RESUMO
This study evaluated the presence of plastics and microplastics in macrophytes in an urbanized sector of the Amazon River. A total of 77 quadrats in 23 macrophyte banks were sampled during the dry (September 2020) and rainy (June 2021) season. Five species were identified: Paspalum repens, Pontederia rotundifolia, Pistia stratiotes, Salvinia auriculata and Limnobium laevigatum, with P. repens being dominant during the dry season (47.54%) and P. rotundifolia during the rainy season (78.96%). Most of the plastic particles accumulated in Paspalum repens (49.3%) and P. rotundifolia (32.4%), likely due to their morphological structure and volume. The dry season showed a higher accumulation of plastic particles than the rainy season. Microplastics were found in most samples, during both the dry (75.98%) and rainy seasons (74.03%). The upstream macrophyte banks retained more plastic particles compared to the downstream banks. A moderate positive correlation was observed between the presence of plastic particles and macrophyte biomass, and a weak positive correlation between the occurrence of microplastics and mesoplastics. White and blue fragments, ranging from 1 to 5 mm were the most common microplastics found in the macrophyte banks. Green fragments and green and blue fibers were identified as polypropylene, blue and red fragments as polyethylene, and white fragments as polystyrene. Therefore, the results of this study highlight the first evidence of the retention of plastic particles in macrophytes of the Amazon and highlight a significant risk due to the harmful effects that this type of plastic can cause to the fauna and flora of aquatic ecosystems.
Assuntos
Monitoramento Ambiental , Plásticos , Rios , Brasil , Rios/química , Poluentes Químicos da Água/análise , Microplásticos/análise , Estações do AnoRESUMO
Microplastic (MP) is yet another form of chronic anthropogenic contribution to the environment. MPs are plastic particles (<5 mm) that have been widely found in the most diverse natural environments, but their real impacts on ecosystems are still under investigation. Here, we studied the toxicity of naturally aged secondary polypropylene (PP) MPs after constant exposure to ultraviolet radiation (26 µm) to the third instar larvae of Chironomus sancticaroli, a dipteran species. The concentrations tested were 13.5; 67.5; and 135 items g-1 of dry sediment. C. sancticaroli organisms were investigated for fragment ingestion, mortality and changes in enzymatic biomarkers after 144 h of exposure. The organisms were able to ingest MPs from the first 48 h, and the amount of items internalized was dose-dependent and time-dependent. Overall, the results show that mortality was low, being significant at the lowest and highest concentrations (13.5 and 135 items g-1). Regarding changes in biochemical markers, after 144 h MDA and CAT activities were both significantly altered (increased and reduced, respectively), while SOD and GST levels were unchanged. In the present study, naturally aged polypropylene MPs induced biochemical toxicity in C. sancticaroli larvae, with toxicity being higher according to exposure time and particle concentration.
Assuntos
Chironomidae , Poluentes Químicos da Água , Animais , Microplásticos , Plásticos/toxicidade , Polipropilenos/toxicidade , Chironomidae/fisiologia , Ecossistema , Raios Ultravioleta , Poluentes Químicos da Água/toxicidade , Poluentes Químicos da Água/análise , LarvaRESUMO
The present study analyzed the presence of microplastics (MPs) in the shrimp Macrobrachium amazonicum, which is an economically important food that is consumed in several regions of the Brazilian Amazon. A total of 600 specimens of M. amazonicum were captured at two sampling sites (urban and rural area). A total of 2597 MP particles were recorded in the shrimps, with a significant difference between the two sites. The presence of MPs in the body parts also differed significantly. No significant difference was found between MPs abundance and sex of the shrimps. The size of the MPs did not differ significantly between the collection sites and between the body parts. Dark blue fiber-type MPs were the most abundant. A positive correlation was observed between the abundance of MPs and the total weight of shrimps. Raman spectroscopy identified the dark blue fibers as polypropylene and the FTIR technique identified the light blue fragments as nylon. The results indicate that the presence of MPs in the M. amazonicum shrimp is associated with the capture sites near the urban area and is present in the diet of the Amazonian population that regularly consumes this crustacean in traditional dishes.