Application of Geostatistical Analysis and Random Forest for Source Analysis and Human Health Risk Assessment of Potentially Toxic Elements (PTEs) in Arable Land Soil

Liang Xiao,Fei Wu,Yu-Jie Liu,Ke Li,Yang Tian,He Huang,Meng-Yao Li,Yong Zhou

doi:10.3390/ijerph17249296

Abstract

Arable land soil is one of the most precious natural resources of Earth, it provides the fundamental material and numerous resources essential for the development of human society. To determine the pollution of potential toxic factors in the surface soil of cultivated land and its risks to human health, concentrations of five different potentially toxic elements (PTEs) were detected in 1109 soil samples collected in Xiangzhou, China, in 2019. In this study, health risk assessment was used to judge the degree of pollution in the study area, the result of Geographic Information System (GIS) was as used to research the spatial distribution characteristics of PTEs, and random forest (RF) was used to assess the natural and man-made influencing factors. We investigated the sources of PTEs through quantifying the indicators, which gave further insights. The main results are: (1) In arable land soil, the average content of PTEs is 0.14 mg/kg cadmium (Cd), 0.05 mg/kg mercury (Hg), 12.89 mg/kg arsenic (As), 29.23 mg/kg lead (Pb), and 78.58 mg/kg chromium (Cr), respectively. The content of As and Pb outpaced the background value of Hubei soil. (2) The human health risk assessment in Xiangzhou indicates that the most important exposure pathway is soil ingestion, occupied about 99% to health risks of PTEs; non-carcinogenic risk from exposure to As, Pb and Cr in soil was higher than the limit (overall potential risk index, HI > 1) for both children and adults. Moreover, carcinogenic risk postured by Cd, Cr, and As was higher than the limit (10−4) through soil exposure for both children and adults, indicating that Cd, As, Pb and Cr in soil have significant effect on people’s health through exposure. (3) We found that the increased PTEs in the arable land soil mainly originated from potential water sources, air and soil pollution sources, breeding farms, and mining areas.

Highlights

Arable land soil is fundamental to the survival of animals and plants, representing an important resource and basic element for human survival and development as well as being an important part of the terrestrial ecosystem [1]
The spatial variation scale of potentially toxic elements (PTEs) can be used as an important basis pollution
PTEs can be used as an important basis for judging for judging the source of each PTEs: the spatial variation scale caused by natural factors is relatively large,ofand thePTEs: humanthe contribution is mainly reflected in the of small and spaces the source each spatial variation scale caused by scale natural factors ismedium relatively large, and the Figure 4 shows that the spatial distribution

Summary

Introduction

Arable land soil is fundamental to the survival of animals and plants, representing an important resource and basic element for human survival and development as well as being an important part of the terrestrial ecosystem [1]. Hg, As, Pb, and Cr are five common potentially toxic elements (PTEs) in arable land [2]. When PTEs accumulate in the arable land soil in considerable amounts, leading to a decrease in the quality of the crops and inhibit the life activities of organisms, and pass through the food chain to enter animals and humans, and enter through exposure pathways such as skin contact and inhalation, posing a huge menace to food safety and human health [3]. Res. Public Health 2020, 17, 9296; doi:10.3390/ijerph17249296 www.mdpi.com/journal/ijerph

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