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

Abstract

Suquía River is a medium-sized hydrological system (basin area of *7,700 km 2 ) 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 SO 4 2-as a consequence of urban activities. However, trace elements dissolved concentrations do not evidence a strong pollution effect. Nutrients [nitrogen species, total phosphorous (TP)] 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-NO 3 -, 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's municipal wastewater treatment plant on the Suquía River water quality.

<b>Prediction of the longitudinal dispersion coefficient for small watercourses

“…The mathematical models used for the simulation of water quality are useful in predicting environmental impacts from pollutants discharged into rivers (Sardinha et al, 2008;Pasquini, Formica, & Sacchi, 2012;Gonçalves & Giorgetti, 2013). These models are made up of parameters that, if poorly estimated, can reduce the accuracy of the produced results.…”

Multidisciplinary approach to assess the water self-depuration characteristics of Suquía River (Córdoba, Argentina)

“…One possible explanation is that during low-flow period, the river receives input from discharges with elevated OM content, which are deposited on stream bed due to the low water velocity. On the other hand, high flow causes dilution of pollutants of discharges as reported by Merlo et al (2011) and Pasquini et al (2012), and the major water velocity favors the drag of OM deposited during low-flow period.…”

“…The flow regime of the rivers that form Suquía River drainage network is exclusively pluvial in origin, with a marked seasonality of the flow due to the irregular distribution of rainfall throughout the year (Pasquini et al 2012). Though there is not a systematic study, the river flow can be estimated from the water released by the San Roque Dam.…”

“…This could be because S1 is near to neighborhoods with small sewage discharges, while, although S4 received a greater sewage discharges, it is located 12 km downstream WWTP. Pasquini et al (2012) showed that the sulfate concentration in Suquía River water increases downstream of Córdoba city. Therefore, in downstream Córdoba city sites, the higher organic C (Merlo et al 2011) and sulfate concentrations in water and the low dissolved O 2 concentration favor the development of sulfate reducers (Leloup et al 2005;Leonov and Chicherina 2008).…”

“…Numerous authors have evaluated the pollution of Suquía River (Cordoba, Argentina) by means of different aspects such as (a) water and sediment heavy metal content, (b) air volatile organic compounds, (c) soil, water, and sediment chemical characteristics, and (d) soil, water, and sediment microbial indicators of sewage pollution (Pesce and Wunderlin 2000;Wunderlin et al 2001;Contardo-Jara et al 2009;Merlo et al 2011;Monferrán et al 2011;Pasquini et al 2012). Besides, the effects of Suquía River pollution on aquatic biota, lichen, and vascular plant also have been assessed (Merlo et al 2011;Maggioni et al 2012).…”