Análises espaço temporais da qualidade da água bruta do Aquífero Bauru na área urbana de Araguari, MG

Abstract

The Bauru Aquifer is considered the most important hydrogeological unit of the city of Araguari, Minas Gerais. The water from this aquifer is exploited due to low cost, which is related to the fact of being a shallow and local subjected to an abundant recharging. However, these characteristics makes it potentially vulnerable to pollutants. This work aimed to provide an overview of the quality of raw water from the aquifer Bauru underlying the urban area of Araguari, identifying possible sources of pollution. Water samples were collected in wells of public water utility. The criteria for selection of the wells were: spatial distribution, operation, structure and risk areas. The samples were collected upstream of disinfectant application point, ensuring the qualitative aspects of raw water. 68 wells were sampled corresponding to 80% of the wells in operation. Were held two field campaigns, the first in November 2012 and the second in December 2014. The samples were subjected to pH tests, nitrate, nitrite, phosphorus, COD, BOD, apparent color, turbidity, total solids, solids total dissolved, total suspended solids, total volatile solids and total fixed. The results of field and laboratory steps allowed the mapping of quality parameters and the identification of critical areas in terms of pollution. The results indicated that wastewater leaks in areas that have high levels of vulnerability may be the cause of nitrate and volatile solids present in some wells examined. Nevertheless, the raw water from the aquifer Bauru still has good quality with physical-chemical and bacteriological appropriate to different uses. Although the concentrations found are still below the limits established by law, it is clear the importance of continuous monitoring of groundwater quality extracted for urban supply.