Application of the Water Quality Index to Assess Groundwater Quality in the Bou Dhar Mining District in Beni Tajjit (High Atlas, Morocco)

Abstract

Water scarcity remains the main problem in Morocco, making water resource conservation paramount. The objective of this study is to shed light on how mining impacts the region of Beni Tajjit's groundwater resources, which are used for irrigation and watering, which includes the Bou Dhar mining district, known for its vast lead and zinc sulfide deposits. The oxidation of sulfide-rich mine tailings generates acid water loaded with sulfates, creating acid mine drainage (AMD), which hurts aquatic ecosystems and the environment through trace metals elements (TME). Hence the need to assess the possible contamination of aquifers by metallic pollutants. This work can help water managers make appropriate decisions for controlling the quality of the groundwater in the Beni Tajjit area. During this study, we adopted a method: the Water Quality Index (WQI), designed to indicate the overall level of water quality by aggregating various weighted measurements. Five samples representing water sources around the mine tailings were taken and analyzed. Their values of dissolved oxygen, electrical conductivity and pH were measured on-site. The results allow us to classify the water into good and bad categories. They showed that the TME values were practically lower than the maximum permitted level according to WHO norms and Moroccan irrigation standards. The main reason for this may be due to the carbonate geological context of the site, which buffers acidity and thus forms a chemical barrier against the transfer of TME to the aquifer. The high chlorine levels appear due to geochemical background or anthropogenies contaminations. The sulfate values recorded are related to the leaching of sulfide minerals from mine tailings.