Assessment Heavy Metals (Pb, Zn, Cd) and Metalloids (Sb, As) Mobility in Carbonated Soils Contaminated by Mining Wastes (Northern Tunisia) Yosra Achour1,2,3, Radhia Souissi1, Haifa Tlil1,3, Mikael Motelica Heino2, Fouad Souissi3 1Laboratoire des Matériaux Utiles, Institut National de Recherche et d’Analyse Physico-chimique, Pôle Technologique, Sidi Thabet, 2020 Tunis, Tunisia 2CNRS/ISTO Institut des Sciences de la Terre d’Orléans, UMR-CNRS 7327 Campus Géosciences, 1A rue de la Férollerie, 41071 Orléans, France 3Universite´ Tunis El Manar, Faculte´ des Sciences de Tunis,2092 Tunis, Tunisia Thursday, 22nd August 2019

Fig.1: Location map of the study areas GOLDSCHMIDT 2019 Purpose of study The main objective of this work was to study the mobility of these potentially toxic elements (PTE) in soils developed on carbonated source rocks near several abandoned mining sites in northern Tunisia (Jalta, Jebel Hallouf - Sidi Bouaouane, Jebel Ghozlane and Hammam Zriba). Fig.1: Location map of the study areas 2

Physico-chemical parameters Test de lixiviation GOLDSCHMIDT 2019 Materials & Analysis techniques Sampling Rhizosphere samples Drying   Seving (2 mm) AFNOR  Grinding Physico-chemical parameters Test de lixiviation Extraction cinétique avec LMWOAS (pH = 2,8) Shan et al. (2003), Wang et al. (2004), Feng et al. (2005) 1-pH 2-Conductivity 3-Carbonate rate 4-Cation Exchange Capacity Mixture of organic acids (pH=2,8)(4/2/1/1/1) Mineralogical Acetic acid C2H4O2 DRX Lactic acid C3H6O3 Citric acid monohydrate C6H8O7.H2O Chemical analysis ICP-AES Malic acid C4H6O5 Formic acid CH2O2

1- Physico-chemical parameters GOLDSCHMIDT 2019 Results 1- Physico-chemical parameters Samples EC (µs/cm) pH % CaCO3 CEC (meq/100g) Jebel Hallouf 217.20 8.31 75.64 127.53 Sidi Bouaouane (Control) 237.50 7.84 39.74 Not measured Sidi Bouaouane 499.00 7.78 46.15 424.18 Jalta 367.50 7.12 1.28 531.22 Hammam Zriba 115.40 7.69 24.36 41.78 Hammam Zriba (Control) 271.50 7.07 21.79 Jebel Ghozlane 865.50 33.33 74.97 Jebel Ghozlane (Control) 233.10 7.99 50.00  Not measured 4

Sidi Bouaouane (control) Jebel Ghozlane (control) GOLDSCHMIDT 2019 Results 2- Chemical analysis Locality As mg/kg Sb Pb Zn Cd Sidi Bouaouane (control) 44 0.5 391 418 7 Sidi Bouaouane 683 145 17350 8620 64 Jebel Hallouf 669 103 10321 7951 55 Jalta 110 Nd 3061 1240 9 Jebel Ghozlane (control) 331 1 Jebel Ghozlane 348 7943 36999 205 Hammam Zriba (control) 8 91 493 nd 2235 12674 35 Nd: not detected The agricultural soils near the old mining sites are rich in EPT, their contents exceed that of the local geochemical background. 5

GOLDSCHMIDT 2019 Results Dissolution of carbonates 3- Evaluation of PTE mobility in soil Dissolution of carbonates Evolution of conductivity and pH as a function of time Dissolution of calcite & dolomite Evolution of the concentration of Mg and Ca as a function of time during extraction with LMWOAs 6

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