INTRODUCTION Accumulation of heavy metals in arable soils is important because of the potential transfer of heavy metals through crops to animals (feed crops) and humans (food crops and vege- tables) 1 . To this respect Cd, Cu, Co, Ni and Pb are important elements, not only because of the long term accumulation in humans but also because of the high potential for root uptake and accumulation in above ground plant parts. Some soil physico-chemical conditions such as pH, organic matter and lime content, texture play a very important role in toxicity of heavy metal in the soil 2 . Physical and chemical soil properties may depend on several factors, both natural and anthropogenic ones, jointly acting over different spatial and temporal scales. Natural pedological processes (e.g., rock weathering and organic matter decomposition) are related to parent material, geomorphology of the area, presence of vegetation, the climate conditions and other interactions with the environment 3 . In addition, anthropogenic sources of heavy metal contamination are mainly combustion processes in industry, transportation and waste water from industrial processes. Moreover, mining activities for extraction and manufacturing of metal products and long-term and extensive use of agricultural land with frequent application of pesticides may result in a large amount Application of Geostatistical Methods to Heavy Metals Status in Çarsamba Plain Soils MUSTAFA SAGLAM 1 , ORHAN DENGIZ 1,* , MEHMET ARIF ÖZYAZICI 2 and RIDVAN KIZILKAYA 1 1 Department of Soil Science, Ondokuz Mayis University, Faculty of Agriculture, Samsun, Turkey 2 Soil and Water Resources Research Institute, Samsun, Turkey *Corresponding author: Fax: +90 362 4576034; Tel: +90 362 3121919/1463; E-mail: odengiz@omu.edu.tr Asian Journal of Chemistry; Vol. 23, No. 8 (2011), 3454-3460 (Received: 14 September 2010; Accepted: 20 April 2011) AJC-9825 The understanding of the spatial variability of soil heavy metals is an important precondition for potential contamination risk and evaluating eco-environment quality in a primary arable soil. To date, little research on soil pollution in Çarsamba delta plain has been conducted. To identify the concentrations and sources of heavy metals, 174 soil samples (0-20 cm) were collected from the study area. Subsequently, the concentrations of Cd, Co, Cu, Ni, Pb and Zn in the samples were analyzed. In order to evaluate natural or anthropogenic sources of heavy metal content and their spatial distribution in agricultural fields of Çarsamba delta plain and near district soil, statistics, geostatistics and geographic information system (GIS) were used. GIS technology was employed to produce spatial distribution maps of the 6 elements. The results showed that the concentration of Ni exceeded its threshold level. The local pollution from Ni was attributed to the natural and anthropogenic influences. The concentrations of the other heavy metals are relatively lower than the critical values. The mean values of the heavy metal contents arranged in the following decreasing order: Ni > Zn > Cu > Co > Pb > Cd in the study area. In some regions of the study area, the Cd, Cu and Zn contents were also slightly raised, possibly due to excessive P fertilization and field traffic. Key Words: Soil pollution, Spatial distribution, Çarsamba delta plain. of pollutants to be released into the atmosphere and, secondly, in the adjoining soils and waters 4 . Therefore, natural factor and human activity are both important in determining the complex spatial variability of heavy metal concentrations in soil 5 . A soil pollution assessment becomes very difficult when different sources of contamination are present and their products are variably distributed. In these cases, geostatistical application of the heavy metal concentrations in soils has vital role for risk assessment, soil remediation, as well as effective management recommendations and widely applied in soil since 1980. Prediction methods to reliably estimate heavy metal distribution in space and time should be based on spatial vari- ability of soil properties. Geostatistical methods that are based on the theory of regionalized variables 6-8 can provide reliable estimates at the unsampled locations provided that the samp- ling interval resolves the variation at the level of interest 9 . Recently, the kriging interpolation method has been used increasingly in spatial distribution of heavy metals by many researchers 10-12 . The spatial variability of soil heavy metals is an important part of environmental supervision and ecosystem evaluation 13 . The main objective of this study is to determine contents of heavy metal status and physico-chemical properties of soil using statistics, geostatistics and geographical information