The wedge clam Donax trunculus L., 1758 as a bioindicator of microplastic pollution

Multi-matrix approach to microplastic pollution in the bivalve Donax trunculus, sediment and water along the Mediterranean coasts

Plastic pollution is a widespread issue in marine ecosystems worldwide, and at the basin level, the Mediterranean represents one of the main hotspots for plastic debris. Here, we present MPs pollution levels in the bivalve Donax trunculus, commonly known as wedge clam, considering both young and adult individuals, as well as sediment and water matrices across a national scale, covering the Tyrrhenian, Ionian, and Adriatic coasts of Italy. The aim is to provide an overview of MPs pollution in coastal ecosystems and assess whether wedge clams can act as an early warning sentinel for sandy habitats. Results highlighted that the Adriatic and Ionian coasts exhibited higher MPs levels than the Tyrrhenian coast across all matrices, with MPs pollution predominantly consisting of blue acrylic fibers. D. trunculus proved to be an excellent sentinel for MPs pollution in sediment. The findings also revealed that young individuals had more MPs than adults, highlighting potentially severe harm to the growth of marine organisms. As a commercially valuable species, this study underscores the urgent need to further investigate this issue, especially given its critical implications for both marine ecosystem health and human well-being.

Monitoring water contamination through shellfish: A systematic review of biomarkers, species selection, and host response

Shellfish are ubiquitous inhabitants of water environments and an important food source. Their presence in habitats affected by human activities and bioaccumulation potential support their use as indicators of contamination. Using these organisms as bioindicators may provide a simple, cost-effective alternative for monitoring contamination risk without requiring complex sample preparation and analytical procedures. However, there is no consensus on biomarkers, species selection, or standard methodologies. This systematic review explores the significance of shellfish as bioindicators, the methodologies employed, and the interactions between contaminants and host response. Research strategy and selection criteria followed PRISMA and SPICE guidelines. Peer-reviewed papers were obtained from Scopus, Pubmed and Google Scholar using the keywords: shellfish, bioindicator, environmental, contaminant, and host response. Out of 3050 results, 20 studies were selected after a rigorous, unbiased process. These studies spanned 14 countries, assessing 26 shellfish species, 24 contaminants, and 35 effects. A wide range of biomarkers was identified, reflecting changes in water condition due to contaminants or adverse environmental parameters. Results indicate that shellfish are highly sensitive to minor environmental changes, making them reliable bioindicators of water quality and potential risks of consumption from contaminated sites. This study highlights the need for standardized protocols to enable consistent shellfish-based monitoring of water conditions worldwide.

Microplastics in wastewater and the role of local wastewater treatment stations in controlling microplastic pollution: a case study from Vietnam

Wastewater has been identified as one of the main contributors to microplastic (MP) pollution in aquatic environments. Hence, this study investigates the presence, characteristics of MPs in wastewater sample types (industrial, domestic, and medical wastewater), and also the removal efficacy of MPs by local wastewater treatment stations. Overall, industrial wastewater showed a higher MP abundance level at 60,881 ± 48,154 items/m3, compared to domestic and medical wastewater with values of 31,494 ± 10,142 items/m3 and 35,453 ± 13,186 items/m3, respectively. Fiber and fragment were the main shapes observed among the MPs found in all wastewater samples, and the dominant form was microfiber, ranging from 63 to 97.5% of total MPs. The performance of local wastewater treatment stations showed varied efficiencies in MP removal, ranging between 15.8 ± 5 and 90.2 ± 1.3%. Domestic wastewater treatment stations showed lower MP removal effectiveness, at 43.9 ± 13.1%, while treatment stations receiving industrial and medical wastewater achieved 59.5 ± 20.7 and 69.6 ± 22.1% of removal efficiencies, respectively. As estimated, 2.9 × 1010 microplastic items could be emitted to the water bodies around Hanoi every day, which MPs originated from domestic wastewater accounted for 80.3% due to its high discharge volume and inadequate treatment capacity. Optimization of the septic tank system operation and the sewage sludge treatment processes could prevent secondary contamination of MPs, while an additional primary sedimentation step could improve the overall MP elimination efficacy of the studied treatment stations. The results from this study suggested that more in-depth investigations were required for a proper understanding of the migration routes of MPs from different anthropogenic activities to wastewater.

Microplastic distribution and composition in mudflat sediments and varnish clams (Nuttallia obscurata) at two estuaries of British Columbia, Canada: An assessment of potential anthropogenic sources

Widespread microplastic contamination affects the marine-coastal ecosystems in British Columbia, Canada. To understand the characteristics and spatial distribution of of microplastics (MPs), we compared the MPs in sediments (n = 159) and Varnish clams (Nuttallia obscurata; n = 160) collected from two estuarine ecosystems (Cowichan and K'ómoks) experiencing different anthropogenic impacts; primarily resource extraction (i.e., logging) at Cowichan and urban development at K'omoks. Our objective wasto determine the MP abundance levels in sediments and clams and infer possible sources of MPs at the two estuaries. Microplastic polymer type was confirmed through FTIR spectrometry. The average abundance of MPs in sediments were 14.37 ± 11.57 particles/kg in the Cowichan Estuary and 30.96 ± 14.58 particles/kg in the K'ómoks Estuary. Varnish clam samples contained average abundance of 3.62 ± 2.58 particles/g and 2.24 ± 1.96 particles/g in Cowichan and K'ómoks estuaries, respectively. The Cowichan Estuary's marine terminal and K'ómoks Marina were found to be hotspots for MPs, likely due to a combination of industrial and local sources. Fibers were the most common type of MPs found in both sediment (53.34 %) and clam samples (53.5 %) from Cowichan, as well as in clam samples in% K'ómoks, indicating a potential link to textile sources contributing to the widespread presence of MPs in the marine environment. There was no clear signal based on the primary use of the estuary. Polyethylene was the predominant polymer type of MPs found in sediment and clam samples at Cowichan, whereas Polyester was most common at K'ómoks. Our study revealed the ubiquitous nature of these emerging pollutants in the sensitive estuarine environments of BC, with implications for plastic waste management and the reduction of plastic pollution at the regional level.

Microplastics in Morocco's most consumed fisheries: Chemical characterization, ecological traits, and implications for human health

The pervasive presence of microplastics (MPs) in the environment is well established, yet many critical questions remain about their distribution and potential impacts on both ecological and human health. To assess the risks that MPs pose, especially through marine ecosystems and human consumption, monitoring their ingestion by fish in natural environments is essential. This study investigated the contamination of 12 fish species, the most commonly consumed in Morocco, collected from the Atlantic Ocean off the Moroccan coast. Analysis of 240 fish (20 individuals per species) revealed that 100 % of the samples contained microplastics. MPs were detected in the gills, gonads, and gastrointestinal tracts of all 12 species. The average abundance of microplastics per fish ranged from 20.6 to 133.2 MPs, with the forms identified as fragments (60 %), fibers (30 %), films (8 %), and pellets and foams (1 %). Additionally, omnivorous and demersal species presented the highest levels of MP contamination. Infrared spectroscopy (ATR-FTIR) analysis identified seven polymers, with high-density polyethylene (34 %), polyethylene terephthalate (30 %), and polypropylene (17.5 %) being the most prevalent. The microplastics were predominantly dark or light in color, with a notable presence of red and blue particles. Fish ingest various sizes of microplastics, primarily particles smaller than 1 mm. Scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM/EDX) revealed that most MPs exhibited visible signs of weathering and contained inorganic components on their surfaces. The potential risk of MPs to fish, as assessed by the polymer hazard index (PHI), was categorized as level V, indicating that MPs may pose significant risks to human health. The highest estimated daily intake (EDI) of microplastics was found in children (1620 MPs/year), whereas the lowest intake was estimated in women (350 MPs/year) and men (337 MPs/year). Given the widespread presence of microplastics in commonly consumed fish species in Morocco, there is an urgent need for regulatory measures to ensure the safety of fisheries, both for domestic consumption and export. Policymakers should consider the development of guidelines for acceptable levels of microplastic contamination in fish to safeguard public health.

