Next Article in Journal
Impact of Infrastructure and Production Processes on Rioja Wine Supply Chain Performance
Next Article in Special Issue
A 10-Year Statistical Analysis of Heavy Metals in River and Sediment in Hengyang Segment, Xiangjiang River Basin, China
Previous Article in Journal
Study on Adaptive-Passive and Semi-Active Eddy Current Tuned Mass Damper with Variable Damping
Previous Article in Special Issue
Non-Competitive and Competitive Adsorption of Pb2+, Cd2+ and Zn2+ Ions onto SDS in Process of Micellar-Enhanced Ultrafiltration
 
 
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Review

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

1
Research Center for Environment and Health, Zhongnan University of Economics and Law, Wuhan 430073, China
2
School of Information and Safety Engineering, Zhongnan University of Economics and Law, Wuhan 430073, China
*
Author to whom correspondence should be addressed.
Sustainability 2018, 10(1), 91; https://doi.org/10.3390/su10010091
Submission received: 10 November 2017 / Revised: 19 December 2017 / Accepted: 28 December 2017 / Published: 4 January 2018

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.

1. Introduction

Toxic metals and their compounds are naturally ubiquitous throughout the soil environment; they are highly toxic and do not easily decompose [1,2,3]. Heavy metals and metalloids that accumulate in the soil can inhibit soil function, poison plants and contaminate the food chain [4,5,6]. When heavy metals and metalloids have been transported from the soil to other environmental media, such as groundwater or crops, they can pose a threat to human health as a consequence of inhalation or ingestion through the water supply and food chain [7,8,9,10,11,12,13]. In addition, direct oral intake of soil particles by humans, particularly children, also poses a health hazard [14,15,16]. As natural components of the Earth’s crust, heavy metals and metalloids are generally present at low concentrations in natural soils. However, 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].
In China, soil contamination by toxic metals has been ubiquitous and serious due to the rapid industrial development and fast urban expansion, with 10 million m2 land and 12 million tons of grains polluted [23,24,25,26,27]. The literature investigating soil metals is growing more and more, and soil contamination has been found in every piece of land in the motherland, like Beijing [28], Shanghai [29], Wuhan [30], Changsha [31]. Most of the existing studies selected a smaller area as the research object, such as a city [32], or even a district [33], and little information is available for whole provinces, not to mention a whole region. Central China is one of the seven geographical divisions in China, including Henan Province, Hubei Province and Hunan Province. Central China has witnessed rapid economic growth, with a gross domestic product (GDP) of RMB 10,370.262 billion in 2016. A representative of the National Development and Reform Commission summed up the key to the rise of the Central China plan as needing to pay attention to solving two problems: the food problem and the issue of environmental protection. It is a pity that environmental problems have not been solved yet, especially soil contamination. In 2006, a sensational soil pollution incident broke out in Hubei Province, with the revelation that over 70% of the area in Heshan Block was polluted and the total amount of earthworks polluted reached about 300,000 cubic meters, with the main pollutants being organic phosphorus and organochlorine pesticides, namely DDT (Clofenotane) and BHC (Benzene hexachloride). In May 2013, it caused a sensation that a large quantity of poisonous rice containing cadmium produced in Hunan was found in Guangdong, China. In recent years, cadmium wheat events occurred frequently in Xinxiang, Henan Province. Therefore, it is of significant importance to systematically study contamination features and the health risks of soil metals in Central China for sustainable green development.
The region of Central China has a long history and strong cultural heritage, and rich mineral and industrial resources, which accounts for the soil metal pollution. 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.

2. Materials and Methods

2.1. Study Area

The region of Central China is located in the central and middle reaches of the Yellow River and the middle reaches of the Yangtze River region, which is one of China’s seven major geographical divisions, including Henan, Hubei and Hunan Provinces, as shown in Figure 1. It has a population of approximately 222 million, within an area of 560,000 square kilometers, accounting for about 5.9% of the total land area. It belongs to a temperate monsoon climate and subtropical monsoon climate zone and its annual average temperature is 15–21 °C. It has strong history and culture, rich mineral resources, a strong industrial base, and convenient water and land transportation. Central China is a slightly more economically developed area, the heart of China’s industry, agriculture and transportation. In 2016, Central China had a GDP of RMB 10,070.262 billion, with Henan, Hubei and Hunan Provinces having a GDP of RMB 4016.001, 3229.791, and 3124.470 billion, respectively. The industrial structure ratio of three kinds of industry—agriculture, industries and services—is 10.7:47.4:41.9 in Henan Province, 10.8:44.5:44.7 in Hubei Province, 11.5:42.2:46.3 in Hunan Province, respectively.

2.2. Data Collection and Processing

This study collected published papers on heavy metal and metalloid concentrations in surface soils in Central China from 2007 to 2017, shown in Table 1, through searching “Hubei/Hunan/Henan”, “heavy metal”, “metals”, “soil” and other relevant key words in databases, such as China National Knowledge Infrastructure (CNKI, http://www.cnki.net/), Wanfang Data (http://www.wanfangdata.com.cn/), VIP (http://www.cqvip.com/), Web of Science (http://login.webofknowledge.com/), Science Direct (https://www.elsevier.com/solutions/sciencedirect), and Baidu Scholar (http://xueshu.baidu.com/). According to the principles of literature screening—for example that the literature is not repeated, the literature data is from a field measurement, the sampling location is clear, the number of samples can be verified, and the detection of heavy metal content is accurate—the search collected a total of 85 papers in 35 cities—specifically 11 cities in Henan Province, 16 cities in Hubei Province, and eight cities in Hunan Province—which covered 105,402 effective data. Seven heavy metals and metalloids—Cu, Cr, Cd, Zn, Pb, Hg and As—were collected in this study.
The sampling sites of the literature mostly adopted an “S” shape, plum blossom point method with random sampling and sampled the surface soil (0–20 cm) with a multi-point mixture. The samples were naturally air dried in the laboratory, acid digested after sieving, and the contents of toxic metal elements were almost always obtained by the same method, including atomic absorption spectrometer (AAS), atomic fluorescence spectrometer (AFS) and inductively coupled plasma mass spectrometry (ICP-MS). In order to control the unexpected uncertainty in the data collection and processing, the data were mostly detected by the recommended methods in the national standard (GB 15618-1995). As for Cu, Cr, Cd, Zn and Pb, data obtained by AAS and ICP-MS accounted for 66.7% and 30.4% respectively, and as for Hg and As, data obtained by AFS accounted for 65.5%. From the collected literature, the minimum data we collected were greater than the maximum instrument detection limits. The instrument detection limit of AAS and ICP-MS were 0.001 ng/mL (AAS) and 0.04 ng/mL (ICP-MS) for Cu, 0.001 ng/mL (AAS) and 0.04 ng/mL (ICP-MS) for Cr, 0.0003 ng/mL (AAS) and 0.012 ng/mL (ICP-MS) for Cd, 0.0001 ng/mL (AAS) and 0.012 μg/mL (ICP-MS) for Zn, 0.005 ng/mL (AAS) and 0.01 ng/mL (ICP-MS) for Pb, respectively. The instrument detection limits of AFS and ICP-MS were 0.001 ng/mL (AAS) and 0.018 ng/mL (ICP-MS) for Hg, 0.001 ng/mL (AAS) and 0.031 ng/mL (ICP-MS) for As, respectively. The concentration ranges were 7.67–126.72 mg/kg (Cu), 2.39–176.15 mg/kg (Cr), 0.05–25.22 mg/kg (Cd), 0.47–863.58 mg/kg (Zn), 17.27–467.92 mg/kg (Pb), 0.03–41.10 mg/kg (Hg) and 6.31–74.44 mg/kg (As), respectively. The value ranges of pH and SOM were 4.69–8.52 and 2.8–72.3 mg/kg, respectively. It should be taken into account that the number of samples varies in each city, and the values of the toxic metal elements in each study area were calculated by the weighted average method. The corresponding number of toxic metals in the region was taken as the weight value multiplied by the corresponding element concentration of the toxic metal, divided by the sum of the number of samples of the toxic metal element in the region, then the value of the toxic metal element in each study area was obtained [110].

2.3. Geoaccumulation Index

The geoaccumulation index (Igeo) was put forward by Muller in the late 1960s [111], and is a geochemical criterion to evaluate pollution level in soils or sediments. It can be calculated by Equation (1).
I geo = log 2 ( Cn 1.5 Bn )
where Cn is the measured concentration of the heavy metals and metalloids in soil (mg/kg), Bn is the geochemical background value of the corresponding heavy metals and metalloids in soil (mg/kg), and the coefficient 1.5 is used to detect very small anthropogenic influences [112]. In this study, Bn refers to the background concentration of the heavy metals and metalloids in the soils of Hubei, Hunan and Henan Province [113,114,115]. According to Muller [111], the geoaccumulation index consists of seven classes. The corresponding relationships between Igeo and the pollution level are given as follows: unpolluted (Igeo ≤ 0), unpolluted to moderately polluted (0 < Igeo ≤ 1), moderately polluted (1 < Igeo ≤ 2), moderately to heavily polluted (2 < Igeo ≤ 3), heavily polluted (3 < Igeo ≤ 4), heavily to extremely polluted (4 < Igeo ≤ 5), or extremely polluted (Igeo > 5).

