# First record of pyroplastic and partially burnt plastic litter along South African shores

Gerardo Zardi, Kevin C.K. Ma, Pierre William Froneman, Katy Nicastro

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## To cite this version:

Gerardo Zardi, Kevin C.K. Ma, Pierre William Froneman, Katy Nicastro. First record of pyroplastic and partially burnt plastic litter along South African shores. Marine Pollution Bulletin, 2025, 214, pp.117817. 10.1016/j.marpolbul.2025.117817. hal-05248575

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Submitted on 11 Sep 2025

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Baseline

# First record of pyroplastic and partially burnt plastic litter along South African shores

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Gerardo I. Zardi<sup>a, b</sup>, Kevin C.K. Ma<sup>b, c</sup>, Pierre William Froneman<sup>b, d</sup>, Katy R. Nicastro<sup>b, e, *</sup>

## ARTICLE INFO

### Keywords:

- Plastic pollution

- Coastal plastic debris

- Environmental monitoring

- Intertidal habitats

- Marine litter

## ABSTRACT

As plastic pollution has accumulated in the natural environment over the last half-century, so too has the body of literature on plastic contamination assessment. Despite this growing research, new, and cryptic forms of plastic debris continue to emerge, with limited data on their composition and abundance. Among these novel pollutants is a type of marine litter derived from the burning or melting of manufactured plastics. In this study, we report for the first time the presence of burned plastic forms at selected intertidal sandy habitats along the South African coast. We examined both pyroplastics—molten items with rock-like properties due to environmental weath-ering—and partially burned plastics, which retain features of the original manufactured objects. Surveys con-ducted across 22 sites spanning over 2000 km revealed this new type of litter at 19 locations, predominantly composed of polyethylene (37 items), polyethylene terephthalate (12 items), polypropylene (5 items) and polystyrene (3 items), with an average weight of 5.4 g per item. These findings highlight the widespread presence of burned plastics in coastal environments in South Africa and emphasize the need for further research into their ecological impacts.

Plastics are an integral part of modern society, with their applica-tions constantly expanding (Europe, 2022). As plastic production con-tinues to soar, excessive use and poor management at both pre- and post-consumer stages have led to global contamination; plastic litter is now found in a wide variety of ecosystems, from urban areas to remote lo-cations (Rangel-Buitrago and Neal, 2023; Velez et al., 2019; Windsor et al., 2019). Most of the plastic litter originates from land, entering waterways, and wastewater systems (e.g., Harris et al., 2021). Once in the marine environment, plastic debris can disperse via wind and cur-rents, accumulating in coastal areas and beyond (Tong et al., 2021; Velez et al., 2020). Evidence highlights the numerous harmful effects of plastic contamination—defined as presence of a substance where it should not be or at concentrations above background levels—on a variety of species in marine, freshwater, and terrestrial ecosystems (Basto et al., 2019; Cozzolino et al., 2021; Zeb et al., 2023). Plastic pollution—defined as a contamination that results in or can result in adverse biological effects to resident communities—arises from both the physical impacts, such as

entanglement and ingestion, and the chemical effects, as plastics leach significant amounts of hazardous chemicals (Cozzolino et al., 2023; Nicastro et al., 2023; Thushari and Senevirathna, 2020).

Plastic debris has been classified in many ways over the years, including by size, chemical composition, shape, and colour. Size cate-gories include nano (<1 µm), micro (1 µm – 5 mm), meso (5–25 mm), macro- (25–1000 mm), and mega- (>1 m; Barnes et al., 2009). Micro-plastics, the most common in marine environments, are further divided into primary (e.g., industrial pellets. microbeads) and secondary types, which result from the breakdown of larger plastics (e.g., Velez et al., 2020). Plastic debris also varies by shape (e.g., fragments, films, foams, pellets, fibres) and colour (Cozzolino et al., 2020; Lusher and Primpke, 2023) with different chemicals often absorbed onto their surfaces (Seuront et al., 2022). Recently, the terminology for plastic debris has expanded to encompass new formations that do not align with previous classifications (Chowdhury et al., 2023; De-la-Torre et al., 2021; Ehlers et al., 2024; Shruti et al., 2023). These formations exhibit altered

<footnote><sup>a</sup> Normandie Université, UNICAEN, Laboratoire Biologie des Organismes et Ecosystèmes Aquatiques, UMR 8067 BOREA (CNRS, MNHN, UPMC, UCBN, IRD-207), CS 14032, 14000 Caen, France</footnote>

