Assessment of Groundwater Quality and Pollution Risks in Tlemcen Province: Implications for Sustainable Water Management

Abstract

Groundwater quality assessment is a crucial factor in ensuring sustainable water resources for drinking and irrigation. This study evaluates the hydrochemical characteristics of groundwater from the Sebdou and Hennaya aquifers in northwestern Algeria, using key physicochemical parameters and water quality indices (WQI) such as drinking water quality index (DWQI), the irrigation water quality index (IWQI) and the nitrate pollution index (NPI). The analysis focused on parameters including temperature, pH, electrical conductivity, chloride, sulfate, and nitrate concentrations to determine the suitability of groundwater for human consumption and agricultural use. The results indicate that while the Sebdou aquifer generally provides water of excellent to good quality for drinking purposes, irrigation remains restricted due to elevated salinity levels. Specific points exhibit severe restrictions, whereas others present only moderate limitations. In contrast, the Hennaya aquifer demonstrates poor water quality, with electrical conductivity exceeding the Word Health Organization standards in all sampled locations and nitrate concentrations consistently surpassing the recommended limit of 50 mg L^–1. In both aquifers, the NPI highlights significant nitrate contamination, particularly in the Hennaya region, where pollution levels remain critically high throughout both wet and dry seasons. This high nitrate pollution could be attributed to the discharge of wastewater and the intensive use of fertilizers, especially in the Hennaya region, which is an agriculturally oriented plain. The study underscores the pressing need for sustainable groundwater management strategies to mitigate pollution, regulate nitrate sources. Without proper intervention, continued degradation of water quality may threaten public health and agricultural productivity in the region. These findings provide a scientific basis for policymakers to develop targeted measures that ensure the long-term viability of groundwater resources in northwestern Algeria.