Evaluating the impact of gadolinium contamination on the marine bivalve Donax trunculus: Implications for environmental health

Gadolinium (Gd), commonly used in contrast agents for medical imaging, has been detected in hospital wastewater and aquatic environments, raising environmental concerns. This study examined the accumulation and cellular impacts of Gd in the clam species Donax trunculus, commonly used as bioindicator of contamination. Gadolinium accumulation in clams increased with exposure and over time. Biological responses varied with Gd levels: low concentrations (10 and 50 µg/L) led to low metabolic activity and glycogen content, but high antioxidant activities and lipid peroxidation levels (LPO); high concentrations (250 and 500 µg/L) resulted in increased metabolic activity, while antioxidant enzyme activity was inhibited and LPO levels were the lowest. Metabolic activity decreased after two weeks, suggesting limited long-term metabolic resilience. The study underscores D. trunculus as an effective early warning species for Gd pollution and highlights the ecological risks of rising Gd levels, emphasizing the need for environmental monitoring and regulation.

Rethinking geological concepts in the age of plastic pollution

This paper attempts to reevaluate traditional geological classifications from sedimentology to stratigraphy as well as the concept of the Holocene/Anthropocene epochs, characterized by the widespread integration of plastics into sedimentary environments. This paper presents a set of novel insights into the interactions between synthetic materials and natural geological processes. We illustrate how plastics not only disrupt sedimentary dynamics and alter the composition of rocks and soils, creating new forms of pollution and also pose escalated threats to marine biodiversity through altered erosion, transport, and deposition patterns. We highlight the emerging role of plastics as distinctive stratigraphic markers, providing a different perspective on human environmental impacts. This analysis challenges the traditional perception of rocks as solely natural, inorganic formations and highlights the critical need for interdisciplinary approaches that meld geology, chemistry, and environmental science. The document calls for intensified research to develop effective strategies for managing these impacts and promotes innovative conservation techniques that address both the symptoms and sources of plastic pollution.

Assessment of persistent and emerging pollutants levels in marine bivalves in the Gulf of Suez, Egypt

Bivalves possess important ecological and economic values. They have been extensively used as bioindicators for both emerging and classical pollutants in the aquatic environment. This study investigates the levels of trace metals, polycyclic aromatic hydrocarbons (PAHs), and organochlorine pesticides (OCPs), alongside microplastic (MPs), in Tridacna maxima, Paphia textile, and Paratapes undulatus, collected from the Gulf of Suez. This work represents the first investigation of MPs in marine bivalves from the Gulf of Suez. MPs were detected in 72% of the specimens examined and four types of MPs were identified. The metal pollution index indicated that bivalves may have long-term toxic effects on human consumers. The results showed minimal hydrocarbon pollution. Diagnostic ratios indicated a combination of pyrolytic and petrogenic sources, with a notable influence from pyrolytic origins. The risk assessment reflected that the levels of certain trace metals, PAHs, and OCP contaminants could present a low risk to human health.

Microplastic characterization and assessment of removal efficiency in an urban and industrial wastewater treatment plant with submarine emission discharge

Wastewater treatment plants (WWTPs) are significant contributors to microplastic (MP) pollution in marine ecosystems when they are inefficient. This study aimed to evaluate the effectiveness of microplastic removal from the effluent of the Anza WWTP (Morocco), which processes industrial and urban wastewater using a lamellar decantation system combined with a submarine emissary for treated water discharge. Additionally, this study investigated the presence of microplastics in the Atlantic seawater where treatment plant effluent is released. Microplastics were collected and extracted from wastewater and seawater samples to assess their abundance, shape, size, polymer type, and removal rates in the treatment plant. The findings revealed an average MP concentration of 1114 ± 90 MPs/L in the influent and 607 ± 101 MPs/L in the effluent, indicating a removal efficiency of 46 %. Seasonal analysis revealed the highest MP concentrations during the summer, with 2181.33 MPs/L in the influent and 1209 MPs/L in the effluent. Seawater samples from the discharge zone of the submarine emissary had an average MP concentration of 1600 MPs/m3. Characterization of the MPs revealed that fibers were the most common form of MPs in all the samples. The 500-100 μm size fraction was predominant in the WWTP samples, while MPs smaller than 1 mm were more abundant in the seawater samples. Seven polymer types were identified using attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR), with PET, PE, PVC, PA, PS, PP, and EVA being the most prevalent. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDX) revealed various degrees of weathering and chemical elements adhering to the MP surfaces. The results of this study provide valuable insights into the effectiveness of conventional treatment systems in removing microplastics and offer a reference for developing management strategies to mitigate MP pollution in Morocco's marine ecosystems.

Scenic degradation and visual pollution along the Agadir coastline (Morocco): Analysis and management

Visual pollution refers to the degradation of landscape aesthetics, manifesting as visible deterioration. On the Agadir coast in Morocco, factors such as urbanization, erosion, marine wracking, litter, sewage, beach driving, and animal waste contribute to this issue, which detracts from coastal scenery. This study employs the coastal scenery evaluation system (CSES) to conduct a scenic assessment of 40 coastal sites, aiming to describe the current state of visual pollution and inform management interventions. The CSES utilizes a checklist comprising 18 physical and 8 human parameters to calculate a scenic evaluation index (D value), which categorizes coastal sites into five classes. These range from Class I - typically undisturbed natural areas with pristine scenic qualities - to Class V - which are degraded natural areas significantly impacted by human activities. The scenic evaluation classified these sites into three classes. Four sites (10 %) were classified as Class III, fifteen (37.5 %) as Class IV, and twenty-one (52.5 %) as Class V. No sites were classified as Classes I or II. The assessments presented here offer a comprehensive overview of the Agadir coastal scenery and establish a baseline for developing strategies to address visual pollution.

