تحليل و پايش مكاني برخي فلزات سنگين در خاك سطحي بخشي از استان مازندران

چكيده انگليسي :

Spatial analysis and environmental assessment of selected heavy metals in surface soils of Mazandaran Province Iran Behrooz Azimzadeh Ismaili Kandi b azimzadeh@gmail com Date of Submission January 13 2013 Department of Soil Science College of Agriculture Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Dr Hossein Khademi E mail hkhademi@cc iut ac ir Abstract Due to rapid growth population industrialization and the degradation of natural resources as a result of today s human activities environmental hazards such as soil pollution by heavy metals have attracted many researchers attention Considering the lack of information about the distribution pattern of heavy metals concentration in soils of Mazandaran Provience this study was carried out in 5500 km2 area of central Mazandaran The main objectives of this study were i to determine the spatial variability and environmental assessment of selected heavy metals concentration including copper Cu zinc Zn nickel Ni lead Pb and cadmium Cd and ii to specify the contribution of controlling factors Using nested classification method 256 composite soil samples were taken from the depth of 0 10 cm including 148 60 and 48 soil samples in agricultural land use paddy field non paddy field and citrus gardens urban area and natural land use forest and rangeland respectively To investigate the vertical distribution of heavy metals and also to distinguishe the effecte of pedogenic lithogenic and biological processes on soil heavy metals 12 soil profiles occurring on dominant parent materials and land uses were also examined Also parent rock samples were collected to determine the concentration of selected elements After preparation and extraction of soil and rock samples with 5 N nitric acid the total concentration of selected heavy metals was measured by an atomic absorption spectrometer Also selected soil chemical and physical properties including pH cation exchange capacity organic matter calcium carbonate equivalent sand silt and clay were also determined to determinethe relationships between heavy metals and soil properties Spatial analysis and horizontal distribution of heavy metals were studied using semivariogram models and interpolation methods such as kriging and co kriging Environmental assessments and recognition of polluted area were carried out using natural background concentration NBC and the criteria such as contamination factor CF and pollution load index PLI The results showed that land use has had significant effect p 0 05 on heavy metals concentration Pb and Zn have highest concentration in urban area whereas Ni and Cd have shown lowest concentration in such area and their concentration may have been affected by parent materials Also Cu may have been affected by both natural and human activities and their high concentration was found in urban areas citrus gardens and rangelands The results showed that vertical distribution of heavy metals is variable depending on parent rock land use and the stage of soil developments Four controlling factors including lithogenic pedogenic phytopedogenic and anthropogenic were identified Spatial distribution of Pb and Zn is well correlated with anthropogenic factor such as traffic and urban development and their highest concentration have been found in urban and residential soils The spatial pattern of Ni and Cd concentrations has been mainly influenced by lithogenic factor Also spatial distribution of Cu is an indication of mutual influence of lithogenic and anthropogenic factors The results of multivariate analysis and correlation between heavy metals well support the results of spatial analysis study Evaluation of interpolation methods showed that co kriging has lower estimation error as compared to kriging because it uses cost effective auxiliary variables such as magnetic parameters remote sensing data and urban position of samples Based on the CF classes most samples 53 84 are moderately

عظيم زاده اسمعيلي كندي، بهروز

تحليل و پايش مكاني برخي فلزات سنگين در خاك سطحي بخشي از استان مازندران

غلظت زمينه , كريجينگ , كوكريجينگ , عامل انسان زاد , عامل زمين زاد