Environmental analysis of the eutrophication and spread of aquatic macrophytes in a tropical reservoir: a case study in Brazil

• Published in: Environmental science and pollution research international 2022-12, Vol.29 (59), p.89426-89437
• Main Authors: Ogura, Allan Pretti, Pinto, Thandy Junio da Silva, da Silva, Laís Conceição Menezes, Sella, Caroline Fernanda, Ferreira, Flaviano Borges de Castro, de Carvalho, Pedro Scherma, de Menezes-Oliveira, Vanessa Bezerra, Montagner, Cassiana Carolina, Osório, Artur de Lima, Espíndola, Evaldo Luiz Gaeta
• Format: Article
• Language: English
• Subjects: Aquatic plants; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Brazil; Caffeine; case studies; climate; Community participation; Contaminants; Earth and Environmental Science; Ecological effects; Ecological function; Ecological risk assessment; ecosystems; Ecotoxicology; Environment; environmental assessment; Environmental Chemistry; Environmental Health; Environmental monitoring; Environmental science; Eutrophication; Government agencies; Heavy metals; iron; Land use; Macrophytes; nitrogen; nonpoint source pollution; Nutrients; Pesticides; Phosphorus; remediation; Research Article; Reservoirs; risk; Risk assessment; Sediment samplers; sediments; stakeholders; Sugarcane; surface area; Waste Water Technology; Water Management; Water Pollution Control; Water quality
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-022-22070-4

Land use changes threaten the maintenance of water quality and challenge the management of tropical reservoirs. In particular, eutrophication alters several ecosystem functions and services, compromising multiple uses of water. For example, in the Lajeado Reservoir (Araraquara, São Paulo, Brazil), aquatic macrophytes rapidly spread and occupied more than 90% of the system’s surface area (from 2016 to 2019). In such a scenario, this research aimed to evaluate the eutrophication causes and impacts to provide technical and scientific support to public agencies and propose remediation alternatives. First, a diagnosis of the study area was performed, using available data on land use, water quality, and climate (between 2010 and 2018). Second, water and sediment samples were collected for physical, chemical, and ecotoxicological analyses. The Ecological Risk Assessment consisted of a triad of Lines of Evidence, including physical-chemical, chemical, and ecotoxicological results. The expansion of agricultural activities (e.g., sugarcane cultivation) and diffuse pollution were highlighted among possible causes, and water quality was affected by increases in the concentration of nutrients (e.g., nitrogen and phosphorus), metals (e.g., iron), and emerging contaminants (e.g., pesticides and caffeine). As a result, the Lajeado Reservoir presented a high ecological risk, and alternatives for macrophyte removal are needed. This research involved several stakeholders (i.e., community, government agencies, and universities) who participated more effectively in environmental monitoring and recovery.