<footnote><sup>b</sup> Department of Zoology and Entomology, Rhodes University, Grahamstown 6140, South Africa</footnote>

<footnote><sup>c</sup> Department of Ocean Sciences, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador A1C 5S7, Canada</footnote>

<footnote><sup>d</sup> Department of Biological Sciences, University of Cape Town, Rondebosch 7700, South Africa</footnote>

<footnote><sup>e</sup> Univ. Lille, CNRS, Univ. Littoral Côte d'Opale, UMR 8187 - LOG - Laboratoire d'Océanologie et de Géosciences, F-59000 Lille, France</footnote>

<footnote>* Corresponding author at: Department of Zoology and Entomology, Rhodes University, Grahamstown 6140, South Africa
E-mail address: katynicastro@gmail.com (K.R. Nicastro).</footnote>
compositions and physical and chemical properties due to interactions with other debris (e.g., brick fragments, glass, sand, wood; Ellrich et al., 2023) and exposure to anthropogenic and environmental factors (e.g., burning, wave action, weathering; Rangel-Buitrago and Neal, 2023; Nguyen et al., 2024). Because of their unique characteristics and formation mechanisms, these new types of plastic litter likely demonstrate different transport dynamics, occurrences, and physicochemical properties compared to their original plastic materials, potentially resulting in varied ecological impacts (e.g., Corcoran and Jazvac, 2020).

One notable new type of plastic debris is pyroplastic, characterised as “an amorphous matrix that appears to be formed by the burning or melting of plastic and that is usually characterised by a single, neutral colour (black-charcoal-grey, off-white or brown), with occasional hues of green, blue, pink or yellow, and is accompanied by cracks and fractures, pits and cavities” (Turner et al., 2019). Since its initial description six years ago, numerous studies have reported the occurrence of pyroplastics, emphasising the global distribution of this new plastic formation. Pyroplastic have been recorded in the Mediterranean Sea (Ehlers and Ellrich, 2020), multiple locations in the North and South Atlantic (i. e., Trindade Island, Brazil, Cornwall, UK, and northern France; Santos et al., 2022; Turner et al., 2019; Zardi et al., 2024), the Bay of Bengal (i. e., Tamil Nadu, India, and Cox's Bazar Beach, Bangladesh; Gunasekaran et al., 2024; Rakib et al., 2023), and the North and South Pacific (i.e., Lima, Peru, and Honshu, Japan; De-la-Torre et al., 2022; Furukuma et al., 2022). Despite widespread global attention, no reports of pyroplastic litter have been published from the African continent to date. This highlights the limited research conducted in Africa to monitor and characterise marine plastic debris, which often does not align with global standards (Jambeck et al., 2018; Naidoo and Rajkaran, 2020).

Here, we provide the first quantitative (number of items and total mass of litter) and qualitative (spectroscopic identification) baseline data on pyroplastics (Turner et al., 2019), as well as partially burned plastics which, like pyroplastics, have undergone burning or melting but still retain some features of the original manufactured objects. Sampling was conducted opportunistically along >2000 km of South African sandy shores (22 sites; Fig. 1) during biodiversity surveys of intertidal habitats between April 2022 and September 2023. The search time at each site varied between 16 and 49 min (averaging 21 min), and the distance covered varied between 270 and 1500 m (averaging 623 m). The strength and limitations of opportunistic sampling strategies for assessing plastic litter contamination have been highlighted in numerous studies (Benjaminsen et al., 2024). South Africa's coastline experiences a wide range of tidal patterns, with tidal ranges varying depending on the location. Predominant wind directions along the coast are south-easterly to south-westerly, with some seasonal variation (e.g., Jury and Goschen, 2020; Lutjeharms and Ansorge, 2001; Zardi et al., 2015). These complex dynamics influence the distribution and accumulation of pyroplastics along the coastline. While the non-standardised sampling approach (e.g., time of day, weather, tidal cycles) does not allow for spatiotemporal analysis (e.g., comparisons among sites or seasons), this method provides crucial initial baseline data essential for identifying potential contamination hotspots of pyroplastics and laying the foundation for formulating hypotheses in more structured future research (e.g., Acampora et al., 2017; Cozzolino et al., 2021; Jossart et al., 2023).

