Assessment of heavy metals bioaccumulation in Silver Birch (Betula pendula Roth) from an AMD active, abandoned gold mine waste.

Acid mine drainage (AMD) is generally outlined as one of the largest environmental concerns, characterized by very low pH value of mine waste, heavy metals and high sulphate content. This extremely hostile environment reduces plant ability to develop and grow. Present study focuses on a silver birch (Betula pendula Roth), a pioneer species that grows on an extremely hostile gold mine waste, to investigate the bioaccumulation of rare metals (thallium (Tl) and indium (In)), as well as nine other more common heavy metals (bismuth (Bi), cadmium (Cd), cobalt (Co), copper (Cu), lead (Pb), manganese (Mn), nickel (Ni), silver (Ag) and zinc (Zn)), and to asses phytoextraction and phytostabilization potential of silver birch. Additionally, parameters determining AMD process and overall contamination (pH, electrical conductivity (EC), sulphates (SO42-), arsenic (As), iron (Fe), oxidation-reduction potential (ORP), turbidity, dissolved oxygen (DO), total dissolved solids (TDS), acidity, hardness, X-ray diffraction (XRD) and radioactivity) were determined in mine waste and drainage water samples. To assess the heavy metals bioaccumulation and mine waste status, statistical geochemical indices were determined: bioaccumulation factor (BCF), pollution load index (PLI), geochemical abundance index (GAI) and exposure index (EI). The results show that silver birch bioaccumulates the essential elements Cu, Ni, Mn and Zn, and the nonessential elements Tl (average BCF = 24.99), In (average BC = 23.01) and Pb (average BCF = 0.84). Investigated mine waste was enriched by Bi, Ag and Cd according to positive values of GAI index. Present research provides a novel insight into bioaccumulation of nonessential heavy metals in silver birches who grow on the extremely hostile mine waste, and they exhibit significant phytoremediation potential.

Highly effective sustainable membrane based cyanobacteria for uranium uptake from aqueous environment.

Wastewater from industrial process of uranium ore mining contains a large amount of this radioactive pollutant. Regarding the advantages of biosorption, it was found that varieties of biomasses such as agricultural waste, algae and fungi are effective for uranium removal. However, there is limited research on cyanobacteria, therefore, cyanobacteria, Anagnostidinema amphibium (CAA) was investigated by batch method for the first time for biosorption of uranium (VI). Optimization of biosorption parameters showed that maximum removal efficiency of 92.91% was reached at pH range of 9-11 with 50 mg of cyanobacteria to 100 mg/L U(VI) initial concentration, at 25 °C within 40 min. Used biosorbent exhibited very good selectivity for U(VI) ions and reusability in IV sorption/desorption cycles. Characterization of CAA surface was performed by FTIR, EDS, EDXRF and SEM analysis and it has shown various functional groups (CONH, COOH, OH, PO alkyl group) and that it is very rich in elements such as iron, potassium and calcium. In binary systems, contained of U(VI) and selected ions, CAA exhibits very good selectivity towards U(VI) ions. Kinetic data revealed the best accordance of experimental data with the pseudo-second-order model and isotherms data agreed with Freundlich model. Thermodynamic data implied that U(VI) biosorption process by A. amphibium exhibited spontaneity and modelling of the investigated process showed that the adsorption of uranium ions occurs mainly via peptidoglycan carboxyl groups. Overall results show that these cyanobacteria with a maximum sorption capacity of 324.94 mg/g have great potential for the processing of wastewater polluted with uranium (VI).

Study of radionuclides and heavy metal migration through soil profiles (0-60 cm) at points near the targets of NATO strikes in 1995: environmental monitoring and assessment.

The activity concentrations of natural and artificial radionuclides (40K, 232Th, 226Ra, 238U, 137Cs) and concentrations of six heavy metals of interest (Cd, Cr, Cu, Ni, Pb and Zn) were investigated in 18 soil samples through soil depths (0-10, 10-20, 20-30, 30-40.40-50, 50-60 cm) at the three selected sites in the Hadzici. Since at this area ammunition with depleted uranium had been used during the NATO strikes in 1995, this study was conducted with the aim to assess the radiological and environmental health hazards. Radioactivity was determined by gamma spectrometry using HPGe and LEGE detectors and content of heavy metals by using a flame atomic absorption spectrometry. The correlation with distribution of the radionuclides and their activity concentrations through depths was found only at the site 1 for 40K, 232Th and 226Ra, where minimum/maximum activity concentrations for 40K were 814.42 Bq/kg/1039.48 Bq/kg, for 232Th 53.98 Bq/kg/74.12 Bq/kg and for 226Ra 50.32 Bq/kg/65.73 Bq/kg. Vertical distribution of 137Cs along 3 site profiles was used for distinction of cultivated and uncultivated soil. Using the activity ratio of 238U/226Ra and 235U/238U, the presence of depleted uranium (DU) was established at the site 3. Obtained Igeo values for determined heavy metals showed that all of three sites were unpolluted to moderately polluted. Pb content in all three sites showed correlation with concentration decreasing with increasing soil depth.