In the present study, we assessed the spatial and temporal distributions of metal contents and their environmental risks in the surface sediments from Essaouira protected coastal area (Atlantic coast of Morocco). Surface sediment samples of the biogenic reefs of Sabellaria alveolata (Annelida: Polychaeta) were collected seasonally, and the fine fraction (<$63\mathrm{\mu }\mathrm{m}$) analysed using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). The sediment characteristics of this coastal zone were comparable to other Moroccan coastlines, and the sequence of metal concentrations decreased Al > Fe > Zn > Cr > Cu > Pb > Cd. Concentrations were lower than mean Earth crustal contents and world average background levels except for Cd. Spatial and temporal variations of metals were highly significant, and largely determined by geochemical background properties and inputs of terrigenous material except for Cd which was associated with upwelling phenomena. Comparison with sediment quality guidelines (SQGs) and ecotoxicological values indicated few exceedances with regard to most metals except for Cd, Cr and Cu. Consequently, the dredged sediment may be dumped at sea with little likelihood of adverse biological effects. However, some sediments had a moderately high Cd content, especially during summer and warrant more detailed assessment.

在本研究中，我们评估了索维拉沿海保护区（摩洛哥大西洋沿岸）表层沉积物中金属含量的时空分布及其环境风险。季节性收集Sabellaria alveolata (Annelida: Polychaeta)生物礁表层沉积物样品，细粒级 (<$63\mathrm{\mu }\mathrm{米}$) 使用电感耦合等离子体原子发射光谱 (ICP-AES) 进行分析。该海岸带的沉积物特征与摩洛哥其他海岸线相当，金属浓度顺序为 Al > Fe > Zn > Cr > Cu > Pb > Cd。除 Cd 外，浓度低于平均地壳含量和世界平均背景水平。金属的时空变化非常显着，主要由地球化学背景特性和陆源物质输入决定，除了与上升流现象相关的 Cd。与沉积物质量指南 (SQG) 和生态毒理学值的比较表明，除 Cd、Cr 和 Cu 外，大多数金属几乎没有超标。最后，疏浚的沉积物可以倾倒在海上，几乎不会产生不利的生物影响。然而，一些沉积物的 Cd 含量中等偏高，尤其是在夏季，需要进行更详细的评估。