Boa Viagem Beach is in the southern coastal zone of Recife, Pernambuco State, northeastern Brazil (Figure 1). Spanning approximately 8 km, the beach is mostly straight and bordered to the south by coordinates 08° 08′ 55″ S and 34° 54′ 24″ W, and to the north by 08° 06′ 06″ S and 34° 53′ 04″ W. As the city's principal ocean-facing beach, it lies within a densely urbanized area. Historically, this region formed part of a broader coastal ecosystem that included dunes, lagoons, mangroves, and small rivers; however, rapid urbanization has significantly reduced these natural habitats. The beach serves both ecological and recreational functions, providing shoreline protection, local climate regulation, and providing nesting habitat for sea turtles, while also acting as a major tourist destination. Although designated as a Special Environmental Protection Zone since 2001, the area faces weak enforcement, resulting in the accumulation of solid waste, coastal erosion, and increasing anthropogenic pressure (Costa et al., 2008). The coast of Pernambuco is wave-dominated and mesotidal, influenced by prevailing trade winds that blow predominantly from the east-southeast during winter (April-September) and from the east-northeast in summer (October-March). The nearshore zone is characterized by sandstone reef outcrops (beachrocks) that are more continuous in the northern portion of the beach and become discontinuous toward the south. These features modulate wave energy and sediment transport, generating alternating protected and exposed zones that influence the retention of floating and stranded debris (Costa et al., 2008; de Gois et al., 2013).

Sedimentologically, Boa Viagem Beach shows high uniformity in texture and composition, with the foreshore composed predominantly of fine quartz sand mixed with bioclastic material. The width of the beach varies considerably along the Boa Viagem-Pina coastal system. The northern portion, corresponding to Pina Beach, exhibits a broader and relatively stable foreshore, while the central and southern areas of Boa Viagem Beach are markedly narrower and subject to active erosion processes (Gregório et al., 2004; de Gois et al., 2013; Gregório et al., 2017).

In early September 2024, a 100 m transect was established along the high-tide line of Boa Viagem Beach (8°07'03” S; 34°53'38” W). A continuous sweep was performed to collect one composite sample of surface sediments and plastic litter (1 kg). The composite sample approach was adopted to obtain an integrated representation of plastic contamination along the selected high-tide sector. The sampling site was located in the southern portion of Boa Viagem Beach, within a coastal stretch between Coronel Benedito Chaves Street and Bruno Veloso Street. This area is characterized by a moderately wide back-beach bordered by a well-defined high-tide scarp and by a more developed line of sandstone reef outcrops offshore, and corresponds to the erosional sector previously described by Gregório et al. (2017). The study site was selected based on its geomorphological setting and exposure conditions, corresponding to a high-energy sector of Boa Viagem Beach characterized by erosive features and discontinuous beachrock formations. This sector is additionally influenced by adjacent urban activities, making it suitable for documenting the characteristics of plastic litter stranded along the high-tide line. The transect was established to generate baseline, site-specific information intended to support future multi-site and comparative monitoring of coastal plastic contamination along Boa Viagem Beach.

To minimize airborne and/or cross-contamination during sampling and laboratory processing, materials in direct contact with the sample were preferentially made of metal, glass, or wood. Sediments were air-dried at room temperature and covered with aluminum foil to reduce exposure to airborne particles. All materials were thoroughly rinsed with distilled water and inspected before use. Both the distilled water and the NaCl solution used throughout the procedures were pre-filtered through 0,45 μm filters. To monitor and prevent cross-contamination during analytical procedures, Petri dishes containing distilled water and 0,45 μm MCE filters were exposed in the working area and examined under a stereomicroscope at the end of each day.

Macroplastics (25-1000 mm) were counted, weighed, and classified based on size, color, and presumed source. The classification followed the Ocean Conservancy survey, which categorizes plastic litter into the following groups: (1) most commonly found items, (2) fishing-related gear, (3) packaging materials, (4) personal hygiene products, and (5) other miscellaneous waste. Plastics smaller than 25 mm were classified based on three criteria: (1) size, following the GESAMP (2019) classification into mesoplastics (5-25 mm) and MPs (<5 mm); (2) shape, including fibers, fragments, pellets, microbeads, sponges, and foam; and (3) color, categorized as white, yellow, gray, transparent, blue, black, red, green, multicolored, or other color (Frias et al., 2018). The quantity of macro-, meso-, and microplastics recovered from the sample was reported as both total items collected and items per kilogram of dry sediment (items/kg). Item concentrations were calculated by dividing the number of particles recovered by the dry mass of the processed sample. As the composite sample analyzed in this study corresponded to 1 kg of dry material, the reported values in items/kg were numerically equivalent to the total number of items recovered.

