Impacto antrópico en la calidad del agua superficial de la cuenca media del Arroyo Claromecó, Argentina

Abstract

The creeks of the middle basin of the Arroyo Claromecó cross the town of Tres Arroyos with over 59 000 inhabitants, where an industrial plant and a wastewater treatment plant city is located. The aim of this paper is to analyze the quality of surface water courses of the basin to study human impact on this sector of the river system. We selected 5 sampling stations for the concentration of heavy metals in the sediment of rivers. In four of them values of nutrients in the water were obtained. These measurements were conducted during August 2007 and repeated in August 2009. The determination of nutrients was performed using a sequential Technicon Autoanalyzer II and the Particulate Organic- Matter was analyzed by spectrophotometry. The nutrient values showed greater variability between 2007 and 2009. The maxima were observed during the first year of measurement, while the maximum of ammonium was observed in the main sewer in 2009. Variables were detected above guideline levels for the protection of aquatic life, as the case of nitrates and phosphates in the Arroyo Claromecó. This trend was maintained for almost all the chemical parameters, which would correspond to secondary sewage and industrial discharges from plants processing by the river that runs through this course in peri-urban areas of the town of Tres Arroyos. The analyzed river sediments showed low to intermediate values of heavy metals. For the tributaries of the Arroyo Claromecó, the analysis of the physical and chemical variables of water reflects substrate characteristics and the influence of surrounding agricultural livestock. The main course presents a predominance of urban and industrial use from the increased supply of nutrients to the water, that come directly from untreated domestic discharges.