بررسي خصوصيات ژئوشيميايي و كاني شناسي گرد و غبار اتمسفري اصفهان

چكيده انگليسي :

Geochemical and mineralogical properties of atmospheric dust in Isfahan Zohre Mahmoodi z mahmoodi@ag iut ac ir Feb 18 2012 Department of Soil Science Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Hossein Khademi hkhademi@cc iut ac irAbstractDust is widely distributed in the environment and has fundamental impact on terrestrial ecosystems Dustdeposition is important from environmental and soil fertility points of view and plays a major role in loessformation and geomorphic processes in arid and semiarid regions Due to the great distribution potentialof dust particles in the environment heavy metals bound to dust particles are easily and widely dispersedin large areas This is why too many studies have been focused on heavy metal concentration inatmospheric dust Isfahan province is an important arid to semiarid area in Iran where natural andindustrially derived dust deposition is an issue To study the properties of deposited dust in the Isfahanarea 36 locations distributed over the cities of Isfahan Khomeinishahr Falavarjan Zarinshahr andMobarakeh were randomly chosen Dust samples were taken from all the locations for a period of 5months The dust sampler was a 2 m2 dry glass tray with a 2x2 mm mesh PVC net fixed on the top Ineach location the dust samplers were placed at the roof of the building about 3 m above the ground Intotal 144 dust samples trapped in 4 different periods were collected The main objectives of this studywere i to evaluate the rate of dust deposition ii to determine physic chemical and mineralogicalproperties of dust iii to determine the concentration of major heavy metals in dust iv to use magneticsusceptibility measurement to predict heavy metal pollution in dust and v to recognize the possiblesource s of dust deposition in the Isfahan region The study area was subdivided into 3 areas including 1 Isfahan an urban area with a heavy traffic 2 Mobarakeh and Zarinshahr an industrial area and 3 Falavarjan and Khomeinishahr an urban area with a low traffic The dust deposition rate DDR wasmeasured in all the locations The concentration of Fe Mn Pb Ni Cu Co Cr Zn and Cd as well as themagnetic susceptibility chemical properties particle size distribution and clay mineralogy of the dustsamples were determined The maximum and minimum DDR were found in October and November December periods respectively The mean DDR decreased with altitude significantly The results alsoshowed that the concentration of all the heavy metals was highest in Nov Dec period when an inversiontemperature event prevailed in the area The highest level of Fe and Mn was found in the dust samplesfrom the industrial locations Mobarakeh and Zarinshahr while the highest Cu and Ni level was found inthe Isfahan city and the maximum Zn Pb and Cd in the urban area having low traffic Both Cr and Co didnot show significant spatial variability The highest concentration of heavy metal followed the order ofFe Mn Zn Pb Ni Cu Co Cr Cd The magnetic susceptibility at both low and highfrequencies were highest in the industrial area during the period of Nov Dec and were well correlatedwith Fe and Mn contents of the dust samples The value of fd was also found minimum in theindustrial area indicating that the atmospheric dust is very much influenced by human activities Themean EC value of the dust samples was 5 6 dS m 1 and was highly affected by the Na concentration This

محمودي، زهره

بررسي خصوصيات ژئوشيميايي و كاني شناسي گرد و غبار اتمسفري اصفهان

نرخ فرونشست , فلزات سنگين , كاني شناسي , خصوصيات شيميايي