An integrated approach for spatial distribution of potentially toxic elements (Cu, Pb and Zn) in topsoil

Azadeh Vaziri,Ahad Nazarpour,Teimor Babainejad,Navid Ghanavati,Michael J Watts

doi:10.1038/s41598-021-86937-1

Abstract

In this study, statistical analysis and spatial distribution were performed to compare raw data and centred log-ratio (clr) transformed data of three copper (Cu), lead (Pb), and zinc (Zn) potentially toxic elements (PTEs) concentration for 550 surface soil samples in Khuzestan plain. The results of both approaches showed that classical univariate analysis and compositional data analysis are essential to find the real structure of data and clarify its different aspects. Results also indicated that spatial distributions of raw data and clr-transformed data were completely different in three studied metals. Raw data necessarily shows the effects of anthropogenic activities and needs an additional evaluation of human health risk assessment for these three studied elements. Data obtained from clr-coefficient maps also demonstrated the role of geological processes in the distribution pattern of potentially toxic elements (PTEs). To improve the understanding of the implications for PTE pollution and consequences for human health, a RGB colour composite map was produce to identify the potential origin of PTEs from areas with higher than typical baseline concentrations.

Highlights

In this study, statistical analysis and spatial distribution were performed to compare raw data and centred log-ratio transformed data of three copper (Cu), lead (Pb), and zinc (Zn) potentially toxic elements (PTEs) concentration for 550 surface soil samples in Khuzestan plain
A geostatistical approach can help to identify contamination sources and the spatial distribution of PTEs in the environment[29,30,31]. These techniques are ideal for the evaluation of interactions between PTEs released to the environment and recipient environment based on the spatial information of pollution distribution sources, processes affecting pollutants distribution and population density[32,33,34]
Studies on PTE concentrations in soil from the Khuzestan plain of Iran have included a limited pollution level assessment by classic statistical procedures and statistical methods such as the cumulative probability and box plot and map analysis based on log-transformation[41,42,43]

Summary

Introduction

Statistical analysis and spatial distribution were performed to compare raw data and centred log-ratio (clr) transformed data of three copper (Cu), lead (Pb), and zinc (Zn) potentially toxic elements (PTEs) concentration for 550 surface soil samples in Khuzestan plain. The results of both approaches showed that classical univariate analysis and compositional data analysis are essential to find the real structure of data and clarify its different aspects. Studies on PTE concentrations in soil from the Khuzestan plain of Iran have included a limited pollution level assessment by classic statistical procedures and statistical methods such as the cumulative probability and box plot and map analysis based on log-transformation[41,42,43]

Objectives

Methods

Results

Discussion

Conclusion