scholarly journals Assessment of Anthropogenic Sources of Potentially Toxic Elements in Soil from Arable Land Using Multivariate Statistical Analysis and Random Forest Analysis

2020 ◽  
Vol 12 (20) ◽  
pp. 8538 ◽  
Author(s):  
He Huang ◽  
Yong Zhou ◽  
Yujie Liu ◽  
Ke Li ◽  
Liang Xiao ◽  
...  

In order to study the spatial distribution and anthropogenic sources of potentially toxic elements in Xiangzhou, soil samples were collected from arable land and were analyzed for five different potentially toxic elements: Cd, Hg, As, Pb, and Cr. Inverse distance weighting (IDW) was used to study the spatial distribution of potentially toxic elements in the soil, while principal component analysis (PCA) and random forest analysis (RFA) were applied to examine the anthropogenic sources. It was shown that the combination of multiple analysis tools provides an effective way of delineating multiple potentially toxic elements from anthropogenic sources. The results showed that the average contents of Cd, Hg, and Cr in soils were lower than the background values of Hubei, whereas the average concentrations of As and Pb in soils were higher than the background values of Hubei. Through PCA, it was concluded that human activities contributed more than 60% of the As, Pb, and Cr concentrations in Xiangzhou soils, which was verified by a random forest simulation methodology. Through random forest analysis, Pb, As, and Cr in the soil were found to originate from factories and enterprises, livestock farms, mining areas, and traffic; Cd in the soil was found to originate from mining and the processing of minerals, human production and construction activities, and agricultural irrigation; and Hg in the soil was found to originate from livestock manure, mining and processing of minerals, and human industrial production. The results of this study could provide support for better management of soil pollution through prevention practices such as specific industrial governance and layout optimization.

Author(s):  
Yang Yu ◽  
Haijiang Luo ◽  
Lihuan He ◽  
Wenqing Liu ◽  
Renji Xu ◽  
...  

The concentrations, chemical availability, distribution, and sources of potentially toxic elements (PTEs) in the soil of Xiangjiang Basin in Hunan Province, China were investigated at 85 sites. The highest mean concentrations of Cd, Cu, Zn, As, and Pb were observed in Hengyang, whereas those for Mn, Co, and Hg were observed in Changde. The pollution index values followed the order: Cd > Hg > Cu > Zn > As > Pb; the mean geo-accumulation index values were in the order: Cd > Hg > Pb > Cu > Zn > As > Co > Mn. Cd was associated with moderate contaminated level, Hg and Pb were associated with moderate contaminated to uncontaminated level, and Cu, Zn, As, Co, and Mn were associated with uncontaminated level of pollution. Furthermore, 64.5% of Cd was water-soluble and exhibited exchangeable fractions; its chemical availability posed a risk to the ecosystem. Spatial analysis, principal component analysis, and a positive matrix factorization model were used to assess the PTE sources. Four principal components contributed to 88.8% of the 8 PTEs concentrations. Mining, smelting, industrial, and agricultural activities, alongside sewage irrigation, the use of agrochemicals, and vehicular emissions are the possible anthropogenic sources that pollute agricultural products and threaten human health in the Xiangjiang Basin.


Author(s):  
Liang Xiao ◽  
Yong Zhou ◽  
He Huang ◽  
Yu-Jie Liu ◽  
Ke Li ◽  
...  

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.


2021 ◽  
Vol 13 (3) ◽  
pp. 1214
Author(s):  
He Huang ◽  
Yong Zhou ◽  
Yu-Jie Liu ◽  
Liang Xiao ◽  
Ke Li ◽  
...  

