Determination of the 180-year variation of concentrations of some heavy metals in the atmosphere using annual rings of corylus colurna

In the last century, anthropogenic effects, such as primarily due to traffic, industrial activities, mining, and urbanization, increased the rate of pollution in the atmosphere. Pollution has reached levels threatening human and environmental health and has become one of the most critical problems worldwide. Among the components of air pollution, heavy metals do not deteriorate and disappear quickly in nature; they can be transported far from their source, they tend to bioaccumulate in living organisms, and some can be toxic, carcinogenic, and deadly even at low concentrations. Therefore, monitoring the change of heavy metal concentrations in the air is essential. One of the most effective methods in determining the change of heavy metal concentrations in the atmosphere from the past to the present is the use of annual rings of trees as biomonitors. In this study, the change of some heavy metal concentrations, which are the most harmful heavy metals in terms of human and environmental health, in the last 180 years, with the help of the annual rings of the Corylus colurna tree, which was cut at the end of 2020 in Kastamonu province, was tried to be determined. In the study, the heavy metal concentrations in the outer bark and inner bark were also compared with the heavy metal concentrations in the woods, and the directional variation of the heavy metal concentrations was also evaluated. As a result, there was a statistically significant (p<0.001) difference between wood and bark in general, and the concentrations obtained in the bark were much higher than in wood. In annual rings, the highest values were generally obtained in the west and north directions in many periods, and there could be significant differences between the directions in the same period. These determined differences can be explained as the effects of the nearest highway and iron and steel factory. The study's results also revealed that C. colurna and the method are very suitable for monitoring the change of heavy metal concentrations, and the transfer of these heavy metals between organs and cells was quite limited.