Microplastic Pollution Along the Beaches of the Gulf of Gabès (Tunisia): Spatial Distribution, Sources, and Implications for Coastal Sustainability

Abstract

Microplastic (MP) pollution is an increasing environmental concern in coastal areas exposed to anthropogenic pressure, although its ecological and human-health implications depend on exposure, bioavailability, and potential effects. This study assesses MP contamination across seven beaches in the Gulf of Gabès, Tunisia, by integrating environmental characterization, polymer identification, and spatial analysis within the context of coastal sustainability. The mean MP abundance was 170.38 ± 17.14 items kg⁻¹ of dry sediment. Microplastics were characterized by shape, color, and size, with fibers and fragments being the most prevalent forms. Fourier-transform infrared spectroscopy (FTIR) identified polyethylene (PE), polypropylene (PP), and polystyrene (PS) among the analyzed particles. Some foam particles exhibited spectral features tentatively consistent with the antioxidant additive Cyanox 53; however, this assignment requires independent analytical confirmation. Spatial variability was explored using the Microplastic Pollution Index (MPPI), the Coefficient of Microplastic Impact (CMPI), hierarchical cluster analysis (HCA), and principal component analysis (PCA). Based on the adopted MPPI classification scheme, five beaches were classified as high, one as very high, and one as moderate. The observed spatial patterns may be associated with local anthropogenic activities, including tourism, fishing, and waste discharge, although these potential sources were not directly investigated. The findings provide baseline information on MP contamination across the surveyed beaches and may inform future monitoring and coastal management initiatives relevant to Sustainable Development Goals 14, 12, and 8. The results should be interpreted in light of the study’s spatial and temporal scope and methodological limitations and should not be considered direct evidence of ecological effects or human-health risks.

1. Introduction

Plastics are synthetic polymeric materials composed of numerous additives and manufactured as thermoplastics and thermosets [1]. Since their invention in 1907, plastics have become essential in daily life and a wide range of industrial applications [2]. To meet global demand, plastic production has rapidly increased, reaching 436 million metric tons in 2023, according to the United Nations Conference on Trade and Development (UNCTAD) [3,4]. This surge is partly attributed to the COVID-19 pandemic and the growing reliance on single-use plastics [5]. However, only 9% of plastic waste is recycled, while the remaining fraction is mismanaged, with 22% ending up as solid waste on beaches and in the marine environment. Continued mismanagement of plastic waste, combined with ever-increasing production, is projected to result in approximately 12 billion tons of plastic debris entering the oceans by 2050 (Organization for Economic Co-operation and Development [OECD]) [6,7]. Plastics are considered hazardous due to their persistence and associated chemical additives, and their accumulation in marine ecosystems poses severe risks to human health and marine biodiversity [8]. Consequently, marine plastic pollution has become an alarming and emerging global environmental challenge [9]. Once released into the marine environment, plastics can persist for hundreds to thousands of years. Large plastic debris is gradually fragmented through physical abrasion, ultraviolet (UV) radiation, and other biotic and abiotic processes, producing smaller particles that integrate with beach sediments [10]. These particles are classified by size into macroplastics (>2.5 cm), mesoplastics (0.5–2.5 cm), and microplastics (MPs; <5 mm) [11]. MPs are the most abundant category and are typically divided by origin: primary MPs, manufactured at microscopic size for specific applications such as cosmetic microbeads, resin pellets, and abrasive blasting media; and secondary MPs, derived from the fragmentation and photodegradation of larger plastic items such as bottles, single-use packaging, and face masks [12]. MPs occur in diverse morphologies, including fibers, fragments, films, foams, pellets, and spherical beads [13,14]. Their small size and similarity to planktonic organisms make them bioavailable to a wide range of marine fauna, increasing the risk of ingestion and potential adverse ecological effects [15]. Growing evidence indicates that numerous marine species, including seabirds, fish, bivalves, sea turtles, stingrays, and zooplankton, ingest MPs, often mistaking them for food [8,16,17].

Sun et al. [18] reported MP retention ranging from 0.13 to 0.35 particles per zooplankton individual in the East China Sea, highlighting the pervasiveness of this phenomenon. MP ingestion has been linked to various ecotoxicological effects, including neurotoxicity, oxidative stress, growth inhibition, immune dysfunction, and liver damage [15,19]. In addition to physical impacts, MPs act as vectors for toxic additives used in their manufacture and exhibit high sorption capacity for environmental contaminants such as pharmaceuticals, persistent organic pollutants, and heavy metals, due to their non-polar surfaces and high specific surface area [8,20]. These combined properties exacerbate their potential risk to marine food webs. For instance, Rochman et al. [21] detected plastic debris in 28% of fish species sampled from an Indonesian market and 25% of those from a Californian market. Similarly, Selvam et al. [22] identified multiple trace metals (Cr, Fe, Mn, As, and Hg) in the muscle and intestines of edible fish from the Gulf of Mannar (Indian Ocean), showing a strong correlation between MPs and metal contamination. Such findings indicate that MPs ingested by marine organisms can serve as vectors of metal transfer through trophic chains. Importantly, seafood consumption represents a direct pathway of MP exposure for humans, with potential health consequences including oxidative stress, enzymatic dysfunction, cellular damage, inflammation, and gastrointestinal lesions, effects comparable to those observed in marine organisms [23].

The Mediterranean region, which hosts approximately 10% of the global coastal population, is both environmentally valuable and highly vulnerable to anthropogenic pressures, as reflected by its exceptional biodiversity and diverse coastal geomorphology [24,25]. Oceanographic models have consistently identified the Mediterranean Sea as one of the world’s most critical hotspots for plastic pollution, where debris can persist for decades to centuries [26,27,28,29]. Plastic litter concentrations in this semi-enclosed basin are estimated to reach approximately 250,000 items km⁻² [30]. Numerous field studies have reported substantial marine debris accumulation along Mediterranean beaches, including the southwestern [25,31,32], eastern [26,33,34], and northern shores [35,36,37,38].

