In situ assessment of ecotoxicological effects on the aquatic community from sugarcane expansion over pasturelands

• Grant number: 19/17132-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2020
• End date: January 31, 2021
• Field of knowledge: Biological Sciences - Ecology - Ecosystems Ecology
• Principal Investigator: Evaldo Luiz Gaeta Espindola
• Grantee: Lais Roberta Sorigotto
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 15/18790-3 - Environmental effects of the pasture-sugarcane conversion and pasture intensification, AP.PFPMCG.TEM

Abstract

Growing environmental concerns and demand for the replacement of fossil fuels by biofuels have made Brazil the world's largest producer of sugarcane for ethanol generation. Crop expansion has been taking place mainly over underused pasturelands, with intensive use of agricultural inputs, in order to increase productivity and reduce pest losses. Among the most used pesticides in sugarcane cultivation are 2,4-D (herbicide) and fipronil (insecticide), in addition to vinasse fertigation, which can reach aquatic ecosystems through runoff and leaching. This research aims to evaluate the ecotoxicological effects of these compounds on three aquatic organisms of different trophic levels (Raphidocelis subcapitata, Chironomus sancticaroli and Danio rerio), from experiments on mesocosms introduced in landscape change matrices (from pasture to sugarcane). The in situ tests will be performed in 9 mesocosms inserted in plots with the treatments of low-intensity pasture, high-intensity pasture and sugar cane, managed in an experimental farm in Brotas-SP. The organisms will be allocated in test chambers within the mesocosms, and the evaluated endpoints will be algal biomass growth (through cell density difference) and mortality and growth in chironomids and fish (through larval growth and ratio weight/size of organisms, respectively). For water characterization of ecosystem models, nutrients (total nitrogen, nitrite, nitrate, ammonium, total phosphorus, total dissolved phosphate, inorganic phosphate, reactive silicate, and hardness) will be monitored in the laboratory and daily variations of the physicochemical parameters will be monitored in situ (pH, temperature, dissolved oxygen, turbidity, chlorophyll, and electrical conductivity) during the period of the toxicity tests. Thus, it will be possible to simulate and predict the environmental effects of pesticides (2,4-D and fipronil) and vinasse on the aquatic environment. (AU)