Unraveling the interplay between environmental microplastics and salinity stress on Mytilus galloprovincialis larval development: A holistic exploration

The rise of plastic production has triggered a surge in plastic waste, overwhelming marine ecosystems with microplastics. The effects of climate change, notably changing salinity, have shaped the dynamics of coastal lagoons. Thus, understanding the combined impact of these phenomena on marine organisms becomes increasingly crucial. To address these knowledge gaps, we investigated for the first time the interactive effects of environmental microplastics (EMPs) and increased salinity on the early development of Mytilus galloprovincialis larvae. Morphological assessments using the larval embryotoxicity test revealed larval anomalies and developmental arrests induced by EMPs and increased salinity. Transcriptomic analyses targeting 12 genes involved in oxidative stress, apoptosis, DNA repair, shell formation, and stress proteins were conducted on D-larvae uncovered the potential effects of EMPs on shell biomineralization, highlighting the role of Histidine Rich Glycoproteine (HRG) and tubulin as crucial adaptive mechanisms in Mytilus sp. in response to environmental shifts. Furthermore, we explored oxidative stress and neurotoxicity using biochemical assays. Our findings revealed a potential interaction between EMPs and increased salinity, impacting multiple physiological processes in mussel larvae. Our data contribute to understanding the cumulative effects of emerging anthropogenic pollutants and environmental stressors, emphasizing the need for a holistic approach to assessing their impact on marine ecosystems.

Plastic pollution on Moroccan beaches: Toward baselines for large-scale assessment

In Africa, Morocco is the 10th largest producer of plastic. The severity of this plastic has attracted increasing amounts of attention in the Moroccan Atlantic and Mediterranean in recent years. However, at the national level, there is limited knowledge of plastic pollution. To obtain an exhaustive and comprehensive evaluation of plastic pollution levels in Morocco, large-scale monitoring is needed on all the coasts of the country. In this context, this paper examined the composition, abundance, distribution, source and quality of beaches on two Moroccan coasts using four beach quality indices along 29 beaches. During two seasons, a total of 72,105 items were counted. The mean litter abundance was 0.31 items/m2, and the Mediterranean beaches were more dense than the Atlantic beaches. In particular, litter density was greater in spring (0.35 items/m2) than in summer (0.29 items/m2). The data indicate considerable differences in the density of marine debris according to the seasonality, beach typology and presence of rivers. Hazardous litter items were collected along both Moroccan coasts, constituting 8.41 % of the total collected items, with a mean of 0.026 items/m2. The use of environmental indices allowed us to classify Moroccan beaches as "moderate cleanliness", "moderate abundance" of plastics, "moderately safe" presence of hazardous litter and "mediocre" environmental status. The findings of the present study indicate that the sources of litter on both Moroccan coasts come mainly from recreational activities and dumping. The waste management practices recommended for Moroccan beaches include reducing sources, mitigating mitigation measures and changing littering behavior.

Microplastics in rocky shore mollusks of different feeding habits: An assessment of sentinel performance

Microplastics (MPs) accumulation in rocky shore organisms has limited knowledge. This study investigated MPs accumulation in filter-feeding oysters, herbivorous limpets and carnivorous snails to assess their performance as sentinel species in the MPs trophic transfer. The samples were obtained along a contamination gradient in the Santos Estuarine System, Brazil. All three studied species showed MPs concentrations related to the contamination gradient, being the oysters the species that showed the highest levels, followed by limpets and snails (average of less and most contaminated sites of 1.06-8.90, 2.28-5.69 and 0.44-2.10 MP g-1, respectively), suggesting that MPs ingestion rates are linked to feeding habits. MPs were mainly polystyrene and polyacetal. The polymer types did not vary among sites nor species. Despite minor differences in percentages and diversity of size, shape, and color classes, the analyzed species were equally able to demonstrate dominance of small, fiber, transparent, black and blue MPs. Thus, oysters, limpets, and snails are proposed as sentinels of MPs in monitoring assessments.

Microplastic in clams: An extensive spatial assessment in south Brazil

Microplastic pollution is becoming a continuously growing environmental concern, while bivalve mollusks are particularly vulnerable due to their sessile habits and feeding through water filtration processes. Microplastic incidence in soft tissues of the clam Amarilladesma mactroides was assessed along unconsolidated substrates distributed in extensive coastal regions of southern Brazil. Influence of urbanization levels, distance to rivers and local hydrodynamics on microplastic accumulation by the clam was tested. The average concentration of microplastics was high (3.09 ± 2.11 particles.g-1), considering 16 sampled sites. Particles were mainly composed by polyamide, polyethylene and polyethylene terephthalate, while were mainly smaller, fibrous and colorless. High urbanization and closer proximity to rivers insured higher contamination, which is a trend observed globally. No influence of coastal hydrodynamics was seen. Considering obtained findings, A. mactroides presents good potential to be used as a valuable tool to assess microplastic contamination in unconsolidated substrates of beach areas.

Occurrence of microplastics in edible tissues of livestock (cow and sheep)

Plastic contamination is widely recognized as a major environmental concern due to the entry of small plastic particles into the food chain, thereby posing potential hazards to human health. However, the current understanding of microplastic (MP; < 5 mm) particles in livestock, which serve as an important food source, is limited. This study aims to investigate the concentration and characteristics of MPs in edible tissues of cow and sheep, namely liver, meat, and tripe, obtained from butcher shops in five areas of Bushehr port, Iran. The mean concentration of MPs in different tissues of cow and sheep were 0.14 and 0.13 items/g, respectively. Among the examined tissues, cow meat exhibited the highest concentration of MPs, with a concentration of 0.19 items/g. Nylon and fiber were identified as the predominant polymer types and shapes of MPs found in cow and sheep tissues, respectively. Furthermore, no statistically significant difference was observed in MP concentration across different tissues of cow and sheep. Significantly, this study highlights the elevated hazards associated with exposure to MPs through the consumption of edible cow and sheep tissues, particularly for children who consume meat. The results underscore the potential transfer of MPs from the environment to livestock bodies through their food, contamination during meat processing, and subsequent health hazards for consumers.

The Occurrence of Microplastics in Donax trunculus (Mollusca: Bivalvia) Collected along the Tuscany Coast (Mediterranean Sea)

Microplastics (MPs) (0.1 µm-5 mm particles) have been documented in oceans and seas. Bivalve molluscs (BMs) can accumulate MPs and transfer to humans through the food chain. BMs (especially mussels) are used to assess MPs' contamination, but the genus Donax has not been thoroughly investigated. The aim of this study was to detect and characterize MPs in D. trunculus specimens collected along the Tuscan coast (Italy), and to assess the potential risk for consumers. The samples (~10 g of tissue and intervalval liquid from 35 specimens) were digested using a solution of 10% KOH, subjected to NaCl density separation, and filtered through 5 μm pore-size filters. All items were morphologically classified and measured, and their mean abundance (MA) was calculated. Furthermore, 20% of them were analyzed by Raman spectroscopy and, based on the obtained results, the MA was recalculated (corrected MA) and the annual human exposure was estimated. In the 39 samples analyzed, 85 items fibers (n = 45; 52.94%) and fragments (n = 40; 47.06%) were found. The MA was 0.23 ± 0.17 items/grww. Additionally, 83.33% of the items were confirmed as MPs (polyethylene and polyethylene terephthalate). Based on the correct MA (0.18 MPs/grww), D. trunculus consumers could be exposed to 19.2 MPs/per capita/year. The health risk level of MPs was classified as level III (moderate).