Tunisia, located on the southwestern Mediterranean coast, faces growing anthropogenic pressures including rapid urbanization, unregulated industrial effluent discharge, tourism expansion, overexploitation of coastal resources, and inadequate solid waste management [39]. Despite the ecological significance of its coastal ecosystems, research on microplastic (MP) pollution in Tunisian marine environments remains scarce and relatively recent [40]. Existing studies nevertheless highlight substantial contamination. For example, beach sediments in the Sidi Mansour area (southeastern Tunisia) showed MP abundances ranging from 252 to 5332 particles m² [31]. Jaouani et al. [41] documented plastic debris along a gradient from lake to lagoon to beach on the northern coast, while Missawi et al. [42] reported MP presence at eight coastal sediment sites, and Abidli et al. [43] identified significant plastic accumulation in the Bizerte Lagoon-Channel system. Collectively, the studies of Abidli et al. [43], Jaouani et al. [41], and Missawi et al. [42] confirm widespread plastic pollution along Tunisian shores while underscoring significant gaps in understanding MP distribution and impacts.

The Gulf of Gabès (GG), located in southeastern Tunisia, was selected as the focus of this study because of its exceptional marine biodiversity and productive coastal ecosystems [44]. However, these assets are increasingly threatened by multiple stressors, including phosphogypsum discharge from phosphate processing, unregulated coastal activities, and other anthropogenic inputs [45,46]. Such pressures, combined with the introduction of invasive species, exacerbate the vulnerability of local fisheries and habitats [47].

Despite the growing body of research on microplastics in Tunisia, important differences remain in the spatial coverage and environmental compartments investigated. In the Gulf of Gabès, previous studies have documented microplastics in surface waters and marine biota, including their abundance, characteristics, polymer composition and spatial distribution [24,48]. Other Tunisian studies have investigated microplastics in coastal sediments and beaches [39,41,49,50]. However, spatially distributed information on microplastic characteristics specifically in beach sediments across multiple locations within the Gulf of Gabès remains limited. The present study addresses this specific gap by characterizing microplastic abundance, morphology, color, size and polymer composition across seven selected beaches.

Sediment samples were collected from seven selected coastal sites representing different geographical settings and levels and types of anthropogenic influence. Site selection was purposive and considered proximity to urban areas, industrial activities, fishing ports and recreational beaches, with the aim of capturing a range of potential contamination settings. The selected sites were intended to provide spatial contrasts among investigated beaches and should not be considered statistically representative of all coastal environments within the Gulf of Gabès.

The specific objectives were to (i) quantify MP abundance and characterize their morphological and polymeric composition, (ii) evaluate spatial distribution patterns using statistical tools, and (iii) compare the Gulf of Gabès with other national and international coastal environments. The results provide a spatial baseline for the investigated beaches during the October 2024 sampling period and can support future monitoring and comparative studies. Because sampling was conducted during a single campaign, the dataset does not allow assessment of seasonal variability or temporal trends in microplastic contamination across the Gulf of Gabès.

Beyond environmental diagnostics, the study situates its findings within a sustainable development framework, emphasizing their relevance to Sustainable Development Goal (SDG 14) (Life Below Water), SDG 12 (Responsible Consumption and Production), and SDG 8 (Decent Work and Economic Growth). The research advocates for integrated coastal management, enhanced waste governance, and stakeholder-driven mitigation initiatives in Tunisia’s vulnerable southern coastal regions.

2. Materials and Methods

2.1. Study Area

The Gulf of Gabès (GG), located in southeastern Tunisia, features one of the widest continental shelves in the Mediterranean, encompassing approximately 33% of the national coastline and extending over half of Tunisia’s 700 km shoreline [45,51].

The gulf plays a pivotal socio-economic role, hosting nearly 52% of the national fishing fleet, around 13,000 vessels, and contributing approximately 39.3% of Tunisia’s total marine fish production [46]. Despite its ecological and economic importance, the GG has undergone progressive environmental degradation driven by multiple anthropogenic pressures. These include uncontrolled disposal of solid waste and the discharge of untreated industrial and domestic effluents, which collectively introduce large quantities of pollutants into coastal habitats each year [52].

Such inputs represent a potential source of plastic contamination and MP accumulation in the marine environment. For this study, sediment samples were collected from seven coastal sites representing different levels and types of anthropogenic influence (Figure 1). Site selection considered proximity to urban areas, industrial activities, fishing ports, and recreational beaches to capture a range of contamination scenarios.

Figure 1. Map of the study area showing the distribution of the seven sampling sites (S1–S7) along the Gulf of Gabès coastline. Insets include photographs of the surveyed beaches and illustrate the sediment sampling procedure.

2.2. Sampling of Microplastics

Sediment sampling was conducted in October 2024 on each of the seven beaches surveyed along the Gulf of Gabès coastline, where a 100 m transect parallel to the shoreline was established along the high-tide line. Along each transect, three sampling positions were established at 0 m (starting point), 50 m, and 100 m (end point). At each position, three replicate quadrats (20 × 20 cm) were sampled, resulting in nine quadrats per beach. Within each quadrat, surface sediment (top 50 mm) was carefully scraped using a stainless-steel spoon to minimize external contamination. The three quadrats collected at each transect position were treated as subsamples and pooled to form one composite sample per position. The three resulting position-level composite samples were subsequently processed and analyzed independently and were used as the three replicates for calculating beach-level mean microplastic abundance and standard deviation. Sediment samples were immediately wrapped in aluminum foil, labelled, and transported to the laboratory for analysis.

Sampling was conducted during a single campaign in October 2024; therefore, the resulting dataset was designed to provide a spatially comparable snapshot of microplastic contamination among the investigated beaches rather than to characterize seasonal or annual variability.

2.3. Extraction and Classification of Microplastics

Strict measures were applied throughout sampling and laboratory procedures to prevent microplastic contamination, including the avoidance of plastic tools and the use of clean laboratory coats and cotton gloves [53,54,55]. Sediment samples were dried at 50 °C for 24–48 h to remove moisture and facilitate sieving. Dried samples were weighed and sieved using stainless-steel meshes of 2 mm and 1 mm. All particles >1 mm were manually sorted, and obvious non-plastic materials were removed.

Regarding quality control, field and procedural blanks were not included in this study, preventing the assessment of potential background contamination and blank correction. Although measures were taken to minimize contamination during sample handling, some contribution from external contamination cannot be excluded. Future studies should incorporate appropriate blanks and airborne-contamination controls to further strengthen the reliability of microplastic quantification.

Density separation was performed following the U.S. National Oceanic and Atmospheric Administration (NOAA) protocol [16], using a saturated sodium chloride (NaCl) solution (360 g L⁻¹; density approximately 1.2 g mL⁻¹) as the flotation medium. For each sample, 100 g of dried sediment was mixed with 300 mL of NaCl solution, stirred for 2 min at 1400 rpm, and allowed to settle for 24 h. The supernatant was then vacuum-filtered through 5 µm filter paper, which was dried overnight at 50 °C. NaCl was selected because of its accessibility, low cost, relatively low hazard, and widespread use in microplastic studies involving sediments [56]. However, its relatively low density may limit the recovery of denser polymers, particularly polyethylene terephthalate (PET) and polyvinyl chloride (PVC) [57,58]. Consequently, the polymer composition reported in this study represents the NaCl-recoverable fraction and may underestimate the contribution of these higher-density polymers.

