Assessment of soil pollution by heavy metals in South and Central Tajikistan

Soils of southern and central Tajikistan are polluted with heavy metals due to economic activities and industrial enterprises located on the territory of Tajikistan - these are numerous thermal power plants, household rubbish, motor transport, mining, soil and rock erosion, as well as transboundary and long-range transfer from neighbouring countries and nearby deserts. Assessment of soil contamination levels by heavy metals is relevant because of their toxicity. In this study, soil samples were collected on the territory of southern and central parts of Tajikistan, from Ayvadzh to Dushanbe, and the content of Sr, Pb, As, Zn, Cu, Ni, Co, Cr, V, Fe₂O₃, TiO₂, MnO were determined by X-ray fluorescence spectrometry. The level of variation in heavy metals concentration and contamination was assessed using coefficient of variation, pollution factor, geo accumulation index, and pollution load index. (author)