Improvement of Spatial Modeling of Cr, Pb, Cd, As and Ni in Soil Based on Portable X-ray Fluorescence (PXRF) and Geostatistics: A Case Study in East China.

Xia Xia,Hu Hu,Shi Shi,Shao Shao,Li Li,Chen Chen,Zhou Zhou,Xu Xu,Huang Huang

doi:10.3390/ijerph16152694

Abstract

To verify the feasibility of portable X-ray fluorescence (PXRF) for rapidly analyzing, assessing and improving soil heavy metals mapping, 351 samples were collected from Fuyang District, Hangzhou City, in eastern China. Ordinary kriging (OK) and co-ordinary kriging (COK) combined with PXRF measurements were used to explore spatial patterns of heavy metals content in the soil. The Getis-Ord index was calculated to discern hot spots of heavy metals. Finally, multi-variable indicator kriging was conducted to obtain a map of multi-heavy metals pollution. The results indicated Cd is the primary pollution element in Fuyang, followed by As and Pb. Application of PXRF measurements as covariates in COK improved model accuracy, especially for Pb and Cd. Heavy metals pollution hot spots were mainly detected in northern Fuyang and plains along the Fuchun River in southern Fuyang because of mining, industrial and traffic activities, and irrigation with polluted water. Area with high risk of multi-heavy metals pollution mainly distributed in plain along the Fuchun River and the eastern Fuyang. These findings certified the feasibility of using PXRF as an efficient and reliable method for soil heavy metals pollution assessment and mapping, which could contribute to reduce the cost of surveys and pollution remediation.

Highlights

Soil is critical to many ecosystem functions, and soil degradation and pollution have gained a great deal of attention worldwide [1,2,3,4,5,6]
Soil pollution has become especially serious in China as a result of the rapid urbanization and industrialization that has occurred in the last several decades [13,14]
Soil heavy metals are measured by several analysis methods conducted in the laboratory, including atomic absorption spectrophotometry (AAS), atomic fluorescence spectrometry

Summary

Introduction

Soil is critical to many ecosystem functions, and soil degradation and pollution have gained a great deal of attention worldwide [1,2,3,4,5,6]. Contaminated soils can pose serious threats to human health through a variety of pathways including diet, inhalation and dermal contact [7,8,9,10,11,12]. Soil pollution has become especially serious in China as a result of the rapid urbanization and industrialization that has occurred in the last several decades [13,14]. A national survey report issued by the Ministry of Natural Resources and the Ministry of Ecology and Environment of the People’s Republic of China in 2014 revealed that the proportion of heavy metals contaminated soil samples in China was 16.1% [15]. Soil heavy metals are measured by several analysis methods conducted in the laboratory, including atomic absorption spectrophotometry (AAS), atomic fluorescence spectrometry. Public Health 2019, 16, 2694; doi:10.3390/ijerph16152694 www.mdpi.com/journal/ijerph

Methods

Results

Conclusion