Approximately 12% of the recovered plastic particles from the first stage (mesoplastics and MPs), and 21 potentially plastic particles recovered after density separation (Second phase) were selected for Raman spectroscopy analysis, a non-destructive technique widely employed for polymer identification (Araujo et al., 2018; Jin et al., 2022). Particle selection aimed to represent the variability of the samples based on size, shape, color, and morphology, ensuring the inclusion of representative particles from the different categories identified. Raman spectra were obtained using a Bruker SENTERRA Confocal Raman Microscope (Ettlingen, Germany), equipped with a 20× Olympus objective (NA = 0.40) and an Andor CCD detector with thermoelectric cooling, operated at -66 °C. Laser excitation was performed at 532 nm or 785 nm, with acquisition parameters optimized according to the sensitivity of each sample. The most frequently used settings included an exposure of 5 mW for 3 seconds with the 532 nm laser and 25 mW for 3 seconds with the 785 nm laser. In all cases, five accumulations were taken to enhance the signal-to-noise ratio. The resulting spectra were compared with published reference spectra available in the literature to support polymer identification (Nava et al., 2021). Raman spectra were processed and analyzed using Spectragryph optical spectroscopy software (F. Menges, Version 1.2.16.1, 2022; http://www.effemm2.de/spectragryph/).

Field sampling yielded 110 macroplastic (Figure 2). According to the classification of plastic litter types (Figure 2A), most recovered items corresponded to common plastics associated with urban and recreational activities (67%), followed by fishing-related materials (18%) and other miscellaneous waste (13%), whereas packaging materials represented the smallest proportion (2%). This distribution indicates the predominance of anthropogenic activities related to tourism and coastal use. Regarding the most frequently recovered objects (Figure 2B), bottle caps (35%), cigarette butts (28%), and plastic wrappers (16%) represented the dominant items, while bags (8%), straws (6%), single-use plastic cups (3%), spoons (3%), and containers (1%) occurred in lower proportions. Approximately 72% of the recovered litter was associated with food and beverage consumption and packaging, emphasizing the contribution of single-use products to plastic accumulation on urban beaches. Similar patterns have been reported for highly frequented coastal environments, where recreational activities constitute an important source of plastic inputs (Parker, 2020). According to GESAMP (2019), food and beverage packaging accounts for approximately 36% of global plastic production.

The packaging industry is projected to remain the largest consumer of plastics, with global production volumes expected to rise from approximately 39,9 million tons in 1990 to 236,3 million tons by 2050. Nevertheless, adopting a 15% reduction target by 2040 could help mitigate this upward trend, with plastic consumption potentially declining by 2050, principally if a growing share of packaging materials is effectively recycled (Dokl et al., 2024). The presence of bottle caps, plastic wrappers, bags, and straws indicates a strong influence from the consumption of single-use plastic products, reflecting the combined impacts of tourism and inadequate waste management in urban environments. Similar patterns of plastic litter accumulation have been reported on beaches in Nueva Cádiz, Spain (Ciufegni et al., 2025), the Mediterranean region of Africa, Tunisia (Baccar Chaabane et al., 2024), and Brazil (Andrades et al., 2020; De Ramos et al., 2021).

The high proportion of cigarette butts (28%), which has also been reported in other studies (Araújo et al., 2022; Dantas et al., 2025), is a concerning finding, as these residues not only contribute MPs through their filters but also release toxic substances into the environment. Previous research has demonstrated that cigarette butts can leach nicotine, heavy metals, and other harmful compounds into seawater, negatively impacting environmental quality and coastal biota (Acarer Arat, 2024). The persistent occurrence of cigarette butts along Boa Viagem Beach suggests persistent inputs associated with recreational beach use.

Additionally, the recovery of fishing-related plastic litter (18%) indicates that pollution is also influenced by local economic activities, both small and large-scale (Garcés Ordóñez, 2022). The concentration of plastic litter along the high-tide line and near tourist access points reflects the influence of tidal deposition and beach morphodynamics in this erosive sector, where the discontinuous beachrock barrier and high recreational use enhance retention and fragmentation. Marine currents and wind can redistribute these materials, favoring their accumulation in localized sections of the beach (GESAMP, 2019; Gamboa et al., 2025a).

Macroplastics recovered from the sample ranged from 25 to 280 mm in size. The most frequent size class corresponded to items between 25 and 50 mm (58%), followed by the 51-100 mm range (31%), whereas plastic litter larger than 100 mm occurred at considerably lower proportions (Figure 3C). This size distribution suggests that fragmentation of larger plastic items may be an ongoing process on the beach, likely driven by environmental factors such as UV radiation, wave action, wind, and abrasion with sand, which promote the mechanical and chemical degradation of macroplastics into smaller particles (Gallo et al., 2018; Öborn et al., 2022).

Color analysis revealed a predominance of white and blue (54%, Figure 3D), consistent with other studies and indicative of the degradation of foamed and colored consumer plastics (Cesarini et al., 2022). The color and size patterns observed here, together with the dominance of packaging materials, highlight the central role of urban consumption patterns and recreational activities as the main drivers of coastal plastic pollution on Boa Viagem Beach.

