Evaluación de la calidad de las aguas de seis sistemas lóticos pampásicos mediante el estudio de variables físicas y químicas

Resumen

Water quality assessment of six pampean lotic systems through the study of physichal and chemical variables. Physical and chemical composition of six lotic systems of Buenos Aires province (Rodríguez, El Gato, El Pescado, Buñirrigo and J. Blanco streams, Samborombón river) was determined seasonally in order to evaluate the water quality of them. Sample sites were stablished in 2 or 3 stations from the headwaters to the mouths (E1 to E3). The systems presented low values of transparency; minimum values corresponded to El Pescado stream (E1) and Samborombón river (E3). Maximum suspended solids concentrations were registered in Rodríguez stream (E1) and in Samborombón river (E3). Rodríguez and El Gato streams were seriously impacted by anthropogenic activities, mostly downstream E2 where industrial efluents are discharged. These streams registered the highest nutrient concentrations in these sites. The lowest value of dissolved oxygen was registered in El Gato stream (E2). J. Blanco system, which is situated in a natural reservation, presented the lowest values of nutrients; minimun values were registered in E1. Nutrient’s concentrations in El Pescado stream were usually higher in E3. Buñirrigo stream is impacted in its lower basin by the discharge of efluents of several industries which caused the increase of nutrients, conductivity and the decrease of dissolved oxygen downstream E3. Samborombón river registered an increased of nutrients and conductivity downstream E2 due to the industrial and extensive agricultural activities developed in this area. Suspended solids concentrations were higher in E3 because of the effect of a coagulation process due to the presence of tides and salinity gradients.