Statistical Analysis of Accumulation and Sources of Heavy Metals Occurrence in Agricultural Soils of Khoshk River Banks, Shiraz, Iran

Abstract

In this study, selected statistical methods (Discriminant analysis, ANOVA, Correlation analysis and Principal component analysis) were used to determine the heavy metal accumulation and its controlling factor and to identify the origin of these metals in soil samples collected from two sites along the Khoshk River banks, Shiraz, Iran. For this purpose, 40 topsoil samples were collected and the levels of Pb, Zn, Cr, Cd, Ni, Cu and alkaline metals (K, Mg and Ca) along with pH and organic matter content were determined in each sample. Discriminant analysis revealed that two investigated sites are different in terms of heavy metal accumulation. From the ANOVA and correlation analysis, it was found that soil organic matter is the most important factor controlling the distribution of heavy metals. Principal component analysis extracted two major components: PC1 with high loading of Pb, Ni, Cr and OM is suggested to be the result of wastewater irrigation at site A and PC2 with contribution of Zn and Cu probably due to extensive use of organic fertilizers and/or solid manure. This study concludes that statistical analysis can provide a scientific basis for monitoring the heavy metal accumulation in soil and for controlling the future soil contamination posed by human activities.