Heavy Metal Contamination Levels and Ecological Impact in Lake Dayet Er-Roumi Sediments, Morocco: A Pollution Index Approach
El Ghizi Sara
*
Environmental Engineering Team, Faculty of Sciences and Techniques, University of Sultan Moulay Slimane, BO. 523, Beni Mellal, Morocco.
Hssaissoune Slimane
National Laboratory for Pollution Studies and Monitoring (LNESP), Rabat, Morocco.
El Bouch Mohammed
National Laboratory for Pollution Studies and Monitoring (LNESP), Rabat, Morocco.
Sadik Mohammed
National Center for Hydrobiology and Fish Farming, Azrou, HCEFLCD, Morocco.
Hasnaoui Mustapha
Environmental Engineering Team, Faculty of Sciences and Techniques, University of Sultan Moulay Slimane, BO. 523, Beni Mellal, Morocco.
*Author to whom correspondence should be addressed.
Abstract
Background: For many years, metallic contamination of surface sediments has attracted the attention of researchers from diverse fields. Lake Dayet Er-Roumi, classified as a Site of Biological and Ecological Interest, is under pressure from various forms of pollution.
Aim: This study aimed to assess the spatio-temporal heavy metal contamination of the sediments of Lake Dayet Er-Roumi, evaluate ecological risks, and identify pollution sources using pollution indices and Principal Component Analysis.
Study Design: Spatio-temporal monitoring of several metallic trace elements.
Place and Duration of Study: The study was conducted at Lake Dayet Er-Roumi during four seasons in 2018/2019.
Methodology: The study was carried out at Lake Dayet Er-Roumi through spatio-temporal monitoring of several metallic trace elements: Al, Pb, Mn, Ba, Zn, Fe, Cu, Co, Cr, Cd, and Ni during four seasons in 2018/2019. Three different sampling points were selected across the study area.
Results: The results reveal very high concentrations of Zn, Pb, Co, Cd, and Mn, which far exceed the recommended standards. The analysis of Cd and Ni shows low concentrations that are almost negligible. Principal Component Analysis shows that the metals studied evolve in the same direction, which may reflect their common origins and behaviours. The calculation of the enrichment factor shows high contamination in Fe, Zn, and Co, medium to low enrichment for Mn and Cr, and no enrichment for the other metallic elements. Analysis of the enrichment factor for all elements allows the following classification to be established: EF Pb > EF Zn > EF Cu > EF Cr > EF Mn > EF Al > EF Ba > EF Co. The calculation of the geo-accumulation index indicates the contribution of anthropogenic activities to pollution.
Conclusion: These results show that the sediments are heavily loaded; regular monitoring and management are necessary to preserve and protect this lake.
Keywords: Lake Dayet Er-Roumi, lake sediments, heavy metals, sediment contamination, geo-accumulation index, enrichment factor, principal component analysis, spatio-temporal variation, anthropogenic inputs, ecological assessment