Organic matter was removed by alkaline digestion using 50% sodium hydroxide (NaOH; Sigma-Aldrich)solution (4 mL solution per 1 g sample) at 50 °C for 24 h. Digestion was repeated when necessary. The samples were then vacuum-filtered, rinsed thoroughly with distilled water to eliminate residual NaOH, and dried overnight at 50 °C. Isolated particles were retrieved using metallic tweezers and stored in clean glass tubes for further characterization. The alkaline digestion procedure was selected to facilitate the removal of residual organic matter prior to particle identification. Previous studies have shown that the effects of chemical digestion on microplastics depend on polymer type and treatment conditions, including reagent concentration, temperature, and exposure time [59,60,61]. However, the specific treatment used in this study (50% NaOH at 50 °C for 24 h) was not independently validated through polymer-spiking and recovery experiments. Therefore, potential polymer-specific effects cannot be entirely excluded.

2.4. Visual Counting and FTIR Spectroscopy

Microplastic particles were visually identified and classified under a LEICA EZ4W stereomicroscope (Leica Microsystems, Wetzlar, Germany) equipped with an integrated HD camera, enabling high-resolution imaging and documentation. Particles were categorized by morphology (e.g., fibers, fragments, filaments, films, pellets, foams) and color, following standardized protocols. Microplastic abundance was expressed as the number of particles per kilogram of dry sediment.

For polymer identification, selected particles representing each morphological category were analyzed using Fourier-transform infrared (FTIR) spectroscopy. Spectra were acquired using a Spectrum Two spectrometer (PerkinElmer, Waltham, MA, USA) equipped with a diamond attenuated total reflectance (ATR) accessory, over the spectral range of 4000–400 cm⁻¹ at a resolution of 2 cm⁻¹. The measured spectra were compared with reference spectra from the PerkinElmer Spectrum IR spectral library (version 10.6.2). A minimum spectral similarity threshold of 60% was used for preliminary polymer assignment. Spectral matching scores were not considered sufficient on their own to confirm polymer identity; assignments were evaluated by examining characteristic absorption bands and their overall agreement with the reference spectra. Particles that did not meet the minimum similarity threshold or showed insufficient agreement with the reference spectra were classified as unidentified. This approach acknowledges that spectral matching may be influenced by spectral quality, reference-library characteristics, and potential particle alteration.

FTIR characterization was performed on 718 selected particles whose size and geometry were compatible with the technical requirements of ATR-FTIR analysis, representing 20.08% of the total visually identified particles. The spectral results indicated that approximately 98% of the analyzed particles exhibited features consistent with synthetic plastic materials. However, these spectral features do not necessarily confirm the identity of a specific polymer in every case. FTIR analysis was restricted to particles larger than 1 mm because smaller particles were difficult to handle and position on the ATR crystal while maintaining adequate contact [62]. Consequently, the spectroscopic findings apply only to the selected fraction analyzed and cannot be extrapolated to the entire collected particle population, particularly particles smaller than 1 mm. Future studies should consider micro-FTIR or Raman microspectroscopy to improve the chemical characterization of smaller particles [63,64,65].

2.5. Data Analysis

Two complementary indices were used to characterize microplastic contamination levels and morphological composition across the investigated beaches:

• Microplastic Pollution Index (MPPI)—was used as a complementary indicator to compare microplastic contamination levels among the investigated beaches, following the classification adopted from the relevant literature [32,66,67]. Microplastic abundance was independently expressed as the number of particles per kilogram of dry sediment (items kg⁻¹). The total physical area covered by the three non-overlapping quadrats measuring 20 × 20 cm was 0.12 m², corresponding to a reciprocal area factor of 8.33 m⁻². This factor represents the inverse of the surveyed area and is distinct from the mass-based abundance measurement. Accordingly, sediment-based abundance and MPPI are treated as distinct indicators and should not be considered directly interchangeable. MPPI values were interpreted according to the classification categories presented in Table 1. This interpretation is limited to the definition of the index and its methodological assumptions; the resulting categories provide a comparative classification and do not represent direct measurements of ecological effects or toxicity.
  Table 1. Classification categories for the Microplastic Pollution Index (MPPI), based on the thresholds adopted from the reference [66].

  MPPI Range	Category	Description
  0–2	Very low	Very low MPPI value
  2–5	Low	Low MPPI value
  5–15	Moderate	Moderate MPPI value
  15–25	High	High MPPI value
  >25	Very high	Very high MPPI value

• Coefficient of Microplastic Impact (CMPI)—was used to characterize the relative contribution of different microplastic (MP) morphological categories, following the method described in references [20,66] and is calculated as:

$$\mathrm{CMPI}={\displaystyle \frac{\mathrm{Specific} \mathrm{MP} \mathrm{shape}}{\mathrm{Total} \mathrm{MPs}}}$$

(1)

According to the classification scheme adopted in this study, CMPI values were assigned to four categories: minimum (0.0001–0.10), average (0.11–0.50), maximum (0.51–0.80), and extreme (0.81–1.00). These categories describe the values obtained under the adopted index classification and should not be interpreted as direct measurements of ecological effects or toxicity.

To explore spatial patterns among the investigated beaches, hierarchical cluster analysis (HCA) was performed using the observed microplastic density and morphological characteristics. Principal component analysis (PCA) was subsequently applied to visualize associations between microplastic morphological variables and sampling sites. Given the limited number of investigated beaches (n = 7), both HCA and PCA were used as exploratory and descriptive tools to identify spatial similarities and differences within the investigated dataset, rather than to establish statistically robust relationships or population-level patterns. Differences in microplastic abundance and morphological composition among beaches were examined descriptively using the available summary statistics. No inferential statistical tests were performed to assess the statistical significance of differences among beaches. Consequently, the observed variations and multivariate patterns were interpreted cautiously and were not considered evidence of statistically significant differences or generalizable relationships across the entire Gulf of Gabès. All statistical analyses and graphical outputs were conducted using OriginPro 2021 (OriginLab Corporation, Northampton, MA, USA).

