Estudio estadístico multivariado aplicado a la evaluación de la calidad del agua potable y residual de la ciudad Cuenca usando parámetros físico químicos, contenido de metales y evaluación biotoxicológica del agua potable mediante el uso de daphnias

Abstract

The concentration of metals in water is an area to be considered in water quality studies, because water whose metal content is not below the permitted concentration limit governed by current regulations represents a major complication, and can cause intoxication in humans who consume it and likewise in animals and plants that are present in this environment. For this reason, a study was conducted on the metal content of drinking water in the city of Cuenca, considering the four main water purification plants: El Cebollar, Tixán, Sustag and San Pedro, which correspond to the water systems of Tomebamba, Machángara, Machángara and San Pedro: Tomebamba, Machángara, Yanuncay and Culebrillas, respectively. Samples were taken at the inlet and outlet of each plant; in addition, drinking water samples were taken within the city corresponding to the distribution circuit of the Tomebamba, Machángara and Yanuncay plants. In addition, inlet and outlet water from the Ucubamba wastewater treatment plant was sampled. With this series of samples, the concentrations of fifteen metals were determined by ICP-OES. In addition, the physicochemical parameters present in the samples were determined in situ. With the data generated, descriptive, inferential and multivariate statistical analyses were performed using R software. It was determined that the drinking and waste water complied in terms of physical-chemical parameters and metal content. Since the plants use aluminum sulfate as a coagulant, it was decided to carry out toxicological bioassays with the crustacean daphnia magna to verify whether the traces of aluminum detected in the treated water and in distribution could affect the ecosystem. Subsequently, chronic toxicity tests were carried out with different concentrations of aluminum and directly using drinking water from different systems. These data were analyzed and interpreted using the SPSS program. In the tests, the CL50 value of the species was found at an aluminum concentration of approximately 0.594 ppm; with respect to the tests with the waters of each system in its distribution, no biotoxicity was found, which indicates that the water is safe for consumption.