Assessment of reproductive effects in a native gastropod exposed to water from Lugano Lake (Buenos Aires City, Argentina)

PAREDES, M. G.; BIANCO, K.; KRISTOFF, G.

Mar del Plata

Congreso; Reunión Anual de Sociedades de Biociencias reunión conjunta SAIC, SAB, AAFE, AACyTAL; 2023

Lugano lake is situated within the Lugano Lake Ecological Reserve in the lower Matanza-Riachuelo basin, one of the most urbanized and industrialized areas in Argentina. It is a refuge for biodiversity, retains rainfall water, and has a high recreational value for the community. Biomphalaria straminea, a native aquatic gastropod in Argentina, is a suitable model in reproductive assays due to its high egg production, rapid development and growth, and short life cycle. The aim of this work was to assess the reproductive effects of B. straminea following a 6-day exposure to water samples from Lugano lake (L1, L2, and L3) over 5 sampling (2022-2023). A control group was exposed to tap water (TW). The egg masses deposited on the 6th day were individually separated, observed for 14 days, and the number of eggs and embryonated eggs per mass, hatching success and, embryo development abnormalities were recorded. Exposure to water samples did not lead to alteration in the number of eggs and embryonated eggs per mass. Significant differences were observed in the % of hatching between the treatments and the TW during the spring 2022 (L1: 43%, L2 and L3: 68%), in summer 2023 (L1: 53%) and in autumn 2023 (L1: 60% and L3: 61%). Egg masses in TW showed hatching rates ranging from 76% to 100%. In autumn 2022 and 2023, alterations in embryonic development were observed, with a maximum of 15% arrested embryos in autumn 2023 in L1, and 5% delayed embryos in autumn 2022 in L3, both significantly higher than in TW (0.4% arrested and 1% delayed embryos). The water samples caused a significant decrease in the % of normal embryos, with a minimum of 85% in autumn 2023 in L1 compared to TW (97%). Our results suggest that exposure to compounds present in the lake caused negative effects on embryo development and hatching of B. straminea. In this sense, embryotoxicity proved to be a sensitive parameter that could serve as a tool for water quality biomonitoring and the protection of aquatic life.