3. Results and Discussion

3.1. Abundance of Microplastics

Microplastics were detected at all sampling sites, confirming their widespread occurrence throughout the study area, with an average abundance of 170.38 ± 17.14 items kg⁻¹ of dry sediment across the seven surveyed beaches (Table 2). However, MP abundance varied substantially among sites and within individual transects (Figure 2, Table 2). The highest abundance was recorded at site S6 in the southern part of the study area (216.67 ± 68.15 items kg⁻¹ of dry sediment), whereas the lowest abundance (118 ± 20.07 items kg⁻¹ of dry sediment) occurred at site S2 located on the northern coast.

Table 2. Microplastic abundance (items kg⁻¹ of dry sediment) at the seven Gulf of Gabès sites, categorized by morphological type. Values are presented as mean ± standard deviation based on three independent transect-position samples (0, 50, and 100 m) per beach; the three quadrats collected at each position were pooled as subsamples before analysis.

Site Code	Beach Name	Coordinates		Fibers	Fragments	Filaments	Films	Pellets	Foams	Total MPs
		Latitude	Longitude
S1	Corniche	33.889596	10.119298	130.33 ± 7.57	7.33 ± 3.51	8.33 ±3.06	7 ± 2	0	0	153 ± 8.54
S2	Chatt Arbi	33.876062	10.128472	107.33 ± 17.21	8 ± 3.61	1.33 ± 1.15	1.33 ± 1.15	0	0	118 ± 20.07
S3	Bungalow	33.855599	10.148204	171 ± 96.56	8.67 ± 5.69	5.67 ± 1.53	1 ± 1	0.33 ± 0.58	0.67 ± 0.58	187.33 ± 93.9
S4	Teboulbou	33.847549	10.157133	139 ± 7.21	8 ± 3.61	6.67 ± 5.77	6 ± 1	0.67 ± 1.15	1 ± 1	161.33 ± 4.04
S5	Chott Hamrouni 1	33.829394	10.176797	154 ± 17.35	10.67 ± 2.52	3.67 ± 1.15	0.67 ± 1.15	0.67 ± 0.58	1.33 ± 1.53	171 ± 18.73
S6	Chott Hamrouni 2	33.825446	10.180877	148 ± 22.00	57 ± 58.39	7 ± 4.36	2.33 ± 3.21	0.33 ± 0.58	2 ± 3.46	216.67 ± 68.15
S7	Chott Hamrouni 3	33.820797	10.186780	141.33 ± 26.50	32.67 ± 21.13	6.33 ± 1.53	2 ± 2.65	0.67 ± 1.15	2.33 ± 1.53	185.33 ± 14.22
Mean				141.57 ± 15.13	18.91 ± 8.96	5.57 ± 1.19	2.90 ± 0.73	0.38 ± 0.27	1.05 ± 0.61	170.38 ± 17.14
Median				141.33	8.67	6.33	2	0.33	1	171

Figure 2. Boxplot of microplastic abundance (items kg⁻¹ of dry sediment) across the seven surveyed beaches of the Gulf of Gabès, Tunisia.

The abundance patterns observed in this study align with previous findings demonstrating that MP distribution can be strongly influenced by beach morphology, hydrodynamics, and proximity to anthropogenic sources [12,68]. To enable comparisons, only studies using similar extraction density solutions (1.2 g mL⁻¹ NaCl) and reporting abundance in items kg⁻¹ were considered (Table 3).

The average MP abundance reported here is comparable to values recorded in several coastal environments worldwide. For example, similar concentrations were reported from beach sediments along the Phuket coastline in Thailand (188 items kg⁻¹), [69] and from beaches of the Baja California Peninsula, Mexico (135 items kg⁻¹) [70]. Our results are also consistent with MP abundances on Mediterranean beaches. Constant et al. [71] reported 166 items kg⁻¹ along French Mediterranean beaches, whereas Filgueiras et al. [72] and Fischer et al. [73] found mean abundances of 113 and 117 items kg⁻¹ along the Spanish Mediterranean shelf and Italian lakes, respectively. Comparable results (173 items kg⁻¹) have also been documented on the northern Tunisian coast [41]. By contrast, some regions exhibit lower MP contamination levels, such as the Caribbean coast of Guatemala (30 items kg⁻¹) [14] and sandy beaches of Puerto Rico (17 items kg⁻¹) [19]. Conversely, far higher concentrations have been reported from mangroves in southern China (2249 items kg⁻¹) [74], Tokyo Bay canal sediments (1800 items kg⁻¹) [75], Lebanese beaches (1126 items kg⁻¹), and Moroccan urban beaches (1109 items kg⁻¹) [32]. Our results are approximately 1.94 times lower than those reported for a highly touristic sandy beach in Argentina (330 items kg⁻¹) [76] and 2.93 times lower than concentrations observed on the German Baltic coast (532 items kg⁻¹) [77].

Table 3. Comparison of microplastic (MP) abundance, predominant shapes, and polymer types reported in beach sediments from various global locations. Concentrations are given in items kg⁻¹ of dry sediment.

Location	Concentration (Items kg−1)	Major Shapes	Major Polymers	References
Phuket coastline, Thailand	188.3	Fiber	PET	[69]
Caribbean, Puerto Rico	17	Fiber	PE	[19]
El Quetzalito, Guatemala	30	Foam	PS	[14]
Gulf of Lion, France	166	Fiber	PES	[71]
Lake Bolsena and Lake Chiusi, Italy	117	Fiber	Unidentified	[73]
Mediterranean continental shelf, Spain	113.2	Fiber	PS	[72]
Lakes and lagoon, Tunisia	130.6	Fragment	PP, PET, PVC	[41]
Gulf of Tunis	531	Fiber	PE, PP	[40]
Beaches of the Island of Djerba	126.67	Fiber	PE, PP, PS	[78]
Gulf of Gabès, Tunisia	170.38	Fiber	PE, PP, PS	Present study

Abbreviations: MP, microplastics; PE, polyethylene; PP, polypropylene; PS, polystyrene; PET, polyethylene terephthalate; PES, polyester; PVC, polyvinyl chloride.

Table 3. Comparison of microplastic (MP) abundance, predominant shapes, and polymer types reported in beach sediments from various global locations. Concentrations are given in items kg⁻¹ of dry sediment.