Fifty-seven burned plastic items (18 pyroplastics and 29 partially burned plastics) were collected and subsequently examined in the laboratory (Figs. 1S and 2S). These items exhibited light blue, whitish, and

<figure><img src="image_5.png" /><figcaption>Fig. 1. Sampling locations described in full in Table 1. Map sourced from Free World Maps.</figcaption></figure>
black hues, reflecting the thermal degradation of plastics, where colour alterations occur due to the breakdown of dyes and polymers under elevated temperatures. While previous studies have focused exclusively on pyroplastics, we recognised the importance of also investigating partially burned plastics. These materials can be considered precursors to fully burned and weathered pyroplastics, and both share a history of burning and melting processes. Such processes alter their physical and chemical structures, which may influence their interactions with the environment and potentially have distinct or cumulative effects on biodiversity. For each item, the maximum length (x-axis: the longest axis of the examined piece), maximum height (y-axis: the axis perpendicular to the x-axis at the thickest part of the examined piece), and maximum width (z-axis: the axis perpendicular to the x- and y-axes at the thickest part of the examined piece) were measured using digital callipers. The mass of each item was assessed to the nearest 0.01 g using an electronic digital balance. Additionally, floating tests were performed in a beaker filled with artificial seawater (33 psu), prepared by dissolving 38.5 g salt in 1 L ultrapure water at room temperature (19 °C). All burned plastic items were less dense than seawater, with masses ranging from 0.23 to 51.5 g (averaging 5.4 g; Table 1).

To accurately differentiate between plastic and natural materials, Fourier-transform infrared (FTIR) microspectroscopy in attenuated total reflectance (ATR) mode was used to identify the polymer types and confirm their classification (e.g., Cozzolino et al., 2021; Seuront et al., 2022). IR-ATR spectra ranging from $500 \text{ cm}^{-1}$ to $3500 \text{ cm}^{-1}$ were acquired using a Nicolet iN10 Fourier infrared microspectroscopy instrument (Thermal Fisher Scientific Co., USA). A Micro Tip ATR probe was brought into contact with the sample to record the spectra, with air serving as the background spectrum. Recorded spectra were compared against commercial FTIR spectral libraries, including the Hummel Polymer and Additives Library and the FBI fibre library. ATR-FTIR analyses revealed that pyroplastics and partially burned plastics comprised polyethylene (PE, 37 items), polyethylene terephthalate (PET, 12 items), polypropylene (PP, 5 items) and polystyrene (PS, 3 items; Fig. 2S).

Sources of anthropogenic waste, in general, are diverse and include various marine- and land-based activities (Harris et al., 2021; Velez et al., 2020). Complex interactions involving prevailing winds, ocean currents, coastal geography, and demographics play pivotal roles in the dispersal and accumulation of plastic waste over vast distances (Mai et al., 2023; Onink et al., 2021). For pyroplastic pollution, it is difficult to pinpoint the exact source as multiple factors could contribute to its presence. Previous studies have suggested that recreational activities of beachgoers contribute to burned plastics contamination, as evidenced by findings of food packaging, burnt charcoal, and signs of campfires or barbecues (Kuś et al., 2023; Velez et al., 2020). However, our current study did not reveal such trends, aligning with a significant body of literature that challenges the perception of beach users being the main source of plastic litter. Poor inland waste management practices, inadequate disposal infrastructure, and informal settlements, where uncontrolled burning of plastic waste leading to the formation of plastiglomerates, plasticrusts, and pyroplastics. Additionally, maritime vessels might contribute by incinerating waste to reduce onboard volume and manage limited storage capacity. Such variability emphasises the complexity of marine litter dynamics and the challenges in identifying consistent patterns of contamination, even within the same geographic region (Fig. 2).

Contrary to our expectations, we found no apparent correlation between the quantity of burned plastic items and the time or area covered during sampling (Table 1). Overall, polyethylene (PE) was the most widespread polymer across all coastal regions, while other polymers, such as polyethylene terephthalate (PET) and polypropylene (PP), exhibited more scattered and inconsistent distributions. This suggests no clear distinction in the presence of these polymers among different coastal environments. Similarly, we observed no clear correlation between the size or weight of plastic items and their locations, indicating that larger or heavier plastics were not preferentially found in specific

