Marine macro-litter composition and distribution along the Kenyan Coast: The first-ever documented study

Assessing the impact of banning the single-use plastic carrier bags: a case study for Kenyan marine environment looking at macro, meso, and microplastics

Poor waste management and unsustainable institutional and individual behaviors, have led to the accumulation of plastic litter in many habitats worldwide. Assessment of plastic pollution in Kenyan marine environment was conducted focusing on the impact of banning the single-use plastic carrier bags in Kenya. The quantification, composition, and distribution of plastics were determined at nine (9) beaches along Kenyan coastline using standing stock method. A total of 750 plastic items were collected and categorized with only 47 pieces being single-use plastic carrier bags. A great number of plastics (n = 383), were identified by their original use, with packaging plastics being the most common (n = 155). Macroplastics were the overall dominant plastics at 76%, mesoplastics, 21% and microplastics, 3%, which were altogether dominated by low-density polyethylene (LDPE) at (46%), followed by polypropylene (PP), 30%; polyethylene tetraphthalate (PET), 9%; polyvinyl chloride (PVC), 8%; and polystyrene (PS), 7%. The absence of identifiable single-use plastic carrier bags in 6 out of 9 beaches signified the effectiveness of the ban in Kenya. Monitoring of trends and sources of plastic debris is encouraged to help enhance the science-policy linkage aimed at reducing marine plastic pollution.

Litter traps: A comparison of four marine habitats as sinks for anthropogenic marine macro-litter in Singapore

The potential for marine litter being trapped in biodiverse marine habitats such as mangrove forests, seagrass meadows and coral reefs is poorly understood. This study presents the first comprehensive investigation on the status of macro-litter across four marine habitats in Singapore during the two monsoonal seasons. Overall, litter density did not vary considerably between the southwest and the northeast monsoon. The litter density in terms of count was generally lower in seagrass meadows and coral reefs compared to mangroves and beaches. Plastic was the major type of litter found across most habitat types. Notably, many fishing-related items were found on coral reefs, while drinking straws were abundant at the mangrove strandlines during the southwest monsoon. Foam fragments and cigarette butts were common at the beach strandlines. These results suggest that mangroves among other habitats examined here should be prioritised for clean-up efforts in order to restore these critical coastal habitats.

The tourism industry keeps beaches clean in Mozambique

In this study, we conducted the first assessment of the litter abundance, diversity and predictors in Mozambique, by collecting approximately 2 tons of litter along six beaches across the country. We tested whether population, touristic industry, fishing, and recreation activities predict the quantity of macro litter for each of the 11 types and 141 subtypes of litter. Overall, we found that plastics made up 60.1 % of the items across all sampled beaches. Following plastics, clothing objects accounted for the second most weight (20.4 %) while foam objects were the second most abundant (15.7 %). More importantly, our results show that the tourism industry is a strong predictor for lower levels of litter across most types of litter while population density and fishing activity were strong predictors for higher levels. Our findings suggest that the tourism industry plays a crucial role in the country by maintaining the beaches clean.

Proximity to coast and major rivers influence the density of floating microplastics and other litter in east African coastal waters

Floating anthropogenic litter occurs in all ocean basins, yet little is known about their distribution and abundance in the coastal waters off east Africa. Neuston net and bulk water sampling shows that meso- and micro-litter (8567 ± 19,684 items∙km^-2, 44 ± 195 g∙km^-2) and microfibres (2.4 ± 2.6 fibres∙L^-1) are pervasive pollutants off the coasts of Tanzania and northern Mozambique, with higher litter loads off Tanzania. Densities of meso- and micro-litter at the start of the rainy season were greater close to the coast and to major river mouths, suggesting that much litter likely originates on land. However, the mass of litter increased with distance from the six major coastal cities. By number, 95% of meso- and micro-litter was plastic, but only 6% of microfibres. Our results highlight the need to reduce plastic use and improve solid waste management in the region.

