Assessment of trace metals contamination in sediment and surface water of quarry lakes from the abandoned Pb mine Zaida, High Moulouya-Morocco

Physicochemical properties and total content of potentially toxic metals (Pb, Zn, As, Cd and Cu) in sediment and surface water samples from the pit lakes of the abandoned Pb mine were determined to assess the contamination level, and to evaluate the impact of the past mining activities on their quality. The results of the metallic trace elements in water samples gave high concentrations especially for Pb, Cd and As, which makes these lakes unusable neither for irrigation nor for drinking water supply. In addition to some statistical analyses, the geoaccumulation index (Igeo), potential ecological risk (E-r(i)), and other pollution indices were applied to assess pollution levels of sediments. The obtained values of Igeo and the comparison with the sediment quality guidelines reveals a high Pb contamination especially for the lakes located near next to the tailings. As for the Ei r, it shows an extreme contamination by As in some studied lakes. The correlation results showed that Pb and As are from different sources. In fact, the tailings could represent the most important source of Pb, while the As can be related to lithogenic or anthropogenic sources.