Location	Concentration (Items kg−1)	Major Shapes	Major Polymers	References
Phuket coastline, Thailand	188.3	Fiber	PET	[69]
Caribbean, Puerto Rico	17	Fiber	PE	[19]
El Quetzalito, Guatemala	30	Foam	PS	[14]
Gulf of Lion, France	166	Fiber	PES	[71]
Lake Bolsena and Lake Chiusi, Italy	117	Fiber	Unidentified	[73]
Mediterranean continental shelf, Spain	113.2	Fiber	PS	[72]
Lakes and lagoon, Tunisia	130.6	Fragment	PP, PET, PVC	[41]
Gulf of Tunis	531	Fiber	PE, PP	[40]
Beaches of the Island of Djerba	126.67	Fiber	PE, PP, PS	[78]
Gulf of Gabès, Tunisia	170.38	Fiber	PE, PP, PS	Present study

Abbreviations: MP, microplastics; PE, polyethylene; PP, polypropylene; PS, polystyrene; PET, polyethylene terephthalate; PES, polyester; PVC, polyvinyl chloride.

To further characterize and compare microplastic contamination among the investigated beaches, two complementary indicators were considered: the Microplastic Pollution Index (MPPI) and the Coefficient of Microplastic Impact (CMPI). The MPPI values reported for the seven surveyed beaches (Table 4) ranged from 14.16 ± 2.41 at S2 to 26.01 ± 8.18 at S6.

Table 4. MPPI values and corresponding classification categories for the seven beaches surveyed along the Gulf of Gabès, Tunisia.

Site Code	Group	MPPI	MPPI Category
S1	A	18.37 ± 1.02	High MPPI value
S2	A	14.16 ± 2.41	Moderate MPPI value
S3	A	22.49 ± 11.27	High MPPI value
S4	A	19.37 ± 0.48	High MPPI value
S5	A	20.53 ± 2.25	High MPPI value
S6	B	26.01 ± 8.18	Very high MPPI value
S7	B	22.25 ± 1.70	High MPPI value
Mean MPPI value		20.45 ± 2.06	High MPPI value

Note: Categories were assigned according to the MPPI thresholds presented in Table 1. They represent classifications based on the adopted index and should not be interpreted as direct measurements of ecological impact or toxicity. Groups A and B correspond to the clusters obtained by hierarchical cluster analysis (Section 3.2).

According to the classification thresholds presented in Table 1, S2 fell within the moderate MPPI category, five beaches (S1, S3, S4, S5, and S7) were classified in the high category, and S6 was classified in the very high category. The mean MPPI across the seven beaches was 20.45 ± 2.06, corresponding to the high category under the adopted classification scheme. These classifications provide a comparative description of the index values across the investigated sites; however, they should be interpreted in the context of the MPPI definition and calculation procedure and should not be considered direct measurements of ecological impact or toxicity. The MPPI categories are therefore discussed as a complementary assessment and are considered alongside the measured sediment-based microplastic abundance, expressed as items kg⁻¹ of dry sediment.

3.2. Microplastic Shape Distribution

Microplastics collected from the Gulf of Gabès exhibited a wide diversity of morphologies, reflecting the mechanical and chemical degradation of larger plastic debris and the influence of ultraviolet (UV) radiation. Six distinct shape categories were identified: fragments, fibers, foams, pellets, filaments, and films. Morphological analysis using stereomicroscopy revealed cracks, surface roughness, and cavities, indicating oxidative aging, polymer weathering, and physical abrasion during environmental exposure (Figure 3). Additionally, the presence of tar residues on some particles suggests interactions with organic pollutants during transport and deposition.

Figure 3. Representative microplastic particles collected from the beaches of the Gulf of Gabès: (a,b) filaments, (c,d) fragments, (e,f) fibers, (g,h) films, (i,j) pellets, and (k,l) foams.

Fibers were the predominant microplastic morphology, accounting for 83.16% of the recovered particles, followed by fragments (11.10%) (Figure 4; Table 2). The Coefficient of Microplastic Impact (CMPI), as defined by Rangel-Buitrago et al. [66], provided a complementary description of the relative contribution of each morphological category to the total microplastic assemblage. Fibers had an overall CMPI value of 0.83, corresponding to the extreme category (0.81–1.00), whereas fragments had a value of 0.11 (average category), indicating a substantially lower relative contribution. Site-specific results showed that fibers reached the extreme CMPI category at beaches S1, S2, S3, S4, and S5, while S6 and S7 fell into the maximum category. Fragments showed lower relative contributions, with minimum CMPI categories at S1-S5 and average categories at S6 and S7. Filaments accounted for 3.27% of the recovered particles, while films, pellets, and foams were less represented. Their overall CMPI values were 0.033, 0.017, 0.002, and 0.006 for filaments, films, pellets, and foams, respectively, all falling within the minimum category. Overall, these results demonstrate that the recovered microplastic assemblage was strongly dominated by fibers across the investigated beaches, although the relative contribution of individual morphologies varied among sites.

Figure 4. Percentage distribution of microplastic shapes across the sampling sites.

These results are consistent with previous studies on Tunisian and Mediterranean beaches, where fibers and fragments dominate the microplastic profiles (Table 3). For instance, Jaouani et al. [41] reported similar trends on the northern Tunisian coast, while Constant et al. [71] found that fibers (59%) and fragments (25%) were the most common shapes on beaches in the Gulf of Lion (NW Mediterranean). A predominance of fibrous particles is also reported globally, including Puerto Rico (40% fibers) [19], Slovenia [35], Italy [79], and Iran [15]. In contrast, foamed and pellet-shaped particles dominate other locations, such as El Quetzalito Beach (Guatemalan Caribbean, 64.5% foams) [14] and Portuguese beaches (50% pellets) [80].

Hierarchical cluster analysis (HCA) was used to explore similarities and differences among the surveyed sites based on microplastic abundance and morphological composition (Figure 5a). Two main groups emerged:

Figure 5. Grouping and similarity patterns among the seven surveyed beaches based on microplastic abundance, derived from (a) Hierarchical cluster analysis (HCA) and (b) Principal Component Analysis (PCA). The PCA scatterplot shows the first two components (PC1 and PC2), with sampling sites represented as active observations and microplastic abundances by shape category as active variables.

• Group A: Beaches S1-S5, accounting for 66.30% of the total MPs (average abundance: 158 items kg⁻¹). Fibers represented 58.83% (140 items kg⁻¹), fragments 3.57% (8 items kg⁻¹), and filaments 2.15% (5 items kg⁻¹). Four beaches fell in the high MPPI category and one in the moderate MPPI category (Table 4).
• Group B: Beaches S6 and S7, representing 33.70% of total MPs (average abundance: 201 items kg⁻¹). Fibers contributed 24.27% (145 items kg⁻¹), fragments 7.52% (45 items kg⁻¹), and filaments 1.11% (7 items kg⁻¹). S6 fell in the very high MPPI category and S7 in the high MPPI category (Table 4).

