This study investigates the occurrence and characteristics of macroplastic and polymer microparticles in the Urias coastal lagoon’s beach sediments, in northwest Mexico. Coastal lagoons, productive and vulnerable ecosystems, are impacted significantly by anthropogenic activities, leadings to their pollution by various contaminants, including plastics. Our research involved sampling sediments from four sites within the lagoon that were influenced by different human activities such as fishing, aquaculture, thermoelectric power plant operations, industrial operations, and domestic wastewater discharge. Our methodology included collecting macroplastics and beach sediment samples, followed by laboratory analyses to identify the plastic debris’ size, shape, color, and chemical composition. The results indicated a notable presence of macroplastic items (144), predominantly bags, styrofoam, and caps made of polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). The polymer microparticles were mainly fibers, with cotton and polyester as the most common polymers, suggesting a significant contribution from clothing-related waste. The dominant colors of the microparticles were blue and transparent. High densities were observed in areas with slower water exchange. Our findings highlight the urgent need for better waste management practices to mitigate plastic pollution in coastal lagoons, preserving their ecological and economic functions.

Scalloped hammerhead sharks (Sphyrna lewini) are critically endangered, according to the International Union for Conservation of Nature Red List, likely due to anthropogenic activities such as intense fishing and pollution. Nowadays, plastic debris contamination is a subject of concern due to its extensive presence in the sea and the digestive tracts of many fish species. The possible effects of plastic debris as a vector of other pollutants are still unknown. We analyzed the digestive tract of 58 hammerhead sharks to investigate the correlation between plastic and other anthropogenic microparticle contamination and their feeding habits in the eastern region of the Gulf of California, revealing a debris contamination occurrence of 79.3%. Out of these, 91.4% corresponded to fibers, and the remaining 8.6% to fragments. The main component of the debris was cellulose (64.4%). According to their diet, these organisms exhibit benthopelagic habits, feeding both in the water column and on the seabed. These results indicate a high level of contamination of anthropogenic cellulosic microfibers in the area. Although cellulosic microfibers are recognized as a biomaterial, they can be harmful to marine species, posing an additional threat to this iconic shark. This changed according to the year, indicating that the anthropogenic microparticle ingestion is related to the discharges of human activities and their seasonality rather than to a selection process by the sharks.

According to the International Union for Conservation of Nature Red List, the scalloped hammerhead (Sphyrna lewini) is a critically endangered species, primarily due to intense fishing and other anthropogenic effects such as pollution. Nowadays, plastic debris contamination is a subject of concern due to its extensive presence in the sea and the digestive tracts of many fish species. The possible effects of plastic debris as a vector of other pollutants are still unknown. We analyzed the digestive tract of hammerhead sharks to investigate the correlation between plastic and other anthropic debris contamination and feeding habits in the eastern region of the Gulf of California. A total of 58 specimens were analyzed from the coastal area, revealing a plastic occurrence frequency of 79.3%. Of these, 91.4% corresponded to fibers, and 8.6% to fragments. The composition of the polymers was primarily cellulose (64.4%). According to their diet, these organisms exhibit benthopelagic habits, feeding both in the water column and on the seabed. These results indicate a high level of contamination of anthropogenic cellulosic microfibers in the area. This changed according to the year, indicating that the anthropic debris ingestion is related to the discharges of human activities and their seasonality rather than to a selection process by the sharks. Although cellulosic microfibers are recognized as a biomaterial, they can harm marine species, posing an additional threat to this iconic shark.

Due to their environmental ubiquity, persistence, and potential effects on living organisms, microplastic pollution has become a global concern. Urban wetlands, catchment basins within cities, are one of the final sinks of these pollutants. We studied the occurrence, abundance, distribution, and physical and chemical characteristics of MPs to determine the impact of anthropogenic activities on the microplastic pollution status in an urbanized wetland. Surface water samples from seven sites inside the urbanized wetland Laguna del Camarón were collected during two climatic seasons (rainy and dry), followed by organic-matter digestion, filtration, microscopic counting and classification by shape and color. Subsequently, the polymers were identified with Fourier-Transform Infrared (FTIR) spectroscopy. MPs concentration was significantly higher in the dry season (2.05 particles/L) than in rainy season (1.17 particles/L), with the higher values occurring in the small inner lagoon (LC6 and LC7), which, according to the Pollution Load Index (PLI), has been considered as unpolluted to moderately polluted and highly polluted with MPs. Fiber shape and black and blue colors are predominant, with polyester (PES), polyethylene (PE), polypropylene (PP), and polystyrene (PS) polymers mainly occurring in this ecosystem consistent with nearby recreational and construction activities. This study revealed spatial and seasonal variations in the MP pollution status, elucidated potential pollution sources, and identified hotspots linked to visitor use and construction activities for targeted intervention (improve onsite waste collection, visitor surveillance, and the placement of bins and informative signs).