Geochemistry of groundwater in the alluvial plain of Tucumán, Argentina

GARCIA, M.G.; HIDALGO M. DEL V.; BLESA, M.A.

HYDROGEOLOGY JOURNAL

Springer

Año: 2001 vol. 9 p. 597 - 610

1431-2174

The Salí River hydrogeological basin is one of the most productive artesian basins in Argentina. It is located in the southeastern part of the province of Tucumán, northwestern Argentina, and its groundwater resources are developed for water supply and irrigation. The chemical composition of the water is strongly influenced by the interaction with the basinal sediments and by hydrologic characteristics such as the flow pattern and time of residence. Three hydrochemical zones are defined in the study area and the processes that control the chemical composition of the water are manifestly different in each zone. The dissolution of halite, sodium sulphate, and gypsum explains part of the contained Na+, K+, Cl?, SO4 2?, and Ca2+, but other processes, such as cation exchange, calcite precipitation, weathering of aluminosilicates, and gas exchange with the atmosphere, also contribute to the water composition. The assessment of contamination indicators, such as pH, dissolved organic matter, dissolved oxygen, phosphate, and nitrate, indicates that the groundwater is suitable for human consumption. However, biological contamination has been detected in samples from some wells, especially those near the Salí River.+, K+, Cl?, SO4 2?, and Ca2+, but other processes, such as cation exchange, calcite precipitation, weathering of aluminosilicates, and gas exchange with the atmosphere, also contribute to the water composition. The assessment of contamination indicators, such as pH, dissolved organic matter, dissolved oxygen, phosphate, and nitrate, indicates that the groundwater is suitable for human consumption. However, biological contamination has been detected in samples from some wells, especially those near the Salí River.