Content and distribution of some chemical elements in the poplar leaves (Populus laurifolia) in Ulaanbaatar

Abstract

In the last more than two decades, technogenic environmental pollution of Ulaanbaatar (Mongolia) has become a critical issue due to the rapid growth of the city’s population and environmental objects such as soil, plant and water in Ulaanbaatar territory have been heavily contaminated through air. The objectives of this study were (1) to determine the toxic and biophilic elements in the leaves of laurel poplar (Populus laurifolia) in Ulaanbaatar (Mongolia) and to study the behaviour and interdependence of its distribution, (2) and to assess the ecological state of laurel poplar (Populus laurifolia). In the leaves of laurel poplar (Populus laurifolia) on the territory of Ulaanbaatar, the distribution of most of the studied toxic and biophilic elements is even, but only Mg, Ca, and Mn are not evenly distributed. The biogeochemical feature of laurel poplar (Populus laurifolia) on the territory of Ulaanbaatar was studied by comparing it with the value of the world clarke and with the average content of elements in plant ash according to Alekseenko and with the background value. Our study revealed the accumulation of Zn, Ni, Cd, Pb and the scattering of Fe, Mn, Co, Cu in the leaves of laurel poplar (Populus laurifolia) in Ulaanbaatar In Populus laurifolia leaves in Ulaanbaatar area the median value of Fe/Mn ratio is 4.2-2.7 times, and the median value of Pb/Mn ratio is 6.7 times higher the normal and Cu/Zn ratio is at an equilibrium. The highest Fe/Mn ratios are found along the main highway (10.45) and in the city centre (11.09).