Z. Mahmoodi, H. Khademi ,
Volume 18, Issue 67 (6-2014)
Abstract
Atmospheric dust is an important source of heavy metals, particularly in urban environments. Heavy metals can easily attach to dust particles and be distributed in large areas. The objective of this study was to evaluate the status of major heavy metals in the atmospheric dust of Isfahan and adjacent cities. A total of 144 dust samples were taken during a period from August to December 2010 from Isfahan, Khomeynishahr, Falavarjan, Mobarake and Zarinshahr cities. Dust samples were extracted with HNO3 65% and the total concentration of metals including Pb, Zn, Cd, Cu, Ni, Co, Cr and Mn in the samples was measured by an atomic absorption spectrometer. The mean concentration of these metals was 223.5, 470.3, 3.5, 71.0, 82.0, 26.5, 24.4 and 426.3 mg kg-1, respectively. Results indicated that heavy metals concentration in any area was different depending on the source of pollution and it was much higher than the mean concentration of the corresponding heavy metal in soils. Besides, the highest deposition rate of all the heavy metals in this study was found in November-December period. This could be attributed to an increase in the use of heating systems and also to a temperature inversion event prevailed in the area. Atmospheric deposition seems to be an important pathway of heavy metals addition to soils. For example, it is responsible for 35-91% and 12-47% of Pb and Cd entering the soil in the area, respectively.
F. Jafari, H. Khademi,
Volume 18, Issue 70 (3-2015)
Abstract
Dust deposition occurs extensively in arid and semiarid regions of the world. Since dust particles are fine-sized, they have a high adsorption capacity and also high contamination potential. The objective of this study was to evaluate the temporal and spatial distribution of the rate of atmospheric dust deposition in different locations in Kerman urban area. Dust samples were collected monthly using glass traps installed on the roof of 35 one-story buildings in Kerman for 7 months from April 20 to Nov. 20, 2012 (a total of 245 samples). After each monthly sampling, traps were washed and dust samples transferred to the laboratory and weighed. The mean dust deposition rate of 7 months was mapped using the inverse distance weighting (IDW) approach. The wind rose of Kerman was drawn by WRPLOT 7.0.0. The results showed that the average rate of dust deposition decreased during the 7 months studied from 17.4 to 5 g/m2. month, which could be attributed to the decrease in wind velocity. The spatial distribution of the samples also showed that the dust deposition rate varied from 4.84 in the southern parts to 14.84 g/m2.month, mostly in the northern locations of the city. The wind rose based on the average wind speed of the 7 months of sampling indicated the prevailing wind blows from north, northeast and northwest and the dust spatial distribution well follows the wind direction. In general, the rate of dust deposition in Kerman city is high and therefore, the source of dust has to be well detected and proper management practices are necessary.
