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In this paper, heavy metal contamination in surface sediments along the Mediterranean coast of Morocco was investigated. Determining pollution degree as well as heavy metal origins were the main objectives of this investigation. For this reason, concentrations of nine heavy metals (Cd, Cu, Cr, Ni, Pb, Zn, Hg, Fe, and Mn) were analyzed at ten stations sampled during three different periods. The obtained concentrations showed significant variation between sampling periods, which was controlled by several environmental and chemical processes. According to contamination indices results using pollution load index (PLI), modified contamination degree (mC d ), geoaccumulation index (I geo ), enrichment factor (EF), and potential ecological risk index (RI), sampling stations were classified between uncontaminated and strongly contaminated without detecting any intense heavy metal pollution in surface sediment. Likewise, the EF values were comprised between no enrichment and moderate to severe enrichment. According to sediment quality guidelines, the calculated M-ERM-Q indicated that heavy metal mixtures have between 9 and 49% probability for being toxic. This result revealed lowest to medium-low potential of adverse effects to biota populations. Regarding heavy metal origins, multivariate statistical investigation showed that Cd, Cu, Hg, Pb, and Zn are derived mainly from anthropogenic activities, while Fe, Mn, Cr, and Ni were derived from natural sources. Despite Cd is considered as a typical anthropogenic metal, the very low concentrations obtained in this study support the involvement of natural factor in the enrichment with this metal. Therefore, the surface sediments contamination along the Mediterranean coasts of Morocco is particularly caused by a combination of anthropogenic and natural factors. As a result, the study area can be considered as not significantly enriched by human activities.

This study aims to identify groundwater salinization origin and to determine seawater intrusion extension toward the inland in Chaouia, Morocco. To reach these objectives, firstly, 46 groundwater samples were analyzed for major chemical elements during January 2012 and, secondly, 10 electrical resistivity tomography (ERT) profiles were performed perpendicularly to the coastal fringe. Statistical analysis provided the distinction between three Clusters reflecting different hydrochemical processes. Cluster I and Cluster II-a showed a high water electrical conductivity (EC) (from 2.3 to 11.2mS/cm) with the dominance of Na + (668mg/L on average) and Cl - (1735mg/L on average) ions as a consequence of seawater intrusion. However, Cluster II-b presented low ECs (from 0.5 to 1.7mS/cm) and Ca 2+ (99.6mg/L on average) and HCO 3 2- (235.2mg/L on average) ions dominance. Water chemistry in these wells was controlled by water-rock interaction, cation exchange, and anthropogenic activities. The Hydrochemical Facies Evolution Diagram highlighted the succession of different water facies developed between intrusion and freshening phases. The formation of Na-HCO 3 facies, which characterizes the last facies of freshening phase, followed the succession of Na-Cl, MixNa-MixCl, MixCa-MixCl, MixCa-MixHCO 3 , and Na-HCO 3 . In contrast, Na-Cl facies formation, which characterizes the last facies of intrusion phase, followed the evolution of Ca-HCO 3 , Ca-MixHCO 3 , Ca-MixCl, MixCa-MixCl, MixCa-Cl, and Na-Cl. Moreover, the obtained ERT results allowed determining the extent of different hydrochemical facies and provided more details about seawater intrusion extension. The conductive level assigned to seawater contamination showed a resistivity less than 36Ω.m, which remains limited to 3000m from the ocean, where Na-Cl water type dominates. The seawater intrusion depth varied between 5 and 40m from the surface. Overall, this original study in Chaouia region demonstrated the effectiveness of combining hydrochemical and ERT methods to investigate seawater intrusion, particularly in areas with restrictive water chemistry data., (Copyright © 2017 Elsevier B.V. All rights reserved.)

This study was based, firstly, on observations and analysis of water table level variations in the Plio-Quaternary and Hauterivian aquifers, Oualidia (Morocco), and secondly, on comparing this behavior to oceanic tidal variations. Recordings were made in the well located at 1318 m from the coast, where the two aquifers are in direct contact. This investigation was subdivided into two periods of 4 months each. Results showed a tidal influence on water table level within the well during semi-diurnal and monthly periods. Water table fluctuation periods were equal to 12 h 25 min identical to oceanic tide propagation period, while time lag between water levels was equal to 3 h 24 min. Moreover, results allowed aquifer diffusivity calculation through a confined aquifer model, which was equal to 6.20 m(2) s(-1) calculated from average value of water amplitude and to 40.6 m(2) s(-1) calculated from average value of time lag. In addition, tidal wave amplitude attenuation occurred exponentially with distance from ocean, which disappeared completely after 2000 m from coast.