Calculating and mapping soil heavy metal levels using CLS methodology

摘要

In this paper, soil heavy metal levels were calculated and mapped using CLS (Cumulative Limitation Scores) methodology. The procedure is based on interpolation heavy metal concentrations using numerous environmental predictors, followed by representing cumulative soil polution by limitation scores. The method was applied to an area of urban and peri-urhan agricultural land with the aims of (i) determinating spatial variability and main anthropogenic sources of soil heavy metals; and (ii) identifing the areas of special concern by mapping the cumulative soil contamination by heavy metals. The data on topsoil (0-20cm) Cd, Cr, Cu, Ni, Pb and Zn aqua regia extractable concentrations were used. Statistical and spatial analysis tools were utilised in order to combine the quantitative information obtained from the chemical analysis of the soil samples with the area-specific qualitative irrformation. For spatial interpolation of heavy metals the regression block kriging was applied. Statistical analysis of interpolated maps confirmed that all studied heavy metals were correlated with correlation coefficient (r) ranging from 0.24 to 0.72. This study was shown that in the Zagreb region, 7.2% of the total area is critically polluted by one or more heavy metals. The procedure is suitable in many decision situations, especially for making decisions about soil remediation, health risk assessment or contaminated land management in general.