Навидҳои рӯз


Assessment of the Toxic Metals Pollution of Soil and Sediment in Zarafshon Valley, Northwest Tajikistan (Part II)

  Abstract: This study discusses contamination of soils and sediments with trace elements such as Mn, Ba,W, V, Co, Cr, Zn, Ni, As, Sb Hg as well as Th and U, the influence of natural and anthropogenic factors on the distribution of elements and the ecological state of the Zarafshon Valley. The elemental composition of 116 soil and sediment samples were analyzed by the neutron activation analysis. The calculation of the geoaccumulation index (Igeo), contamination factor (CF) and pollution load index (PLI) showed that some places in the investigated region with developed the industrial zones (around mining and processing plants of “Anzob”, “Konchoch”, “Kumargi bolo” and “Mogiyon”) are mostly polluted by As, Sb, Hg, and in rare cases, the high concentration ofWand V were determined.


Geochemical and isotope anomalies in Sioma river gorge, central Tajikistan

  Abstract: For a better understanding of the previously observed increased natural radioactivity at the confluence of Varzob and Sioma rivers, the activity concentration of natural radioactive 40K, Th and U daughters as well as of the anthropogenic 137Cs were determined in nine sampling points covering the entire Sioma river. The radiometric determinations evidenced, beside increased activity concentrations of Th and U daughter radionuclides, an anomalous accumulation of anthropic 137Cs and natural 210Pb in the middle of the Sioma gorge.


Assessment of the ecological and geochemical conditions in surface sediments of the Varzob river, Tajikistan

  The aims of present study consist of collecting more information on the geochemistry of the Varzob river unconsolidated sediments as reflecting the diversity of the South-Hissar range together with a comprehensive evaluation of the anthropogenic contamination of the same sediments. Accordingly, the content of nine major, rock forming elements - Na, Mg, Al, Si, K, Ca, Ti, Mn and Fe as well as of other 27 trace ones - Sc, V, Cr, Co, Ni, Zn, As, Br, Rb, Sr, Zr, Sb, Cs, Ba, La, Ce, Nd, Sm, Eu, Gd, Tb, Yb, Hf, Ta, W, Th, and U was determined by Epithermal Neutron Activation Analysis.


Distribution of radioactive isotopes in the mountain and piedmont regions of Central Tajikistan Varzob river valley

  The Varzob Valley in the Central Tajikistan, due to its proximity to the Gissar mountains range, acts like a funnel for the air mass transported by the southern winds. For a better understanding this local phenomenon, the gross alpha and beta as well as 40K, 137Cs, 232Th and 238U activity concentrations together with the Th/U ratio were studied.