Open Access

ARTICLE

Natural pollution (As, F) and eutrofication (N, P) in the basin of El Divisorio stream, Argentina

Espósito ME^1,3, MdelC Blanco¹, ME Sequeira^2,4, JD Paoloni³, SN Fernández², NM Amiotti^1,4, SL Díaz¹

1 Depto. de Agronomía, Universidad Nacional del Sur (UNS), San Andrés 800, 8000 Bahía Blanca, Argentina.
2 Depto. de Ingeniería, Universidad Nacional del Sur (UNS), Av. Alem 1253, 8000 Bahía Blanca, Argentina.
3 Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina.
4 Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Camino La Carrindanga km 7, 8000 Bahía Blanca, Argentina.

Address correspondence to: Martín Eduardo Espósito, e-mail:

Phyton-International Journal of Experimental Botany 2016, 85(all), 51-62. https://doi.org/10.32604/phyton.2016.85.051

Abstract

The interrelation between hydrochemistry and hydrodinamics was analyzed in the basin of El Divisorio stream. This was to gain undestanding in the magnitude, distribution of toxic ions (As, F) and behaviour in the discharge of main nutrients (P, N) contributing to the eutrofication of Paso de las Piedras Dam. During two years, 47 sites were sampled determining several parameters: geographical position for each sampling point, phreatic level depth, and As, F, PO₄ and N-NO₃ concentrations. Repeated measures, Fisher test, correlation and regression analysis were applied to all variables. Highly significant space and time differences (P<0.01) with increments of 0.3 m were detected for isohypses. At every site, differences with a variable degree of significance were recognized for chemical parameters (As, F, PO₄ and N-NO₃). Hydrodinamics behaves mainly in accord with the seasonal rainfall contribution; run off affects some of the hydrochemical parameters giving rise to a variability that influences water quality. N-NO₃ and PO₄ concentrations are the main factors that cause eutrofication expressed through algae bloom episodes and deterioration of stored water quality. P is the critical element and in the dry periods the highest contribution is through groundwater flux and to a lesser extent by the continuous discharge of surface water. In the period of greater runoff, these elements incorporated to the sedimentary charge as a result of soil erosion, and coming by fertilizers and pesticides are transported in suspension towards the reservoir.

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