Mobilization of some trace elements from ashes of Turkish lignites in rain water

Short-term water solubility characteristics of bottom ashes and fly ashes from two important Turkish lignites were investigated in association with the concentrations of some heavy metals. For this, the alkaline ashes were interacted with acidic rain water and dilute acidic solutions for leaching times changing from 10 min to 2 days to assess the mobilization potential during ash-water interactions. The concentrations of leachable trace elements such as chromium, lead, cadmium, zinc, and nickel were determined in leachate using Atomic Absorption (AA) Spectrometry. Iron concentrations were also investigated since it plays a critical role on trace element enrichment mechanism. The mineralogical and structural identification of the parent ash samples were carried out by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) techniques. The extent of the mobility of the ashes was identified regarding the physical and chemical properties of the ashes. Concentrations of the trace elements in leachates were compared to the several guideline values regulating the maximum contaminant levels in drinking water and irrigation water as well as the regulatory threshold concentrations in leachate.