Avaliação de risco ecológico em complexos lagunares costeiros urbanizados no Estado do Rio de Janeiro: riscos associados à presença de fármacos, hormônios e aditivos plásticos

Abstract

Coastal lagoons account for 15% of the global coastal zone, standing out as one of the most productive ecosystems. Human activities impact these water bodies, compromising their ecological functions. The Jacarepaguá Lagoon Complex (CLJPA) and Piratininga Lagoon (LP) (Rio de Janeiro, Brazil) receive untreated or inadequately treated sewage due to unplanned population densification and real estate exploitation in surrounding areas. Ecological Risk Assessment (ERA) is a crucial tool for managing contaminated areas, as it identifies and evaluates the adverse effects of contaminants on the environment. This study aimed to conduct an ERA in CLJPA and LP using four lines of evidence (LoE). Four sampling campaigns were conducted for surface water collection throughout 2022 and 2023, with quarterly frequency in CLJPA, LP, and the reference site (Açude do Camorim). The water quality LoE was based on the analysis of physical, chemical, and microbiological parameters for the calculation of its index (WQI). The chemical LoE focused on the identification and quantification of pharmaceutical compounds, hormones, and plastic additives. The ecotoxicological LoE included chronic and acute ecotoxicity assays with microalgae and microcrustacean species, as well as an evaluation of the estrogenic activity of the samples. The ecological LoE analyzed phytoplankton species richness and abundance in the studied water bodies. The integrated environmental risk was calculated by combining the risks obtained from the four LoEs. The WQI data indicated poor water quality, particularly in the dry season. Ecotoxicity assays demonstrated very high risk in 50% of the sampling sites in LP and 100% in CLJPA. The concentration of estradiol equivalents in the lagoon samples ranged from <LOD (limit of detection) to 65.4 ng L⁻¹ in LP and from 0.07 to 51.3 ng L⁻¹ in CLJPA, indicating estrogenic activity at the monitored sites. Phytoplankton analyses revealed that the lagoons exhibit lower species diversity and ecological balance when compared to the reference site. The Integrated Ecological Risk ranged from 0.68 (high) to 0.97 (very high) in LP and from 0.87 to 0.98 (very high) in CLJPA. This study introduces significant innovations in ERA, including the consistent application of a methodology to water bodies with distinct characteristics (saline and freshwater), demonstrating the adaptability of the analysis in complex aquatic systems. In addition to integrating the conventional triad of LoEs, it incorporated a fourth LoE, providing a more holistic view of environmental impacts. The research revealed alarming results, reinforcing the urgent need for corrective actions. This innovative approach expands the horizons of environmental management in urban coastal areas, offering a model for impact analysis and mitigation in aquatic ecosystems.