title: Heavy elements in the phosphorite from Kalaat Khasba mine (North-western Tunisia): potential implications on the environment and human health.
abstract: Tunisia is one of the largest phosphate producers in the world (more than 10 million tons per year since the early nineties). The Kalaat Khasba mine (NW of Tunisia) has operated from 1893 until 1993 and data demonstrate that, in the phosphorites of Kalaat Khasba, Cd is enriched 105-208 times, when compared with shales, and U is enriched by a factor varying between 18 and 44. The general trend shows an increase in heavy elements content with decreasing particle size. On the other hand, concentrations of Sr, Cr and U exhibit the same distribution for the different size fractions. It was found that Cd concentrations exceed the allowed EC soil limits for growing crops. Hence, owing to the tailings exposure and to the mobilisation of the finest particles by rainfall and wind, Cd could have detrimental effects on human health and on the environment because a significant portion of Cd was found in the exchangeable form.
authors.affiliation: Geobiosciences, Geotechnologies and Geoengineering Research Center, University of Aveiro, 3810-193 Aveiro, Portugal. eafsilva@ua.pt
authors.forename: Eduardo Ferreira
authors.initials: EF
authors.lastname: da Silva
authors.forename: Ammar
authors.initials: A
authors.lastname: Mlayah
authors.forename: Celso
authors.initials: C
authors.lastname: Gomes
authors.forename: Fernando
authors.initials: F
authors.lastname: Noronha
authors.forename: Abdelkrim
authors.initials: A
authors.lastname: Charef
authors.forename: Cristina
authors.initials: C
authors.lastname: Sequeira
authors.forename: Valdemar
authors.initials: V
authors.lastname: Esteves
authors.forename: Ana Raquel Figueiredo
authors.initials: AR
authors.lastname: Marques
mesh_terms: D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000032:analysis*; D006801:Humans; D019216:Metals, Heavy / Q000032:analysis*; D008855:Microscopy, Electron, Scanning; D008903:Minerals / Q000737:chemistry*; D008906:Mining; D010316:Particle Size; D010710:Phosphates / Q000737:chemistry*; D014416:Tunisia; D014961:X-Ray Diffraction
chemical_list: D004785:Environmental Pollutants; D019216:Metals, Heavy; D008903:Minerals; D010710:Phosphates; C090013:phosphorite