Soil is both an important sink and a source for contaminants in the agricultural ecosystem. To research the sources and ecological risk of potentially toxic elements in Xiangzhou, China, 326 soil samples from arable land were collected and analyzed for five potentially toxic elements: cadmium (Cd), mercury (Hg), arsenic (As), lead (Pb), and chromium (Cr). In this research, ecological risk assessment was used to determine the degree of contamination in the research area, the outcome of the Geographic Information System was as used to study the spatial distribution characteristics of potentially toxic elements, and random forest was used to evaluate the natural and artificial influencing factors. We surveyed the sources of potentially toxic elements through quantifying the indicators, which gave further opinions. The results were as follows: (1) The average contents of potentially toxic elements were 0.14 mg/kg (Cd), 0.05 mg/kg (Hg), 12.33 mg/kg (As), 28.39 mg/kg (Pb), and 75.21 mg/kg (Cr), respectively. The results compared with the background value of Hubei, neighboring regions, and countries for Cd, As, Pb, and Cr showed mild pollution. (2) The total evaluation of soil pollution via the comprehensive pollution index indicated slight contamination by Cd. Assessment by the potential ecological risk index indicated low ecological risk due to Cd and moderate contamination by Hg. Evaluation through the geo-accumulation index evinced the low ecological risk for Cd, As, and Pb and moderate contamination by Hg. (3) We found that in addition to natural factors (such as soil parent material, soil pH, etc.), long-term industrial pollution, mineral mining and processing, exhaust emissions from transportation, the application of manure from farms as farmyard manure, and sewage irrigation were the primary anthropogenic sources of potentially toxic element contamination in the soil.


Author(s):  
Hongyu Tian ◽  
Cheng Zhang ◽  
Shihua Qi ◽  
Xiangsheng Kong ◽  
Xiangfei Yue

Potentially toxic elements (PTEs) in Chinese agricultural soils, including those in some heritage protection zones, are serious and threaten food safety. Many scientists think that these PTEs may come from parent rock. Hence, at a karst rice-growing agricultural heritage area, Babao town, Guangnan County, Yunnan Province, China, the concentrations of eight PTEs (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) were determined in 148 surface soil, 25 rock, and 52 rice grain samples. A principal component analysis (PCA) and hierarchical cluster analysis were used to divide the surface soil into groups, and inverse distance weighting (IDW) was used to analyze the spatial distribution of PTEs. Soil pollution was assessed with the geoaccumulation index (Igeo). The results show that Cd, Hg, Zn, and Cr were polluting the soil (average Igeo > 0). The highest concentration of PTEs was distributed in the southwest of Babao town in the carbon rock area, which had the highest pH and soil total organic carbon (Corg), Mn, and TFe2O3 contents. PCA biplots of soil samples showed that the carbon rock area was associated with the most species of PTEs in the study area including Pb, Cd, Hg, As, and Zn. The clastic rock area was associated with Cu and Ni, and the lime and cement plants were associated with CaO, pH, Corg, TC, and aggravated PTE pollution around factories. In high-level PTE areas, rice was planted. Two out of 52 rice grain samples contained Cd and 4 out of 52 rice grain samples had Cr concentrations above the Chinese food safety standard pollutant limit (Cd 0.2 mg/kg; Cr 1 mg/kg). Therefore, the PTEs from parent rocks are already threatening rice safety. The government should therefore plan rice cultivation areas accordingly.


Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 330
Author(s):  
Libo Pan ◽  
Xiao Guan ◽  
Bo Liu ◽  
Yanjun Chen ◽  
Ying Pei ◽  
...  

Acid mine drainage (AMD) from abandoned coal mines can lead to serious environmental problems due to its low pH and high concentrations of potentially toxic elements. In this study, soil pH, sulfur (S) content, and arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), zinc (Zn), iron (Fe), manganese (Mn), and mercury (Hg) concentrations were measured in 27 surface soil samples from areas in which coal-mining activities ceased nine years previously in Youyu Catchment, Guizhou Province, China. The soil was acidic, with a mean pH of 5.28. Cadmium was the only element with a mean concentration higher than the national soil quality standard. As, Cd, Cu, Ni, Zn, Mn, Cr, and Fe concentrations were all higher than the background values in Guizhou Province. This was especially true for the Cd, Cu, and Fe concentrations, which were 1.69, 1.95, and 12.18 times their respective background values. The geoaccumulation index of Cd and Fe was present at unpolluted to moderately polluted and heavily polluted levels, respectively, indicating higher pollution levels than for the other elements in the study area. Spatially, significantly high Fe and S concentrations, as well as extremely low pH values, were found in the soils of the AMD sites; however, sites where tributaries merged with the Youyu River (TM) had the highest Cd pollution level. Iron originated mainly from non-point sources (e.g., AMD and coal gangues), while AMD and agricultural activity were the predominant sources of Cd. The results of an eco-risk assessment indicated that Cd levels presented a moderate potential ecological risk, while the other elements all posed a low risk. For the TM sites, the highest eco-risk was for Cd, with levels that could be harmful for aquatic organisms in the wet season, and may endanger human health via the food chain.