coastal regions, and other factors may influence their distribution (Table 2). Although we anticipated bays to retain more particles due to their sheltered nature (Nicastro et al., 2008), we found no relationship between plastic debris and bay locations. Tidal excursion along the South African coastline varies due to factors such as coastal topography, bathymetry, and local oceanographic conditions. On the west coast, the tidal range exceeds 2 m between Mean Low Water Springs (MLWS) and Mean High Water Springs (MHWS), while locations such as Cape Town and Port Elizabeth have a tidal range of about 1.5 m between MLWS and MHWS. Durban, on the east coast, experiences a larger tidal range of approximately 1.8 m between MLWS and MHWS (Rautenbach et al., 2019). This, again, highlights the absence of any apparent pattern between tidal fluctuations and plastic litter accumulation. Taken together, these findings suggest that other factors, such as local currents, wind patterns, or land-based pollution sources, may play a substantial role in the distribution of plastic debris along the South African coast. The absence of predictable or linear distribution patterns for burned plastic items aligns with global observations, highlighting the patchy and irregular nature of marine litter distribution and emphasising the complexity of factors influencing plastic debris accumulation in coastal environments. We observed a higher incidence of burned plastics, particularly near the Port of Durban, which stands as the largest and busiest shipping terminal in sub-Saharan Africa. This high throughput contributes to a larger amount of plastic waste in the surrounding areas. Elevated densities of burned plastics were also recorded on the beaches of the small coastal towns of Kenton-on-Sea and Port Alfred in the Eastern Cape province of South Africa. These locations are popular tourist destinations, contributing to increased waste generation. Moreover, their proximity (<300 m) to large rivers such as the Bushmans and Kariega Rivers, as well as the Kowie River, suggests that riverine pathways play a crucial role in transporting plastic waste into marine ecosystems (Fig. 3S). These results highlight the diverse sources and pathways through which plastic pollution accumulates in coastal regions, influenced by industrial activities, presence of river outlets, and local tourism. The sources and origins of pyroplastics and partially burned plastics (as for most secondary plastic items) are difficult to determine due to their altered state resulting from burning and/or melting processes, which obscure the original plastic structure. However, microspectroscopy assessments, combined with in situ observations of prevalent types of plastic waste and knowledge of local activities such as tourism, fisheries, shipping, and industry, can provide insights into the sources, origins, and potential impacts of plastic particles (Velez et al., 2019).

Because pyroplastics and partially burned plastics have only recently been reported and described, they are not yet included in established guidelines for monitoring marine litter on beaches (e.g., OSPAR, CCAMLR Marine Debris Program, US National Marine Debris Program). However, their unique formation processes and physical structure needs separate classification within the broader category of plastic debris. The need for a separate categorisation is further supported by recent findings showing that pyroplastic leachates have distinct effects compared to non-burnt plastic on the key adaptive behaviours of coastal ecosystem engineers (Zardi et al., 2024). Specifically, the ability of mussels to move and aggregate is affected by pyroplastic leachates, particularly those from beached pyroplastics as opposed to those that have not been in the marine environment (raw). These effects likely stem from qualitative and quantitative differences in contaminants associated with raw and beached plastics, as well as distinct adsorption-desorption dynamics.

As global plastic contamination continues to rise, baseline data like those presented here are crucial for assessing whether novel plastic debris, such as pyroplastics and partially burned plastics, represent a global concern. While we acknowledge the limitations of our opportunistic sampling, this study provides an important data on these emerging pollutants and underscores the need for future systematic surveys to enhance our understanding and inform mitigation efforts.
<caption>**Table 1**</caption>

Description of retrieved items found on sandy beaches. In the first column, numbering corresponds to those represented in the map in Fig. 1. Codes for each item refer to labelled photos in Fig. 1S. The table also includes coordinates, exposure (i.e., bay or open coast), item counts, distance surveyed (metre) and time (minute), dimensions (x, y, z in cm), mass (g), and polymer type. In the last column, bold text represents pyroplastics, while non-bold text indicates partially burned plastics.