Principal component analysis (PCA) was used as an exploratory tool to examine the relationships between microplastic morphological categories and the seven investigated beaches (Figure 5b). The first two principal components (PC1 and PC2) explained 72.2% of the total variance. PC1 showed a separation between sites characterized by comparatively lower microplastic abundances, located on the left side of the PCA plot, and sites with higher abundances, located on the right side. Sites S4, S5, S6, and S7, which were characterized by relatively high fiber abundances, also showed associations with fragments, foams, and pellets in the PCA ordination, whereas S1 displayed a distinct association with films. These patterns provide a descriptive overview of similarities and differences in morphological composition among the surveyed beaches. However, because the PCA was based on only seven site-level observations, these relationships should be interpreted as exploratory patterns within the sampled sites rather than as statistically robust associations or evidence of general patterns across the entire Gulf of Gabès.

The morphology and distribution of microplastics observed in the investigated beaches may provide indications of potential sources, although particle characteristics alone cannot establish definitive source attribution. The predominance of fibers may be consistent with inputs from several sources, including the release of textile fibers through domestic wastewater and surface runoff, as well as the degradation or loss of synthetic fibers from fishing gear and other materials used in coastal activities [16,81,82]. However, fibers can originate from multiple sources, and their presence does not independently demonstrate the relative contribution of any specific activity. Fragments and films may be associated with the weathering and fragmentation of larger plastic items, including packaging and other consumer products [83,84]. Similarly, the occurrence of pellets and foam particles may be compatible with inputs from industrial materials, packaging, fishing-related equipment, or aquaculture activities, depending on the local context. The presence of foam particles at sites S5-S7 may warrant further investigation of nearby coastal activities, but it does not establish a direct link with fishing or aquaculture [14]. Overall, these interpretations should be regarded as source-related hypotheses rather than confirmed attributions. Future investigations combining detailed surveys of potential sources, characterization of local wastewater and runoff pathways, and appropriate chemical or polymer-fingerprint analyses would help clarify the origins and transport pathways of microplastics in the Gulf of Gabès.

3.3. Microplastic Color Distribution

The color of MPs is an important parameter influencing their ingestion by marine organisms, as many predators rely on visual cues to identify potential food sources [13]. In the surveyed area, MPs exhibited a variety of colors, including black, white, green, blue, and pink (Figure 6). Among these, black particles were dominant, accounting for 82.49% of the total MPs, followed by white particles (10.15%). The remaining 7.35% consisted of green, blue, and pink items.

Figure 6. Color distribution of microplastic particles across the seven investigated beaches of the Gulf of Gabès, Tunisia.

This predominance of dark-colored MPs is consistent with previous studies on Tunisian beaches, which also reported black and white as the most abundant colors [49]. However, our findings contrast with those of Chouchene et al. [31], who observed that the Sidi Mansour Harbor beach (Southeast Tunisia) was primarily contaminated by white and red MPs. The high proportion of black particles observed in our study is likely associated with the dominance of microfibers, which are frequently derived from textiles and fishing gear.

The distribution of white MPs (10.15%) showed that fragments represented the majority (90.9%), followed by filaments (5.78%), pellets, and foams (3.3%). White fragments, often originating from the degradation of drinking water bottles and food packaging, were particularly abundant at sites S6 and S7. Blue, green, and pink particles were present in smaller proportions, mostly as fragments, fibers, and filaments. Green and blue fibers are commonly linked to fishing activities, as they are often derived from nets and ropes.

Colored MPs pose a significant ecological risk, as their resemblance to natural prey increases the likelihood of ingestion by marine species [16]. For instance, transparent, white, and blue MPs have been documented in the gastrointestinal tracts of 17 marine species from the Western Ionian Sea [85], while transparent and blue-yellow MPs are frequently detected in edible bivalves. Furthermore, black and red MPs were reported in dolphins from the Western Mediterranean Sea [86], and various MP colors have been observed in the intestines and muscles of fish species collected from the Gulf of Mannar in the Indian Ocean [22].

3.4. Microplastic Size Distribution

A broad range of MP sizes was observed in the surveyed area, as illustrated in Figure 7. The MPs were classified into three size categories: >2 mm, 2–1 mm, and <1 mm. More than half of the collected particles were smaller than 1 mm, highlighting the extensive fragmentation and weathering of larger plastic debris in the region. The prevalence of small-sized MPs (<1 mm) is consistent with previous studies conducted in various marine environments [16,85,87,88].

Figure 7. Percentage distribution of microplastic sizes across the sampling sites.

The size distribution of MPs varied among the sampling sites, but in all cases, the proportion of particles <1 mm exceeded that of larger particles, indicating that degradation processes such as mechanical abrasion, UV radiation, and chemical oxidation are actively occurring in the Gulf of Gabès. The predominance of small MPs has important ecological implications. Particles <1 mm can be easily ingested by a wide range of marine organisms due to their size similarity to planktonic prey, which forms the basis of many marine food webs [13]. Additionally, smaller MPs have been associated with increased toxicity, as they are more likely to translocate into tissues and cause cellular-level effects [85]. Their higher surface area-to-volume ratio also facilitates the adsorption and transport of environmental contaminants such as persistent organic pollutants and heavy metals, increasing the risk of pollutant bioavailability in marine ecosystems [89].

3.5. Microplastic Polymer Identification via FTIR Spectroscopy

Representative MP particles from each morphological category (fragments, fibers, films, filaments, foams, and pellets) were analyzed using Fourier-transform infrared (FTIR) spectroscopy. Characteristic absorption bands were compared with reference spectra to identify polymer types and provide insight into potential sources of plastic pollution along the Gulf of Gabès coastline (Figure 8). However, the use of saturated sodium chloride (NaCl) solution (density approximately 1.2 g mL⁻¹) for density separation may have limited the recovery of higher-density polymers, particularly polyethylene terephthalate (PET) and polyvinyl chloride (PVC). Consequently, these polymers may be underrepresented among the particles analyzed by FTIR, and the identified polymer composition should not be considered an exhaustive representation of all polymers potentially present in the sediments.

Figure 8. FTIR spectra of representative microplastic samples collected from the Gulf of Gabès beaches: (a) fragment, (b) film, (c) fiber, (d) filament, (e) pellet, and (f) foam. In the foam sample, illustrated by the incorporated image, additional absorption bands were observed, similar to those reported for 2,2′-thiobis(3-methyl-5-tert-butylphenol), the active component of the phenolic antioxidant additive Cyanox 53.

