Hydrochemistry and nutrients dynamic in the Suquía River urban catchment´s, Córdoba, Argentina

PASQUINI, A.I., FORMICA, S, SACCHI, G.

ENVIRONMENTAL EARTH SCIENCES

SPRINGER

Año: 2012 vol. 65 p. 453 - 467

1866-6280

Suquía River is a medium-sized hydrological system that supplies fresh water to Córdoba city, a town of 1,500,000 inhabitants in central Argentina. This paper examines the present-day hydrochemistry of Suquía River urban catchment analyzing its major and minor dissolved components, and the nutrients variability by means of QUAL-2K modeling software. The Suquía River has bicarbonate-type waters upstream the city and sulfate-type waters right downstream, whereas they exhibit a mixed-to-alkali-type cationic composition. The seasonal analysis of its major dissolved constituents clearly showed a dilution process during the wet season (i.e. austral summer). In the last 20 years, the Suquía River has modified its anionic composition, now showing higher relative concentrations of SO42- as a consequence of urban activities. However, trace elements dissolved concentrations do not evidence a strong pollution effect. Nutrients (nitrogen species, total phosphorous) and related parameters, such as biochemical oxygen demand (BOD), and dissolved oxygen (DO), evidence a clear influence of human activities. The QUAL-2K model was used to evaluate the spatial behavior of selected nutrients and associated variables, (i.e. TP, N-NH4, N-NO3 -, DO, BOD). Nutrient  concentrations are affected by point sources of contaminants, particularly domestic waste and sewage, as well as by diffuse agricultural pollution. A calibrated QUAL-2K modeling exercise clearly shows the impact of the Córdoba city municipal wastewater treatment plant on the Suquía River water quality.