<table><thead><tr><th>Number. location<br>CODE</th><th>Coordinates</th><th>Bay/open<br>coast</th><th>Item<br>counts</th><th>Distance<br>surveyed (m)</th><th>Search time<br>(min)</th><th>x-Axis length<br>(cm)</th><th>y-Axis length<br>(cm)</th><th>z-Axis length<br>(cm)</th><th>Mass<br>(g)</th><th>Polymer<br>type</th></tr></thead><tbody><tr><td rowspan="15">1. Durban DU</td><td rowspan="15">29°50'47.66"S<br>31°2'15.60"E</td><td rowspan="15">Open<br>coast</td><td rowspan="15">17</td><td rowspan="15">270</td><td rowspan="15">25</td><td>1:11.7</td><td>1:6.5</td><td>1:1.1</td><td>1:3.9</td><td>1:PE</td></tr><tr><td>2:3.9</td><td>2:2.5</td><td>2:1.5</td><td>2:0.2</td><td>2:PE</td></tr><tr><td>3:5.7</td><td>3:3</td><td>3:0.2</td><td>3:0.4</td><td>3:PE</td></tr><tr><td>4:3.1</td><td>4:2</td><td>4:0.6</td><td>4:0.9</td><td>4:PP</td></tr><tr><td>5:3.2</td><td>5:3</td><td>5:1.2</td><td>5:5.3</td><td>5:PE</td></tr><tr><td>6:4.3</td><td>6:2.9</td><td>6:0.8</td><td>6:5.5</td><td>6:PE</td></tr><tr><td>7:4.7</td><td>7:4.6</td><td>7:0.4</td><td>7:1.7</td><td>7:PET</td></tr><tr><td>8:5.2</td><td>8:3.1</td><td>8:0.7</td><td>8:1.8</td><td>8:PE</td></tr><tr><td>9:4.6</td><td>9:3</td><td>9:0.8</td><td>9:1.7</td><td>9:PE</td></tr><tr><td>10:5.7</td><td>10:4.3</td><td>10:1</td><td>10:8.3</td><td>10:PE</td></tr><tr><td>11:7.1</td><td>11:3.7</td><td>11:0.4</td><td>11:1.5</td><td>11:PE</td></tr><tr><td>12:3.8</td><td>12:3.8</td><td>12:0.8</td><td>12:2.1</td><td>12:PE</td></tr><tr><td>13:15.9</td><td>13:8</td><td>13:1.7</td><td>13:7.8</td><td>13:PE</td></tr><tr><td>14:6.7</td><td>14:5.2</td><td>14:2.2</td><td>14:6.2</td><td>14:PE</td></tr><tr><td>15:10.3</td><td>15:7.1</td><td>15:2.1</td><td>15:14.3</td><td>15:PE</td></tr><tr><td>16:1.9</td><td>16:1.7</td><td>16:0.5</td><td>16:0.4</td><td>16:PE</td></tr><tr><td>17:15</td><td>17:7.4</td><td>17:2.9</td><td>17:37.2</td><td>17:PET</td></tr><tr><td rowspan="3">2. Port St. Johns PJ</td><td rowspan="3">31°38'56.38"S<br>29°31'6.22"E</td><td rowspan="3">Open<br>coast</td><td rowspan="3">3</td><td rowspan="3">1500</td><td rowspan="3">15</td><td>1:7</td><td>1:3.1</td><td>1:0.5</td><td>1:2.8</td><td>1:PET</td></tr><tr><td>2:3.9</td><td>2:2.8</td><td>2:0.3</td><td>2:0.9</td><td>2:PE</td></tr><tr><td>3:7</td><td>3:3.5</td><td>3:0.4</td><td>3:8.1</td><td>3:PE</td></tr><tr><td rowspan="2">3. Gonubie GO</td><td rowspan="2">32°56'5.83"S<br>28°1'55.96"E</td><td rowspan="2">Open<br>coast</td><td rowspan="2">0</td><td rowspan="2">350</td><td rowspan="2">20</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td></td><td></td><td></td><td></td><td></td></tr><tr><td rowspan="2">4. East London EL</td><td rowspan="2">33°0'35.23"S<br>27°55'25.26"E</td><td rowspan="2">Open<br>coast</td><td rowspan="2">2</td><td rowspan="2">340</td><td rowspan="2">16</td><td>1:5.4</td><td>1:3</td><td>1:0.8</td><td>1:1</td><td>1:PS</td></tr><tr><td>2:2.6</td><td>2:1</td><td>2:0.7</td><td>2:0.3</td><td>2:PET</td></tr><tr><td rowspan="2">5. Kidds Beach KB</td><td rowspan="2">33°8'43.92"S<br>27°42'5.64"E</td><td rowspan="2">Open<br>coast</td><td rowspan="2">1</td><td rowspan="2">300</td><td rowspan="2">15</td><td>1:5</td><td>1:4.4</td><td>1:0.3</td><td>1:1.6</td><td>1:PET</td></tr><tr><td></td><td></td><td></td><td></td><td></td></tr><tr><td