Author(s):  
Aneta Olszewska ◽  
Anetta Hanć

Abstract Purpose Tooth enamel might provide past chronological metabolic, nutritional status and trace metal exposure during development. Thus, the trace elements distribution embedded in tooth tissues represents an archive of the environmental conditions. The choice of biomarker is estimated as critical to the measurement of metal exposure. Natal teeth are defined as teeth being present at birth. Methods LA-ICP-MS provides a quantitative assessment of spatial distribution of trace elements in a natal tooth. The objective of the current study was to compare concentrations of building and other elements in a rare but reliable and valid biomarker - natal tooth. Results It have been reported presence of potentially toxic elements: Pb, Cu, Mn, Cd, Ni distributed in prenatally and perinatally formed enamel and dentine. Conclusions Analyses of deciduous enamel can provide answers into individuals’ earliest development, including critical pre- and perinatal period.


Atmosphere ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1307
Author(s):  
Jin-Young Choi ◽  
Hyeryeong Jeong ◽  
Kongtae Ra ◽  
Kyung-Tae Kim

Road and industrial origin particulate matters (PM) are a significant source of potentially toxic elements (PTEs), with health risks to the surrounding residents. In Korea for 60 years, although industries, roads and automobiles have increased aggressively, there are still few PTEs data in PM in road-deposited sediment (RDS) of industrial complexes (ICs). Therefore, this study aimed to investigate the PTE composition of on-road PM10 from nine major ICs and its pollution degree in Korea and evaluate its human health risks. The geo-accumulation index (Igeo) and pollution load index (PLI) elucidated that on-road PM10 were severely polluted by Sb, Zn, Ag and Pb. A combination of principal component analysis (PCA) and chemical tracers was used to define the PTEs sources. The results showed that non-exhaust emission from vehicles’ activity is the primary source of PTEs in on-road PM10, and industrial emissions are the secondary source. The riskiest pathway on carcinogenic and non-carcinogenic by on-road PM10 with PTEs was in-gestion. Traffic origin PTEs including Pb, As, Sb and Cd had a more significant impact on carcinogenic and non-carcinogenic health than those of industrial origins. These results could help mitigate public health risks arising from on-road PM10 and improve air quality in ICs.


Author(s):  
Long Ma ◽  
Jilili Abuduwaili ◽  
Wen Liu

A geographically weighted regression and classical linear model were applied to quantitatively reveal the factors influencing the spatial distribution of potentially toxic elements of forty-eight surface soils from Bosten Lake basin in Central Asia. At the basin scale, the spatial distribution of the majority of potentially toxic elements, including: cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), thallium (Tl), vanadium (V), and zinc (Zn), had been significantly influenced by the geochemical characteristics of the soil parent material. However, the arsenic (As), cadmium (Cd), antimony (Sb), and mercury (Hg) have been influenced by the total organic matter in soils. Compared with the results of the classical linear model, the geographically weighted regression can significantly increase the level of simulation at the basin spatial scale. The fitting coefficients of the predicted values and the actual measured values significantly increased from the classical linear model (Hg: r2 = 0.31; Sb: r2 = 0.64; Cd: r2 = 0.81; and As: r2 = 0.68) to the geographically weighted regression (Hg: r2 = 0.56; Sb: r2 = 0.74; Cd: r2 = 0.89; and As: r2 = 0.85). Based on the results of the geographically weighted regression, the average values of the total organic matter for As (28.7%), Cd (39.2%), Hg (46.5%), and Sb (26.6%) were higher than those for the other potentially toxic elements: Cr (0.1%), Co (4.0%), Ni (5.3%), V (0.7%), Cu (18.0%), Pb (7.8%), Tl (14.4%), and Zn (21.4%). There were no significant non-carcinogenic risks to human health, however, the results suggested that the spatial distribution of potentially toxic elements had significant differences.


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