Monitoring Changes in Airborne Sodium Pollution and the Feasibility of Using Pseudotsuga menziesii for Pollution Reduction

Sodium (Na) is the seventh most abundant element in the Earth's crust. It is one of the essential elements for living organisms and is a widely occurring metal. Therefore, determining Na accumulation in wood, the largest organ of trees with long lifespans and large biomass, is important. In this study, the variation of Na in the trunk organs of Douglas fir (Pseudotsuga menziesii), commonly used in landscaping, was evaluated based on organ, direction, and season. The samples used in the study were obtained from Düzce, one of the provinces with the most polluted air in Europe. The results of the study determined that Na concentrations in the outer bark were higher than those in the inner bark and wood. The highest values in all organs were obtained in the western direction, where agricultural areas are concentrated. Furthermore, it was found that Na concentrations in wood generally varied within a narrow range. These results suggest that atmospheric Na pollution is likely caused by agricultural activities and that Pseudotsuga menziesii, the subject of this study, is not a suitable biomonitor for tracking changes in atmospheric Na pollution.