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Öğe Acid pond sediment and mine tailings contaminated with metals: physicochemical characterization and electrokinetic remediation(Springer, 2017) Karaca, Oznur; Cameselle, Claudio; Reddy, Krishna R.Mine tailings and acid pond sediment from a former mining area in Canakkale (Turkey) were analyzed for physical (e.g., moisture content, particle size, specific gravity and hydraulic conductivity) and chemical parameters (e.g., organic content, pH, ORP and EC) as well as metal content and sequential extraction analysis, in an attempt to evaluate their risk as a source of contaminants. Column extraction tests were conducted to investigate the leachability under model field conditions using simulated rainwater. The toxicity characteristic leaching procedure and synthetic precipitation leaching procedure (SPLP) methods were performed to evaluate the expected concentrations in the water in contact with the solid material. The column tests proved that Fe and Pb can be released to the waterbodies in contact with the solid materials. Pb was released easier than Fe due to its content in the more labile fractions in the sequential extraction analysis. SPLP-Pb in both tailings and sediment exceeded the USEPA regulatory limit, confirming the hazardousness of those materials. Electrokinetic remediation has been tested as a possible technology for the removal of metals from mine tailings and sediment. Electrokinetics removed 20% of Pb and Fe in 9 days of treatment at 1 VDC/cm. The metal removal efficiency was very affected by metal speciation. Electrokinetics could remove metal fractions I-IV [as described by Tessier et al. (Anal Chem 51(7): 844-851, 1979) especially in the closest section to the anode of the solid matrix, and the metals accumulated in the following sections. The results suggested that Fe and Pb could be effectively removed from the mine tailings and sediment if the advance of the acid front was favored and the treatment time increased. However, considering the physicochemical characterization and the results from the electrokinetic treatment, other green and more sustainable remedial strategies have to be proposed for mitigation of environmental risks of former mining areas. Instead of focusing on metal removal, the results of this work suggest that the immobilization and stabilization of metals in the site are more practical solutions. Thus, phytocapping is recommended as a practical green and sustainable method to mitigate the environmental risks of former mining areas.Öğe Characterization of Heavy Metals in Mine Tailings and Lake Sediments: Implications on Remediation(Amer Soc Civil Engineers, 2016) Karaca, Oznur; Cameselle, Claudio; Reddy, Krishna R.Mine tailing and lake sediment from a former mining area in Canakkale (Turkey) were analyzed for physical (e.g. moisture content, particle size, specific gravity, and hydraulic conductivity) and chemical parameters (e.g. organic content, pH, ORP, and EC) as well as heavy metal content and sequential extraction analysis, in an attempt to evaluate their risk as a source of contaminants. Column extraction tests were conducted to investigate the leachability under model field conditions using simulated rainwater. The toxicity characteristic leaching procedure (TCLP) and synthetic precipitation leaching procedure (SPLP) methods were performed to evaluate the expected concentrations in the water in contact with the solid material. The results showed that both tailing and sediment in the study area were highly acidic (pH=2.2-2.92) and electrical conductivities were high. The column tests proved that Fe and Pb can be released to the waterbodies in contact with the solid materials. Pb was released easier than Fe due to its content in the more labile fractions in the sequential extraction analysis. SPLP-Pb in both tailing and sediment exceeded the U.S. EPA regulatory limit confirming the hazardousness of those materials. All of these results were used to evaluate the most appropriate remedial strategy and to recommend phytocapping as a practical green and sustainable method to mitigate the environmental risk.Öğe Electrokinetic Removal of Heavy Metals from Mine Tailings and Acid Lake Sediments from Can Basin, Turkey(Amer Soc Civil Engineers, 2016) Karaca, Oznur; Cameselle, Claudio; Reddy, Krishna R.This work focuses on the evaluation of electrokinetic remediation as a technology for the removal of heavy metals from mine tailings and acid lake sediments sampled in a former mining area in Can Basin (Canakkale, Turkey). The electrokinetic treatment of mine tailing and sediment removed 20% of Pb and Fe in 9 days of treatment at 1 VDC/cm. The removal of metals was very affected by metal speciation which was determined by Tessier method. Electrokinetics could remove metal fractions I-IV in the Tessier method, especially in the closest section to the anode of the solid matrix, and the metals migrated towards the cathode and accumulated in the following sections. The results suggested that Fe and Pb could be effectively removed from the mine tailing and sediment if the advance of the acid front was favored and the treatment time increased.