• Polyethylene (PE)

Spectra of fragments (Figure 8a), films (Figure 8b), and fibers (Figure 8c) exhibited characteristic PE bands, including strong asymmetric and symmetric -CH₂- stretching vibrations at 2915 and 2848 cm⁻¹, CH₂ bending vibrations at 1472 and 1462 cm⁻¹, and doublet rocking modes at 730 and 720 cm⁻¹, confirming long-chain polymer structures [90,91]. Additional peaks at 1717 and 1652 cm⁻¹ suggested the formation of carbonyl groups, indicative of photooxidative degradation during environmental exposure [92].

• Polypropylene (PP)

Filament samples (Figure 8d) displayed diagnostic PP peaks at 2950 and 2800 cm⁻¹ (C-H stretching of CH₃ and CH₂ groups), with additional peaks at 1457 and 1375 cm⁻¹ corresponding to CH₃ and CH₂ bending vibrations [49]. Minor peaks near 1738 and 1650 cm⁻¹ reflected early-stage oxidative weathering, consistent with environmental aging [65].

• Polystyrene (PS)

Pellet samples (Figure 8e) were identified as polystyrene (PS) based on aromatic C-H stretching (~3025 cm⁻¹), aliphatic C-H stretching (2920–2851 cm⁻¹), and aromatic C=C stretching vibrations at 1600 and 1493 cm⁻¹ [90,93]. Peaks at 1452, 1028, 755, and 695 cm⁻¹ corresponded to in-plane and out-of-plane aromatic C-H bending, confirming mono-substituted benzene rings typical of PS [94,95,96]. All analyzed pellet samples matched polystyrene reference spectra, a polymer widely used in packaging and aquaculture-related materials [91,97].

• Polymer additives: Cyanox 53-like spectral features in foam MPs

The FTIR spectra of some foam MP particles (Figure 8f) exhibited additional absorption bands that differed from the characteristic features of the polymer backbone. These bands included a broad absorption region at approximately 3600–3200 cm⁻¹, signals near 2954 and 2851 cm⁻¹, and additional bands around 1650, 1420, and 1080 cm⁻¹. The overall spectral pattern showed similarities to those reported for 2,2′-thiobis(3-methyl-5-tert-butylphenol), the active compound associated with the antioxidant additive Cyanox 53 [98]. These spectral similarities suggest the possible presence of an antioxidant-related compound associated with the foam particles, although they do not establish its chemical identity conclusively.

Antioxidants are incorporated into certain polymer formulations to improve material stability and limit oxidative degradation. Accordingly, the observed spectral features may be consistent with a compound originating from an additive incorporated into the original polymer matrix. Such a compound could migrate toward the particle surface and potentially be released into the surrounding environment. Alternatively, the observed features could reflect a compound acquired through environmental sorption during exposure to seawater and sediments. Both additive migration and environmental sorption are recognized processes governing interactions between plastics and associated chemicals [99,100,101,102]. However, the available results do not allow these mechanisms to be distinguished or the origin of the observed compound to be established.

The possible association of antioxidant-related compounds with foam MPs highlights the importance of considering chemical constituents alongside polymer composition when investigating marine plastic pollution. Complementary analytical techniques, such as gas chromatography–mass spectrometry (GC-MS), liquid chromatography–mass spectrometry (LC-MS), and nuclear magnetic resonance (NMR) spectroscopy, together with appropriate reference standards, would help verify the compound’s identity and investigate its possible origin [103]. Further investigations of additive release and environmental interactions could also improve understanding of the occurrence, fate, and potential ecological relevance of these compounds in the coastal environment.

Microplastics have attracted increasing attention because of their potential interactions with marine organisms and their possible implications for environmental and human health. However, the occurrence and characteristics of microplastics do not, by themselves, demonstrate biological uptake, adverse effects, or a measurable level of risk. The World Health Organization has highlighted important knowledge gaps concerning exposure to environmental microplastics and their potential implications for human health [104]. In the present study, no biological samples, exposure pathways, or toxicological endpoints were investigated. Therefore, the observed abundance, morphology, color, size, and polymer composition cannot be used to establish ecological damage or health effects attributable to microplastics at the investigated beaches.

The wider environmental context of the Gulf of Gabès nevertheless supports the importance of continued environmental monitoring. Previous research has documented trace-metal contamination in coastal sediments surrounding the industrial complex of Gabès [105]. In addition, a regional clinical study investigated associations between outdoor air-pollution indicators and the severity and outcomes of community-acquired pneumonia [106]. These studies concern pollutants and exposure pathways different from those investigated here and do not establish a causal relationship between microplastic contamination and health outcomes among local residents. Accordingly, the present findings provide baseline information for further environmental monitoring and future studies of exposure and toxicity rather than a direct assessment of ecological or human-health risk.

3.6. Integrated Sustainable Development Perspective

The findings of this study have significant implications for sustainable development strategies in the Gulf of Gabès. The high levels of MPs, especially in areas near fishing, tourism, and urban activities, highlight the connection between environmental degradation and socioeconomic vulnerabilities. Gabès, which depends on coastal fisheries, artisanal aquaculture, and ecotourism, faces a dual challenge: sustaining economic livelihoods while preserving ecosystem services. The presence of polymers such as PE and PP, along with the possible Cyanox 53-related spectral features, may indicate an influx of industrial and consumer waste, revealing deficiencies in regional waste management infrastructure and policy enforcement. This situation aligns with previous spatial-environmental studies in Tunisia, which show that unchecked industrialization and poor resource governance exacerbate environmental injustice and hinder long-term development prospects [107]. Consequently, addressing MP pollution in Gabès should be part of a comprehensive sustainable coastal governance framework that integrates solid waste management, community-based monitoring, green innovation and inclusive policymaking [108,109,110]. Such measures are vital not only for ecological restoration but also for improving public health, enhancing the resilience of the blue economy [111,112], and fulfilling Tunisia’s commitments to the SDGs, particularly SDG 14 (Life Below Water), SDG 12 (Responsible Consumption and Production), and SDG 8 (Decent Work and Economic Growth).

