Chemical and mineralogical characterization of weathering products in mine wastes, soil, and sediment from the abandoned Pb/Zn mine in Skikda, Algeria

The Sidi Kamber Zn/Pb mine located 60 km from Skikda is one of the abandoned mining areas of northeastern Algeria for more than 40 years. Currently, this mining area is considered as a real environmental problem. The purpose of this work is to identify and characterize different sources of polymetallic pollution and their impact on the Guénitra dam sediments quality by analyzing the metal content of the weathering products in mine wastes (tailings and waste rock), soil affected by acid mine drainage and Guenitra dam sediments. Moreover, this study aims to determine the mineralogical composition of new compounds occurring in the fine-grained sediments (less than 250 µm) of the mining area. The chemical analysis and the concentration of Fe, Cd, Zn, Cr, Pb, Cu, Mn, Ni, and Hg metals of the studied samples were performed using atomic absorption spectroscopy analysis, inductively coupled plasma optical emission spectrometer, and X-fluorescence ray analysis. The mineralogical composition of all samples was characterized by several techniques such as Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. The obtained data were analyzed using multivariate statistical analysis, correlation matrix, hierarchical cluster analysis (HCA), and principal component analysis (PCA). The results showed very high content of Pb, Zn, Cd, Cr, and Hg toxic metals in all samples and suggest taking corrective measures should be taken to reduce the spread of these hazardous elements into the environment. A rehabilitation of the abandoned Sidi Kamber mine should be recommended, as well. The obtained results of HCA and PCA suggest two principal origins of metals pollution: Cu, Mn, Hg, and Pb are derived from anthropogenic sources of mine wastes from the tailings piles, while, Ni, Zn, Cr, and even Fe are derived from lithogenic and anthropogenic sources. Mineralogical characterization results of weathering products in mine wastes, soil, and sediment highlighted the presence of the following minerals: quartz, muscovite, kaolinite, goethite, hematite, lepidocrocite, ferrohexahydrite, and jarosite.