Öğe ENVIRONMENTAL ASSESSMENT OF MINE TAILINGS: CAN-ETILI BASIN (TURKEY) AS A CASE STUDY(Stef92 Technology Ltd, 2014) Karaca, Oznur; Reddy, Krishna R.Improper mining activities cause various environmental problems. A major problem is the heavy metal pollution. Can-Etili Basin (Northwest Turkey) has been subjected to intense mining activities with open/underground mining operations in several locations within the basin. Acid mine lakes have been also created at the abandoned mining sites. This study was conducted to investigate physical and chemical characteristics of the mine tailings and sediments and the types of contaminants present in them. Further, the leachability and associated environmental risk of the contaminants present was also investigated. Two locations of the basin were selected for this study, and several representative samples of mine tailings, rock outcrops, and lake sediments were collected. These samples were tested for physical properties such as moisture content, particle size, specific gravity and hydraulic conductivity and for chemical properties such as organic content and pH. The metal contamination in each of the samples was also determined. Subsequently, batch and column experiments were conducted to quantify the leachate/bioavailable toxic metals. The results showed that the sediments, mine tailings and outcrops contain several toxic metals at elevated concentrations. The most dominant metal contaminants found were: Pb (79 mg/kg), Ba (190 mg/kg) and Ni (470 mg/kg) in mine tailings; Pb (64 mg/kg), Ba (310 mg/kg) and Ni (570 mg/kg) in lake sediments; and Pb (96 mg/kg), Ba (279 mg/kg) and Ni (760 mg/kg) in outcrop rocks. The extent of leachable/bioavailable metals was dependent on the physical and chemical characteristics of the media, and the toxic metals such as Pb, Cu, Zn, and Ni were found to leach in the amounts ranging from 5 to 15 mg/kg. The total and leachable toxic metals found in the materials at the basin have potential to impact the public health and surrounding environment. Additional research is being conducted to quantify the risk as well as to develop practical green and sustainable methods to mitigate the environmental risk.Öğe Environmental assessment of mine tailings: Can-Etili Basin (Turkey) as a case study(International Multidisciplinary Scientific Geoconference, 2014) Karaca, Oznur; Reddy, Krishna R.Improper mining activities cause various environmental problems. A major problem is the heavy metal pollution. Can-Etili Basin (Northwest Turkey) has been subjected to intense mining activities with open/underground mining operations in several locations within the basin. Acid mine lakes have been also created at the abandoned mining sites. This study was conducted to investigate physical and chemical characteristics of the mine tailings and sediments and the types of contaminants present in them. Further, the leachability and associated environmental risk of the contaminants present was also investigated. Two locations of the basin were selected for this study, and several representative samples of mine tailings, rock outcrops, and lake sediments were collected. These samples were tested for physical properties such as moisture content, particle size, specific gravity and hydraulic conductivity and for chemical properties such as organic content and pH. The metal contamination in each of the samples was also determined. Subsequently, batch and column experiments were conducted to quantify the leachate/bioavailable toxic metals. The results showed that the sediments, mine tailings and outcrops contain several toxic metals at elevated concentrations. The most dominant metal contaminants found were: Pb (79 mg/kg), Ba (190 mg/kg) and Ni (470 mg/kg) in mine tailings; Pb (64 mg/kg), Ba (310 mg/kg) and Ni (570 mg/kg) in lake sediments; and Pb (96 mg/kg), Ba (279 mg/kg) and Ni (760 mg/kg) in outcrop rocks. The extent of leachable/bioavailable metals was dependent on the physical and chemical characteristics of the media, and the toxic metals such as Pb, Cu, Zn, and Ni were found to leach in the amounts ranging from 5 to 15 mg/kg. The total and leachable toxic metals found in the materials at the basin have potential to impact the public health and surrounding environment. Additional research is being conducted to quantify the risk as well as to develop practical green and sustainable methods to mitigate the environmental risk. © SGEM2014.Öğe Mine tailing disposal sites: contamination problems, remedial options and phytocaps for sustainable remediation(Springer, 2018) Karaca, Oznur; Cameselle, Claudio; Reddy, Krishna R.Mining practices and the absence of proper mine land reclamation has led to heavy metal contaminated sites with serious impact on the ecosystems and risk for human health. The origin of the contamination is often associated to mine tailing deposits because they are a source of the acid mine drainage (AMD). These areas are devoid of vegetation due to the harsh soil conditions that prevent the rooting of plant species. The remediation of these areas followed by revegetation is necessary to suppress the generation of the AMD and its negative effects on the ecosystems. Conventional remediation technologies for heavy metal contaminated sites are usually not applicable because of the high cost associated with chemicals and energy requirements, as well as the long treatment time to remediate large areas. In this study, the use of phytocapping for the remediation of mine tailing deposits and abandoned mine areas is reviewed. Phytocapping is cost effective, environmentally friendly and has multifunctional role against various problems of mine tailings: it provides erosion control, landscape rehabilitation, enhances the soil properties for further colonization of other more demanding vegetal species, reduces the leachability of metals downwards the groundwater, and favors the immobilization of metals forming less bioavailable species. The most critical step in phytocapping is the developing of the first vegetative cover because of the biotoxicity of the mine soil and mine tailings. Several amendment materials can be used to ameliorate soil conditions creating a favorable environment for the rooting of plants, as well as serving as a source of nutrients. Local plant species with fast growing are preferable because their adaptation to the soil and climate conditions favors their self-propagation.
