Study of Phytoextraction at Some Locations of Ajaristskali River Based of Soils and Plants Analysis

Abstract

The gorge of the Ajaristskali River and its surrounding areas are important habitats for biodiversity. The territories adjacent to the gorge are a refugium of tertiary moisture-loving Colchis relic forest ecosystems, which have been awarded the status of a UNESCO World Natural Heritage Site. Ongoing work on the construction of a cascade hydroelectric power station in the gorge poses a risk of loss of the natural habitats. The article presents studies of assessing the ecological state of forest ecosystems in locations: Shuakhevi settlement, Shuakhevi water intake and Shuakhevi hydroelectric power station (HPP). In order to evaluate the current ecological state in the Ajaristskali gorge, the phytoextraction capacity of the dominant tree species forming the main natural forest in this area was studied. The alkalization of the soil samples taken from the Ajaristskali gorge was observed at the Shuakhevi HPP intake and Shuakhevi HPP. The soils are poor in total humus and nitrogen evidencing their decreased fertility. Data of the soil pollution hazard ratio show that the hazard of pollution with heavy metals, As, Ba, Cd, and Pb, exceeds 1-near Shuakhevi HPP intake and Shuakhevi HPP; pollution with Mo, Zn is observed at Shuakhevi HPP location; and Mn pollution is observed at all three locations. Based on the calculation of biological absorption coefficient of heavy metals, we have identified the dominant tree species forming the main natural forests on the study sites, whose vegetative parts have a good phyto-extraction ability for toxic elements. Such plants are: pine (needles), oak (leaves), and alder (leaves).