2.4. Health Risk Assessment

Generally, an individual is exposed to soil metals through three main pathways—ingestion, inhalation and dermal contact—so the exposure scenarios we made are the most stringent settings including all the three exposures. This may need to be adapted to local conditions, because there may be a risk factor for only one or two pathways of exposure. The methodology used in this study to calculate the exposure risks of adults or children to soil metals is based on those developed by the United States Environmental Protection Agency for health risk assessment [116,117] and the Dutch National Institute of Public Health Agency [118]. The corresponding dose received through each of the three pathways was evaluated by Equations (2)–(4) [116,117,119].
ADI ing = C × IngR × EF × ED BW × AT × 10 6
ADI inh = C × InhR × EF × ED PEF × BW × AT
ADI dermal = C × SA × AF × ABS × EF × ED BW × AT × 10 6
where ADIing, ADIinh and ADIdermal are the average daily intake from soil ingestion, inhalation and dermal contact, respectively (mg/kg·day); C is the concentration of the metal element in the soil (mg/kg); IngR and InhR are the ingestion and inhalation rate of soil, respectively (mg/day, m3/day); EF is the exposure frequency (day/year); ED is the exposure duration (year); BW is the average bodyweight of the exposed individual (kg); AT is the averaged contact time (day); PEF is the particle emission factor (m3/kg); SA is the exposed skin surface area (cm2); AF is the adherence factor (mg/m2·day); and ABS is the dermal absorption factor (unitless). Detailed information of the probabilistic parameters is provided in Table 2, and all the parameters refer to the literature [36,37,38,40], and to decrease the corresponding parameter uncertainty, the local parameters BW, SA, EXF, ED, AF, and AT included were preferentially adopted [120].
The doses calculated for each element and exposure pathway were subsequently divided by the toxicity threshold value, which is referred to as the reference dose (RfD, mg/kg·d) of a specific chemical to yield a non-carcinogenic hazard quotient (HQ), and hazard index (HI) is presented as the sum of HQ for each exposure pathway to a certain toxic metal, whereas carcinogenic risk (CR) is multiplied by the corresponding slope factor (SF, kg·d/mg) to produce a level of cancer risk [121]. They were calculated by Equations (5) and (6):
HI = HQ i = ADI i RfD i
CR = ADI i × SF i
where RfDi is the corresponding reference dose for each toxic metal and for exposure pathway i; SFi is the corresponding carcinogenic slope factor for each toxic metal and for exposure pathway I; non-carcinogenic risk is accepted when the HI value is below one; and the degree of risk increases as HI increases [117,120]. For carcinogenic risk, the exposure doses at each exposure pathway were multiplied by the SF to produce a level of cancer risk. CR represents the probability of an individual developing any type of cancer from lifetime exposure to carcinogenic hazards. The acceptable risk level for regulatory purposes is 1 × 10−6, i.e., one over one million of the population [120]. The RfD and SF values of the studied metals are shown in Table 3, which were taken from the literature [121,122,123,124,125].
Although the seven metals in this study have chronic non-carcinogenic health risks, only three metals (As, Cd and Cr) have a carcinogenic risk [126]. Among them, the carcinogen of As for all three exposure pathways was calculated in the model, whereas the carcinogenic risks for Cd and Cr were considered only through inhalation. The aggregate risk was calculated by summing the individual cancer risks across all exposure pathways [119,121].

2.5. Statistics Methods

To explore the relationship between the contents of soil metals, a correlation analysis (CA) was performed with the software package SPSS version 17.0. CA refers to the analysis of two or more variable elements with dependencies to measure the relative degree of correlation between the two variables. To make the calculated data visualization spatially, the rendering method was employed by ArcGIS 9.3. According to the concentration range, the concentrations are divided into different levels, and the different levels are rendered in corresponding colors in order to distinguish between different concentration areas. The rendering method was used to spatially analyze the distribution and induce the health risk of soil metals.

3. Results and Discussion

3.1. Overview of Concentrations of Soil Metals in Central China

Basic descriptive statistics were derived to provide a summary of the concentration of soil metals in Central China, shown in Table 1 and Table 4. The mean concentrations of all toxic metals exceeded their corresponding background values (BVs), especially for Cd, Pb and Hg, which were about 13.48, 1.71 and 2.92 times greater than their BVs, respectively. According to the current Chinese Environmental Quality Standard for Soils (GB 15618-1995), Class I was developed to protect the natural ecology of the region and to maintain the natural background of the soil quality, Class II was developed to protect agricultural production and corresponding human health, and Class III was developed to ensure the normal growth of agriculture, forestry and plants [127]. 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. Specifically, the mean concentrations of all toxic metals in three provinces surpassed their corresponding BVs, except Cr in Hubei Province and As in Henan Province. The mean concentrations of all soil metals in the three provinces were within their corresponding class II values, except Cd, which accounted for the whole situation in Central China.

3.2. Spatial Distribution Patterns of Toxic Metals in Central China

Owing to the fact that the spatial distribution of metals is a useful way to identify hotspot areas with high metal concentrations [27,128], the corresponding distribution maps were produced and are shown in Figure 2. The percentage of high Cu concentrations decreased in the order of Hunan Province > Henan Province > Hubei Province, which was similar to Cd, Zn, Pb and Hg. The high-value zones of Cd, Zn, Pb and Hg appeared in Xiangtan city, Chenzhou city and Changsha city in Hunan Province, while that of Cu appeared in Daye city in Hubei Province. The concentration of Cr as a whole was the highest in Henan Province, followed by Hunan and Hubei Province, while the concentration of As was much higher in Hunan Province than that in Hubei and Henan Province. On the whole, the concentration of toxic metals was higher in Hunan and Henan Province, the southern and northern parts of Central China, contrasting the lowest contents in the middle parts. The analysis suggested that Huangshi city, which is rich in minerals and one of the six major copper production bases in China, accounted for the high concentration of Cu. A large number of chromium salt chemical plants in Henan Province led to the high concentration of Cr. Hunan Province, known as the town of nonferrous metal and the land of non-metal, accounted for the high background value of Zn and Pb. At the same time, the economic layout of heavy chemical industry made the toxic metal pollution more severe, with the percentage of toxic metal concentration of Hg, Cd and As in the sewage in the Xiangjiang river basin was 54.5%, 37% and 14.1%, respectively, in 2007. It has been found that areas with high levels of toxic metals are generally rich in mineral resources and in industry structure. Specifically, Huangshi city, with high-value for Cu, is famous as China’s old industrial base, called the “ancient capital of bronze”. As for Jiaozuo city, with a high-value for Cr, due to the regional division of labor in the state’s macro-industrial layout and the advantages of abundant mineral resources in the region, in Jiaozuo, industry has formed a heavy-duty structural layout with prominent industrial positions for a long time. As for Chenzhou city, with high values for Zn, Pb and As, it is a famous non-ferrous metal town in the world. Now it has discovered about 110 kinds of mineral, which increased its heavy industry. As for Changsha city, with high values for Hg, it has a wide range of minerals, especially non-metallic minerals. Furthermore, Changsha is a medium-sized integrated city, with developed mining and transportation, which contributed to the high level of Hg.

3.3. Geoaccumulation Indexes of Metals

The boxplots of the geoaccumulation index (Igeo) values and the percentages of class distribution for the pollution assessment of heavy metals and metalloids are presented in Figure 3 and Table S1. The results showed that the Igeo values of Cd and Hg varied the most, ranging from the unpolluted level to the extremely polluted level. In particular, more than half of the Igeo values of Cd (62.2%) and Hg (52.6%) were higher than zero, suggested that soils should be unpolluted by Cd and Hg in Central China, similar to the pollution situation in the whole of China [111,128]. Specifically, more than 80% of the sites of each metal, except Cd, were unpolluted in Hubei Province, contrasting to 60% in Hunan Province. Only 11.8% sites of Cd and 5.9% sites of Pb fell into class three, which means moderate to heavily pollution. Soil in Henan Province was heavily polluted by Cd, Zn, Pb and As, especially Cd. Even 50.0% of the sites with Cd and 28.6% of the sites of Hg were extremely polluted, which accounted for the whole pollution situation in Central China. Although the concentrations of toxic metals were higher in Hunan Province than those in Henan Province, the Igeo values of metals were the opposite, because the background values in Hunan Province are higher than those in Henan Province.

3.4. Human Health Assessment of Children and Adults in Central China

After investigating the spatial distribution and geoaccumulation indexes of the studied metals, a health risk assessment for children and adults from exposure to soil metals in Central China through possible exposure pathways was calculated using Equations (2)–(6), and the results are shown in Table 5 and Table 6 and Figure 4 and Figure 5.
For non-carcinogenic risk, the total HIs of studied metals for children in Central China were 1.10 (Hubei), 1.41 (Hunan), 0.852 (Henan), respectively, and the total HIs for adults were 0.158 (Hubei), 0.202 (Hunan), 0.122 (Henan), respectively. It was obviously that the children in Hubei and Hunan Province faced non-carcinogenic risks, in contrast with the children in Henan and the adults in Central China. The HQ of each toxic metal for children and adults in Central China decreased in the order of As > Cr > Pb > Cd > Cu/Hg/Zn. Cr, Pb and As caused relatively higher non-carcinogenic risks to possible receptors than the other four toxic metals. For instance, the HQ of As (0.564), Cr (0.365) and Pb (0.14) accounted for 51.31%, 33.19%, and 12.71% of the entire HI value for children in Hubei, respectively. HIs for the studied metals in Central China were higher for children than for adults [128]. In particular, the HQs for children through ingestion were averaged at 7.14 times higher than those for adults, with dermal contact 4.92 times higher and inhalation 1.36 times higher [27]. The HQ of the three exposure pathways for both children and adults in Central China decreased in the following order: ingestion > dermal contact > inhalation, which was similar to other reports [121,129,130].
For carcinogenic risk, the average carcinogenic risk values for children in Central China were 2.55 × 10−4 (Hubei), 3.44 × 10−4 (Hunan), 1.69 × 10−4 (Henan), respectively, and the average carcinogenic risk values for adults were 3.67 × 10−5 (Hubei), 4.92 × 10−5 (Hunan), 2.45 × 10−5 (Henan), respectively, which mean children and adults faced unacceptable and acceptable carcinogenic risk in Central China, respectively, shown in Table 6 and Figure 5. The results show that As appeared to be the main metal for both children and adults causing the high carcinogenic risk, followed by Cr, and the carcinogenic risks of Cd and Cr were generally within the internationally accepted precautionary criterion (1.0 × 10−6), which was similar to other reports [101]. The carcinogenic risk of As for both children and adults in Central China decreased in the following order: ingestion > dermal contact > inhalation [130], which was similar to the non-carcinogenic risk. Therefore, based on the results of the geoaccumulation indexes and health risks for the studied metals, the carcinogenic risk levels of toxic metals in Central China were unacceptable, and As should be regarded as a priority control pollutant, especially for children.