Exploring marine biofouling on anthropogenic litter in the Atlantic coastline of Morocco

Today, the world is increasingly concerned about marine litter and its interaction with marine biodiversity. However, knowledge concerning the fouling organisms associated with marine litter is very limited in many of the world's marine environments. In this survey, we investigated biofouling on different types of marine litter washed up on all the coasts of the central Atlantic of Morocco. The findings revealed 21 fouling species belonging to 9 phyla (Arthropoda, Mollusca, Echinodermata, Annelida, Bryozoa, Porifera, Chlorophyta, Ochrophyta, and Ascomycota). More specifically, frequently observed fouling species include Mytilus galloprovincialis, Balanus laevis, Megabalanus coccopoma, and Pollicipes pollicipes species. Large marine litter items recorded the highest colonization of marine organisms in comparison to small ones. The frequency of occurrence (FO) of the species most commonly fouled on all coasts was Perforatus perforatus (FO = 48.60), followed by Mytilus galloprovincialis (FO = 45.80), Balanus trigonus (FO = 32.05), Balanus laevis (FO = 30.25), Megabalanus coccopoma (FO = 25.25), Bryozoa species (FO = 19.40), Spirobranchus triqueter (FO = 18.18), Lepas pectinata (FO = 14.45), and Pollicipes pollicipes (FO = 13.05). The majority of the species registered in this study are sessile. Substrate coverage by fouling taxa was significantly different between plastic substrate and other types of marine litter. Likewise, this study revealed that the proportion of fouling organisms is higher on rough surfaces. Overall, this research could be crucial to understanding the little-known subject of marine litter and its colonization by marine biota. Given that these marine litters can act as vectors and cause ecological, biogeographical, and conservation issues in the marine environment, minimizing the quantity of anthropogenic litter reaching the Moroccan Atlantic could significantly reduce its accumulation on the sea surface and seabed, thereby reducing the risk of invasion by non-indigenous species.

Unveiling the impact of environmental microplastics on mussel spermatozoa: First evidence of prothymosin-α detection in invertebrate's male gametes

Mytilus galloprovincialis mussels, like many other marine invertebrates, employ external fertilization as a mating strategy, exposing their gametes to various contaminants upon release into seawater. Environmental microplastics (EMP) are prevalent marine pollutants that pose a significant threat to aquatic biota. In this regard, our study aimed to investigate the potential effects of exposing mussels' male gametes to increasing concentrations of EMP (1, 10, 50, and 100 μg/l) collected from a Mediterranean sandy beach. We focused on assessing gamete quality by analysing physiological parameters such as viability, mitochondrial membrane potential, oxidative status, and motility. Additionally, we evaluated DNA integrity and activation of apoptosis. Furthermore, our study aimed to detect the presence of the prothymosin-α (PTMA) protein, which has never been previously investigated in invertebrate spermatozoa. Our data revealed that exposure of mussel spermatozoa to EMPs altered their oxidative status and mitochondrial membrane potential, induced a decrease in motility, DNA integrity, and an increased apoptotic occurrence, leading to a decline in overall viability. The localization of PTMA into the head and flagellum of spermatozoa further supported its presence and susceptibility to the effects of microplastics. These findings raise concerns about the reproductive capacity of mussels under environmental microplastic pollution and highlight potential long-term threats to population sustainability.

Effect of bioturbation of the mitten crab on distribution of tire wear particles and their combined effect on sediment ecosystem

Tire wear particles (TWPs) are a major source of environmental microplastic pollution which gradually settle and accumulate in sediments after entering the aquatic environment, which can affect the behaviors of benthic organisms. Bioturbation of benthic species could affect the fate, impacts and potential risks of TWPs by altering the properties and structure of sediments. Therefore, in this study, the effect of TWPs on the burrowing activity of Chinese mitten crab (Eriocheir sinensis) was investigated. In addition, the effects of crab bioturbation on the distribution of TWPs and their additives were studied. The combined effects of TWPs and crab bioturbation on the microbial communities in the sediments were also explored. The results of this study showed that both TWPs and the leachate significantly inhibited the burrowing activity of crabs. TWPs in the surface layer of sediments were re-distributed by crab bioturbation and enriched mainly in the sediments near the burrow walls. Meanwhile, the heavy metals (i.e., Zn, Ca, Mg, Ba and Al) used as additives during the tire production in the burrow walls significantly increased as the accumulation of TWPs near burrow walls. In this study, TWP exposure decreased the bacterial diversity and abundance, as well as the functional genes related to carbon and nitrogen cycling process, but crab bioturbation increased them in the sediments of burrow walls by constructing a unique habitat. However, after TWPs entering into burrows, they were significantly decreased in the sediments near the burrow walls like the effects of TWPs, suggesting the negative effects of TWPs could play a dominant role in this combined system. Overall, this study is important for evaluating the distribution and effects of TWP pollution in the sediment ecosystem under biological factors such as bioturbation.

Seasonal variation in the abundance of microplastics in three commercial bivalves from Bandon Bay, Gulf of Thailand

This study investigated the abundance of microplastics in three commercial bivalves found at Bandon Bay. Spatial-temporal differences in the concentration of microplastics were evaluated during the dry and wet seasons. The results showed that the highest abundance of microplastics in oysters, blood cockles, and green mussels was observed in fishery and aquaculture areas during the dry season, with 1.42 particles/g (w/w), 1.01 particles/g (w/w) and 0.87 particles/g (w/w), respectively. Microplastics were more abundant during the dry season compared to the wet season (p < 0.05), with fibre being the predominant shape and black being the major colour of particles. Cellophane was the most common type of polymer in all bivalves. This result is an important reference for understanding the status of microplastics in three commercial bivalves during different seasons and in different human activities, which should aid in understanding the sources of microplastics in Bandon Bay.

Microplastics in marine invertebrates from the Red Sea Coast of Egypt: Abundance, composition, and risks

This study marked the first exploration of microplastics in marine invertebrates in the Red Sea Coast of Egypt. 110 individuals from 11 different species, including Bivalvia, Gastropoda, Echinoidea, and Holothuroidrea, were collected near a popular tourist destination. The average concentrations of microplastics varied among species, ranging from 8.2 to 136.5 items per individual or 0.2 to 18.1 items per gram of tissue wet weight, with 100 % occurrence. Bivalves had higher concentrations per gram of tissue compared to sediment dwellers and grazers, with Brachidontes pharaonis showing the highest levels. Actinopyga crassa, a sea cucumber, displayed the highest abundance per individual due to its large size and behavior. The identified plastic polymers suggested sources associated with tourism and maritime activities. The estimated human exposure to microplastics through bivalve consumption was minimal. Further research is needed to examine microplastics contamination in the Red Sea and its potential impacts on ecosystems and human well-being.

Microplastic accumulation in bivalves collected from different coastal areas of Vietnam and an assessment of potential risks

Microplastic (MP) pollution is an emerging problem in many areas around the world and in coastal areas of Vietnam, requiring more studies dedicated to the accumulation of this pollutant in the food chain as well as its potential risk to human health. This study investigated MP levels in tissues of five common bivalve species collected from aquaculture areas along the coast of Vietnam. MPs were found in all bivalve samples, with average values of 10.84 ± 2.61 items/individual or 2.40 ± 1.34 items/g wet weight. Impacts of feeding habits of bivalves showed influences on MP abundance in the samples. Fibers were the dominant shape of MPs recorded, most of which accumulated in the gills and digestive glands of all bivalve samples, with the majority falling within the size range of 300-2000 µm. MPs found in all studied species had relatively similar chemical compositions, mainly composed of polypropylene (PP) and polyethylene (PE). In this study, a diverse diet consisting of different bivalve species and detailed data on the consumption rate of these species were used to assess the human health risk of MPs dedicated to the coastal communities of Vietnam. The results suggested a significant part of MP uptake by human could be via bivalve consumption, in which removing viscera and proper depuration should be applied prior to eating, thereby reducing the risk.

