چکیده:
This paper presents a survey on soil Pb concentration around Sepahanshahr town located in vicinity of Isfahan. Due to the lack of regulation and environmental education and awareness, Sepahanshahr is now a rapid growing residential area suffering from the considerable consequences of poorly regulated mining activities operating in its vicinity. The aim of this study is to explore the spatial structure of Pb distribution and to map Pb pollution using geostatistical techniques. 100
near-surface soil samples were collected and analyzed for Pb and some other related soil physical and chemical variables such as pH, organic matter content, electrical conductivity, clay, silt and sand contents. The variography results show a strong spatial dependency in Pb data due to the dilution effects of natural factors including atmospheric dispersion and precipitation. The almost same range values calculated for both Ln-transformed Pb data and sand content suggest presence
of co-regionalization. Kriged Pb map shows a strong gradient of Pb concentration around the three mining sites activating in the area. The results of this study provide insight into identification of the extent and the spatial variability of Pb pollution in the mining sites and surrounding area.
خلاصه ماشینی:
The results of this study provide insight into identification of the extent and the spatial variability of Pb pollution in the mining sites and surrounding area.
The major sources of lead pollution in urban environments are exhaust emission from petrol vehicles, mining, smelting and foundry activities, and application of sewage sludge to agricultural soils (Hooker and Nathanail, 2006).
Mean values reported for background concentrations were 10 mg/kgThe exponential model is: (Alloway, 1995);15 mg/kg (Page and Chang, 1993); 2 to 44 mg/kg (Kabata-Pendias and h h C0 C 1 exp a The Gaussian model is: h 2 h C0 C 1 exp a 2 Where C0 is the nugget variance (h=0), represents the experimental error and field variation within the minimum sampling spacing.
Acquired simple correlation coefficients (Pearson coefficient) between Ln-transformed Pb data and other physical and chemical soil variables indicated that there is only (linear) correlation between Pb concentrations and sand content (p<0.
The kriged map showes the spatial variation of soil lead estimates.
The kriged map of Pb clearly shows high Pb concentrations in vicinity of mining sites with a decreasing gradient from south to northern parts of the study area.
Kriged map of soil-Pb concentration in the study area Pb (mg/Kg) 2.
Conclusion In this study, a geostatistical approach was adopted to analyzing and interpreting the near- surface soil Pb concentration data and other related soil chemical and physical variables collected around Sepahanshahr town, Isfahan.