Surface water quality and heavy metal pollution assessment in the Middle Moulouya Basin (Morocco): Implication to sustainable water management

¹ Laboratory of Applied Sciences, research Team of Water and Environment Management (G2E), ENSAH, Abdelmalek Essaâdi University, Tetouan, Morocco
² Geosciences, Water and Environment Laboratory, Faculty of Sciences, Mohammed V University of Rabat, Rabat, Morocco
³ Geology and Sustainable Mining Institute (GSMI), Mohammed VI Polytechnic University (UM6P), Lot 660, Hay Moulay Rachid, Ben Guerir 43150, Morocco
⁴ Instrumentation and Control Laboratory, Center for Sci-Tech Research in Earth System and Energy–CREATE, 4 Escola de Ciências e Tecnologia, University of Évora, 7000-671 Évora, Portugal

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Assessing surface water quality is important for recognizing changes in freshwater ecosystems and proposing ways to reduce pollution sources. This study attempts to assess surface water quality using water quality index (WQI) based on ten physicochemical parameters such as (T°C, pH, Cond, TDS, DO, Ca2+, Mg2+, Cl-, SO42-, Pb, Zn, Cu, As, Ni, Cr and Cd) for eleven samples collected from different locations. Our results, taken together, indicate that the water of Moulouya River have been impacted by a variety of human activities. Because it flows through a big area, many sources contribute to the contamination/pollution of its aquatic ecology such as abandoned mine sites, domestic wastewater and intense agricultural activities. results showing Pb, As, and Cd levels exceeding the WHO limits for drinking purposes. Pollution indices shown low to high water contamination, with HPI values range from (12.76-774.03 and 16.41-862.18) in rainy and dry season, exceeded the critical limit of 100, needing significant actions to decrease the pollution caused by heavy metals, MI values within a range 0.70-18.41 suggesting various pollution degree in this area. The WQI ranged from 91.20 to 239.23 in dry period. Specifically, 36.36 % of samples fall within "Very poor", 54.54% of samples fall within "Poor", and only 9.09% fall within "Good". Conversely, in wet period WQI ranged from 84.75 to 231.24. Notably 18.18% of samples fall within "Very poor", 63.63% of samples are classified "Poor", and tow samples classified "Good". This study can help decision-makers to manage surface water resources sustainably in the Moulouya region.