Are tropical mangroves a sink for litter leaking from land-and sea-based sources? Evidence from selected Kenyan mangroves

Marine litter surveys were carried out to determine the role of mangroves as a sink for litter. General litter density in the mangroves was 0.088 ± 0.076 items m^-2, composed mainly of plastic (85.9 %). Higher litter densities occurred in the middle (0.162 ± 0.150 items m^-2) compared to the landward (0.066 ± 0.049 items m^-2) and the seaward zones (0.036 ± 0.028 items m^-2), indicating the important role played by the middle zone in providing a sink for litter from both land and sea-based sources. Landward zones were a sink for heavier litter from land that could easily be trapped by mangrove roots (plastic and clothing). The middle zones retained mainly the litter that are not easily trapped by the mangroves' roots in seaward and landward zones, particularly soft plastics. The seaward zones acted as a sink for litter from sea-based sources mainly marine and fishing gears, and materials used for fishing and boat repairs.

Dunal plants intercepting macrolitter: Implications for beach clean-ups

Coastal vegetation intercepts macroplastics and, consequently, it may represent a reservoir of anthropogenic litter and organic wrack. We aimed at investigating (i) the abundance variation of macrolitter from the beach to foredune and backdune (three cross-shore plots over 20 long-shore sectors) and (ii) the role of the halo-psammophilous plants and Phragmites australis reedbed in intercepting the macrolitter, respectively, in the foredunes and backdunes. The vegetation in the foredunes (mainly halo-psammophilous species) acted as a first interception belt for macrolitter, while the bigger litter reached the backdunes. Our results might be of great concern with implications for beach clean-ups - which must also be mainly focused in foredunes and backdunes, however warning operators in advance that they could damage the vegetation by trampling on.

Personal protective equipment (PPE) pollution driven by COVID-19 pandemic in Marina Beach, the longest urban beach in Asia: Abundance, distribution, and analytical characterization

COVID-19 pandemic has enforced the use of personal protective equipment (PPE, masks and gloves). However, the mismanagement of litter are exacerbating the increasing plastic issue worldwide. In the present study, we sampled discarded PPE in 10 sites along Marina Beach, India. We characterized the litter types by chemical analysis techniques. A total of 1154 COVID-19-associated PPE items were found on Marina beach. The highest number of items were face masks (97.9 %) and the mean PPE density in the sites studied was 4 × 10^-3 PPE m^-2. The results demonstrate that poor solid waste management and lack of awareness are the main causes of pollution at Marina beach. FTIR spectroscopy revealed that face masks and gloves were principally made of polypropylene and latex, respectively. The FTIR spectra also showed signs of chemical degradation. Our results suggest that plastic pollution is increasing, possibly becoming more impactful to marine biota. Beach management measures were discussed.

Evaluating Canada's single-use plastic mitigation policies via brand audit and beach cleanup data to reduce plastic pollution

Single-use plastics (SUPs) represent a major threat to marine environments and require proactive policies to reduce consumption and mismanagement. Many SUP management strategies exist to reduce SUP use and mitigate environmental impacts, including extended producer responsibility (EPR), deposit-return schemes, SUP bans or taxes, and public outreach and education. This study analyzed brand audit and beach cleanup data in four densely populated Canadian cities (Vancouver, Toronto, Montréal, Halifax) and a remote island (Sable Island) to determine efficacy of ongoing SUP mitigation measures. Cities were found to have similar litter type proportions, and six brands were found to disproportionally contribute to Canadian SUP litter, comprising 39% of branded litter collected. Results confirm that current Canadian SUP management appears to be insufficient to address leakage of SUPs into the environment. Recommendations to strengthen SUP management strategies and mitigate plastic pollution are recommended to improve future Canadian SUP reduction policies.

Are tropical estuaries a source of or a sink for marine litter? Evidence from Sabaki Estuary, Kenya

Litter surveys were carried out in August and September 2020 to determine the contribution of Sabaki River and estuary in modifying the quantities of litter entering the oceans. The river discharged 0.035 items m^-3s ^-1 translating to an estimated annual litter flux of between 6,622,560 and 614,952,000. The surveys in the estuary revealed that plastics contributed 90.8% of the total litter. Wet and dry zones had mean litter accumulation rates of 2.7 ± 1.1 and 4.4 ± 3.5 items m^-1 day^-1 respectively. 69.8% and 77.4% of branded litter were of Kenyan origin and food packaging material respectively. The litter turnover was slightly higher in the dry beach zone compared to the wet zone with a Whitakker Beta diversity of 0.36 and 0.33 respectively. Sabaki estuary acted as a sink for litter during flooding (through burial) and as a source (through exposure of buried litter due to wind and rain action).

