The problem of cyanobacteria in the Jaguari and Jacarei reservoirs (Cantareira System, SP, Brazil)

• Grant number: 21/11283-0
• Support Opportunities: Regular Research Grants
• Start date: April 01, 2022
• End date: March 31, 2024
• Field of knowledge: Engineering - Sanitary Engineering - Environmental Sanitation
• Principal Investigator: Viviane Moschini Carlos
• Grantee: Viviane Moschini Carlos
• Host Institution: Instituto de Ciência e Tecnologia. Universidade Estadual Paulista (UNESP). Campus de Sorocaba. Sorocaba , SP, Brazil
• Associated researchers: Eduardo Vicente Pedrós ; Marcelo Luiz Martins Pompêo

Abstract

The eutrophication process and, consequently, the proliferation of potentially toxic cyanobacteria is increasing in frequency, magnitude and duration. This increase represents an ecological risk for the reservoirs, which may interfere with ecosystem services such as the multiple uses (good water quality for public supply, irrigation, fishing and recreation) that these ecosystems provide. In CONAMA Resolution 357 of 2005, chlorophyll-a, density and biovolume of cyanobacteria were included as biological indicators, due to the need to monitor and control blooms and, consequently, the production of cyanotoxins. On May 4, 2021, Ordinance No. 888 amended Annex XX of Consolidation Ordinance No. 5. This new Ordinance No. 888 establishes the frequency of cyanobacteria monitoring based on estimated cell density and cyanotoxin analysis (microcystins, cylindrospermopsin and saxitoxins) in the water body. However, these regulations did not cover the ecological aspects of the occurrence of flowering and, its consequent, cyanotoxin production. This monitoring can be carried out quickly, using in situ measuring instruments such as probes. Thus, the development of research that incorporates in situ fluorometric methods capable of measuring the concentrations of chlorophyll-a and phycocyanin are important complementary tools to develop an early warning system for the presence of cyanobacteria. This research project aims to open new possibilities for studies on water quality, using cyanobacteria as environmental discriminators and predictors. Thus, it proposes to analyze the spatial and temporal variation of cyanobacteria and cyanotoxins in the Jaguari and Jacareí reservoirs (Cantareira System), as a function of the physical, chemical and biological characteristics of the water. For this, it aims to use a fluorimeter and a multiparameter probe for in situ measurements and laboratory determinations of chemical, physical and biological variables of water, as well as qualitative and quantitative analyzes of cyanobacteria and cyanotoxins, in order to determine which are the environmental predictors responsible for these regular occurrences in these reservoirs. It also aims to contribute to the discussion of a new water quality alert system, through the use of probes with measurements of chlorophyll-a and phycocyanin. Thus, this research is innovative in Brazil and also applied (monitoring and management), in order to support managers and decision makers in the direction of better public policies, which in fact contribute to solutions to prevent and reverse situations of quality degradation of the waters of these reservoirs. (AU)