Application of Water Quality Index for the Assessment of Boudaroua Lake in the Moroccan Pre-Rif

Abstract

This work aims to assess the quality of surface water in Boudaroua Lake which is located 3 km far from Ouazzane city, in northern Morocco. The water quality index (WQI) was used to assess the potential incidence of toxicity in the elements studied on human health on the one hand, and on aquatic microorganisms on the other hand. To this end, samples and hydrochemical analyzes were carried out for five sites spreading around the lake, during the study period (July 2019, October 2019, January 2020). The study was based on 13 parameters considering namely pH, electrical conductivity (CE), turbidity (TUR), dissolved oxygen (O2), total hardness (DT), calcium( Ca2+), magnesium (Mg2+), sodium (Na+),potassium (K+), ammonium (NH4+), chloride (Cl-), sulfate( SO42 -) and nitrate (NO3-). The observed values of these physicochemical parameters have been compared to the Moroccan standard (MS) for surface water and the World Health Organization (WHO). The results indicated that the values of the physicochemical parameters increased significantly and seasonally from summer to autumn and then decreased in January with the precipitation rate variation. The impact of various anthropogenic activities has been well defined via specific pollution parameters particularly ammonium, whose value reaching 1.09 mg/L remains above standards (MS) and (WHO) which could cause harm to the ecosystem of the lake. It is observed that the water in the lake remains in good quality with WQI values ranging from 58.82 to 74.57 (summer 2019), 66.39 to 87.32 (autumn), and 53.69 to 70.43 (winter).