Who to blame for groundwater fluoride anomaly in Sao Paulo, Brazil? Hydrogeochemistry and isotopic evidence

Autor(es)

Martins, Veridiana T. de S. ^[1] ; Pino, Daphne Silva ^[2] ; Bertolo, Reginaldo ^[1] ; Hirata, Ricardo ^[1] ; Babinski, Marly ^[3] ; Pacheco, Diego Felipe ^[4] ; Rios, Ana Paula ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Geosci Inst, Sedimentary & Environm Geol Dept, Sao Paulo - Brazil

^[2] Univ Sao Paulo, Geosci Inst, Postgrad Studies Program Mineral Resources & Hydr, Sao Paulo - Brazil

^[3] Univ Sao Paulo, Geosci Inst, Mineral & Geotecton Dept, Sao Paulo - Brazil

^[4] Petrobras SA, Rio De Janeiro, RJ - Brazil

• Tipo de documento: Artigo Científico
• Fonte: APPLIED GEOCHEMISTRY; v. 90, p. 25-38, MAR 2018.
• Citações Web of Science: 1

Resumo

Fluoride concentrations up to 10 mg.L-1 have been described in the groundwater of the biggest South American City, Sao Paulo, Brazil. Possible suspects were minerals in crystalline or sedimentary rocks, or industrial activities. Hydrochemistry tools pointed that the fluoride occurrence has positive correlation with Na and HCO3- concentrations and negative correlation with Ca2+. The saturation index are negative for fluorite in all samples, but samples with high fluoride content have calcite saturation index close to zero, indicating the precipitation of calcite maybe a mechanism that is taking out the Ca+2 and enhancing fluorite dissolution. Samples with fluoride concentrations > 1.5 mg.L-1 are related to samples more depleted in H and O heavier isotopes and deeper groundwater flow with higher temperature. This anomaly is probably associated with fluorite dissolution, present in a fault system with an ancient hydrothermal activity, with deep circulation of groundwater flows in the crystalline basement rocks. (AU)

• Processo FAPESP: 10/20876-0 - Aplicação de isótopos de Pb, Sr, H e o como ferramentas de investigação de recarga e contaminação da água subterrânea na região Oeste da cidade de São Paulo, Bacia do Alto Tietê
• Beneficiário: Veridiana Teixeira de Souza Martins
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 08/08601-5 - Estudos de isótopos de estrôncio, oxigênio e hidrogênio em um caso de contaminação de flúor no município de São Paulo
• Beneficiário: Daphne Silva Pino
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica