Aspectos preliminares de la calidad del agua del arroyo Tapalqué en la ciudad de Olavarría, provincia de Buenos Aires

Abstract

In Tapalqué stream, different recreational and farming activities are developed, and on its way through Olavarría city, it receipts rainwater and sewage residues previously treated. The aim of this study is to evaluate the quality of the resource, through the determination of conventional physicochemical and bacteriological parameters, heavy metals and organochloride derivatives. Four sampling stations were monitored each 45 days (2009-2010), before and after the city, after the treatment plant and downstream near Sierra Chica town. The water was classified as oligohaline and sodium bicarbonated. Hypoxia is common at stations 3 and 4. Metals as Pb, Cd and Hg were not detected. Arsenic exceeded the allowed limits for some applications, decreasing its concentration downstream. Organochlorides substances were detected in two points, in one of them Aldrin and in the other Heptachlor and/or its derivates with values above the permitted limits. An important increase in the number of total and fecal coliform organisms in downstream stations was detected.