rowspan="7">6. Port Alfred PA</td><td rowspan="7">33°35'43.96"S<br>26°54'43.71"E</td><td rowspan="7">Open<br>coast</td><td rowspan="7">6</td><td rowspan="7">500</td><td rowspan="7">15</td><td>1:11.4</td><td>1:4.3</td><td>1:0.6</td><td>1:16.7</td><td>1:PE</td></tr><tr><td>2:4.9</td><td>2:3</td><td>2:0.3</td><td>2:10.9</td><td>2:PE</td></tr><tr><td>3:7</td><td>3:4.9</td><td>3:0.9</td><td>3:17.4</td><td>3:PE</td></tr><tr><td>4:1.6</td><td>4:1</td><td>4:0.3</td><td>4:0.5</td><td>4:PET</td></tr><tr><td>5:17.2</td><td>5:1.3</td><td>5:0.8</td><td>5:6.9</td><td>5:PE</td></tr><tr><td>6:4.3</td><td>6:0.4</td><td>6:0.3</td><td>6:0.3</td><td>6:PP</td></tr><tr><td>7:4.3</td><td>7:3.5</td><td>7:0.4</td><td>7:0.4</td><td>7:PET</td></tr><tr><td rowspan="7">7. Kenton on sea KS</td><td rowspan="7">33°41'46.33"S<br>26°39'20.14"E</td><td rowspan="7">Open<br>coast</td><td rowspan="7">6</td><td rowspan="7">600</td><td rowspan="7">20</td><td>1:3.1</td><td>1:3</td><td>1:0.4</td><td>1:4.4</td><td>1:PE</td></tr><tr><td>2:3.8</td><td>2:2.1</td><td>2:0.4</td><td>2:2.4</td><td>2:PET</td></tr><tr><td>3:2.8</td><td>3:2.4</td><td>3:0.4</td><td>3:1.5</td><td>3:PS</td></tr><tr><td>4:5.6</td><td>4:3.5</td><td>4:1.4</td><td>4:10.1</td><td>4:PE</td></tr><tr><td>5:1.9</td><td>5:1.1</td><td>5:0.3</td><td>5:0.4</td><td>5:PP</td></tr><tr><td>8. Port Elizabeth PE</td><td>33°58'49.87"S<br>25°39'32.93"E</td><td>Bay</td><td>0</td><td>500</td><td>20</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td rowspan="2">9. Plettenberg Bay<br>PB</td><td rowspan="2">34°5'31.12"S<br>23°22'22.66"E</td><td rowspan="2">Bay</td><td rowspan="2">2</td><td rowspan="2">600</td><td rowspan="2">20</td><td>1:3.7</td><td>1:2.2</td><td>1:0.3</td><td>1:1</td><td>1:PE</td></tr><tr><td>2:5.7</td><td>2:3.4</td><td>2:0.4</td><td>2:2</td><td>2:PP</td></tr><tr><td rowspan="2">10. Wilderness WN</td><td rowspan="2">33°59'46.28"S<br>22°34'33.06"E</td><td rowspan="2">Open<br>coast</td><td rowspan="2">2</td><td rowspan="2">500</td><td rowspan="2">30</td><td>1:5</td><td>1:2.2</td><td>1:0.2</td><td>1:0.1</td><td>1:PE</td></tr><tr><td>2:3.5</td><td>2:0.9</td><td>2:0.4</td><td>2:1</td><td>2:PE</td></tr><tr><td rowspan="5">11. Glentana GL</td><td rowspan="5">34°3'3.29"S<br>22°18'36.44"E</td><td rowspan="5">Open<br>coast</td><td rowspan="5">3</td><td rowspan="5">600</td><td rowspan="5">15</td><td>1:4.8</td><td>1:3.1</td><td>1:0.2</td><td>1:0.4</td><td>1:PET</td></tr><tr><td>2:4</td><td>2:3.8</td><td>2:0.3</td><td>2:1.4</td><td>2:PE</td></tr><tr><td>3:3.9</td><td>3:2.5</td><td>3:0.3</td><td>3:0.6</td><td>3:PE</td></tr><tr><td>1:3.7</td><td>1:3.5</td><td>1:0.4</td><td>1:2.3</td><td>1:PE</td></tr><tr><td>2:2.1</td><td>2:1.2</td><td>2:0.3</td><td>2:0.4</td><td>2:PE</td></tr><tr><td>13. Cape Agulhas<br>CA</td><td>34°48'53.80"S<br>19°56'39.19"E</td><td>Open<br>coast</td><td>1</td><td>600</td><td>20</td><td>1:4</td><td>1:1.5</td><td>1:1.4</td><td>1:3.7</td><td>1:PET</td></tr><tr><td rowspan="2">14. Cape Town CT</td><td rowspan="2">34°5'57.74"S<br>18°29'42.49"E</td><td rowspan="2">Open<br>coast</td><td rowspan="2">0</td><td rowspan="2">700</td><td