Impact of Point Sources on the Water Quality of the Camalote River, Oaxaca, Mexico

Objective: This study assesses the water quality of domestic wastewater discharges into the Camalote River, Oaxaca, Mexico, and evaluates their environmental impact. The findings aim to support the development of preventive and mitigation measures to benefit both the environment and the communities relying on this resource. Design/methodology/approach: Seven domestic wastewater discharges into the river were analyzed following the methodology outlined in NOM-001-ECOL-1996 for water sample collection and analysis. Results: The analysis shows that the discharges exceed the maximum permissible limits established by NOM-001-SEMARNAT-2021, particularly for total suspended solids (256.67 mg L⁻¹) and biochemical oxygen demand (392.22 mg L⁻¹) in discharge 4, as well as total coliforms (27,333,333.33 NMP 100 mL-1) and fecal coliforms (10,000,000.00 NMP/100 mL) in discharge 6. Limitations/implications: The findings indicate significant risks to public health and aquatic ecosystems. Continuous monitoring of the river is strongly recommended, particularly during drought periods when the river's dilution capacity decreases, leading to higher pollutant and organic matter concentrations and anaerobic conditions that harm aquatic biodiversity. Findings/conclusions: The study underscores the urgent need to implement preventive and mitigation strategies, including wastewater treatment and revegetation of key areas, to reduce pollution and safeguard water quality for the benefit of the environment and the local communities dependent on this vital resource.