Evaluación del riesgo toxicológico por la probable presencia de arsénico en fuentes de agua para consumo humano, en las ciudades de Cuenca y Azogue

Abstract

Arsenic presence on water sources from Cuenca and Azogues cities was determined, and the possible toxicological risk was evaluated by water consumption without previous treatment. Likewise, Ecotoxicological effect that can occur in sowings through irrigation water and the effect that can exist in animals that drink it that zones was analyzed. A monitoring program was established with two campaigns during August, September, October and November of 2017; it was executed in Tomebamba, Yanuncay, Tarqui and Machángara rivers, inside University of Cuenca aquifers, Quimsacocha paramo in Cuenca city, and finally in Burgay and Tabacay rivers both from Azogues city. Monitoring covers two representative climatic periods. Defined control stations were located in rivers, and toxicological risk was evaluated in all samples that presented an arsenic positive value. Some physical-chemical quality indicators were determined such as: pH, color, turbidity, conductivity and temperature in each supply source. Those indicator was used to establish some possible relation with arsenic presence, whose values were compared with those established in Ecuadorian Regulation TULSMA (Texto Unificado de la Legislación Secundaria del Medio Ambiente; Secondary Environment Legislation Unified Text). Findings indicated that all rivers were contaminated with arsenic, and concentrations were higher due to transport by runoff in winter. Paramos and aquifers were free from Arsenic. Assessing all sources indicated there is no toxicological risk for water supply, nor ecotoxicological risk that limits water use, because all concentrations detected were below permissible limits