rowspan="2">20</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td></td><td></td><td></td><td></td><td></td></tr><tr><td rowspan="2">15. Bloubergstrand<br>BB</td><td rowspan="2">33°49'19.39"S<br>18°28'31.27"E</td><td rowspan="2">Bay</td><td rowspan="2">2</td><td rowspan="2">400</td><td rowspan="2">49</td><td>1:22</td><td>1:7</td><td>1:0.1</td><td>1:1.8</td><td>1:PE</td></tr><tr><td>2:7</td><td>2:2</td><td>2:0.1</td><td>2:0.6</td><td>2:PE</td></tr><tr><td rowspan="2">16. Yzerfontein YF</td><td rowspan="2">33°21'19.07"S<br>18°91'0.71"E</td><td rowspan="2">Open<br>coast</td><td rowspan="2">1</td><td rowspan="2">290</td><td rowspan="2">20</td><td>1:2.7</td><td>1:2.3</td><td>1:0.4</td><td>1:0.9</td><td>1:PE</td></tr><tr><td>1:3.9</td><td>1:1.3</td><td>1:0.1</td><td>1:0.2</td><td>1:PET</td></tr><tr><td>17. Saldanha Bay<br>SB</td><td>32°59'46.10"S<br>17°58'19.82"E</td><td>Bay</td><td>1</td><td>900</td><td>25</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td rowspan="2">18. Jacobs Bay JB</td><td rowspan="2">32°57'46.42"S<br>17°53'3.13"E</td><td rowspan="2">Bay</td><td rowspan="2">0</td><td rowspan="2">700</td><td rowspan="2">15</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td></td><td></td><td></td><td></td><td></td></tr><tr><td rowspan="2">19. Elands Bay EB</td><td rowspan="2">32°19'0.19"S<br>18°19'31.94"E</td><td rowspan="2">Bay</td><td rowspan="2">1</td><td rowspan="2">950</td><td rowspan="2">20</td><td>1:5.5</td><td>1:2</td><td>EB1:0.1</td><td>EB1:0.4</td><td>EB1:PE</td></tr><tr><td></td><td></td><td></td><td></td><td></td></tr><tr><td>20. Lamberts Bay<br>LB</td><td>32°6'38.14"S<br>18°18'7.82"E</td><td>Bay</td><td>0</td><td>1000</td><td>25</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td rowspan="7">21. Doring Bay DB</td><td rowspan="7">31°49'17.33"S<br>18°14'4.97"E</td><td rowspan="7">Bay</td><td rowspan="7">2</td><td rowspan="7">1000</td><td rowspan="7">25</td><td>1:4</td><td>1:3.5</td><td>1:0.4</td><td>1:9.4</td><td>1:PS</td></tr><tr><td>2:2.5</td><td>2:1</td><td>2:0.1</td><td>2:0.3</td><td>2:PP</td></tr><tr><td>1:7.8</td><td>1:5.1</td><td>1:0.9</td><td>1:51.5</td><td>1:PET</td></tr><tr><td>2:7</td><td>2:3.4</td><td>2:0.5</td><td>2:12.2</td><td>2:PE</td></tr><tr><td>3:4.5</td><td>3:3.6</td><td>3:0.5</td><td>3:5.5</td><td>3:PE</td></tr><tr><td>4:3.9</td><td>4:2.4</td><td>4:0.4</td><td>4:8.6</td><td>4:PE</td></tr><tr><td>5:3.3</td><td>5:2.2</td><td>5:0.4</td><td>5:0.7</td><td>5:PE</td></tr><tr><td>6:5.6</td><td>6:4</td><td>6:0.9</td><td>6:21.3</td><td>6:PET</td></tr><tr><td>22. Port Nolloth PN</td><td>29°15'16.97"S<br>16°52'4.35"E</td><td>Open<br>coast</td><td>6</td><td>700</td><td>25</td><td></td><td></td><td></td><td></td><td></td></tr></tbody></table>
<figure><img src="image_6.png" /><figcaption>**Fig. 2.** (A) Pyroplastic items collected at Port Nolloth (top) and Port Alfred (bottom). Insets show the beach environment at each location and a close-up of the pyroplastic fragments. (B) A photo of the Nicolet iN10 Fourier infrared microspectroscopy instrument used for the analysis and examples of FTIR spectra confirming the polymer composition of the pyroplastic samples (photos of additional all items are available in Supplementary material, Fig. S1).</figcaption></figure>

