Sediment Toxicity Assessment Using Marine Organism Bioassays from an Urban Coastal Lagoon (Padre Lagoon, Southeastern Brazil)

Freitas, A.S.; Pompermayer, L.L.O.; Santos, A.D.O.; Nascimento, M.T.L.; Félix, L.C.; Bila, D.M.; Neto, J.A.B., and Fonseca, E.M., 2024. Sediment toxicity assessment using marine organism bioassays from an urban coastal lagoon (Padre Lagoon, southeastern Brazil).

This study aimed to evaluate the environmental quality of Padre Lagoon, an urban coastal lagoon, by using ecotoxicological fossil organisms (dinoflagellate cysts) for biomarker analysis associated with ¹⁴C radiocarbon dating. This is the first toxicity study in this anthropogenic coastal lagoon. A total of 15 surface sediment samples and a sediment core were analysed by radiocarbon dating, grain size, dinoflagellate cysts, and acute toxicity bioassays to assess the influence of land use changes in accelerated urban development in recent decades. Sediments varied between coarse sand and mud at different proportions. Radiocarbon dating placed the oldest age at 470–314 calibrated YBP in the sediment core base according to ¹⁴C radiocarbon dating. Artemia sp. showed high toxicity in both surface and core sediment samples. Vibrio fischeri showed a toxicity gradient in the sediment core and high toxicity in several surface samples. A major dinoflagellate cyst occurrence was observed in the sediment core; however, the highest accumulation was observed in the surface sediments. The data obtained in this study revealed high toxicity in the analysed sediment samples and the need for greater monitoring of this coastal lagoon.