Sludge drying and dewatering processes influence the abundance and characteristics of microplastics in wastewater treatment plants

Wastewater treatment plants (WWTPs) have been identified as high-load receptors of microplastics (MPs) from different sources. However, the influence of specific treatment stanges requires further research. The main objective of this research was to evaluate the abundance and chemical characteristics of MPs in the sludge of two major wastewater treatment plants in the Agadir metropolis (Central Atlantic of Morocco). The Aourir plant receives urban influents and the inputs of the M'zar facility were urban and industrial. Samples were collected from the sludge matrices after primary settling, clarifying, dewatering, and drying systems. In addition, the effect of seasonality on MP load was assessed. The results showed that a higher abundance was noticed in raw sludge than in dewatered one in Aourir WWTP, while in M'zar WWTP, a very low decrease is noticed in dried sludge compared to raw sludge. The concentration of MPs in the summer season was significantly higher compared to other seasons for Aourir WWTP, while the winter season was higher for M'zar WWTP. Moreover, the most abundant shapes were fibers and the fraction 100-500 μm was the most preponderant. Eleven polymers were identified by ATR-FTIR, being polyester, polyethylene, polypropylene, and polystyrene the most abundant ones. Scanning Electron Microscopy coupled with Energy Dispersive X-ray revealed the visible degradation and fragmentation of MPs from sewage sludge and their ability to adsorb inorganic elements. It was estimated that between 2.2 × 107 and 7.4 × 108 MPs were evacuated with the sludge per day. The obtained findings confirmed that WWTP sludge acts as a vector of MPs with a high level of hazard to various matrices, such as landfills, agricultural soils, and groundwater. Overall, consideration must be given to the regulatory system managing the fate of sewage sludge to mitigate the collateral effects and provide solutions.

Examining the influence of COVID-19 lockdowns on coastal water quality: A study on fecal bacteria levels in Moroccan seawaters

Fecal bacteria in bathing seawater pose a substantial public health risk and require rigorous monitoring. The unexpected beach closures during the COVID-19 lockdowns have afforded unique opportunities to evaluate the impact of human activities on bathing water quality (BWQ). This study examined the temporal changes in fecal coliforms (FC) and streptococci (FS) within bathing seawater across a popular coastal region in Morocco during two lockdown periods (2020 L and 2021 L), comparing these data with observations from pre-lockdown years (2018, 2019) and post-lockdown periods (2020, 2021, 2022). Our findings illuminate the influential role the hiatus periods played in enhancing bathing water quality, attaining an "excellent" status with marked reductions in fecal coliform and streptococci levels. Consequently, the FC/FS analysis exposed a clear preponderance of humans as the primary sources of fecal contamination, a trend that aligns with the burgeoning coastal tourism and the escalating numbers of beach visitors. Additionally, the presence of domestic animals like camels and horses used for tourist rides, coupled with an increase in wild animals such as dogs during the lockdown periods, compounded the potential sources of fecal bacteria in the study area. Furthermore, occasional sewage discharge from tourist accommodations and wastewater treatment plants may also contribute to fecal contamination. To effectively mitigate these concerns and bolster public health, a commitment to relentless surveillance efforts, leveraging novel and innovative tools, is essential. These findings underline the crucial interplay between human activities and the health of our coastal ecosystems, emphasizing the need for sustainable practices for a safer and healthier future.

Marine plastic pollution in Morocco: state of the knowledge on origin, occurrence, fate, and management

Plastic pollution presents a major challenge facing stakeholders and decision-making worldwide. Plastics in the ocean damage biodiversity and marine ecosystem services that the blue economy relies upon. The present work analyses and reviews the literature on plastic pollution and the background knowledge about marine plastic pollution in Morocco. The economy of Morocco depends mainly on marine activities, including fisheries, tourism, and maritime trade. These sectors were identified as the main in-situ sources of plastics entering Moroccan coastal waters. The analysis results showed that the increasing abundance of plastics in such marine systems causes substantial economic loss to blue economy activities. In contrast, the lack of data on the plastic waste quantity entering Moroccan water is a limiting factor for assessing plastic pollution. This highlights the need for a risk assessment and more field investigations to value the weight impacts of marine activities generators of plastics on biodiversity and the economy. In addition, implementing laws and rules forbidding the disposal of plastic waste (PW) in public spaces, mainly beaches, and streets, is urgently needed. Raising awareness of plastic waste management and prioritizing improved waste collection, sorting, and management would boost Morocco's establishment and adoption of circular economy strategies. It is worth noting that while implementing the management projects and regulatory frameworks of plastic waste, considering their source and usage purpose is mandatory.

The impact of microplastics on bivalve mollusks: A bibliometric and scientific review

Bivalves are important members of the ecosystem and their populations are declining globally, making them a concern for their role in ecosystem services and the fishing industry. Bivalves are excellent bioindicators of MPs pollution due to their widespread distribution, filtering capabilities, and close association with human health. Microplastics (MPs) have direct and indirect impacts on bivalves, affecting their physiology, habitat structure, food sources, and persistence of organic pollutants. This review provides an extensive overview of the impact of MPs on bivalves, covering various aspects such as their economic significance, ecological roles, and importance in biomonitoring environmental quality. The article presents the current state of knowledge on the sources and pathways of MPs in aquatic environments and their effects on bivalves. The mechanisms underlying the effects of MPs on bivalves, including ingestion, filtration activity, feeding inhibition, accumulation, bioaccumulation, and reproduction, are also discussed. Additionally, a bibliometric analysis of research on MPs in bivalves is presented, highlighting the number of papers, geographical distribution, and keyword clusters relating to MPs. Finally, the review emphasizes the importance of ongoing research and the development of mitigation strategies to reduce the negative effects of MPs pollution on bivalves and their habitats in oceans and coastal waters.

Multiple species ingest microplastic but few reflect sediment and water pollution on sandy beaches: A baseline for biomonitoring

Databases recording the ingestion of microplastics by marine animals are growing. This is also recurrent on sandy beaches, where different biomonitors have been proposed to monitor the impacts of plastic pollution. We aimed to record the occurrence of suspected microplastic (SMP) in the digestive tract of multiple taxa (n = 45 identified species) and test whether some macroinvertebrates and fishes ingested SMPs proportionally with the pollution level of sediment and water; thus, we aimed to depict which sandy beach species could be used as biomonitors. Among all taxa, 10 macroinvertebrates and 12 fish species were reported to ingest SMP for the first time. SMP morphotypes proportion differed between abiotic and biotic compartments. Moreover, 10 of 12 taxa did not have SMP concentration linearly related with SMP in sediment and water. Our findings suggest that few species from sandy beaches can be used as efficient biomonitors, although almost all ingest plastic polymers.

