?Water quality of an urban river from the province of San Luis: estimation through physicochemical variables and biotic indices?

TELLO, JESICA; GONZÁLEZ, PATRICIA; ORTIZ, CHYNTIA; JOFRÉ, MARIANA

Otro; XXXIV Reunión Anual de la Sociedad de Biología de Cuyo; 2016

WATER QUALITY OF AN URBAN RIVER FROM THE PROVINCE OF SAN LUIS: ESTIMATION THROUGH PHYSICOCHEMICAL VARIABLES AND BIOTIC INDICESOrtiz C1, Tello J2,4, González P3 y Jofré M1. 1Área de Biología; 2Área de Química Física; 3Área de Química Analítica, Facultad de Química Bioquímica y Farmacia, Universidad Nacional de San Luis; 4INQUISAL-CONICET. E-mail: cintia831@hotmail.comUrban rivers are between the ecosystems most affected by contamination. Aquatic macroinvertebrates are bioindicators of widespread use in biotic indices, which complement physicochemical data in assessments of ecologic health of water bodies. The objective of this study was to evaluate the degree of pollution of Chorrillos River, San Luis, integrating biotic indices, a diversity index and physicochemical variables. In four sites along the course of the river, during a high flow period, samples of macroinvertebrates, using a D net, and water samples for physicochemical analysis were taken. Physicochemical variables measured were pH, temperature (ºC), turbidity (NTU), conductivity (μS cm-1), total dissolved and suspended solids (mg L-1), color (PtCo), dissolved oxygen (mg L-1 O2), organic matter (mg L-1 O2), and nitrates, sulfates, fluoride, iron and phosphorus concentrations (mg L-1). A simplified index of water quality (SIWQ) was calculated. Organisms were identified to the required taxonomic level for the application of the Biotic Index of San Luis Sierras (BISLS), the Biological Monitoring Working Party index (BMWP) and the Shannon diversity index (H). Differences between sites in physicochemical variables were not significant, except for nitrates. The SIWQ evidenced sites moderately contaminated to contaminated, and a quality decrease that correspond to the urban gradient. Water quality judgments based on biotic and diversity indices showed a gradient from slightly to heavily contaminated environments. The application of biotic and diversity indices, complementing physicochemical data, allowed to perform a preliminary evaluation of the environmental condition of the river, to assess impact of human activities and to generate basic information that may be used in remediation and restoration actions.