3.5. Correlation Analysis

There is a certain correlation between the content of soil metals due to the similarity of geochemical conditions and the coexistence of pollutant metal elements. If the correlation between the elements is significant, it means that the elements are generally homologous or complex pollution [131,132,133]. Pearson’s correlation coefficients of soil metals in Central China were performed, and the results are shown in Table 7. The element pairs Zn-Cd, Zn-Pb, Zn-As and As-Pb had a significantly positive correlation at p < 0.01 significance level, and the element pair As-Cd had a significantly positive correlation at p < 0.05 significance level, which means there was high possibility that the Zn, Cd, As and Pb came from a common source [126,128]. The abundant mineral resources and rapid development of optoelectronic, metallurgical and alloy manufacturing, have had a great impact on the contents of Cd, Zn, As and Pb [134,135,136]. Hg is a kind of volatile heavy metal, and it has been found that the released amount of Hg from the combustion industry accounts for about 60% of the total amount of Hg in the air and it becomes a soil pollutant after atmospheric settlement [137]; this is responsible for the high concentration in Central China. Cr has the lowest pollution level of heavy metals in the soil, 1.36 times the background value, generally considered by the impact of geochemistry, which is similar to other reports [80,138,139].

3.6. Sustainable Management

Based on the above analysis of the spatial characteristics and the health risk assessment, there are four suggestions for Central China’s sustainable development. First of all, the priority control soil metals need to be given enough attention. According to comparisons with the environmental quality standard for soils in Central China, the mean concentration of Cd was 2.18 times higher than its corresponding class II value, which is hazardous to agricultural production and corresponding human health. Thus, Cd should be selected as a priority control heavy metal. Based on the pollution assessment using the geoaccumulation index, the soils in Central China have been polluted by Cd and Hg, which identify Cd and Hg. Ultimately, people are most exposed to Cr, Pb and As, among all the investigated toxic metals. In conclusion, Cd, Hg, Cr, Pb and As are selected as the priority control soil metals in Central China, to which special attention should be paid in order to target the lowest threats to human health.
Second, importance should be attached to sources control. As for Henan Province, more importance should be attached to Cr in Jiaozuo city and Cd in Xinxiang city. In Hubei Province, more attention should be paid to Cu in Huangshi city, and Pb in Jingmen city. In Hunan Province, more attention should be paid to Zn, Pb and As in Chenzhou city, Cd and Zn in Xiangtan city, Hg in Changsha city and As in Changde city. At the same time, we recommend that decision-makers pay attention to the remediation of the highly-contaminated soil, especially in the areas where it could endanger the groundwater. For example, Huangshi city and Changsha city should be concerned, not only due to the high values of Cu and Hg, but also because the Yangtze River and the Xiang River flow there.
Third, the secondary industry ratio in central China is too high at present, causing serious pollution. Therefore, it is necessary to appropriately adjust the industrial structure to increase the tertiary service industry, promote entrepreneurship and employment, and reasonably optimize urban planning. Furthermore, the three provinces should engage in more cooperation to form a complete economic zone.
Moreover, publicity and education for sustainable development should be given due attention, to popularize a series of issues such as environmental pollution, health risks and sustainable development with the media by means of television, radio, the Internet and so on, so that the public will participate more actively.

4. Conclusions

In this study, data on soil metals in Central China were collected, with a comprehensive description and a systematic evaluation performed. According to the pollution assessment, it is apparent that the concentration of soil metals in Central China, especially Cd of 1.31 mg/kg and Hg of 0.19 mg/kg, surpass their corresponding background values, indicating anthropogenic input. The concentrations of toxic metals were higher in Hunan and Henan Province, the southern and northern parts of Central China, contrasting with the lowest contents in the middle parts. For non-carcinogenic risk, the children in Hubei Province (HI = 1.10) and Hunan Province (HI = 1.41) faced non-carcinogenic risks, with higher health risks to children than adults. The exposure pathway that resulted in the highest levels of exposure risk for children and adults was ingestion, followed by dermal contact and inhalation. For carcinogenic risk, children and adults faced unacceptable and acceptable carcinogenic risks in Central China, respectively, and arsenic (As) appeared to be the main metal 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, which were identified as the priority control soil metals. Importance should also be attached to public education, source control, and remediation of highly-contaminated soil, 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.

Supplementary Materials

The following are available online at www.mdpi.com/2071-1050/10/1/91/s1, Table S1: Percentages (unitless) of class distribution for pollution assessment of soil metals in Central China using geoaccumulation index.

Acknowledgments

This study was financially supported by the Humanities and Social Sciences Foundation of Ministry of Education of China (17YJCZH081), the Science and Technology Research Project of Hubei Provincial Education Department (B2017601) and the Graduate Innovative Education Program of Zhongnan University of Economics and law (2017Y1407).

