Presence of microplastics in the native crustacean Palaemon argentinus from a shallow Pampean lagoon

CHIODI BOUDET, L. N.; DOLAGARATZ CARRICAVUR, A.; STASI, C.; ROMERO, M.B; POLIZZI, P.; GERPE, M.S

Montevideo

Congreso; SETAC Latin America 15th Biennial Meeting; 2023

Society of Environmental Toxicology and Chemistry (SETAC)

Microplastics (MPs) are one of the emerging contaminants in aquatic environments around the world. The effects of plastic pollution on environmental ecosystems and organisms have been mainly analyzed from marine environments, however, studies for freshwater environments are scarce. The shrimps of the genus Palaemon (Crustacea: Decapoda: Caridea) are considered good bioindicators of environmental pollution due to their sensitivity to a wide variety of pollutants, including MPs. Palaemon argentinus is an abundant freshwater shrimp with wide distribution in South America, being found in most of the Pampean lagoons. According to their trophic and ecological habits, each species presents a particular situation with respect to MPs. This study aimed to evaluate the presence and abundance of microplastics in P. argentinus from a shallow lake in Buenos Aires Province, Argentina. Shrimp were obtained from Los Padres lagoon (37°57’S, 57°44’W), a typical shallow Pampean lagoon, which has a tributary that crosses a large expanse of horticultural fields and an effluent that drains through a gate regulating the level of the lagoon. Likewise, it is close to a residential area with a commercial and tourist center. Shrimp (n=3, 15 individuals in each pool) were collected using a hand net and immediately transferred to the laboratory to they were sacrificed and the exoskeleton was removed. Simultaneously, samples of water (n=3, 5 L. each) were taken with a bucket and filtered with a net of 36 μm mesh size. All samples were digested with hydrogen peroxide (30%) and filtered with nitrocellulose filters (0.45 μm). Each piece was photographed, and information about the maximum length (mm), shape, and color was collected to classify the MPs into four categories: fibers, films, fragments, and pellets. To discard airborne contamination, Petri dishes with control filters (blanks, n=3) were left exposed to air during all procedures; and it was considered to be negligible (0 to 1 MPs found). Both shrimp and water samples presented MP with a clear dominance of fibers followed by fragments and films. The fibers present in water were generally longer than those found in shrimp tissues, and the dominant color was black. Pellets were found in 33.3 % of the water samples, but not in shrimp tissues. The findings confirm the presence of MPs in the natural habitats of P. argentinus and indicate that shrimp can ingest them.