The investigation of the influence of mining activities on surface and subsurface water quality

It is well known that mining activities have negative impacts on surface and subsurface water quality. These impacts could cause an environmental disaster, especially when necessary mitigation and rehabilitation activities are not implemented. Interaction of pyritic ores with oxygen and water in abandoned non-rehabilitated open pit mines of coal and iron is responsible for the formation of Acidic Mining Lakes. In addition to high acidity associated with average pH levels of around 2, these lakes also have high heavy metal and trace element concentrations and are considered to influence surface and subsurface water quality. Within the scope of this research, an acidic mining lake that formed as a result of the inundation of an abandoned open pit lignite mine located in Çan district of Çanakkale province was investigated limnologically in order to assess water quality. In this study, lake water has been sampled from a total number of 56 points (23 surface samples and 33 depth samples) in order to determine the vertical and areal distribution patterns of numerous water quality parameters including primary physical parameters, major anions and cations and heavy metal and some trace elements. Furthermore, morphological characteristics of the lake (i.e., bathymetry, area and volume) were also computed to predict the possible risks if lake waters seep into groundwater and in case the lake is intentionally emptied. Finally, possible rehabilitation techniques for acidic mining lakes were explained. Upon the analysis of these techniques, neutralization and metal adsorption with fly ash option was recommended for the lake under consideration.