The relationship between benthic bioindicators and the pollution by metals and metalloids in reservoirs belong to Cantareira Complex, São Paulo, Brazil

Author(s)

Frederico Guilherme de Souza Beghelli

• Document type: Doctoral Thesis
• Press: Sorocaba. 2016-07-04.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Ciência e Tecnologia. Sorocaba
• Defense date: 2016-05-12
• Advisor: Viviane Moschini Carlos; Marcelo Luiz Martins Pompêo

Abstract

A global water crisis is in course. This crisis include quantitative and qualitative aspects and it threatens the water security of human societies and of the Earth’s ecosystems. In Brazil, the Paraná hydrographic region is the one with highest population density, economic and industrial development. As consequence, it is the hydrographic region in Brazil that demands highest amounts of water. São Paulo state is suffering the effects of the hydrological crisis. Qualitatively, the Metropolitan Region of São Paulo includes some of the most impaired aquatic environments. The Cantareira Complex is formed by five reservoirs. It is one of the main water suppliers of the region, which has high water demand and produces intensive environmental impairments. The pollution of aquatic environments by metals and metalloids is a worldwide problem and it is frequently related to the impairments generated in urban and industrialized regions. A problem related with this type of pollution is the fact that metals and metalloids are not metabolized by biota. As consequence, these chemicals have the tendency to accumulate through the time in the environment, especially in the sediments. Therefore, the pollution of the sediments can favor water pollution and the contamination of organisms living in aquatic ecosystems. In the present research, data referring to water and sediment quality from three reservoirs from Cantareira Complex (Jaguari and Jacareí were considered as a whole) were obtained. Posteriorly, the benthic macroinvertebrates fauna from those reservoirs were analyzed in order to verify the impacts of metal pollution over them. Experiments aiming to verify the responses of these organisms to sediment pollution by metals, especially copper were performed. The results points that water and sediments of the reservoirs analyzed here are polluted by metals and metalloids (Al, Cd, Cr, Cu, Ni, Pb and Zn). From field data and statistical analyses, it could be concluded that morphological alterations in Chironomidae larvae varied as a response to copper concentration in the sediments and that the copper concentrations were sufficiently high to cause bioaccumulation in the organisms. Posteriorly, it was demonstrated by an in situ assay that sediments from Paiva Castro were really contaminated and them induced lethal and sublethal effects on Chironomus sancticaroli larvae. A similar experiment performed in laboratory with spiked sediments leads to the conclusion that the copper in the sediments really can produce toxic effects on the larvae. Toxic effects included an increasing in “total damage” probabilities (morphological alteration or death) and they were recorded at concentrations similar to that recorded in the sediments from Paiva Castro reservoir. Another analysis included the use of statistical models to predict response of the organisms collected in the field to the toxicity of metals considering the community level. With this last approach, some basis to the development of a benthic macroinvertebrates community index to the assessment of pollution by metals (Al, Cr e Cu) in the region of Cantareira Complex was provided. (AU)

• FAPESP's process: 13/03494-4 - The reservoirs of the Cantareira System (Brazil, São Paulo): the relations between bioindicators benthic organisms and the heavy metals contamination.
• Grantee: Frederico Guilherme de Souza Beghelli
• Support Opportunities: Scholarships in Brazil - Doctorate