Author Contributions

Fei Li organized this study, conducted the study design, and drafted the manuscript. Ying Cai contributed to the study design, prepared datasets, performed the statistical analysis, and drafted the manuscript. Jingdong Zhang contributed to study design, interpretation of analysis, and revision of the manuscript.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Hu, Y.; Cheng, H. Application of stochastic models in identification and apportionment of heavy metal pollution sources in the surface soils of a large-scale region. Environ. Sci. Technol. 2013, 47, 3752–3760. [Google Scholar] [CrossRef] [PubMed]
  2. Odukudu, F.B.; Ayenimo, J.G.; Adekunle, A.S.; Yusuff, A.M.; Mamba, B.B. Safety evaluation of heavy metals exposure from consumer products. Int. J. Consum. Stud. 2014, 38, 25–34. [Google Scholar] [CrossRef]
  3. Li, F.; Huang, J.; Zeng, G.M.; Huang, X.L.; Liu, W.C.; Wu, H.P. Spatial distribution and health risk assessment of toxic metals associated with receptor population density in street dust: A case study of Xiandao District, Changsha, Middle China. Environ. Sci. Pollut. Res. 2015, 22, 6732–6742. [Google Scholar] [CrossRef] [PubMed]
  4. Duan, X.W.; Zhang, G.L.; Rong, L.; Fang, H.Y.; He, D.M.; Feng, D.T. Spatial distribution and environmental factors of catchment scale soil heavy metal contamination in the dryhot valley of Upper Red River in southwestern China. Catena 2015, 135, 59–69. [Google Scholar] [CrossRef]
  5. Wu, S.H.; Shi, Y.X.; Zhou, S.L.; Wang, C.H.; Chen, H. Modeling and mapping of critical loads for heavy metals in Kunshan soil. Sci. Total Environ. 2016, 191, 569–570. [Google Scholar] [CrossRef] [PubMed]
  6. Li, F.; Zhang, J.D.; Jiang, W.; Liu, C.Y.; Zhang, Z.M.; Zhang, C.D.; Zeng, G.M. Spatial health risk assessment and hierarchical risk management for mercury in soils from a typical contaminated site, China. Environ. Geochem. Health 2017, 39, 923–934. [Google Scholar] [CrossRef] [PubMed]
  7. Culbard, E.B.; Thornton, I.; Watt, J.; Wheatley, M.; Moorcroft, S.; Thompson, M. Metal contamination in British urban dusts and soils. J. Environ. Qual. 1988, 17, 226–234. [Google Scholar] [CrossRef]
  8. Folinsbee, L.J. Human health effects of air pollution. Environ. Health Perspect. 1993, 100, 45–46. [Google Scholar] [CrossRef] [PubMed]
  9. Sánchez-Camazano, M.; Sánchez-Marthín, M.J.; Lorenzo, L.F. Lead and cadmium in soils and vegetables from urban gardens of Salamanca (Spain). Sci. Total Environ. 1994, 146–147, 163–168. [Google Scholar] [CrossRef]
  10. Madrid, L.; Diaz-Barrientos, E.; Madrid, F. Distribution of heavy metal contents of urban soils in parks of Seville. Chemosphere 2002, 49, 1301–1308. [Google Scholar] [CrossRef]
  11. Laidlaw, M.S.; Filippelli, G.M. Resuspension of urban soils as apersistent source of lead poisoning in children: A review and new directions. Appl. Geochem. 2008, 23, 2021–2039. [Google Scholar] [CrossRef]
  12. Li, H.B.; Yu, S.; Li, G.L.; Deng, H.; Luo, X.S. Contamination and source differentiation of Pb in park soils along an urban-rural gradient in Shanghai. Environ. Pollut. 2011, 159, 3536–3544. [Google Scholar] [CrossRef] [PubMed]
  13. Okorie, A.; Entwistle, J.; Dean, J.R. The application of in vitro gastrointestinal extraction to assess oral bioaccessibility of potentially toxic elements from an urban recreational site. Appl. Geochem. 2011, 26, 789–796. [Google Scholar] [CrossRef]
  14. Gong, M.; Wu, L.; Bi, X.Y.; Ren, L.M.; Wang, L.; Ma, Z.D. Assessing heavy-metal contamination and sources by GIS-based approach and multivariate analysis of urban-rural top soils in Wuhan, central China. Environ. Geochem. Health 2010, 32, 59–72. [Google Scholar] [CrossRef] [PubMed]
  15. Li, F.; Huang, J.; Zeng, G.M.; Huang, X.L.; Liu, W.C.; Wu, H.P. Toxic metals in topsoil under different land uses from Xiandao District, middle China: Distribution, relationship with soil characteristics, and health risk assessment. Environ. Sci. Pollut. Res. 2015, 22, 12261–12275. [Google Scholar] [CrossRef] [PubMed]
  16. Liang, J.; Feng, C.T.; Zeng, G.M.; Zhong, M.Z.; Gao, X.; Li, X.D.; He, X.Y.; Li, X.; Fang, Y.L.; Mo, D. Atmospheric deposition of mercury and cadmium impacts on topsoil in a typical coal mine city, Lianyuan, China. Chemosphere 2017, 189, 198–205. [Google Scholar] [CrossRef] [PubMed]
  17. Facchinelli, A.; Sacchi, E.; Mallen, L. Multivariate statistical and GIS-based approach to identify heavy metal sources in soils. Environ. Pollut. 2001, 114, 313–324. [Google Scholar] [CrossRef]
  18. Thornton, I.; Farago, M.E.; Thums, C.R.; Parrish, R.R.; McGill, R.A.; Breward, N.; Fortey, N.J.; Simpson, P.; Young, S.D.; Tye, A.M.; et al. Urban geochemistry: Research strategies to assist risk assessment and remediation of brownfield sites in urban areas. Environ. Geochem. Health 2008, 30, 565–576. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  19. Li, F.; Huang, J.H.; Zeng, G.M.; Yuan, X.Z.; Li, X.D.; Liang, J.; Wang, X.Y.; Tang, X.J.; Bai, B. Spatial risk assessment and sources identification of heavy metals in surface sediments from the Dongting Lake, Middle China. J. Geochem. Explor. 2013, 132, 75–83. [Google Scholar] [CrossRef]
  20. Giller, K.E.; McGrath, S.P. Pollution by toxic metals on agricultural soils. Nature 1988, 335, 676. [Google Scholar] [CrossRef]
  21. Abrahams, P.W. Soils: Their implications to human health. Sci. Total Environ. 2002, 291, 1–32. [Google Scholar] [CrossRef]
  22. Rodrigues, S.M.; Cruz, N.; Coelho, C.; Henriques, B.; Carvalho, L.; Duarte, A.C. Risk assessment for Cd, Cu, Pb and Zn in urban soils: Chemical availability as the central concept. Environ. Pollut. 2013, 183, 234–242. [Google Scholar] [CrossRef] [PubMed]
  23. Teng, Y.G.; Ni, S.J.; Wang, J.S.; Zuo, R.; Yang, J. A geochemical survey of trace elements in agricultural and non-agricultural topsoil in Dexing area, China. J. Geochem. Explor. 2010, 104, 118–127. [Google Scholar] [CrossRef]
  24. Chen, H.M.; Zheng, C.R.; Tu, C.; Zhu, Y.G. Heavy metal pollution in soils in China: Status and countermeasures. Ambio 1999, 28, 130–134. [Google Scholar]
  25. Wang, Q.R.; Dong, Y.; Cui, Y.; Liu, X. Instances of soil and crop heavy metal contamination in China. Soil Sediment Contam. 2001, 10, 497–510. [Google Scholar]
  26. Cheng, S. Heavy metal pollution in China: Origin, pattern and control. Environ. Sci. Pollut. Res. 2003, 10, 192–198. [Google Scholar] [CrossRef]
  27. Huang, J.H.; Li, F.; Zeng, G.M.; Huang, X.L.; Liu, W.C.; Wu, H.P. Integrating hierarchical bioavailability and population distribution into potential eco-risk assessment of heavy metals in road dust: A case study in Xiandao District, Changsha city, China. Sci. Total Environ. 2016, 541, 969–976. [Google Scholar] [CrossRef] [PubMed]
  28. Tang, R.; Ma, K.; Zhang, Y.; Mao, Q. The spatial characteristics and pollution levels of metals in urban street dust of Beijing, China. Appl. Geochem. 2013, 35, 88–98. [Google Scholar] [CrossRef]
  29. Zhu, Y. Investigation and assessment of heavy metal in soil from Shanghaiqingpu industrial zone. Environ. Sanitat. Eng. 2017, 25, 39–42. [Google Scholar]
  30. Gong, M.; Wu, L.; Bi, X.Y.; Ren, L.M.; Wang, L.; Ma, Z.D.; Bao, Z.Y.; Li, Z.G. Assessing heavy-metal contamination and sources by GIS-based approach and multivariate analysis of urban-rural top soils in Wuhan, central China. Environ. Geochem. Heal. 2010, 32, 59–72. [Google Scholar] [CrossRef] [PubMed]
  31. Xi, C.Z.; Dai, T.G.; Huang, D.Y. Contamination characteristics of heavy metals in soil from Changsha, Hunan Province. Earth Environ. 2008, 36, 136–141. (In Chinese) [Google Scholar]
  32. Shen, X.; Ji, B.Y.; Tian, X.Y.; Yao, Z. Heavy metal pollution evaluation of soil in the eastern Qinghai. Geophys. Geochem. Explor. 2014, 38, 1246–1251. [Google Scholar]
  33. Wang, X.F.; He, C.C. Pollution characteristics and evaluation of soil heavy metals in surrounding areas of Xinxianghuanyu avenue industrial zone. Soil Bull. 2014, 43, 962–966. (In Chinese) [Google Scholar]
  34. Hou, Q.; Ma, J.H.; Wang, X.Y.; Duan, H.J. Biological activity and potential ecological risk of heavy metals in soils from Kaifeng kindergarten. Environ. Sci. 2011, 32, 1764–1771. (In Chinese) [Google Scholar]
