Changes in some nutrient elements in soil and plants due to mining activities: The case of copper mining

In the last century, mining activities, which are necessary to provide the raw materials needed in the industry, have been increasing continuously. These activities directly or indirectly affect soil, water, and air significantly. As a result of these activities, various elements are released into nature, and the structure of the soil can change considerably. Determining the effects of mining activities, especially on soil, is vital for evaluating the environmental impacts of mining activities and for the studies to be carried out on restoring these sites after mining activities. In this study, soil samples were taken from different soil depths in a copper mining site where copper mining has been carried out for many years, in a waste site, in a rehabilitation site with revegetation and adult trees at least 20 years old, and in a forested area within the mining site but without any treatment. Soil samples were taken from soils where Pinus nigra Arnold., Pinus silvestris L., and Robinia pseudoacacia L. species grow in the rehabilitation site and forest area, and leaf, bark, wood, and root samples were collected from trees in the same areas. Within the scope of the study, the variation of element concentrations in soils by species and soil depth and in plants by species and organs were evaluated. Thus, the element concentrations in soils and plants were evaluated, and the bioconcentration factor (BCF) and translocation factor (TF) were calculated for each plant organ to determine the most suitable species and organs for phytoremediation studies. As a result of the study, it was determined that element concentrations in both soils and plant organs varied significantly. As a result of the study, it was determined that Cu concentration accumulated within the determinable limits only in Pinus sylvestris species in the leach fields in the subsoils. Cu concentrations were below the determinable limits in both the tailings and rehabilitated tailings sites, other than Pinus sylvestris, indicating that Cu was largely removed from the soil during mining activities. In terms of species, the highest concentrations of many elements were generally obtained in Pinus nigra. TF values of plant organs were calculated within the scope of the study. Trees with TF values greater than 1 for heavy metals are considered strong accumulators. As a result, TF values could not be calculated for most of the organs for the elements B and Ge, except Cu. On the other hand, including these elements, the TF value was calculated to be above 1 in the organs of at least 1 species in all studied elements except Pb. This result reveals that the species subject to the study can be used in phytoremediation studies for many elements. In conclusion, it was determined that the concentrations of some elements, such as Cr and Cd, which are highly harmful to human health, were below the determinable limits. Apart from this, Cu concentration was also below the determinable limits to a great extent in the soils in the tailings area. However, the concentrations of these elements in plants are quite high. This result shows that soil is not the only source of heavy metal pollution in mining sites. It is recommended that the sources of heavy metal pollution during the mining process at these sites be evaluated separately.