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Rare Earth Elements and yttrium (REEs+Y) were measured by inductively Coupled Plasmas -Mass Spectrometry in two previously dated sediment cores collected from Sidi Moussa lagoon, located in the Moroccan Atlantic coast, in order to establish the historical inputs of these elements and to determine the contribution of anthropogenic activities. In an attempt to clarify the phase associations of REE+Y, the Ce anomaly profiles were partitioned into three parts: the upper part with negative anomalies, except for a positive Ce/Ce* peak in 1983, the middle part with positive anomalies rising to high Ce/Ce*, and the lower part with also fairly increasing positive anomalies. Pearson correlations were calculated between REE+Y and major elements (Mn, Fe and Al) in different parts of Core-1. REE+Ys, except for Pr, were significantly correlated only with Mn, which suggests that the associated phase in the upper part consists of Mn oxides. The central part is characterized by a negative correlation of REE+Y with Mn and a positive correlation with Fe. The maximal concentrations were observed in two horizons in the sediment cores being attributed to both natural and industrial sources. The association of REEs with manganese oxides, iron-rich minerals and detritus material was changing in different parts of the cores. Only in specific layers, all REEs were weakly to moderately enriched, while yttrium was moderately to strongly enriched. The notable reduction in the upper layers is a reflection of the environmental management plan implemented by the phosphate company and the change in the morphology of the lagoon, which has reduced communication with the ocean.

In this work, we considered the concentrations of natural and anthropogenic radionuclides (namely the 40K, 210Pb, 226Ra, 137Cs, 234Th, 228Th and 228Ra) in sediments from Moroccan coast areas by considering estuaries (Sebou and Loukkos) and marine ecosystems (M’diq Bay and three Lagoons: Moulay Bousselham, Sidi Moussa and Oualidia). Sediment samples were analyzed using Gamma spectrometry. The objective was to establish radioactivity levels in Moroccan coastal areas as well as radiological risk assessment by using the ERICA tool. The software allows the estimation of dose rates to biota (a set of reference organisms by default). The highest activity concentrations were found in sediment samples of Sidi Moussa Lagoon, possibly due to the anthropogenic activities, while the lowest levels were reported in Sebou estuary, attributed most probably to a flooding event that occurred in the same year of sampling. Also, 210Pb and 40K have the most significant concentrations, while 137Cs has the lowest concentrations with a great resemblance with similar works. The World Wide Average concentration of 226Ra was exceeded in the three lagoons and that of 40K only exceeded at Sidi Moussa Lagoon. The application of ERICA tool allowed the assessment of total dose rates that are mainly due to internal exposure with strong contribution of 226Ra mainly for phytoplankton in the case of marine ecosystems and insect larvae, mollusc-bivalve, mollusc-gastropod and zooplankton for estuary ecosystems. The total dose rates were far lesser than the admissible dose rate proposed by ERICA tool (10 μGy h−1) and, therefore, unlikely to cause harmful effects to organisms.