The unheeded inherent connections and overlap between microplastics and poly- and perfluoroalkyl substances: A comprehensive review

Microplastics (MPs) and poly- and perfluoroalkyl substances (PFASs) are receiving global attention due to their widespread presences and considerable level in the environment. Although the occurrence and fate of MPs and PFASs alone have been extensively studied, little was known about their unheeded connection and overlap between the two. Therefore, this review attempts to reveal it for the purpose of providing a new view from joint consideration of the two in the future studies. Initially, the critically examined data on the co-sources and existence of MPs and PFASs are summarized. Surprisingly, some products could be co-source of MPs and PFASs which are general in daily life while the distribution of the two is primary influenced by the human activity. Then, their interactions are reviewed based on the fact that PFASs can be sorbed onto MPs which are regarded as a vector of contaminations. The electrostatic interaction and hydrophobic contact are the predominant sorption mechanisms and could be influenced by environmental factors and properties of MPs and PFASs. The effects of MPs on the transport of PFASs in the environments, especially in aquatic environments are then discussed. Additionally, the current state of knowledge on the combined toxicity of MPs and PFASs are presented. Finally, the existing problems and future perspectives are outlined at the end of the review. This review provides an advanced understanding of the overlap, interaction and toxic effects of MPs and PFASs co-existing in the environment.

Oysters and mussels as equivalent sentinels of microplastics and natural particles in coastal environments

Filter-feeder organisms such as oyster and mussels are exposed to particles like microplastics (MPs). Although widely used to monitor MPs contamination, little is known about their performance as sentinels, which are biological monitors accumulating contaminants without significant adverse effects. This study comparatively evaluated the quantitative and qualitative accumulation of MPs by oysters (Crassostrea brasiliana) and mussels (Perna perna) along a gradient of contamination in a highly urbanized estuarine system of Brazil. In the most contaminated site, both species presented the worst status of nutrition and health, and also one of the highest MPs levels reported for molluscs to date (up to 44.1 particles·g^-1). Despite some inter-specific differences, oysters and mussels were suitable and showed an equivalent performance as sentinels, reflecting the gradient condition demonstrated for other contaminants in the region. The similarity in MPs accumulation was also observed for qualitative aspects (polymer composition, sizes, shapes and colors). Particles were mostly <1000 μm, fibrous, colorless and composed by cellulose and polymethyl methacrylate (PMMA). Thus, despite small variations, the usage of C. brasiliana and P. perna is recommended and provides reliable information for environmental levels of microplastics.

Comparative study of pristine and polluted estuaries in Souss Massa National Park (Morocco): Implications for conservation strategies

Estuaries are among the ecosystems most affected by human actions worldwide. Economic development in Morocco puts pressure on these aquatic systems, making them vulnerable. This study compares the state of benthic communities between a pristine estuary (Massa estuary) and a polluted one (Souss estuary). Both ecosystems belong to the Souss Massa National Park (SMNP), registered in the Ramsar list for its ecological importance as a Marine Protected Area (MPA). Twenty-one benthic species were identified in the pristine estuary, but only six species in the polluted one. Similar differences were detected for the species abundance and biomass. The total organic matter and the water-dissolved oxygen also revealed a notable negative effect of the sewage discharge. The results confirmed human disturbances on faunal communities related to direct wastewater inputs and indirect anthropogenic activities such as the urbanization and the litter generation. A combination of ending wastewater discharge and adding tertiary-level water treatment plants is recommended. The findings highlight the importance of MPAs in conservation strategies if coupled with continuous surveillance of pollution.

Micro- and mesoplastic pollution along the coast of Peru

Peru suffers from poor solid waste and coastal management, as well as evidenced plastic pollution in various forms. However, studies in Peru focusing on small plastic debris (i.e., meso- and microplastics) are still limited and inconclusive. Thus, the present study investigated the abundance, characteristics, seasonality, and distribution of small plastic debris along the coast of Peru. The abundance of small plastic debris is predominantly driven by specific locations, where a source of contamination is present, rather than presenting seasonal patterns. Meso- and microplastics were strongly correlated in both seasons (summer and winter), suggesting meso-plastic constantly breaking down as microplastic sources. Additionally, heavy metals (e.g., Cu, Pb) were found in low concentrations (mean concentrations < 0.4%) on the surface of some mesoplastics. Here, we provided a baseline on the multiple factors involving small plastic debris on the Peruvian coast and preliminarily identify associated contaminants.

Bioaccumulation and metabolism of polybrominated diphenyl ethers (PBDEs) in coenobitid hermit crabs from marine litter-polluted beaches in remote islands

Plastic litter containing additives is potentially a major source of chemical contamination in remote areas. We investigated polybrominated diphenyl ethers (PBDEs) and microplastics in crustaceans and sand from beaches with high and low litter volumes on remote islands that were relatively free of other anthropogenic contaminants. Significant numbers of microplastics in the digestive tracts, and sporadically higher concentrations of rare congeners of PBDEs in the hepatopancreases were observed in coenobitid hermit crabs from the polluted beaches than in those from the control beaches. PBDEs and microplastics were detected in high amounts in one contaminated beach sand sample, but not in other beaches. Using BDE209 exposure experiments, similar debrominated products of BDE209 in field samples were detected in the hermit crabs. The results showed that when hermit crabs ingest microplastics containing BDE209, BDE209 leaches out and migrates to other tissues where it is metabolized.

Binational survey using Mytilus galloprovincialis as a bioindicator of microplastic pollution: Insights into chemical analysis and potential risk on humans

Microplastic (MP) contamination in edible mussels has raised concerns due to their potential risk to human health. Aiming to provide valuable insights regarding the occurrence, physicochemical characteristics, and human health implications of MP contamination, in the present study, two nationwide surveys of MP contamination in mussels (Mytilus galloprovincialis) were conducted in Morocco and Tunisia. The results indicated that MP frequency ranged from 79 % to 100 % in all the analyzed samples. The highest MP density was detected in mussels from Morocco (gills "GI": 1.88 MPs/g ww^-1; digestive glands "DG": 0.92 MPs/g ww^-1) compared to mussels of Tunisia (GI: 1.47 MPs g^{- 1}; DG: 0.79 MPs g^{- 1}). No significant differences in MP density were found between the two organs (GI and DG) for both countries. MPs were predominantly blue and black fibers, and smaller than 1000 μm. Seven polymeric types were identified, of which PET, PP, and PE were the most abundant, accounting for >87 % of all samples. Scanning Electron Microscopy (SEM) coupled with Energy dispersive X-ray (EDX) showed that most MPs have noticeable signs of weathering and inorganic components on their surface. The highest MP daily intake was found in children, while the lowest was estimated in women and men. Moreover, the annual dietary exposure of MPs through mussel consumption was estimated to be 1262.17 MPs/year in Morocco and 78.18 MPs/year in Tunisia. The potential risk assessment of MPs in mussels based on the polymer hazard index (PHI) was estimated in the high-risk levels, implying that MPs may pose health risks to humans. Overall, this research suggests that the consumption of mussels represents a considerable MP exposure route for the Moroccan and Tunisian populations.