  35. Li, Y.M.; Ma, J.H.; Liu, D.X.; Sun, Y.; Chen, Y.F. Pollution and potential ecological risk of soil heavy metal in Kaifeng city. Environ. Sci. 2015, 36, 1037–1044. (In Chinese) [Google Scholar]
  36. Chen, Z.F.; Fan, L.D.; Chen, Y.D.; Xing, L.T.; Yang, Y.J.; Xiang, Z.T.; Wang, X.L. Characteristics and source distribution of heavy metals in farmland soils of urban and rural area—A case study of urban and rural area in the eastern suburb of a city in Henan Province. J. Anhui Norm. Univ. (Philos. Soc. Sci. Ed.) 2016, 36, 1317–1327. (In Chinese) [Google Scholar]
  37. Liu, Y.N.; Zhu, S.F.; Wei, X.F.; Miao, J.; Zhou, J.; Guan, F.J. Characteristics and evaluation of heavy metal pollution in different functional areas of Luoyang City, Henan Province. J. Environ. Sci. 2016, 37, 2322–2328. (In Chinese) [Google Scholar]
  38. Zhao, Y.X.; Yang, Z.J. Investigation and analysis of soil heavy metals in Yima city and its surrounding areas. J. Northwest A&F Univ. (Nat. Sci. Ed.) 2014, 40, 171–174. (In Chinese) [Google Scholar]
  39. Ma, B.J.; Gao, C.L.; Wang, H.L.; Li, X.C.; Zhang, Y.H.; Liu, J. Evaluation of heavy metal pollution in soil farmland in Wuzhi county. J. Henan Agric. Sci. 2015, 44, 71. (In Chinese) [Google Scholar]
  40. Li, Y.L.; Xiao, C.Y.; Wang, S.Q.; Liu, K.P. Pollution characteristics and assessment of heavy metal in soil from urban areas of Jiaozuo city. Bull. Soil Water Conserv. 2014, 34, 271–276. (In Chinese) [Google Scholar]
  41. Pang, S.P. Research on the Biological Effectiveness of Heavy Metals in Soil-Crop in Coal Mining Area. Master’s Thesis, Henan Polytechnic University, Jiaozuo, China, 2015. (In Chinese). [Google Scholar]
  42. Gao, J.; Dang, H.N.; Zheng, M.; Liu, L.; Jiang, L.Y. Evaluation of heavy metal pollution in farmland in suburban farmland of Zhengzhou city. Chin. Agric. Sci. Bull. 2013, 29, 116–120. (In Chinese) [Google Scholar]
  43. Gu, D.N.; Li, L.P.; Xing, W.Q.; Zhao, C. Soil heavy metal distribution and soil quality assessment in Zhengzhou city. Soil Bull. 2009, 40, 921–925. (In Chinese) [Google Scholar]
  44. Shen, A.L.; Wang, Y.; Sun, S.K. Pollution characteristics and assessment of heavy metals in vegetable base in suburban from Zhengzhou City. J. Gansu Agric. Univ. 2009, 44, 126–131. (In Chinese) [Google Scholar]
  45. Li, L.; Wu, K.N.; Zhang, L.; Lv, Q.L. Analysis of soil heavy metal pollution in the suburbs of Zhengzhou. Chin. J. Soil Sci. 2008, 39, 1164–1168. (In Chinese) [Google Scholar]
  46. Yu, G.X.; Zhang, J.Z.; Wang, Y.; Ding, L.; Fu, Z.H. Soil heavy metal pollution status and quality evaluation in Zhengzhou City. Rock Miner. Anal. 2015, 34, 340–345. (In Chinese) [Google Scholar]
  47. Gao, J.X.; Jiang, L.Y.; Dang, H.N.; Li, Q.Z.; Liu, L. Different types of soil heavy metal pollution assessment in the east of Zhengzhou City. Henan Agric. Sci. 2014, 43, 76–81. (In Chinese) [Google Scholar]
  48. Wang, X.F.; Su, X.Y.; Shang, F.; Chen, Y.Q. Ecological risk assessment of soil heavy metals in the surrounding areas of Mengzhuang industrial zone in Xinxiang. Sci. Technol. Eng. 2014, 14, 105–109. (In Chinese) [Google Scholar]
  49. Zhou, K.; Wang, Z.F.; Ma, L.L.; Zhou, D.; Yao, L.F. Soil heavy metal Pb, Cd, Cr and Hg pollution evaluation of vegetable soil in the suburb of Xinxiang city. J. Ecol. Environ. 2013, 22, 1962–1968. (In Chinese) [Google Scholar]
  50. Chen, Y.Q. Study on the Potential of Soil Heavy Metal Pollution and Wild Plant Restoration in Xinxiang City. Master’s Thesis, Henan Normal University, Xinxiang, China, 2013. (In Chinese). [Google Scholar]
  51. Ma, X. Analysis of the Morphological Analysis and the Influence of pH and Acid of Heavy Metal in Soil in Xinxiang. Master’s Thesis, Henan Normal University, Xinxiang, China, 2013. (In Chinese). [Google Scholar]
  52. He, C.C. Research and Governance of Soil Heavy Metal Pollution in Typical Industrial Areas of Xinxiang City. Master’s Thesis, Henan Normal University, Xinxiang, China, 2012. (In Chinese). [Google Scholar]
  53. Wang, X.F.; Ma, M.; Chen, Y.Q. The concentrations and risk assessment of heavy metals in the soil of Xinxiang residential area. Soil Bull. 2014, 43, 490–495. (In Chinese) [Google Scholar]
  54. Li, F.; Wang, X.Y.; Tang, F.Q. Ecological risk assessment of soil heavy metals in farmland in Xinxiang suburb. J. Henan Norm. Univ. (Nat. Sci. Ed.) 2011, 39, 84–87. (In Chinese) [Google Scholar]
  55. Wang, X.F.; Yang, L.Y.; Wang, K.Y.; Wang, Y.G. Pollution characteristics and assessment of heavy metals in soil from Xinxiang urban park. Environ. Pollut. Prev. 2009, 31, 78–80. (In Chinese) [Google Scholar]
  56. Chen, Y.Z.; Li, T.Q.; Ma, J.H.; Dong, W.; Ruan, X.L. Health risks of heavy metals in soil and groundwater in the typical cancer areas of Huai river valley. Environ. Sci. 2016, 36, 4537–4545. (In Chinese) [Google Scholar]
  57. Dong, W.J. Soil Heavy Metal Pollution and Risk Assessment in High Cancer Areas in Huai River Basin. Master’s Thesis, Henan University, Kaifeng, China, 2014. (In Chinese). [Google Scholar]
  58. Ma, J.H.; Du, P.; Wang, X.Y. Studies on the quality of the mountain medicine in the soil in Huilou, Henan Province. J. Saf. Environ. 2011, 11, 106–110. (In Chinese) [Google Scholar]
  59. Zou, X.Y.; Li, Y.H.; Yang, L.; Li, H.R.; Yu, J.P.; Wang, W.Y. The relationship between longevity and soil environment in Xiayi county, Henan Province. Environ. Sci. 2011, 32, 1415–1421. (In Chinese) [Google Scholar]
  60. Sun, X.; Ning, P.; Tang, X.L.; Yi, H.H.; Zhou, L.B.; Li, K. Evaluation of heavy metal pollution in the surrounding areas of red mud Banks in Henan Province. J. Northwest A&F Univ. (Nat. Sci. Ed.) 2015, 43, 122–128. (In Chinese) [Google Scholar]
  61. Gu, D.N.; Li, G.M.; Zhang, Z.H.; Yang, Y.J.; Sheng, J.; Ma, H.L. Soil heavy metal background value and quality evaluation of Puyang industrial park. China Environ. Monit. 2015, 31, 50–52. (In Chinese) [Google Scholar]
  62. Li, S.B.; Tian, S.H.; Chen, S.J. Research on soil heavy metal pollution and environmental capacity in Xianyang suburb of Anyang city, Henan Province. Soil Bull. 1987, 4, 40–43. (In Chinese) [Google Scholar]
  63. Han, P.P.; Xie, J.; Wang, J.; Qiang, X.Y.; Ai, L.; Shi, Z.H. Soil heavy metals in farmland in Danjiangkou reservoir. China Environ. Sci. 2016, 36, 2437–2443. (In Chinese) [Google Scholar]
  64. Wang, J.; Yin, W.; Qiang, X.Y.; Zhu, X.Y.; Shi, Z.H. Ecological hazard assessment of heavy metal in farmland soil from Danjiangkou reservoir new area. Environ. Sci. Res. 2015, 28, 568–574. (In Chinese) [Google Scholar]
  65. Zhou, X.J.; Wan, X.; Wan, N.; Zeng, M.Z. Effects of heavy metal elements on soils in typical mountainous areas of eastern Enshi. Resour. Environ. Eng. 2017, 31, 49–55. (In Chinese) [Google Scholar]
  66. Mu, M.H.; Shi, Y.C.; Zhang, X.Q.; Qian, Y.M.; Zhao, L. The soil heavy metals and fluorine content and risk assessment of Enshi tea plantation. J. Henan Agric. Sci. 2016, 45, 61–65. (In Chinese) [Google Scholar]
  67. Zhai, K. Analysis of organic pesticide and heavy metal residue in medicinal materials of beimu and soil, Hubei Province. J. Soil Sci. 2011, 42, 976–979. (In Chinese) [Google Scholar]
  68. Zhai, K.; Xiang, D.S. Pollution characteristics and assessment of heavy metals in the planting base of konjac. Henan Agric. Sci. 2015, 44, 81–84. (In Chinese) [Google Scholar]
  69. Huang, J.; Liao, Z.J.; Yang, L. Ecological risk assessment and source analysis of soil heavy metal pollution in vegetable soils in Enshi city. Guangdong Agric. Sci. 2013, 40, 142–146. (In Chinese) [Google Scholar]
  70. Tu, M. Nano-FeS for Soil Heavy Metal Pollution Repair Study. Master’s Thesis, Beijing University of Civil Engineering and Architecture, Beijing, China, 2012. (In Chinese). [Google Scholar]
  71. Zhang, H.F.; Li, X.L.; Dai, Z.L.; Xu, T.; Luo, Y.H.; Huang, Y.P. The fuzzy number of the soil heavy metals of Xiangxi River and its upper margin. J. Wuhan Univ. (Nat. Sci. Ed.) 2016, 62, 299–306. (In Chinese) [Google Scholar]
  72. Xiong, J.; Wang, F.; Mei, P.S.; Zhang, L.P.; Huang, Y.P.; Zhang, S. Ecological risk assessment of soil heavy metals in Xiangxi river in the three gorges reservoir area. Environ. Sci. Res. 2011, 24, 1318–1324. (In Chinese) [Google Scholar]
  73. Li, Z.; Xiang, W.X. Statistical analysis and evaluation of heavy metal pollution in surface soil of Wuchang district. Resour. Environ. Eng. 2016, 30, 704–708. (In Chinese) [Google Scholar]
