The first baseline estimation of marine litter in Port Elizabeth, South Africa
Introduction
Globally between 0.5 and 12.7 million tonnes of plastic are estimated to enter the ocean annually (Jambeck et al., 2015; Lebreton et al., 2017; Schmidt et al., 2017). Once in the environment, plastic may persist for decades or even centuries (Andrady, 2015) and can be distributed over large distances across international borders (Barnes and Milner, 2005). Litter is among the most persistent threats to the marine environment (Tiller et al., 2019).
Plastic litter is known to have social, economic and ecological repercussions (UNEP, 2018; Beaumont et al., 2019). In Africa where dependency on marine resources is high, plastic and other marine litter threatens food security and economic development (Jambeck et al., 2018). For example, South Africa has over 30,000 subsistence fishers whose food security is directly dependant on marine resources (DAFF, 2016). A decline in marine resources would thus have a direct impact on their livelihoods and welfare. The waste management infrastructure of most African countries is unable to keep up with the rapid urbanization currently taking place on the continent (UNEP, 2018), resulting in incremental loads of litter entering the sea. Litter and its ramifications are only expected to worsen with continuous population and economic growth in Africa (Jambeck et al., 2018; UNEP, 2018).
In efforts to combat the global litter crisis, many African countries became signatories to international treaties, such as the Abidjan and Nairobi Conventions, regarding the regulation and reduction of marine litter. To meet litter reduction targets set by these international treaties, quantitative data are required to determine current litter baselines and to monitor changes in litter loads over time, to assess the efficacy of management interventions. Such quantitative data are lacking in Africa (Jambeck et al., 2018; UNEP, 2018). To rectify this, the Western Indian Ocean Marine Science Association (WIOMSA) initiated a programme across seven countries bordering the Western Indian Ocean, all of which are signatories to the Nairobi Convention, to establish a litter monitoring programme for the region. This programme is being co-ordinated by Sustainable Seas Trust, South Africa, through their African Marine Waste Network (AMWN) Programme. Participants in the WIOMSA Marine Litter Monitoring Programme have committed to determine marine litter baselines in their respective locations by conducting beach litter surveys (AMWN and WIOMSA, 2019).
Beaches are ideal habitats to monitor marine litter as they are usually easily accessible and relatively easy to survey (requiring very little training and specialized equipment) compared to other habitats (GESAMP, 2019). In addition, a large portion of floating plastic entering the ocean via rivers (the primary source of ocean plastics; Jambeck et al., 2015; Lebreton et al., 2017; Schmidt et al., 2017) is predicted to wash up on nearby beaches (Collins and Hermes, 2019; Lebreton et al., 2019), making beaches ideal habitats to understand marine litter loads. Understanding the origin, source, and dynamics of marine litter on local beaches is necessary to adopt appropriate management measures. For example, if beach litter derives primarily from land-based sources of local origin (Duhec et al., 2015; Ryan et al., 2018; Okuku et al., 2020), it would indicate that mitigation efforts on land may be warranted.
In South Africa, effective waste management is hampered by issues such as the lack of compliance and capacity to enforce regulations, poor education of stakeholders within the waste sector, a short supply of suitable land for waste disposal, and operational costs of municipal waste management (STATS SA, 2018). In 2017, South Africa generated 54.2 million tonnes of solid waste, of which only 38.6% was recycled (DEA, 2018). To improve the country's overall waste management, it is important to have baselines of litter from different locations.
The aim of this study was to determine the litter baselines at two beaches in Port Elizabeth (now Gqeberha), Eastern Cape, South Africa, to guide future litter reduction measures. To date, most beach litter surveys in South Africa have been conducted in the Western Cape province, in and around Cape Town (Lamprecht, 2013; Chitaka and von Blottnitz, 2019; Ryan et al., 2020). The only other litter study in the Eastern Cape estimated monthly litter accumulation rates in the rural region of the Transkei, in the north-eastern part of the Eastern Cape (Madzena and Lasiak, 1997). In this study, we conducted daily beach litter accumulation surveys in the city with the largest population in the Eastern Cape. This province is considered to be the poorest in South Africa, with the lowest municipal waste collection rate (36%), and greatest leakage of waste into the environment per year (>19,500 tonnes; IUCN-EA-QUANTIS, 2020). The objectives of the study were to determine the origin, abundance, and composition of marine litter in Port Elizabeth, and to identify potential problem items and sources of litter.
Section snippets
Methods
Macro-litter (≥2.5 cm, sensu GESAMP, 2019) composition and origin, as well as daily rates of accumulation were studied on two beaches in Port Elizabeth, Eastern Cape, South Africa, in June 2019, October 2019, February 2020, and June 2020. The study sites were Cape Recife beach (34°01′21″S; 25°41′49″E) and Bluewater Bay beach (33°51′16″S; 25°38′19″E; Fig. 1). These sites contrasted in their exposure to potential sources of litter e.g., nearby rivers, their primary use (recreational use/fishing)
Results
Across the year of our sampling, between June 2019 and June 2020, a total of 20,511 items (200.23 kg) was collected. Of these, 11,289 items (32.56 kg) were collected at Bluewater Bay beach (BWB) and 9,222 items (167.67 kg) were collected at Cape Recife beach (CR).
Discussion
The Eastern Cape is both the poorest province in South Africa and the one with the most waste entering the environment (IUCN-EA-QUANTIS, 2020). However, studies assessing the origin, amount, type, and sources of marine litter are lacking for this province. Our study in Port Elizabeth, the city with the largest population in the Eastern Cape, South Africa is the first to explore daily litter accumulation rates in this province and revealed relatively low rates of litter accumulation on the
Funding
We thank the Norwegian Ministry of Foreign Affairs and the Western Indian Ocean Marine Science Association for funding received. The funders had no role in study design; in the collection, analysis and interpretation of data; in the writing of the manuscript; and in the decision to submit the article for publication.
CRediT authorship contribution statement
Toshka Barnardo: Conceptualization, Methodology, Validation, Investigation, Resources, Writing – original draft, Writing – review & editing, Visualization, Supervision, Project administration. Tanna Mae van Niekerk: Investigation, Writing – original draft, Writing – review & editing, Visualization, Project administration. Lorien Pichegru: Conceptualization, Methodology, Formal analysis, Resources, Data curation, Writing – original draft, Writing – review & editing, Visualization. Danica Marlin:
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
We thank Prof Peter Ryan for initial advice on the study design and all the volunteers who assisted in the litter collection. We thank Irene Joubert for assisting with obtaining weather data.
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