The Table 5 summarizes the implications of the study’s findings across environmental, economic, social, and policy dimensions, illustrating the systemic nature of microplastic pollution in the Gulf of Gabès [113]. Ecologically, the high microplastic levels threaten marine ecosystems, while economically, they exert pressure on fisheries and tourism-key sectors for local livelihoods. The possible presence of a Cyanox 53-related compound further underscores the relevance of chemical constituents associated with plastic waste. These observations highlight structural policy gaps in waste management and enforcement that must be addressed through an integrated sustainable development framework. Aligning intervention strategies with SDG 14, SDG 12, and SDG 8 can help position Gabès as a model for sustainable coastal governance in Tunisia and the broader Mediterranean region [114,115].

Table 5. Summary of microplastic pollution impacts and their implications for sustainable development in Gabès, Tunisia.

Dimension	Findings from Current Study	Sustainable Development Implication (Gabès Context)
Environmental	Microplastics were detected at all seven beaches with a mean abundance of 170.38 ± 17.14 items kg−1 of dry sediment. The predominant shapes observed were fibers, accounting for over 83%, along with fragments, indicating prolonged plastic degradation and widespread distribution.	This level of contamination indicates considerable environmental stress in Gabès’ coastal zone. The presence of microplastics in beach sediments disrupts marine biodiversity and the functioning of ecosystems, jeopardizing fish stocks, seabird populations, and benthic habitats that are vital for the region’s ecological balance. This situation underscores the urgent need for ecosystem restoration strategies and marine conservation efforts that align with SDG 14 (Life Below Water).
Economic	MPs were associated with significant economic activities, including tourism, fishing, and domestic waste management, such as the production of synthetic textiles, fishing gear, and packaging. Areas near tourist and fishing zones exhibited higher concentrations of microplastics.	The contamination of Gabès’ coastal environment directly threatens the livelihoods of those who depend on the sea. Plastic pollution harms fish habitats, diminishes fish quality, and can result in health-related trade restrictions. Additionally, the growing tourism sector in Gabès may suffer due to polluted beaches. Tackling this issue is crucial for protecting income and job opportunities, in line with SDG 8 (Decent Work and Economic Growth).
Social	The possible presence of Cyanox 53, a synthetic antioxidant additive of environmental concern, was suggested by FTIR spectra of some foam particles.	The possible presence of an additive-related compound as (Cyanox 53-like spectral features) may warrant attention from a public-health perspective. These compounds can leach into water and enter the food chain through the consumption of seafood. Prolonged exposure to these chemicals may hurt human health, particularly for vulnerable communities residing near polluted beaches. These findings underscore the pressing need for social awareness campaigns, environmental education, and the implementation of enhanced ecological justice practices.
Policy	The findings indicate that solid waste management is inadequate and that enforcement of environmental regulations in coastal zones is limited. The majority of plastic pollution stems from poorly managed urban and industrial sources.	The policy implication is clear: Gabès requires a localized, integrated coastal zone management (ICZM) approach. To achieve this, it should adopt a circular economy framework focused on source reduction, recycling, and pollution prevention. Involving municipalities, civil society, and coastal stakeholders in co-designed interventions can enhance waste governance and promote community stewardship. This approach aligns with both SDG 12 (Responsible Consumption and Production) and Tunisia’s national environmental commitments.
SDGs Impacted	The study intersects with several Sustainable Development Goals (SDGs), particularly: SDG 14: Life Below Water SDG 12: Responsible Consumption and Production SDG 8: Decent Work and Economic Growth	The findings highlight the connections between environmental degradation, socioeconomic vulnerability, and governance gaps. Addressing microplastic pollution can help achieve multiple SDGs through integrated, multisectoral interventions that enhance ecological health, promote sustainable livelihoods, and foster long-term resilience in Gabès. This regional perspective also supports Tunisia’s overall development strategy for its southern coastal areas.

4. Conclusions

This study provides a spatial assessment of beached MP pollution across seven selected beaches in the Gulf of Gabès, southern Tunisia. The mean MP abundance was 170.38 ± 17.14 items kg⁻¹ of dry sediment, with variability among the investigated sites. Fibers and fragments were the predominant morphologies. Their occurrence may be consistent with inputs from multiple sources, potentially including synthetic textiles, fishing-related activities, wastewater pathways, and the fragmentation of plastic consumer products. However, these potential sources were not directly identified or quantified in the present study. FTIR analysis identified polyethylene (PE), polypropylene (PP), and polystyrene (PS) among the spectroscopically characterized particles. In addition, some foam particles exhibited spectral features tentatively consistent with a Cyanox 53-related compound, a synthetic antioxidant additive of environmental concern. This interpretation remains preliminary and requires confirmation using complementary analytical techniques.

The observed variability in MP abundance and morphology highlights spatial differences in contamination among the investigated beaches. Exploratory hierarchical cluster analysis (HCA) and principal component analysis (PCA) further illustrated similarities and differences among the seven sites. These findings complement previous investigations of microplastics in the Gulf of Gabès by providing additional information on the beach-sediment compartment. Nevertheless, the limited number of sites, the single sampling campaign in October 2024, and the exploratory nature of the multivariate analyses restrict the temporal and spatial generalizability of the results. Moreover, although the observed patterns may reflect differences in local anthropogenic pressures, the contributions of specific sources cannot be established from the available data.

Importantly, this study assessed microplastic occurrence and characteristics but did not investigate biological uptake, trophic transfer, bioaccumulation, organism-level effects, human exposure, or toxicological endpoints. Therefore, the observed contamination cannot, by itself, establish ecological damage or adverse human-health effects. Likewise, the potential presence of a Cyanox 53-related compound does not confirm its chemical identity, release into the environment, bioavailability, or associated health risks. These aspects require further investigation using appropriate chemical characterization, exposure assessment, and biological or toxicological analyses.

The results provide baseline information on microplastic contamination at the investigated beaches during the October 2024 sampling campaign and may support future monitoring and evidence-informed coastal management. Further research should expand spatial coverage, incorporate repeated seasonal sampling, strengthen contamination-control procedures, validate particle recovery and identification methods, and improve the chemical characterization of particles, particularly those smaller than 1 mm. Complementary analyses are also needed to confirm the identity and investigate the possible origin of plastic-associated additives. Continued efforts to improve waste management, reduce plastic inputs, and promote stakeholder collaboration may contribute to more sustainable coastal environments. Overall, this study provides site-specific information that may inform the sustainable management of coastal resources in the Gulf of Gabès and contribute to broader efforts related to SDG 14 (Life Below Water) and SDG 12 (Responsible Consumption and Production). Its potential relevance to SDG 8 (Decent Work and Economic Growth) is indirect, as the present study did not assess economic impacts or employment outcomes.