  74. Dang, L.N.; Mei, Y.; Liao, X.S.; Liu, Y.Y. Urban traffic circle with different soil heavy metal and space distribution research of multivariate statistical analysis in Wuhan city. Resour. Environ. Yangtze Basin 2016, 25, 925–931. (In Chinese) [Google Scholar]
  75. Zhang, B.; Li, W.D.; Zhang, C.R. Soil heavy metal pollution situation and influencing factors of Wuhan east lake high-tech development zone. Environ. Chem. 2013, 32, 1714–1722. (In Chinese) [Google Scholar]
  76. Yang, H.Z. Study on the Accumulation of Soil Heavy Metals and the Chemical Regulation of Cadmium Pollution in Wuhan. Master’s Thesis, Wuhan University of Technology, Wuhan, China, 2011. (In Chinese). [Google Scholar]
  77. Yang, Y.; Christakos, G.; Guo, M.; Xiao, L.; Huang, W. Space-time quantitative source apportionment of soil heavy metal concentration increments. Environ. Pollut. 2017, 223, 560–566. [Google Scholar] [CrossRef] [PubMed]
  78. Zhang, C.; Yang, Y.; Li, W.; Zhang, C.; Zhang, R.; Mei, Y.; Liao, X.; Liu, Y. Spatial distribution and ecological risk assessment of trace metals in urban soils in Wuhan, central China. Environ. Monit. Assess. 2015, 187, 556. [Google Scholar] [CrossRef] [PubMed]
  79. Du, W.; Li, A.M.; An, K.D. Evaluation of soil heavy metal pollution in a vegetable soil in Wuhan, Hubei Province. Environ. Sci. Technol. 2015, 38, 469–473. (In Chinese) [Google Scholar]
  80. Zhang, T.; Zhou, T.; Zhou, L.; Zhao, L.; Li, J.L.; Wang, L.; Wang, W.N.; Li, J.J. Heavy metal content and its relationship with soil fertility condition of smoke zone soil in Fangxian county, Hubei Province. J. Shanxi Agric. Sci. 2012, 40, 1195–1199. (In Chinese) [Google Scholar]
  81. Shen, C.X.; Zhu, M.X.; Xiao, J. The characteristics and health risk assessment of heavy metals in the soil of rice system in Tianmen. J. Soil Sci. 2014, 45, 221–226. (In Chinese) [Google Scholar]
  82. Shen, Z.; Tao, Q.C.; Peng, W.Y.; Li, Q.R. Evaluation and potential ecological hazards of soil heavy metal accumulation in the vegetable base of Tianmen city. Hubei Agric. Sci. 2013, 52, 2016–2020. (In Chinese) [Google Scholar]
  83. Zhang, J.Q.; Li, X.; Zhang, Q.; Li, Q.; Xiao, W.S.; Wang, Y.K.; Zhang, J.C.; Gai, X.G. The characteristics and risk assessment of heavy metal water-soil in the shoreline of Daye lakeside. Environ. Sci. 2015, 36, 194–201. (In Chinese) [Google Scholar] [CrossRef] [PubMed]
  84. Cai, L.M.; Xu, Z.C.; Qi, J.Y.; Feng, Z.Z.; Xiang, T.S. Assessment of exposure to heavy metals and health risks among residents near Tonglushan mine in Hubei, China. Chemosphere 2015, 127, 127–135. [Google Scholar] [CrossRef] [PubMed]
  85. Zou, J.J. Contamination Characteristics of Heavy Metals in the Soil of DMCC in Hubei Province. Master’s Thesis, Huazhong Agricultural University, Wuhan, China, 2015. (In Chinese). [Google Scholar]
  86. Zhang, L.; Li, X.; Zhang, J.Q.; Li, J.L.; Li, Q.; Wang, Y.K. Evaluation of heavy metal pollution in typical agricultural soil in Huangshi city. Environ. Sci. Technol. 2014, 37, 230–235. (In Chinese) [Google Scholar]
  87. Chen, F.; Liu, H.Y.; Cao, Y. Investigation and evaluation of soil heavy metal pollution in surrounding steel enterprises. Sichuan Environ. 2010, 29, 52–54. (In Chinese) [Google Scholar]
  88. Cai, W. Investigation on soil heavy metal pollution in basic farmland in Huangshi city. Environ. Sci. Manag. 2009, 34, 80–82. (In Chinese) [Google Scholar]
  89. Yin, C.Q.; Sun, Q.B.; Deng, J.F. Characteristics and potential ecological evaluation of heavy metal pollution in the cropland of the ring. J. HuBei Polytech. Univ. 2013, 29, 17–22. (In Chinese) [Google Scholar]
  90. Weng, T.F.; Gao, J.P.; Cui, X.M. Preliminary evaluation of heavy metal pollution in agricultural soil in Xiaogan district, Xiaogan city. Guangzhou Environ. Sci. 2008, 23, 40–43. (In Chinese) [Google Scholar]
  91. Cui, X.Y. Spatial Analysis and Pollution Evaluation of Cadmium and Zinc Lead in Soil Cadmium in Hubei Province. Master’s Thesis, Huazhong Agricultural University, Wuhan, China, 2009. (In Chinese). [Google Scholar]
  92. Xiong, H.F.; Lu, J.H.; Li, Q.; Zhan, S.Q.; Liao, Q.Z.; Wu, Q.F. Evaluation of heavy metal pollution in vegetable soil in Ezhou city. Mong. Environ. Sci. 2008, 20, 36–39. (In Chinese) [Google Scholar]
  93. Zhao, X. Investigation and evaluation of heavy metal pollution in farmland in Xiangyang city. J. Green Sci. Technol. 2014, 2, 207–209. (In Chinese) [Google Scholar]
  94. Zhu, X.; Yang, F.; Wei, C. Factors influencing the heavy metal bioaccessibility in soils were site dependent from different geographical locations. Environ. Sci. Pollut. Res. 2015, 22, 13939–13949. [Google Scholar] [CrossRef] [PubMed]
  95. Li, C.X.; Zhu, G.Q.; Peng, K. Study on the characteristics of heavy metal pollution in the soil of green belts and its enrichment of plants, taking Changsha as an example. J. Cent. South Univ. For. Technol. 2016, 36, 101–107. (In Chinese) [Google Scholar]
  96. Hu, Y.B. Characteristics and Environmental Risk of Soil Heavy Metal in Changsha Section of Xiangjiang River. Master’s Thesis, Hunan University, Changsha, China, 2014. (In Chinese). [Google Scholar]
  97. Li, J.N.; Hou, H.; Wei, Y.; Xu, Y.F.; Li, F.S. Evaluation of soil heavy metals in farmland in Zhuzhou city. Environ. Sci. Res. 2013, 26, 1139–1146. (In Chinese) [Google Scholar]
  98. Xi, C.Z.; Dai, T.G.; Huang, D.Y. Distribution characteristics and pollution evaluation of soil heavy metals in Zhuzhou, Hunan Province. China. Geol. 2008, 35, 524–530. (In Chinese) [Google Scholar]
  99. Wang, Z.X.; Guo, Q.W.; Yang, Z.H. A land use-based spatial analysis method for human health risk assessment of heavy metals in soil and its application in Zhuzhou, Hunan Province. J. Cent. South Univ. 2016, 23, 1915–1923. [Google Scholar] [CrossRef]
  100. Pan, Q.; Pan, F. Status and assessment of soil heavy metal pollution in metallurgical city of Hunan Province. J. Jiangsu Agric. Sci. 2015, 43, 405–410. (In Chinese) [Google Scholar]
  101. Yang, M.; Teng, Y.; Ren, W.J.; Huang, Y.; Xu, D.F.; Fu, Z.C. The pollution and health risk assessment of heavy metal in surrounding farmland of Shimenhuangmine. Soil Bull. 2016, 48, 1172–1178. (In Chinese) [Google Scholar]
  102. Yu, X.F.; Peng, P.; Xiao, L.H. Content analysis and repair of heavy metal in acidic soil. J. Southwest Agric. 2013, 26, 1090–1093. (In Chinese) [Google Scholar]
  103. Zeng, F.; Wei, W.; Li, M.; Huang, R.; Yang, F.; Duan, Y. Heavy metal contamination and potential health risks in rice-producing soils of Hunan Province. Int. J. Environ. Res. Public Health 2015, 12, 15584–15593. [Google Scholar] [CrossRef] [PubMed]
  104. Zhou, N.; Tang, D.S.; Deng, Q.W.; Zhang, X.W.; Li, M.; Li, Y.L. Pollution and the health risk assessment of soil and vegetables in the surrounding farmland of some tailings reservoir in Hunan Province. J. Green Sci. Technol. 2016, 6, 1–5. (In Chinese) [Google Scholar]
  105. Sun, R.; Shu, F.; Sun, W.L.; Hao, W.; Li, L. The characteristics of heavy metal pollution and their relationship with soil properties in paddy soil in typical lead-zinc mining areas. J. Peking Univ. (Nat. Sci. Ed.) 2014, 48, 139–146. (In Chinese) [Google Scholar]
  106. Xi, C.Z.; Dai, T.G.; Zhang, H.J.; Liu, W.H. Investigation and evaluation of soil heavy metal pollution in Xiangtan, Hunan Province. J. Water Soil Conserv. Bull. 2008, 28, 133–137. (In Chinese) [Google Scholar]
  107. Huang, S.; Yuan, C.; Li, Q.; Yang, Y.; Tang, C.J.; Ouyang, K. Distribution and risk assessment of heavy metals in soils from a typical Pb-Zn mining area. J. Environ. Stud. 2017, 26, 1105–1112. [Google Scholar] [CrossRef]
  108. Song, D.P.; Zhuang, D.F.; Jiang, D.; Fu, J.Y.; Wang, Q. Integrated Health Risk Assessment of Heavy Metals in Suxian County, South China. Int.J. Environ. Res. Public Health 2015, 12, 7100–7117. [Google Scholar] [CrossRef] [PubMed]
  109. Liang, J.; Feng, C.T.; Zeng, G.M.; Gao, X.; Zhong, M.Z.; Li, X.D.; Li, X.; He, X.Y.; Fang, Y.L. Spatial distribution and source identification of heavy metals in surface soils in a typical coal mine city, Lianyuan, China. Environ. Pollut. 2017, 225, 681–690. [Google Scholar] [CrossRef] [PubMed]
