توزيع مكاني كروم، كبالت و نيكل در خاك سطحي و تجمع آنها در تعدادي از محصولات زراعي استان همدان

چكيده انگليسي :

117 Spatial Distribution of Chromium Cobalt and Nickel in Surface Soil and Their Accumulation in Some Crops of Hamadan Province Soheila Barati Email address barati iut@yahoo com Date of Submission 2011 3 8 Department of Natural Resources Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisors Dr N Mirghafari mnorolah@cc iut ac ir Dr A Soffianian shahedim@cc iut ac irAbstract Heavy metals are very important from environmental consideration due to their toxicity andaccumulative properties Although these elements present generally at low concentrations in thesoil but the increase of their concentration either naturally or through human activity pose thedivers problems The heavy metals accumulate mostly in the surface soil and thus exposure moreto plant uptake and transport The understanding of the spatial variation of heavy metals in the soilis an important precondition for monitoring and evaluating eco environment quality in theagricultural lands The aim of this study is the evaluation of spatial distribution of Cr Co and Ni inthe surface soil of Hamadan province determination of the accumulation of these metals in thesome crops and assessment of health risks from heavy metals in wheat and potato For thispurpose the surface soil samples 0 20 cm were taken using systematic random sampling methodand the concentration of heavy metals and some soil parameters such as pH EC the percentage oforganic matter sand clay and silt were analyzed The soil sampling points located on agriculturallands were determined using satellite images and potato wheat barely alfalfa and corn weresampled For interpolation and mapping the spatial distribution of heavy metals the accuracy ofKriging methods and their models were compared by the Mean Absolute Error MAE values andMean Bias Error MBE and the method with lowest error was selected Maps of chromium andnickel distribution were prepared by ordinary Kriging with a Spherical model and that of cobalt bydisjanctive Kriging with Exponential model The regions of the western Hamedan province had thehighest concentration of chromium cobalt and nickel The accordance of the maps with the highestconcentration and igneous and metamorphic bedrock showed that the geology is the most importantfactor affecting the concentration of these elements The mean concentration of the studiedelements in the province of Hamedan except for nickel was in the range of maximum acceptableconcentration for agricultural land Background concentrations of chromium and cobaltcorresponded to the world mean The assessment of soil contamination using GeoaccumulationIndex Igeo based on the mean background concentration in the study area as well as the averageconcentration in the earth crust classified the contamination as low to negligible in the region Onthe other hand due to consistency of the areas with high concentrations of the elements withagricultural landuse the Integrated Pollution Index IPI indicated that agricultural activities couldalso increase the concentration of these elements in the soils The mean concentration of theelements in crops except for chromium and nickel in alfalfa was in the normal range of plants The Bioconcentration Facor BCF of the elements in plants was low and the highest factorobtained in the alfalfa plant The health risks potential from each elements in the potato and wheatcalculated by Hazard Qoantient HQ showed no risk to human However the calculation ofHazard Index HI showed the health risks potential from a combination of three elements in wheatplants Key words Hamadan Province Soil pollution Kriging Crops Health risk Heavy metals

براتي، سهيلا

توزيع مكاني كروم، كبالت و نيكل در خاك سطحي و تجمع آنها در تعدادي از محصولات زراعي استان همدان

آلودگي خاك , كريجينگ , ريسك سلامتي , فلزات سنگين