Spatial Characteristics, Health Risk Assessment and Sustainable Management of Heavy Metals and Metalloids in Soils from Central China

Fei Li,Ying Cai,Jingdong Zhang

doi:10.3390/su10010091

Abstract

The contents of seven toxic metals (Cu, Cr, Cd, Zn, Pb, Hg and As) in soils from Central China, including Henan Province, Hubei Province and Hunan Province, were collected from published papers from 2007 to 2017. The geoaccumulation index, health risk assessment model and statistics were adopted to study the spatial contamination pattern, to assess the human health risks and to identify the priority control pollutants. The concentrations of soil metals in Central China, especially Cd (1.31 mg/kg), Pb (44.43 mg/kg) and Hg (0.19 mg/kg), surpassed their corresponding background values, and the Igeo values of Cd and Hg varied the most, ranging from the unpolluted level to the extremely polluted level. The concentrations of toxic metals were higher in the southern and northern parts of Central China, contrasting to the lowest contents in the middle parts. For non-carcinogenic risk, the hazard index (HI) values for the children in Hubei Province (1.10) and Hunan Province (1.41) exceeded the safe level of one, with higher health risks to children than adults, and the hazard quotient (HQ) values of the three exposure pathways for both children and adults in Central China decreased in the following order: ingestion > dermal contact > inhalation. For carcinogenic risk (CR), the CR values for children in Hubei Province (2.55 × 10−4), Hunan Province (3.44 × 10−4) and Henan Province (1.69 × 10−4), and the CR for adults in Hubei Province (3.67 × 10−5), Hunan Province (4.92 × 10−5) and Henan Province (2.45 × 10−5) exceeded the unacceptable level (10−4) and acceptable level (10−6), respectively. Arsenic (As) appeared to be the main metalloid for both children and adults causing the high carcinogenic risk. For sustainable development in Central China, special attention should be paid to Cd, Hg, Cr, Pb and As, identified as the priority control soil metals. Importance should also be attached to public education, source control, and the remediation of the highly contaminated soils, especially in the areas where it can endanger the groundwater. Furthermore, it is necessary to appropriately adjust the industrial structure and cooperate more to form a complete economic zone.

Highlights

Toxic metals and their compounds are naturally ubiquitous throughout the soil environment; they are highly toxic and do not decompose [1,2,3]
To investigate soil pollution status in Central China and to provide important information for soil pollution management, this study aims to (i) collect heavy metal and metalloid concentrations, (ii) survey their spatial distribution, (iii) assess the pollution level of heavy metals and metalloids using a geoaccumulation index, (iv) evaluate the health risks, (v) identify the priority control metals and areas, and (vi) provide sustainable management suggestions to Central China
The results showed that the mean concentrations of all soil metals were lower than their corresponding class II values, except Cd, which was 2.18 times greater than its corresponding class II value

Summary

Introduction

Toxic metals and their compounds are naturally ubiquitous throughout the soil environment; they are highly toxic and do not decompose [1,2,3]. The toxic metal contents in soils has greatly increased through anthropogenic toxic metal inputs, including dumping wastes, waste incineration, vehicle emissions, smelting, smokestack emissions, fertilizer application and sewage sludge production [17,18,19]. Due to their potential toxic, persistent and irreversible characteristics, toxic metals such as Cd, Cr, As, Hg, Pb, Cu, Zn and Ni, have been listed as priority control pollutants by the United States Environmental Protection Agency (USEPA) and caused more and more attention in many parts of the world [20,21,22]

Objectives

Methods

Results

Conclusion