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Microplastic contamination in bivalves from urban estuaries: Are they sentinels for differences in pollution levels?
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Researchers examined microplastic contamination in clams from two estuaries in southwestern Spain with different levels of human activity. Surprisingly, microplastic concentrations were similar in both areas despite differing pollution pressures, suggesting that water flow patterns and seasonal dynamics may matter more than local sources. The most common plastics found were dark PET fibers, and smaller clams tended to accumulate more microplastics relative to their size.
Bivalves are often used as sentinel organisms for assessing microplastic (MP) pollution in marine ecosystems. However, MP contamination in estuaries remains under-studied despite their high vulnerability to this type of pollution. This study aimed at evaluating MP contamination in Scrobicularia plana from two estuaries in SW Spain (Guadiana and Guadalquivir), subjected to different levels of human pressure (low vs. high, respectively). A total of 231 suspected MP items were detected, with an average abundance of 1.96 ± 1.22 items per individual in the Guadalquivir estuary and 3.09 ± 1.96 items per individual in the Guadiana estuary, but no significant differences were found between them. GLMM models showed a significant negative effect of bivalve weight on MP accumulation. Micro-FTIR analysis confirmed that 59.8 % of the particles were plastic, 26.8 % were anthropogenic non-plastics, and 13.4 % were organic materials. The majority of MPs found in both estuaries were dark fibers composed of PET. The PERMANOVA analysis revealed significant differences in polymeric composition between the two estuaries, with PET and cellulose being more prevalent in Guadiana compared to Guadalquivir. Our findings indicate that MP concentrations in the two estuaries are similar despite varying human pressures, suggesting that factors like hydrodynamics and seasonal dynamics could play a key role in MP transport and deposition beyond local pollution sources. This study highlights how the occurrence of MPs in bivalves is a matter of concern, particularly given their importance as a food source. Further research is needed to comprehensively assess the spatial and temporal dynamics of MP contamination in estuarine ecosystems.
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Researchers measured microplastic contamination in oysters, clams, and mussels from a heavily urbanized estuary in Brazil, finding that industrial and port activities were stronger predictors of contamination than population density. Clams accumulated the most microplastics, and the study highlights how shellfish from polluted coastal areas can serve as indicators of the microplastic levels humans may be exposed to through seafood.
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Researchers assessed microplastic contamination in clams collected from extensive coastal regions of southern Brazil. They found microplastics in the soft tissues of clams across all sampling sites, with contamination levels influenced by proximity to urban areas, rivers, and local water flow patterns. The study highlights that even organisms in less urbanized coastal areas are accumulating microplastics, raising concerns about widespread contamination in shellfish habitats.
Microplastics in a large Brazilian bay: Multispecies bivalve approach reveals an association with population density.
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Researchers tested clams, oysters, and mussels from Todos os Santos Bay in Brazil for microplastics, finding contamination at all 16 sites, mostly fibers and transparent particles. Areas with higher human population density showed more microplastics in oysters, suggesting a link between crowded coastal areas and contamination levels.
Profiling microplastic fibers in the intertidal sentinel mussel Brachidontes rodriguezii from the coast of Buenos Aires, Argentina
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Does habitat influence bivalve microplastic concentration?
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When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.