From the sieving process, a total of 422 plastic particles (422 items/kg dry sediment) were recovered, of which 56% corresponded to mesoplastics (237 items; 5-25 mm) and 44% to MPs (185 items; <5 mm). Most particles were classified as fragments of various colors and white foam pieces or spheres (Figure 3). Of the 185 MPs recovered, 37 were identified as primary MPs (pellets). The coexistence of fragments and primary pellets on Boa Viagem Beach has been previously documented (Costa et al., 2010; Pinheiro et al., 2019), showing patterns consistent with those observed in this study. The higher proportion of mesoplastics suggests that fragmentation of larger litter is an active process, continuously supplying smaller size fractions in this coastal environment.

In 2010, Costa et al. documented the presence of virgin plastic pellets (90 cylindrical, oval, or flattened particles), likely originating from long-distance marine transport, due to the absence of nearby industrial sources to Boa Viagem Beach. They also reported 2661 secondary plastic fragments of various colors (white, red, green, blue, and pink), predominantly irregular hard-plastic pieces formed through photodegradation and mechanical abrasion in the marine environment. Nearly a decade later, Pinheiro et al. (2019) recorded a predominance of blue fragments (49,7%) and a very low occurrence of pellets (only three items). Their spatial analysis showed that smaller particles (<1 mm) were more abundant in protected zones behind rocky formations (60,1%), whereas larger fragments predominated in wave-exposed sectors (75,9%).

For comparative purposes, the MPs abundance obtained during the first phase was expressed relative to the mass of the composite sediment sample (185 items/kg of sediment). This value was lower than those reported for Chancay (306 items/kg), Carpayo (479 items/kg), and Asia (260 items/kg) beaches in Peru (Zarate & Iannacone, 2021), but higher than that reported for San Mateo Beach (12,5 items/kg) in Ecuador (Zambrano Tigua & Pardo Reyes, 2024). Such variability among sites across the Pacific and Atlantic coasts reflects differences in local hydrodynamic conditions, beach morphology, and proximity to pollution sources (Jamšek et al., 2024). Regarding color distribution, white, blue, green, and transparent particles were the dominant categories for both mesoplastics and MPs (Figure 4), which is consistent with previous observations reported for Boa Viagem Beach (Costa et al., 2010; Pinheiro et al., 2019).

To determine the polymeric composition, 50 particles (~12%), including mesoplastics as well as secondary and primary MPs, were analyzed. As shown in Figure 5, foam spheres (classified as mesofoam or microfoam) were identified as polystyrene (PS). Considering the predominance of foam particles in the recovered assemblage, PS appeared as one of the predominant polymers among the analyzed particles. Mesofibers were composed of PP and PE. Analysis of fragments revealed that most were made of PP (10 mesofragments and 7 microfragments) and PE (7 mesofragments and 2 microfragments). Polymer identification of the selected primary MPs (pellets) indicated the presence of PE and PP. Representative Raman spectra obtained during the analysis are shown in Figure 6.

The prevalence of PS, PP, and PE reflects the dominance of packaging and foam-derived materials, already observed in the larger plastic size fractions discussed previously. These low-density polymers are easily transported and reworked by wave and tidal processes. This pattern is consistent with global production data for 2024, which identifies PE (high or low-density) as the most produced polymer (26%), followed by PP (19%), and PS (5.1%) (Plastics Europe, 2025). Similar polymeric compositions have been reported on other urban beaches influenced by recreational and commercial activities (Gamboa et al., 2025a,b; Garcés Ordóñez, 2022; García-Varens et al., 2025; Pelegrini et al., 2024).

The granulometric analysis based on sieved sediment fractions revealed a predominance of particles within the 1.00-0.25 mm range (F3), corresponding predominantly to medium-sized sand fractions according to the mesh-based Wentworth classification adopted in this study and representing 68% of the total sediment mass. A total of 49 potential plastic particles retained on the filters were recovered following density separation of all five granulometric fractions (Figure 7). Of the 49 potentially plastic particles recovered after density separation, a subset of 21 particles was subjected to Raman spectroscopy analysis. Polymer identification was successfully achieved for five particles (23.81% of the analyzed particles; Figure 7), including two foam particles (green and white) identified as PS and three blue fragments identified as PP. Initial spectra from several additional particles suggested polymeric characteristics; however, reliable identification was limited by fluorescence effects and particle alteration during analysis.

The reduced spectral resolution observed in some particles may reflect the effects of prolonged environmental exposure, suggesting degradation processes such as oxidation, photodegradation, or biofouling that can modify the optical and chemical properties of plastics (Shi et al., 2024). Figure 8 shows representative Raman spectra of MPs recovered during this phase. The analyzed MPs ranged from 160 to 350 μm in size, emphasizing the occurrence of small plastic particles that, through continued environmental weathering, may further fragment into even smaller particles with greater environmental mobility and bioavailability. The characteristic Raman bands corresponding to each identified polymer are summarized in Table 1.