Rajids ovipositing on marine litter: A potential threat to their survival

Marine litter is a complex environmental issue threatening the well-being of multiple organisms. In the present study, we present an overlooked pathway by which marine litter interaction with certain ovigerous skates (Family: Rajidae) communities could compromise their survival. We propose that skates from the genus Sympterygia deposit their egg capsules on marine litter substrates by accident, which are then washed ashore still unhatched. We conducted 10 monitoring surveys on three beaches of La Libertad Region, on the north coast of Peru, looking for marine litter conglomerates to determine the presence of egg capsules. We registered a total of 75 marine litter conglomerates, containing 1595 egg capsules, out of which only 15.9 % were presumably hatched, and 15.8 % were still fresh. Fishing materials were identified as the main item in marine litter conglomerates. We conclude that this behavior could contribute to the decline of Sympterygia communities, although further research is needed.

Occurrence, characteristics, and removal of microplastics in wastewater treatment plants located on the Moroccan Atlantic: The case of Agadir metropolis

Wastewater treatment plants (WWTPs) are some of the main sources of microplastics (MPs) in the environment. However, studies on the occurrence and removal efficiency of MPs in WWTPs are still scarce, especially in African countries. Thus, the aim of this work was to study the abundance of MPs in the influent and effluent of two WWTPs (Aourir and M'zar) from the Agadir metropolis (Moroccan Atlantic). The two WWTPs receive different wastewater inputs (domestic and industrial). In addition, the impacts of seasonality on the fate and removal efficiency were investigated. The results showed that the MPs abundance in the wastewater decreased from 188 MPs/L in the influent to 50 MPs/L in the effluent for Aourir WWTP (domestic inputs); while the abundance was greater in the M'zar WWTP (urban and industrial inputs) recording a mean value of 519 MPs/L and 86 MPs/L in the influent and effluent, respectively. MPs collected in the Aourir WWTP ranged from 290 to 3200 μm, while MPs from the M'zar WWTP, ranged from 330 to 4200 μm. Overall, the size range of 100-500 μm was the most abundant for both WWTPs. Fibers were the highest MPs morphotype found, followed by fragments. MP colors were mainly red, black, blue, and transparent for both treatment plants. Additionally, FTIR spectroscopy showed the presence of eight different polymers, mainly polyethylene (PE), polypropylene (PP), and polystyrene (PS). Seasonal variation analysis showed that MPs abundance in summer was significantly higher compared to other seasons. However, the comparison of the removal efficiency (RE) between the different seasons indicated that the winter season (74 %) recorded the highest RE for Aourir WWTP. Conversely, spring (87 %) recorded the highest RE for M'zar WWTP. SEM/EDX micrographs showed different degrees of weathering and chemical elements adhering to the surface of the MPs. The findings of the current study will serve as a baseline for future considerations about management strategies, wastewater reuse, as well as the understanding of the occurrence of microplastic pollution along the marine ecosystems of Morocco.

The halophyte Cakile maritima Scop. 1772 as a trap of plastic litter on the Moroccan coast

Some plant communities of coastal dunes may affect the magnitude and distribution of litter on the ecosystem. In this study, the aim is to assess the aptitude of the halophyte Cakile maritima Scop. 1772 to be a trap and sink of plastic litter on the Moroccan Atlantic coast. Overall, a significant difference was noted between plastic litter trapped in C. maritima patches (1173 items) and control plots (502 items). Food containers and ropes were the most common trapped items. Shoreline and recreational activities, followed by dumping and ocean/waterway activities are the main sources of the trapped plastic items. The findings suggest the expansion of the cleaning operations to include coastal dunes, the need to change behavior among beachgoers in regard to food plastics disposal, as well the control of C. maritima distribution in the study area, and similar plant species in other regions.

Abundance and characterization of personal protective equipment (PPE) polluting Kish Island, Persian Gulf

Plastic pollution is one of the major environmental threats the world is facing nowadays, which was exacerbated during the COVID-19 pandemic. In particular, multiple reports of single-use plastics driven by the pandemic, namely personal protective equipment (PPE) (e.g., face masks and gloves), contaminating coastal areas have been published. However, most studies focused solely on counting and visually characterizing this type of litter. In the present study, we complement conventional reports by characterizing this type of litter through chemical-analytical techniques. Standardized sampling procedures were carried out in Kish Island, The Persian Gulf, resulting in an average density of 2.34 × 10-4 PPE/m2. Fourier transformed infrared spectroscopy confirmed the polymeric composition of weathered face masks and showed the occurrence of additional absorption bands associated with the photooxidation of the polymer backbone. On the other hand, the three layers of typical surgical face masks showed different non-woven structures, as well as signs of physical degradation (ruptures, cracks, rough surfaces), possibly leading to the release of microplastics. Furthermore, elemental mapping through energy-dispersive X-ray spectroscopy showed that the middle layer of the masks allocated more elements of external origin (e.g., Na, Cl, Ca, Mg) than the outer and inner layers. This is likely to the overall higher surface area of the middle layer. Furthermore, our evidence indicates that improperly disposed PPE is already having an impact on a number of organisms in the study area.

Trace metals in urbanized coasts: The central Atlantic of Morocco as a case study

This study describes the contamination, accumulation, and ecological risk assessment of five trace metals (Cd, Pb, Cu, Zn, and Cr) in sediments of an urbanized beach in the central Atlantic coastline of Morocco. The two-year investigation (2018 and 2019) included six sampling sites along a 6 km coastal reach. In both years, none of the studied trace metals exceeded the background or the sediment quality guidelines (SQGs). The eco-toxicological indices revealed low degree of contamination, unpolluted ecosystem, and low ecological risk of metals. However, Cd exceeded the background value and some SQGs following the increase of anthropogenic activities in 2019. Likewise, it indicated unpolluted to moderately polluted sediment as well as moderate ecological risk. Overall, it is highly recommended to mitigate the avoidable anthropogenic activities (marine litter generation, sewage discharge, intense urbanization, and vehicle traffic on the beach) that lead to the elevation of metal pollution in the study area.

Can oviposition on marine litter pose a threat to marine fishes?

Marine litter colonization is widely investigated as an important pathway for the dispersal of potentially invasive species. However, this phenomenon may be impacting marine biota in other ways as well. In this viewpoint, we express our concerns regarding the potential loss of viable eggs of numerous oviparous fishes deposited on marine litter when large-scale stranding events occur. Our concerns are supported by personal observations of stranded marine litter harboring fresh and viable egg capsules (Sympterygia sp.) and eggs (Family: Blenniidae), as well as reports in the literature. The loss of viable eggs from oviparous fishes is widely overlooked and poorly understood. Based on these knowledge gaps, we make a call for research and propose several research priorities to understand the impact of these events.

Has the "Covid-19" lockdown an impact on beach faunal communities? The central Atlantic coast of Morocco as a case study

The restrictions related to the COVID-19 pandemic have led to a global hiatus in anthropogenic activities; several scientists have utilized this unique opportunity to assess the human impact on biological systems. In this study, the study describes for a period of five years (2018-2022) how the faunal community have been affected by human disturbances, as well as the effect of the "anthropause" period driven by the COVID-19 lockdown. The results confirmed human disturbances on faunal communities related to coastal urbanization. It was found that the "anthropause" period showed the highest values of abundance and biomass, hence the "COVID-19 lockdown" allowed recovery of faunal communities. The findings highlight the impact of human disturbances and that the community showed resilience. Overall, the authorities must perform restrictive measures aiming to mitigate the impact of anthropogenic activities in the study area including the banning of off-road and recreational vehicles, carrying out efficient cleaning and grooming operations, monitoring the severe harvesting of edible species, as well as penalizing the disposal of anthropogenic waste and sewage discharge from the touristic facilities. Likewise, management actions such as the temporal beach closures and the regular surveillance could be advantageous to provide a more sustainable exploitation of sandy beaches.