<table><caption>**Table 2**
Average and standard deviations (±SD) of the dimensions for the retrieved items by site. Codes correspond to map 1.</caption><thead><tr><th>Code</th><th>Average x-axis length (cm)</th><th>Average y-axis length (cm)</th><th>Average z-axis length (cm)</th><th>Average mass (g)</th><th>SD x-axis length (cm)</th><th>SD y-axis length (cm)</th><th>SD z-axis length (cm)</th><th>SD mass (g)</th></tr></thead><tbody><tr><td>DU</td><td>6.635</td><td>4.223</td><td>1.111</td><td>5.835</td><td>4.142</td><td>1.955</td><td>0.742</td><td>8.902</td></tr><tr><td>PJ</td><td>5.967</td><td>3.133</td><td>0.400</td><td>3.933</td><td>1.790</td><td>0.351</td><td>0.100</td><td>3.731</td></tr><tr><td>EL</td><td>4.000</td><td>2.000</td><td>0.750</td><td>0.650</td><td>1.979</td><td>1.414</td><td>0.071</td><td>0.495</td></tr><tr><td>KB</td><td>5.000</td><td>4.400</td><td>0.300</td><td>1.600</td><td>0</td><td>0</td><td>0</td><td>0</td></tr><tr><td>PA</td><td>7.733</td><td>2.480</td><td>5.533</td><td>58.783</td><td>5.675</td><td>1.863</td><td>12.429</td><td>126.850</td></tr><tr><td>KS</td><td>9.440</td><td>8.420</td><td>6.580</td><td>9.760</td><td>13.127</td><td>13.436</td><td>13.323</td><td>12.681</td></tr><tr><td>PL</td><td>4.700</td><td>2.800</td><td>0.350</td><td>1.500</td><td>1.414</td><td>0.848</td><td>0.071</td><td>0.707</td></tr><tr><td>WN</td><td>4.250</td><td>1.550</td><td>0.300</td><td>0.550</td><td>1.061</td><td>0.919</td><td>0.141</td><td>0.636</td></tr><tr><td>GL</td><td>4.233</td><td>3.133</td><td>0.267</td><td>0.800</td><td>0.494</td><td>0.650</td><td>0.057</td><td>0.529</td></tr><tr><td>MB</td><td>2.900</td><td>2.350</td><td>0.350</td><td>1.350</td><td>1.131</td><td>1.626</td><td>0.071</td><td>1.343</td></tr><tr><td>CA</td><td>4.000</td><td>1.500</td><td>1.400</td><td>3.700</td><td>0</td><td>0</td><td>0</td><td>0</td></tr><tr><td>BB</td><td>14.500</td><td>4.500</td><td>0.100</td><td>1.200</td><td>10.606</td><td>3.535</td><td>0</td><td>0.848</td></tr><tr><td>YF</td><td>2.700</td><td>2.300</td><td>0.400</td><td>0.900</td><td>0</td><td>0</td><td>0</td><td>0</td></tr><tr><td>SB</td><td>3.900</td><td>1.300</td><td>0.100</td><td>0.200</td><td>0</td><td>0</td><td>0</td><td>0</td></tr><tr><td>EB</td><td>5.500</td><td>2.000</td><td>0.100</td><td>0.400</td><td>0</td><td>0</td><td>0</td><td>0</td></tr><tr><td>DB</td><td>3.250</td><td>2.250</td><td>0.250</td><td>4.850</td><td>0</td><td>0</td><td>0</td><td>0</td></tr><tr><td>PN</td><td>5.350</td><td>3.450</td><td>0.600</td><td>16.633</td><td>0</td><td>0</td><td>0</td><td>0</td></tr></tbody></table>

**CRediT authorship contribution statement**

**Gerardo I. Zardi:** Writing – original draft, Validation, Methodology, Data curation, Conceptualization. **Kevin C.K. Ma:** Writing – review & editing, Investigation. **Pierre William Froneman:** Writing – review & editing, Investigation. **Katy R. Nicastro:** Writing – original draft, Methodology, Funding acquisition, Conceptualization.

**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.

**Acknowledgements**

This research was funded by ANR (project SAN22202). GI Zardi is a
laureate of the WINNINGNormandy Region. This project has received funding from the European Union's Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie grant agreement No. 101034329 and the South African Research Chairs Initiative (SARChI) of the Department of Science and Technology and the National Research Foundation (Grant No. 64801). We also acknowledge the financial support of the Institut de Recherche pour le Développement (IRD), France. We thank Lorenzo Cozzolino and Amy Bernier-Desmarais for their valuable field assistance.

## Appendix A. Supplementary data

Supplementary data to this article can be found online at https://doi.org/10.1016/j.marpolbul.2025.117817.

### Data availability

Data will be made available on request.

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