Spatial distribution and risk assessment of some heavy metal ions in the surface sediments of the lagoon of Nador

Due to poor mixing and longer residence times in coastal lagoons,the impacts of anthropogenic activities are often more marked than in other coastal ecosystems. with a view to bring a contribution to the inventory of the spatial organization of metal pollution history in the surface sediments of the nador lagoon,we conducted a comparative study on five heavy metals namely chromium,copper,iron,manganese and zinc in the superficial sediment covering 11 positions along the continental side of the lagoon. for this,we carried out two sampling campaigns: the first in november 2007 and the second in april 2008. the results were spatialized using geographic information system gis in view to establish the relation between the levels of contamination observed for each species and their spatial distribution. according to the experimental conditions adopted in the present work,our results showed that the five metal ions can be detected in the range of mg/kg in the sediment samples with an acceptable confidence level. in these conditions,the most important levels were observed for iron and manganese which exhibit a variation with the sampling position indicating the impact of old iron mining near this area. © 2017,university of mohammed premier oujda morocco.