Are sediment textural parameters an "influencer" of microplastics presence in beach environments?

Diverse litter studies on Colombia's Central Caribbean Coast have presented the Microplastic issues regarding typology, magnitudes, and distribution. No studies have examined MPs' presence and abundances in relation to sediment grain size and the sediments statistical parameters (mean, median, sorting, skewness, kurtosis). This work attempts to fill this information gap in a study of 15 sampling sites along Colombia's Central Caribbean Coast. Sediment samples were collected and analysed to determine sediment granulometric properties, in association with the presence, magnitudes, shapes, and impact of MPs, and their possible relationships. Within the study area, grain size distribution was similar between surveyed sites, with a dominance of three textural groups: sands, slightly gravelly sands, and slightly gravelly muddy sands. In terms of size-sorting categories, the percentages were moderately well sorted (60 %), moderately sorted (20 %), well sorted (13 %), and very well sorted (7 %). Microplastic abundances (densities) ranged from 160 to 1120 MPs/kg, similar to other global beaches. Microplastic fibers were the dominant typology at 86.8 % of the combined beaches total. Multiple linear regression analysis suggested that approximately 30 % of the MPs' presence could be related to changes in the five sediment statistics used in this work, being the most important statistical parameter sorting with 11 % (r² = 0.27 - F-Statistic = 0.67). To manage the MP issue, reducing the current elevated plastic inputs into the environment is necessary/mandatory. Approaches to reach this goal must be focused on the entire plastic life cycle (extraction, design, production, use, disposal, recovery, recycling).

Floating microplastics pollution in the Central Atlantic Ocean of Morocco: Insights into the occurrence, characterization, and fate

This work presents preliminary results about abundance, distribution, characteristics, sources, and fate of microplastics (MPs) in the Central Atlantic Ocean (CAO) of Morocco. The investigation was conducted into three subsections, each characterized by different types of human activities and covering rural, village, and urban areas. MPs were detected in 100 % of the sampling sites. The abundances varied from 0.048 to 3.305 items/m³, with a mean abundance of 0.987 ± 1.081 items/m³. MPs abundance was higher in surface seawater linked to urban areas compared to village and rural areas. The dominant polymer type was polyester (PET-53.8 %) followed by polypropylene (PP-24.36 %), polyamide (PA-7.56 %), polystyrene (PS-6.88 %), polyvinyl chloride (PVC-2.64 %), ethylene vinyl acetate (EVA-2.60 %), polyetherurethane (PUR-1.36 %), and acrylic (AC-0.8 %). Fibers were the most dominant shapes accounting for over 50 %. MPs were mainly smaller than 2 mm in size (71 %) and characterized by colorful aspects. These findings suggested that wastewater treatment plant (WWTP) effluents and anthropogenic activities (industry, tourism, sanitation, and fishing) are the major pollution sources of MPs in the study area. SEM/EDX micrographs showed different weathering degrees and chemical elements adhered to the MPs surface.

First record of plastiglomerates, pyroplastics, and plasticrusts in South America

Beaches in the Anthropocene carry the heavy burden of human-derived pollution, like that induced by plastic litter. For decades, plastic debris has been classified based on its source or physical size. In recent years, studies described and documented new forms of plastic formations, including plastiglomerates, plasticrusts, and pyroplastics. However, reports of these newly described formations are substantially lacking. Therefore, in the present study, we reported the first evidence of plasticrusts (plastic encrusting rock surfaces), plastiglomerates (organic/inorganic composite materials in a plastic matrix), and pyroplastics (burned and weathered plastics) in Peru. The plastic pollutants were recovered from the field through marine litter surveys on four beaches where illegal litter burning and campfires take place. All the suspected plastic formations were analyzed and confirmed using Fourier transformed infrared (FTIR) spectroscopy, and one of each type was analyzed by X-Ray fluorescence (EDX) spectrometry. Plastiglomerates consisted of a high-density polyethylene (HDPE) or polypropylene (PP) matrix with rock and sand inclusions. Pyroplastics were found in various stages of weathering and consisted of various polymers, including HDPE, PP, polyethylene terephthalate (PET), and polyamide (PA). Interestingly, our field observations suggest a new plasticrust formation pathway based on plastic burning and filling of rock crevices with molten plastic. The latter was identified as either PP or HDPE. Elements typically found in the sand and seawater (e.g., Na, Cl, Ca, Si, Fe) were identified on the surface of the plastic formations, as well as others that could potentially be associated with the leaching of additives (e.g., Ti, Br). Although the present study contributed to the knowledge concerning the occurrence of the new types of plastic formations, as well as possible formation pathways, there are still many questions to answer. Hence, we encourage future studies to focus on the toxicity that new plastic formations may induce in contrast with conventional plastics, the release of secondary contaminants (e.g., microplastics, additives), and their degradation in the environment. Lastly, standardized sampling and data treatment protocols are required.

Microplastics pollution in sediments of Moroccan urban beaches: The Taghazout coast as a case study

This work describes the spatiotemporal analysis of microplastics (MPs) pollution in sediments collected on a high urbanized beach located in Taghazout coast, central Atlantic part of Morocco. The study area is mainly composed of moderately well-sorted fine sands with an average density of MPs that ranged between 915 MPs/kg in 2018 and 1448 MPs/kg in 2019. The most polluted sites were in the south part of Taghazout coast, close to facilities of where beachgoers are often found. Microplastic Pollution Index (MPPI), Microplastic Impact Coefficient (CMPI), Agglomerative Hierarchical Clustering (AHC), and Multidimensional Scaling (MDS) revealed spatiotemporal variation of MPs pollution. Thus, the principal component analysis (PCA) showed a low correlation between the sediment characteristics (i.e., grain size, sorting, skewness) and MPs densities. Overall, the outputs of this baseline recommend implementing plastic management strategies to eliminate or at least minimize the collateral effects generated by MPs pollution in sediments of urbanized beaches.

Can the bioturbation activity of the fiddler crab Minuca rapax modify the distribution of microplastics in sediments?

Fiddler crabs are known as "eco-engineers" who maintain habitat health through sediment bioturbation. They regularly interact with microplastics (MPs) due to their contact with the sediment. In this study we compared MPs concentration between burrows and pellets resulting from bioturbation, and MPs bioaccumulation in the soft tissues of Minuca rapax (Smith, 1870), along a gradient of urbanization in Isla del Carmen, southern Gulf of Mexico. Overall, MPs shape and color in the pellets and in the tissues reflected those of the burrow's sediments. MPs were more abundant and diverse in burrows (9 ± 12 MPs.g^-1) than in pellets (5 ± 5 MPs.g^-1) or in the soft tissues (1.3 ± 1.2 MPs.g^-1). Bioturbation can concentrate MPs in pellets and tissues, depending on the MPs contamination and urbanization level. M. rapax is an important structuring agent of sedimentary MPs, showing a strong top-down translocation of MPs in subtropical tidal flats.