Statistical evaluation of fluoride contamination in groundwater resources of Santiago del Estero Province, Argentina

• Main Authors: K. Rondano Gómez, C.E. López Pasquali, G. Paniagua González, P. Fernández Hernando, R.M. Garcinuño Martínez
• Format: Article
• Language: English
• Published: Elsevier 2020-11-01
• Series: Geoscience Frontiers
• Subjects: Source water protection; Santiago del Estero; Multivariate statistical analysis; Fluoride; Spectrophotometry
• Online Access: http://www.sciencedirect.com/science/article/pii/S1674987120300670

This study investigates the suitability of statistical techniques for evaluating the fluoride content and the groundwater quality from Robles Department (RD) and Banda Department (BD) in Santiago del Estero (Argentina). For the original statistical study, evaluation of nine parameters (fluoride, pH, conductivity, atmospheric and water temperature, total dissolved solids, chloride, hardness, and alkalinity) of 110 collected underground water samples from 23 dispersed rural areas was proposed. Groundwater samples were obtained by sampling taken from wells at different depths. Fluoride levels were determined by a standard colorimetric method in two seasonal periods, the dry (from April to September) and rainy (from October to March) period. The analytical results obtained for physicochemical parameters such as pH, total dissolved solids (TDS), and temperature does not reveal any notable difference between the rainy and dry seasons studied. In both seasons, the atmospheric temperature average was 22 ​°C. With respect to fluoride content, approximately 50% of the analysed groundwater samples exceeded the limit established by current legislation (1.0 ​mg/L), obtaining concentration levels in the range of 0.01–2.80 ​mg/L. This study demonstrates the usefulness of the univariate statistical method (quartiles calculation, interquartile range IQR), multivariate principal component analysis (PCA), and cluster analysis to establish a better understanding of the state of the contamination of the waters in the region studied.