  110. Chen, T.B.; Zheng, Y.M.; Lei, M.; Huang, Z.C.; Wu, H.T.; Chen, H.; Fan, K.K.; Yu, K.; Wu, X.; Tian, Q.Z. Assessment of heavy metal pollution in surface soils of urban parks in Beijing, China. Chemosphere 2005, 60, 542–551. [Google Scholar] [CrossRef] [PubMed]
  111. Muller, G. Index of geoaccumulation in sediments of the Rhine River. Geo J. 1969, 2, 108–118. [Google Scholar]
  112. Loska, K.; Wiechula, D.; Korus, I. Metal contamination of farming soils affected by industry. Environ. Int. 2004, 30, 159–165. [Google Scholar] [CrossRef]
  113. CNEMC. The Soil Background Value in China; China National Environmental Monitoring Center, China Environmental Science Press: Beijing, China, 1990. (In Chinese) [Google Scholar]
  114. Shao, F.S.; Zhou, H.Y. Background values of the main elements in soil environment in Henan Province. Henan Agric. 1998, 10, 29. [Google Scholar]
  115. Wei, Z.S.; Yang, G.Z.; Jiang, D.Z.; Liu, Z.H.; Sun, B.N. Basic statistics of soil elements in China and their characteristics. China Environ. Monit. 1991, 7, 1–6. [Google Scholar]
  116. USEPA. Soil Screening Guidance: Technical Background Document; EPA/540/R-95/128; Office of Solid Waste and Emergency Response, Environmental Protection Agency: Washington, DC, USA, 1996.
  117. USEPA. Supplemental Guidance for Developing Soil Screening Levels for Superfund Sites; OSWER9355; Office of Solid Waste and Emergency Response: Washington, DC, USA, 2001; pp. 4–24.
  118. Van den Berg, R. Human Exposure to Soil Contamination: A Qualitative and Quantitative Analysis towards Proposals for Human Toxicological Intervention Values; Report No. 725201011; National Institute for Public Health and the Environment: Bilthoven, The Netherlands, 1994.
  119. USEPA. Risk Assessment Guidance for Superfund Volume 1. Human Health Evaluation Manual (Part A); EPA/540/1-89/002; Office of Emergency and Remedial Response, Environmental Protection Agency: Washington, DC, USA, 1989.
  120. MEPPRC (Ministry of Environmental Protection, PRC). Technical Guidelines for Risk Assessment of Contaminated Sites; HJ 25.3-2014; Ministry of Environmental Protection, PRC: Beijing, China, 2014. (In Chinese)
  121. Ferreira-Baptista, L.; De, M.E. Geochemistry and risk assessment of street dust in Luanda, Angola: A tropical urban environment. Atmos. Environ. 2005, 39, 4501–4512. [Google Scholar] [CrossRef] [Green Version]
  122. Li, X.F.; Chen, Z.B.; Zhang, Y.H.; Chen, Z.Q. The heavy metals of road dust in Fuzhou City: The concentrations sources and health risk assessment. Environ. Sci. Res. 2013, 26, 906–912. (In Chinese) [Google Scholar]
  123. Wang, Z.; Liu, S.Q.; Chen, X.M.; Lin, C.Y. Health risk assessment and of Chinese skin exposure. J. Saf. Environ. 2008, 8, 152–156. (In Chinese) [Google Scholar]
  124. Zhang, N.; Liu, J.S.; Wang, Q.C.; Liang, Z.Z. Health risk assessment of heavy metal exposure to street dust in the zinc smelting district, Northeast of China. Sci. Total Environ. 2010, 408, 726–733. [Google Scholar] [CrossRef] [PubMed]
  125. Lu, X.W.; Zhang, X.L.; Li, L.Y.; Chen, H. Assessment of metals pollution and health risk in dust from nursery schools in Xi’an, China. Environ. Res. 2014, 128, 27–34. [Google Scholar] [CrossRef] [PubMed]
  126. Chen, Y.N.; Ma, J.H. Evaluation of Heavy Metal Pollution and Health Risk of Surface Dust in a City of Henan Province. J. Environ. Sci. 2016, 36, 3017–3026. (In Chinese) [Google Scholar]
  127. NEPAC (National Environmental Protection Agency of China). Environmental Quality Standard for Soils; GB 15618-1995; National Environmental Protection Agency: Beijing, China, 1995. (In Chinese)
  128. Chen, H.Y.; Teng, Y.G.; Lu, S.J.; Wang, Y.Y.; Wang, J.S. Contamination features and health risk of soil heavy metals in China. Sci. Total Environ. 2015, 512–513, 143–153. [Google Scholar] [CrossRef] [PubMed]
  129. Shi, G.; Chen, Z.; Bi, C.; Li, Y.; Teng, J.L.; Wang, L.; Xu, S. Comprehensive assessment of toxic metals in urban and suburban street deposited sediments (SDSs) in the biggest metropolitan area of China. Environ. Pollut. 2010, 158, 694–703. [Google Scholar] [CrossRef] [PubMed]
  130. Liu, L.; Zhang, X.; Zhong, T. Pollution and health risk assessment of heavy metals in urban soil in China. J. Hum. Ecol. Risk Assess. 2016, 22, 424–434. [Google Scholar] [CrossRef]
  131. Qiu, H.Y. Evaluation of potential ecological hazards of heavy metals in soil. J. Resour. Conserv. Environ. Prot. 2011, 1, 68–70. (In Chinese) [Google Scholar]
  132. Lu, X.; Wang, L.; Li, L.Y.; Lei, K.; Huang, L.; Kang, D. Multivariate statistical analysis of heavy metals in street dust of Baoji, China. J. Hazard. Mater. 2010, 173, 744–749. [Google Scholar] [CrossRef] [PubMed]
  133. Saeedia, M.; Li, L.Y.; Salmanzadeh, M. Heavy metals and polycyclicaromatic hydrocarbons: Pollution and ecological risk assessment in street dust of Tehran. J. Hazard. Mater. 2012, 227–228, 9–17. [Google Scholar] [CrossRef] [PubMed]
  134. Fong, F.T.; Hee, P.S.; Ahmood, A.A. Possible source and pattern distribution of heavy metals content in urban soil at Kuala Terengganu Town Center. J. Anal. Sci. 2008, 2, 458–467. [Google Scholar]
  135. Sun, Y.B.; Hou, Q.; Xie, X.K. Spatial sources and risk assessment of heavy metal contamination of urban soils in typical regions of Shenyang, China. J. Hazard. Mater. 2010, 74, 455–462. [Google Scholar] [CrossRef] [PubMed]
  136. Wei, B.; Gang, L.S. A review of heavy metal contaminations in urban soils, urban road dusts and agricultural soils from China. J. Microchem. 2010, 4, 99–107. [Google Scholar] [CrossRef]
  137. Zhao, S.N.; Wu, L.S.H. Contamination Characteristics of Heavy Metal and Its Morphological Simulation. Master’s Thesis, Inner Mongolia Agricultural University, Hohhot, China, 2013. (In Chinese). [Google Scholar]
  138. Lv, J.S.; Liu, Y.; Hang, Z.L. Multivariate geostatistical analyses of heavy metals in soils: Spatial multi-scale variations in Wulian, eastern China. Ecotoxicol. Environ. Saf. 2014, 107, 140–147. [Google Scholar] [CrossRef] [PubMed]
  139. Sun, C.Y.; Liu, J.S.; Yang, Y. Multivariate and geostatistical analyses of the spatial distribution and sources of heavy metals in agricultural soil in Dehui, northeast China. Chemosphere 2013, 2, 517–523. [Google Scholar] [CrossRef] [PubMed]
Figure 1. Map of soil sampling sites in Central China.
Figure 1. Map of soil sampling sites in Central China.
Sustainability 10 00091 g001
Figure 2. Spatial distribution of Cu (a), Cr (b), Cd (c), Zn (d), Pb (e), Hg (f) and As (g) in soils from Central China.
Figure 2. Spatial distribution of Cu (a), Cr (b), Cd (c), Zn (d), Pb (e), Hg (f) and As (g) in soils from Central China.
Sustainability 10 00091 g002aSustainability 10 00091 g002bSustainability 10 00091 g002c
Figure 3. Boxplots of the geoaccumulation index for soil metals in Central China.
Figure 3. Boxplots of the geoaccumulation index for soil metals in Central China.
Sustainability 10 00091 g003
Figure 4. Non-carcinogenic hazard indices of Cu, Cr, Cd, Zn, Pb, Hg and As for children (a,c,e,g,i,k,m) and adults (b,d,f,h,j,l,n) in soils from Central China.
Figure 4. Non-carcinogenic hazard indices of Cu, Cr, Cd, Zn, Pb, Hg and As for children (a,c,e,g,i,k,m) and adults (b,d,f,h,j,l,n) in soils from Central China.
Sustainability 10 00091 g004aSustainability 10 00091 g004bSustainability 10 00091 g004cSustainability 10 00091 g004d
Figure 5. Carcinogenic risk of As for children (a) and adults (b) in soils from Central China.
Figure 5. Carcinogenic risk of As for children (a) and adults (b) in soils from Central China.
Sustainability 10 00091 g005
Table 1. The concentrations (mg/kg) of soil metals in different cities in Central China.
Table 1. The concentrations (mg/kg) of soil metals in different cities in Central China.
ProvinceCityCuCrCdZnPbHgAsReferences
Henan ProvinceKaifeng33.9156.151.19172.9046.15 6.31[34,35,36]
Luoyang47.3866.470.65190.2551.23 [37,38]
Jiaozuo31.57176.150.3981.4324.32 17.25[39,40,41]
Zhengzhou21.8254.460.1670.5530.900.058.74[42,43,44,45,46,47]
Xinxiang40.28116.8312.46219.9352.630.32 [33,48,49,50,51,52,53,54,55]
Zhoukou26.7156.730.0567.9329.66 [56,57]
Shangqiu22.4255.260.1866.9319.51 [58,59]
Sanmenxia45.25118.730.2581.7721.270.167.97[38,60]
Puyang36.2040.600.13118.0049.20 [61]
Anyang22.7451.960.1155.1017.270.08 [62]
Nanyang20.7554.361.1275.8129.76 12.68[63,64]
