Unusual physico-chemical parameters in the public water supply of a town in the northeast of the São Paulo State (Brazil)

• Autor(a) principal: Dovidauskas, Sergio
• Data de Publicação: 2017
• Outros Autores: Okada, Isaura Akemi, Iha, Maria Helena, Cavallini, Álvaro Gennari, Okada, Marina Miyuki, Briganti, Rita de Cássia
• Tipo de documento: Artigo
• Idioma: por; eng
• Título da fonte: Vigilância Sanitária em Debate
• Texto Completo: https://visaemdebate.incqs.fiocruz.br/index.php/visaemdebate/article/view/840
• topic: Qualidade da Água; Análise Físico-química; Análise de Componente Principal; Vigilância Sanitária; Water Quality; Physicochemical Analysis; Principal Component Analysis; Sanitary Surveillance

Public water supply samples (n = 4347) from 88 municipalities in the northeast of the State of São Paulo (Brazil) were analysed in 21 physico-chemical parameters: temperature, conductivity (by conductimetry), free residual chlorine (colorimetry with N,N-diethyl-p-phenylenediamine), pH (potentiometry), apparent color (spectrophotometry), turbidity (nephelometry), and concentrations of Li+, Na+, NH4+, K+, Ca2+, Mg2+, F-, ClO2-, BrO3-, Cl-, Br-, ClO3-, NO3-, PO43-, SO42- (ion chromatography). The results were submitted to multivariate data analysis. The principal component analysis of 12 variable medians (pH, conductivity, Li+, Na+, K+, Ca2+, Mg2+, Cl-, ClO3-, NO3-, PO43-, SO42-) from 88 municipalities indicated Ibitinga as the locality with the public water supply having physicochemical characteristics unique in the region, characterized by higher relative concentrations of sulphate, chloride, lithium, and sodium, and higher values of pH and conductivity. Additionally, Ibitinga was the only municipality that systematically presented bromide in the water composition. A second principal component analysis on 79 samples of Ibitinga has indicated a sample with higher concentrations of chloride and sulphate, and 4 samples where the presence of nitrate was characteristic. Hierarchical cluster analysis exhibited the clustering of these groups produced in two component analysis. Validation of methods based on ion chromatography is also presented.