Spatio-Temporal Assessment of Microplastic Contamination in the Intertidal Mussel Brachidontes rodriguezii from Buenos Aires, Argentina

LANDRO, S.M.; RICCIARDOLO, D.; CAJARAVILLE, M.P.; ARRIGHETTI, F.

Congreso; SETAC Latin America 15th Biennial Meeting; 2023

Microplastic (MP) accumulation has become a widespread social and scientific concern/problem in the last decade. Its ingestion has been documented over marine species from different trophic levels. Mussels are one of the most studied groups in marine contamination and have been proposed as suitable bioindicators for monitoring MP pollution. The present study evaluates the MP accumulation in the mussel Brachidontes rodriguezii, collected on the Southwestern Atlantic coast (Buenos Aires, Argentina). Individuals were collected in the intertidal, seasonally (every 3 months), during a year in three places with different anthropogenic impact: Camet, located next to a sewage treatment plant; Mar del Plata harbor, located in the most important fishing harbor in Argentina and, Las Brusquitas, a site far from urban centers. After the collection, individuals were placed in sealed plastic bags at −20 °C until analysis. In the laboratory, samples were measured and dissected and the soft tissues were removed and weighed. Microplastics were extracted using a 10 % potassium hydroxide digestion method. The digested solutions were filtered on a cellulose nitrate filter (1.2 μm of porosity) and then the filters were dried at room temperature in a closedglass Petri. All laboratory procedures were carefully performed with the aim of preventing MPcontamination. Visual identification and characterization were conducted under a tereomicroscope and MPaccumulation was registered. Results showed that all the observed MP were fibers and were present in all the analyzed specimens. The whole abundance of MP in the sampling area was 14.6 ± 0.9 items/individual and 73.3 ± 7.8 items/g of wet tissue (n = 120). According to the two-way analysis of variance, MP accumulation significantly changed with sampling sites and sampling sites*season interaction. The highest mean abundance of MP was recorded for the individuals collected from Camet during the autumn season (21.5 ± 4.1 items/individual and 112.4 ± 24.2 items/g) followed by the spring season (19.6 ± 8.7 items/individual and 99.0 ± 18.3 items/g). Mar de Plata city is the major seaside resort of the country, so during summer and winter vacations the population increases, and in consequence, the sewage discharge increases. In conclusion, the sewage outfall of Mar del Plata could possibly impact the intertidal population of B. rodriguezii by releasing microplastics into the environment.