along most of Qingdao beaches, suggested management practices involve mitigation measures, source reduction, change in littering behavior to improve further quality of beaches.

The influence of monsoons on the spatial distribution and composition of floating marine litter

Floating marine litter (FML) surveys were conducted in the near shore waters of Mombasa, Kilifi and Kwale Counties of Kenya through trawling using a manta net. A mean density of 26,665 ± 2869 items km−2 composed of 34.8% hard plastic, 40.5% soft plastics and 22.0% plastic lines/fibers was reported in this study. Litter densities in Kwale, Kilifi and Mombasa Counties were not influenced by monsoons, however, litter composition was influenced by monsoons with NEM and SEM being dominated mainly by hard plastics and soft plastics respectively. Litter categories diversity, evenness and richness were also not influenced by the monsoons during both NEM (1.01, 0.78 and 3, respectively) and SEM (1.09, 0.78 and 4, respectively). Fishing and recreational beaches had higher litter densities during NEM compared to SEM attributed to higher beach visitation and increased fishing activities during the calmer NEM season.