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.

A first assessment of marine meso-litter and microplastics on beaches: Where does Mauritius stand?

Marine litter is a major global concern that is threatening marine ecosystems. This study assessed the meso-litter and microplastics density around Mauritius Island, South West Indian Ocean (SWIO) region. WIOMSA guidelines were used for meso-litter and microplastics sampling from October to December 2019 at 12 sites. A total of 1095 meso-litter items (weighing 1250 g) was sampled. Plastics were the most abundant litter category. 'Shoreline and recreational activities' were the main meso-litter source. Microplastics density was highest at the vegetation line (VL) zone. Fragments, mostly blue-coloured, were the most encountered type of microplastics, and polyethylene was the most prevalent polymer type. This study provides important baseline data which can be used by relevant authorities for more effective waste management strategies and awareness campaigns that will help further mitigate the marine litter problem in Mauritius, and to check the effectiveness of management measures in place.

The macro-debris pollution in the shorelines of Lake Tana: First report on abundance, assessment, constituents, and potential sources

Macro-debris monitoring in the shores of freshwater systems is critical to estimate the macro-and micro-plastic pollution levels for the subsequent investigation of ecological pollution. The study aims to report the composition of macro debris and their distribution on the shore of Lake Tana, Ethiopia, as a first baseline document. The distribution of litter surveys was conducted at seven different town/village shorelines of Lake Tana. The debris was categorized, and its constituent, abundance, and accumulation rates were computed. The findings showed that the mean accumulation rates of Lake Tana debris ranged between 4.9 ± 3.9 and 30.5 ± 20.2 items m^-1 day^-1 in counts and between 0.32 ± 0.21 and 0.04 ± 0.09 ± 0.03 g m^-1 day^-1 in mean weight. Also, the plastic polymers were identified as PET, PE, and HDPE. The litter categories abundance is different in different sampling locations. Plastics as packaging materials were extensively distributed in surveyed areas. A significant quantity of litter are local products and a locally feasible solid waste management system can be used to eradicate outflow into Lake Tana and can reduce pollution.

The first baseline estimation of marine litter in Port Elizabeth, South Africa

Data on marine litter is crucial to guide waste management but is scarce in third-world countries such as South Africa. We established the first baseline measurement of litter accumulation on two beaches differing in public access in Port Elizabeth, Eastern Cape, the poorest province in South Africa. Four 10-day surveys were conducted on each beach between June 2019 and June 2020. Results revealed that most of the litter (95.7%) was of South African origin and likely came from local land-based sources (e.g., beachgoers or a local river). Daily accumulation rates at the study sites ranged between 24.58 and 86.54 items·100 m^-1·day^-1, an order of magnitude lower than rates from other cities in Africa. However, like elsewhere, plastic (including foam) made up the bulk (74.2%) of litter with food packaging contributing a large portion of this. These findings indicate that local interventions are warranted to reduce litter in Port Elizabeth.

Temporal trends of marine litter in a tropical recreational beach: A case study of Mkomani beach, Kenya

Six marine litter standing stock surveys were carried out to determine the influence of monsoon on the temporal abundance and composition of macro-litter in Mkomani beach, Mombasa Kenya. Foam (0.073 items m^-2) and plastic (0.042 items m^-2) fragments had the highest densities. The brand audit indicated that 66.9% of branded marine litter was of Kenyan origin. Food product packaging contributed 78.4% of the branded litter with PET bottles being the most abundant type of packaging (48.2%). Foreign products contributed 35.6% of branded marine litter during South East Monsoon (SEM) whereas only 11.7% during North-East Monsoon (NEM). Worth noting, PET packaging dominated during SEM (53.6%) compared to NEM (20.2%). Mkomani beach could be considered "extremely dirty" with a Clean-Coast Index greater than 20. The study concludes that monsoons influences litter diversity, richness and evenness.