Evaluation of Water Quality Through Physicochemical Analysis and the Use of Aquatic Macroinvertebrates in a Section of the Chimbo River

This study addresses the water quality of the Chimbo River, located in the province of Bolívar, San Miguel Canton, through a methodology that integrates physicochemical, microbiological analyses, and the evaluation of aquatic macroinvertebrates. Three sampling points were selected for repeated analyses at different times of the day (7:00 am, 12:00 pm, and 5:00 pm), identifying significant variations in parameters that exceeded the maximum limits permitted by environmental legislation. In situ analyses included temperature and pH, while other parameters such as dissolved oxygen (DO), chemical oxygen demand (COD), biochemical oxygen demand (BOD₅), nitrates (NO)³⁻, phosphates (PO₄) ³⁻, ammonium (NH₄)⁺, and fecal coliforms were evaluated in the laboratory. Additionally, a thorough study of the macroinvertebrates found was conducted, whose count and identification provided data to calculate the ABI (Arroyo Biological Index), obtaining a value of 40 in the parish of Cañi, 19 in the community of Lotan, and 27 in Chirijo, indicating poor water quality in Lotan and Chirijo and fair in the parish of Cañi. Furthermore, the study of biological diversity using the Shannon index showed a medium diversity with a value of 1, indicating medium diversity at each point of the river.