Contents lists available at ScienceDirect Applied Geochemistry journal homepage: www.elsevier.com/locate/apgeochem Bioaccumulation of cadmium and thallium in Pb-Zn tailing waste water by Lemna minor and Lemna gibba Merve Sasmaz a,1 , Erdal Öbek b,2 , Ahmet Sasmaz c,*,3 a Firat University, Environmental Engineering, 23119, Elazig, Turkey b Firat University, Bioengineering, 23119, Elazig, Turkey c Firat University, Geological Engineering, 23119, Elazig, Turkey ARTICLE INFO Keywords: Accumulation Lemna gibba Lemna minor Cadmium Thallium Tailing waste water Keban ABSTRACT The present study investigated the removal ability to phytoremediate cadmium and thallium from tailing waste water of Lemna gibba and Lemna minor. These plants were separately adapted to the reactors, placed in the water and daily collected during the eight days. During the study, the plant and water samples were taken daily and the pH, temperature and electric conductivity of the tailing waste water were daily measured in situ. L. minor and L. gibba were firstly washed, dried in and then ashed at 300 °C for 24 h in an oven. Both ashed plant and water samples were analyzed by ICP-MS to find out the concentrations of cadmium (Cd) and thallium (Tl). Although Cd and Tl are at low values (11.4 ± 0.5 μgL -1 for Cd and 2.85 ± 0.5 μgL -1 ) in tailing waste water, the Cd and Tl were accumulated at the highest amounts by L. minor (31.08 mg L -1 for Cd and 13.43 mg L -1 for Tl) and L. gibba (38.9 mg L -1 for Cd and 17.18 mg L -1 for Tl). Our study on the fourth day showed that L. minor accumulated more removal abilities of Cd (94.56 times) and Tl (7.33 times) than in L. gibba L. (25.89 times on the third day for Cd and 6.16 times on the fourth day for Tl) but L. gibba accumulated higher Cd and Tl concentrations (38.9 mg Cd kg -1 and 17.18 mg Tl kg -1 ) than in L. minor. Therefore, these plants can use to remove Cd and Tl in tailing waste water polluted by Cd and Tl. 1. Introduction Toxic effects of heavy metals (HM) such as Cd, As, Hg, Tl, Zn and Pb. have been worked their effects on human health by US EPA (United States Environmental Protection Agency), OECD (The Organization for Economic Cooperation and Development) and WHO (World Health Organization)(Jarup, 2003; Kabata-Pendias and Mukherjee, 2007; Liu et al., 2008). Contamination of aquatic systems/environments by heavy metal contamination is one of the main global problems for all people in the world. Cadmium and thallium occur naturally in ore deposits to- gether with lead, zinc, silver and copper release into the soil and water from different sources such as fuel production, smelting processes, in- dustrial effluents, mining, agricultural chemicals, small-scale industries (OECD, 2003; Babarinde et al., 2016; Chidi and Kelvin, 2018; Siddique et al., 2018; Mehta et al., 2018). Cadmium and thallium accumulate firstly in the kidney and has a long biological half-life in living human and animals. According to WHO (2006), Cd and Tl are among the highest toxic metals in compared to the other heavy metals. Cadmium toxicity can result in kidney failure and chronic renal failure (Gobe and Crane, 2010; Bawaskar et al., 2010; Płachno et al., 2015). Thallium enters to human body with food, vegetables and water and causes fetal demise, degenerative changes and adverse health effects in living or- gans (Hoffman, 2000; Cvjetko et al., 2010; Karatepe et al., 2011). Water resources are rapidly contaminated by human activities over recent years. The HM levels in drinking water of different countries are higher than in WHO (2006)‘s levels. The HM contamination in aquatic areas is one of the biggest global problems for some countries (USEPA, 2000; OECD, 2003; Bulut et al., 2016; Demir et al., 2017; Aras et al., 2017; Koç Orhon et al., 2017; Solak et al., 2018; Muhammetoglu et al., 2018). Phytoremediation is fairly cheap and has eco-friendly technology in compared with the different techniques used to remove the heavy metals (Obek, 2009; Chandra and Yadav, 2011; Sood et al., 2012; Tatar and Obek, 2014; Sasmaz et al., 2015, 2016a, 2016b and 2018). Floating https://doi.org/10.1016/j.apgeochem.2018.12.011 Received 26 August 2018; Received in revised form 14 November 2018; Accepted 6 December 2018 * Corresponding author. E-mail addresses: msasmaz91@hotmail.com.tr (M. Sasmaz), eobek@firat.edu.tr (E. Öbek), asasmaz@gmail.com, asasmaz@firat.edu.tr (A. Sasmaz). 1 Tel: +904242370000/5979; fax: +904242411226. 2 Tel: +904242370000/5554; fax: +904242411226. 3 Tel: +904242370000/5950; fax: +904242411226. Applied Geochemistry 100 (2019) 287–292 Available online 08 December 2018 0883-2927/ © 2018 Elsevier Ltd. All rights reserved. T