The PM_(10) and PM_(2.5) dust generation potential of soils/sediments in the Southern Aral Sea Basin, Uzbekistan

摘要

The objective of this study was to assess the contribution of the major soil/sediment surfaces in the Southern Aral Sea Basin to the dust generation potential of this region. Eight crusts and soils/sediments from seven sites, representative of these surfaces, were sampled in the field and their major characteristics (particle size distribution, organic carbon content, carbonate content, salt content and composition) that are related to dust generation, were determined. The PM_(10) and PM_(2.5) dust generation potential of the materials was determined in the laboratory using the Lubbock Dust Generation, Analysis and Sampling System (LDGASS). The highest amount of PM_(10) dust (579.3 mg.m~(-3)) was generated from the Takyr crust material. The lowest by one Solonchak salt crust material (39.6mg.m~(-3)). Salt crusts from the desiccated Aral Sea bottom generated intermediate amounts of dust. The experimental results indicate that the Takyrs and Takyr-like soils, that occupy over 1 million ha in the Southern Aral Sea Basin, constitute the surfaces with the highest potential for being the source for the severe dust storms of the area. Second to the Takyr soils, the Solonchaks and Solonchak-like soils, also with an extent of over 1 million ha, contribute highly saline dust. To these must be added a large, as yet uncharted, proportion of the approximately 4 million ha of exposed sea bed, that exhibit Solonchak-like characteristics.