Análise espaço-temporal de sólidos totais dissolvidos, nitrato e cloreto total no Aquífero Bauru (2007-2009)

• Autor(a) principal: Cardoso, Amanda Botelho
• Data de Publicação: 2021
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/214154
• topic: Groundwater; Chloride; Geostatistics; Nitrate; Total dissolved solids; Águas subterrâneas; Cloreto; Geoestatística; Nitrato; Sólidos dissolvidos totais

For millennia, the challenge of civilizations was the management of water and the use of its potential, but currently the great challenge is the conservation and recovery of the quantity and, mainly, quality of water. Data from Companhia Ambiental Paulista (CETESB) shows that 39% of Brazilian municipalities are supplied by underground water and 14% have mixed supply systems. It also indicates that the state of São Paulo has more than half of its municipalities supplied only by groundwater. The Bauru Aquifer System (BAS) is one of the most used systems for water supply in the state of São Paulo and, due to its characteristic subsurface formation, it is vulnerable to contamination by agricultural activities, sanitary sewage, etc. CETESB monitors the BAS through collection wells, which provide important system information, however punctual. Thus for spatiotemporal monitoring, geostatistics is a tool that makes it possible to analyze the variability and correlations between different parameters. The present study used data from 75 CETESB monitoring wells, in the 2007-2009 triennium, and aimed to evaluate the spatial and temporal variability of the concentrations of total dissolved solids (TDS), nitrate (NNO3) and chloride (Cl-) in the BAS. Data evaluation consisted of descriptive statistical analysis, linear and semivariographic correlation and, finally, the production of maps of concentration estimates, by kriging. The results indicated a high linear correlation between the parameters, mainly between nitrate and chloride (R² = 0.810) and BAS and chloride (R² = 0.734). And, by geostatistics, good results were also observed, since all parameters showed spatial dependence, regardless of the period analyzed, visible by semivariographic adjustments and well-delineated maps of spatial variability. Only nitrate concentrations above the potability limit established by the Ministry of Health were verified – which corroborated with previous work carried out at the BAS.