Hubei ProvinceEnshi32.8893.280.6996.7531.950.1213.78[65,66,67,68,69,70]
Yichang26.312.390.260.4729.16 [70,71,72]
Wuhan28.7559.021.6087.7334.000.2312.92[70,73,74,75,76,77,78,79]
Shiyan34.7367.950.3978.7230.720.0613.78[64,70,80]
Tianmen27.8967.940.1669.9723.020.116.85[70,81,82]
Huangshi126.7239.111.3295.6779.120.1733.72[70,83,84,85,86,87,88,89]
Xiaogan25.8578.750.2563.6546.21 [70,90,91]
Ezhou7.6762.680.1070.0529.210.0910.50[70,92]
Xiangfan24.7660.100.1066.4827.250.099.96[70,93]
Xiantao29.7287.300.1477.2925.82 8.25[70,94]
Huanggang35.06 0.1270.1524.15 [70]
Jingmen24.28 0.1155.67284.00 [70]
Jingzhou33.55 0.1489.2932.99 [70]
Qianjiang32.06 0.1178.3324.98 [70]
Shennongjia44.36 0.1169.6628.63 [70]
Suizhou24.46 0.1363.3530.10 [70]
Xianning24.87 0.1160.0131.98 [70]
Hunan ProvinceChangsha57.1356.646.26249.1391.460.4842.78[31,95,96]
Zhuzhou44.65115.501.31170.1581.980.2520.05[97,98,99,100]
Changde31.4726.000.49102.0829.430.4568.86[101,102,103]
Hengyang57.6331.561.59184.6286.430.4241.50[100,104,105]
Xiangtan37.5077.4325.22863.5868.810.2561.20[103,106]
Chenzhou36.68 4.33634.30467.92 74.44[100,107,108]
Loudi33.2693.030.59107.2437.820.1814.96[109]
Table 2. Distribution of parameters used to evaluate exposure risks of soil metals in Central China.
Table 2. Distribution of parameters used to evaluate exposure risks of soil metals in Central China.
ParameterSymbolUnitsDistribution
Soil ingestion rateIngRmg/day200 a; 100 b
Soil inhalation rateInhRm3/day7.6 a; 20 b
Exposure frequencyEFday/year350
Exposure durationEDyear6 a; 24 b
Body weightBWkg15.9 a; 56.8 b
Exposure skinSAcm22448 a; 5075 b
Adherence factorAFmg/m2·day0.2 a; 0.07 b
Dermal absorption factorABSunitless0.001
Particle emission factorPEFm3/kg1.36 × 109
Average contact timeATdayED × 365 (non-carcinogens)
74 × 65 (carcinogens)
a Children; b Adults.
Table 3. The reference dose and slope factor of metals.
Table 3. The reference dose and slope factor of metals.
ElementsRfD/(mg/kg·d)SF/(kg·d/mg)
inginhdermalinginhdermal
Cu4.00 × 1024.02 × 1021.20 × 102---
Cr3.00 × 1032.86 × 1056.00 × 105-42-
Cd1.00 × 1031.00 × 1031.00 × 105-6.3-
Zn3.00 × 1013.00 × 1016.00 × 102---
Pb3.50 × 1033.52 × 1035.25 × 104---
Hg3.00 × 1043.00 × 1042.40 × 105---
As3.00 × 1041.23 × 1043.00 × 1041.515.13.66
Table 4. Descriptive statistics of soil metal concentrations (mg/kg) in Central China.
Table 4. Descriptive statistics of soil metal concentrations (mg/kg) in Central China.
CuCrCdZnPbHgAs
Central Chinan16,56514,50616,97416,37617,10811,78412,089
WA34.7283.081.31112.9344.430.1916.23
SD18.6333.794.52160.1081.4040.2820.42
CV (%)1.511.726.883.353.8518.093.93
Henan Provincen6983656170946934701166036895
WA28.3068.592.07108.1634.290.079.29
SD10.1033.317.73275.71135.8061.4821.73
CV (%)3.387.8617.9511.9314.9727.806.30
Hubei Provincen6667509068426375687837903789
WA37.0980.690.8087.8239.910.1214.00
SD24.2124.620.4421.0060.370.057.93
CV (%)4.153.987.501.767.426.097.22
Hunan Provincen2915285530383067321913911405
WA35.1391.251.47138.1453.530.2618.87
SD9.2338.263.3554.0512.590.103.62
CV (%)2.644.1419.884.263.1816.075.59
BVChina a22.6610.09774.2260.06511.2
BVHenan b2063.20.06562.522.30.0259.8
BVHubei c30.7860.1783.626.70.0812.3
BVHunan d25680.0796300.0713.41
Class I e35900.2100350.1515
Class II e1002500.63003501.025
Class III e4003001.05005001.540
a CNEMC (1990) [113]; b Soil background value of Henan Province, China [114]; c Soil background value of Hubei Province, China [113]; d Soil background value of Hunan Province, China [115]; e Environmental quality standard secondary grade for soils, soil limitations to ensure agricultural production and human health (NEPAC 1995); n the number of samples, WA weighted average, SD standard deviation, CV coefficient of variation.
Table 5. Hazard quotients (unitless) of soil metals in Central China for children and adults.
Table 5. Hazard quotients (unitless) of soil metals in Central China for children and adults.
ElementsProvinceChildrenAdults
HQingHQinhHQdermalHQHQingHQinhHQdermalHQ
CuHenan8.53 × 10−32.37 × 10−76.96 × 10−58.60 × 10−31.19 × 10−31.75 × 10−71.41 × 10−51.21 × 10−3
Hubei1.12 × 10−23.11 × 10−79.13 × 10−51.13 × 10−21.57 × 10−32.29 × 10−71.85 × 10−51.58 × 10−3
Hunan1.06 × 10−22.95 × 10−78.64 × 10−51.07 × 10−21.48 × 10−32.17 × 10−71.76 × 10−51.50 × 10−3
CrHenan2.76 × 10−18.08 × 10−43.38 × 10−23.10 × 10−13.86 × 10−25.95 × 10−46.86 × 10−34.61 × 10−2
Hubei3.24 × 10−19.51 × 10−43.97 × 10−23.65 × 10−14.54 × 10−27.00 × 10−48.07 × 10−35.42 × 10−2
Hunan3.67 × 10−11.08 × 10−34.49 × 10−24.13 × 10−15.13 × 10−27.92 × 10−49.12 × 10−36.13 × 10−2
CdHenan2.50 × 10−26.97 × 10−76.11 × 10−33.11 × 10−23.49 × 10−35.14 × 10−71.24 × 10−34.73 × 10−3
Hubei9.60 × 10−32.68 × 10−72.35 × 10−31.20 × 10−21.34 × 10−31.98 × 10−74.78 × 10−41.82 × 10−3
Hunan1.78 × 10−24.97 × 10−74.35 × 10−32.21 × 10−22.49 × 10−33.66 × 10−78.84 × 10−43.37 × 10−3
ZnHenan4.35 × 10−31.22 × 10−75.32 × 10−54.40 × 10−36.09 × 10−48.95 × 10−81.08 × 10−56.20 × 10−4
Hubei3.53 × 10−39.87 × 10−84.32 × 10−53.57 × 10−34.94 × 10−47.27 × 10−88.78 × 10−65.03 × 10−4
Hunan5.55 × 10−31.55 × 10−76.80 × 10−55.62 × 10−37.77 × 10−41.14 × 10−71.38 × 10−57.91 × 10−4
PbHenan1.18 × 10−13.28 × 10−61.93 × 10−31.20 × 10−11.65 × 10−22.42 × 10−63.92 × 10−41.69 × 10−2
Hubei1.38 × 10−13.82 × 10−62.24 × 10−31.40 × 10−11.92 × 10−22.81 × 10−64.56 × 10−41.97 × 10−2
Hunan1.84 × 10−15.13 × 10−63.01 × 10−31.87 × 10−12.58 × 10−23.78 × 10−66.11 × 10−42.64 × 10−2
HgHenan2.63 × 10−37.35 × 10−88.05 × 10−52.71 × 10−33.68 × 10−45.42 × 10−81.64 × 10−53.85 × 10−4
Hubei4.81 × 10−31.34 × 10−71.47 × 10−44.96 × 10−36.73 × 10−49.90 × 10−82.99 × 10−57.03 × 10−4
Hunan1.05 × 10−22.92 × 10−73.20 × 10−41.08 × 10−21.46 × 10−32.15 × 10−76.50 × 10−51.53 × 10−3
AsHenan3.73 × 10−12.55 × 10−59.14 × 10−43.74 × 10−15.23 × 10−21.87 × 10−51.86 × 10−45.25 × 10−2
Hubei5.63 × 10−13.84 × 10−51.38 × 10−35.64 × 10−17.88 × 10−22.83 × 10−52.80 × 10−47.91 × 10−2
Hunan7.59 × 10−15.17 × 10−51.86 × 10−37.61 × 10−11.06 × 10−13.81 × 10−53.77 × 10−41.07 × 10−1
Table 6. Carcinogenic risk (unitless) of soil metals in Central China.
Table 6. Carcinogenic risk (unitless) of soil metals in Central China.
ElementsProvinceChildrenAdults
CRingCRinhCRdermalCRCRingCRinhCRdermalCR
CrHenan9.71 × 10−89.71 × 10−87.15 × 10−77.15 × 10−7
Hubei1.14 × 10−71.14 × 10−78.41 × 10−78.41 × 10−7
Hunan1.29 × 10−71.29 × 10−79.51 × 10−79.51 × 10−7
CdHenan4.39 × 10−94.39 × 10−93.24 × 10−93.24 × 10−9
Hubei1.69 × 10−91.69 × 10−91.25 × 10−91.25 × 10−9
Hunan3.13 × 10−93.13 × 10−92.30 × 10−92.30 × 10−9
AsHenan1.68 × 10−44.73 × 10−81.00 × 10−61.69 × 10−42.35 × 10−53.48 × 10−82.04 × 10−72.38 × 10−5
Hubei2.53 × 10−47.13 × 10−81.51 × 10−62.55 × 10−43.55 × 10−55.25 × 10−83.07 × 10−73.58 × 10−5
Hunan3.41 × 10−49.60 × 10−82.04 × 10−63.44 × 10−44.78 × 10−57.07 × 10−84.14 × 10−74.83 × 10−5
Table 7. Pearson correlation matrix for toxic metal concentrations.
Table 7. Pearson correlation matrix for toxic metal concentrations.
CuCrCdZnPbHgAs
Cu1
Cr−0.0731
Cd0.1300.1241
Zn0.1460.1020.840 **1
Pb0.112−0.0910.1530.515 **1
Hg−0.0640.121−0.088−0.059−0.0621
As0.227−0.3240.535 *0.716 **0.639 **−0.1191
* Correlation is significant at the 0.05 level (two-tailed); ** correlation is significant at the 0.01 level (two-tailed).

Share and Cite

MDPI and ACS Style

Li, F.; Cai, Y.; Zhang, J. Spatial Characteristics, Health Risk Assessment and Sustainable Management of Heavy Metals and Metalloids in Soils from Central China. Sustainability 2018, 10, 91. https://doi.org/10.3390/su10010091

AMA Style

Li F, Cai Y, Zhang J. Spatial Characteristics, Health Risk Assessment and Sustainable Management of Heavy Metals and Metalloids in Soils from Central China. Sustainability. 2018; 10(1):91. https://doi.org/10.3390/su10010091

Chicago/Turabian Style

Li, Fei, Ying Cai, and Jingdong Zhang. 2018. "Spatial Characteristics, Health Risk Assessment and Sustainable Management of Heavy Metals and Metalloids in Soils from Central China" Sustainability 10, no. 1: 91. https://doi.org/10.3390/su10010091

APA Style

Li, F., Cai, Y., & Zhang, J. (2018). Spatial Characteristics, Health Risk Assessment and Sustainable Management of Heavy Metals and Metalloids in Soils from Central China. Sustainability, 10(1), 91. https://doi.org/10.3390/su10010091

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop