Pollution Characteristics Of Heavy Metals Research Articles

Characteristics of nutrients pollution and ecological risk assessment of heavy metal in sediments of Fenhe River, Taiyuan section, China

AbstractThis study aimed to reveal the characteristics of nutrients and heavy metals associated with ecological risks in the sediments of Fenhe River, Taiyuan section. The concentrations of nutrients (total nitrogen, total phosphorus, total organic matter) and heavy metals (As, Cu, Zn, Pb, Cr, Ni, Hg, Cd) were investigated. Spatial distribution, correlation analysis and source identification were facilitated to indicate nutrient and heavy metal pollution characteristics. Evaluations of heavy metals’ contamination degree were achieved by comprehensive ecological risk indexes including Igeo, Iin, Cf, pollution load index and risk index. The results showed that nutrients accumulated in the middle region and were mainly from embryophyte, zooplankton and phytoplankton or algae, based on C/N values. Large spatial variabilities existed in heavy metal distribution patterns; source identification for heavy metals revealed they were from natural sources and anthropogenic activities based on a principal component analysis model. Results of different ecological risk indexes showed that pollution associated with Hg was rated as a moderate ecological risk but was significant contamination, higher ecological risks mainly existed in the middle region.

Analysis and Evaluation on Characteristics of Heavy Metal Pollution in the Coastal Farmland Soil along the Wuma River

The thesis is aimed to provide a reference for the sustainable utilization of farmland soils along the Wuma River, an upstream tributary of the Chishui River in Guizhou Province. Geo accumulation index method, Nemero comprehensive pollution index method, and potential ecological hazard index method were used based on the experimental data for analyzing and evaluating the heavy metal pollution status of farmland soil along Wuma River. The results showed that: (1) The contents of heavy metals Ni, Cu, Zn, Pb and Hg in farmland soil exceeded the soil background values of 9.82%, 47.80%, 13.72% and 76.06% in Guizhou Province, respectively, but did not exceed the standard limit class II based on the environmental quality. (2). The pollutants of Pb and Zn in the research area mainly come from mineral exploitation, waste residue accumulation, and transportation. The enrichment of Cr and Cu may originate from the domestic garbage dumping and incinerated waste by residents along the coast and irrational agricultural activities. The main contents of Cd, As and Hg come from soil geochemistry. (3) The ranking of accumulations of eight heavy metals was IPb>IHg>ICu>INi>IZn>ICr>IAs>ICd, among which Pb was non-moderately polluted and the remaining heavy metals were at the clean level; Nemero comprehensive pollution index showed that As, Cr, Zn, and Ni were mildly polluted, while Pb, Hg, and Cu were moderately polluted. The ranking of potential ecological risk levels for the eight heavy metals was Hg, Pb, Cu, Ni, As, Cd, Cr, Zn. The overall ecological risk level is mild.

Assessment of heavy metal pollution and ecological risk in river water and sediments in a historically metal mined watershed, Northeast Japan.

Mining legacies continue to impact the geochemical cycles in historically mined watersheds after mine closure. The Hokuroku District in Northeast Japan is a famous metal mining area with a long mining history; however, studies on the distribution mechanisms and pollution characteristics of heavy metals in these historically mined watersheds after the boom period of mining activities are lacking. This study aims to provide fundamental insights into the effects of the mining activities and hydrological conditions on heavy metal pollution in the Kosaka watershed, Hokuroku District. Sampling was performed in terms of watershed segmentation, and the outlet of the tributary within each sub-watershed was also sampled to capture the diffusional pollution status. The distributions of Zn, Cu, Cd, Pb and As in river water and sediments, as well as their pollution characteristics and ecological risks, were analysed under different hydrological conditions. Our findings provide evidence of the ecological risk in surface water induced by Zn, Cu and Pb pollution in the Kosaka River system. In a high proportion of the sub-watershed, there was moderate to strong enrichment in Cd, Cu and Zn in the river sediments. The sub-watersheds with high pollution levels and ecological risk were highly consistent with the sub-watersheds encompassing abandoned mine sites. Suspended particles carried large amounts of Pb and Cu, especially on rainy days. The heavy metal contents in river water were very sensitive to occasional rainfall events; rainy days posed the most risk to organisms in the Kosaka River, followed by the low-water-level season and the high-water-level season.

Heavy metal pollution characteristics and health risk assessment of dust fall related to industrial activities in desert steppes.

China’s desert steppe is the transition zone between the grasslands in central China and the arid desert. Ecological security in this region has long been a subject of debate, both in the local and academic communities. Heavy metals and other pollutants are readily released during industrial production, combustion, and transportation, aggravating the vulnerability of the desert steppes. To understand the impact of industrial activiteis on the heavy metal content of dust fall in the desert steppe, a total of 37 dust fall samples were collected over 90 days. An inductively-coupled plasma mass spectrometer (NexION 350X) was used to measure the concentration of heavy metals Cu, Cd, Cr, Pb, Mn, Co, and Zn in the dust. Using comprehensive pollution index and multivariate statistical analysis methods, we explored the characteristics and sources of heavy metal pollution. We also quantitatively assessed the carcinogenic risks of heavy metals resulting from dust reduction with the help of health risk assessment models. The heavy metals’ comprehensive pollution index values in the study area’s dust fall were ranked as follows: Zn > Cd > Pb > Mn > Cu > Co > Cr. Among these, Zn, Cd, and Pb were significant pollution factors in the study area, and were affected by industrial production and transportation. The high pollution index was concentrated in the north of the research industrial park and on both sides of a highway. The seven heavy metals’ total non-carcinogenic risk index (HI) values were ranked as follows: Mn > Co > Pb > Zn > Cr > Cu > Cd (only the HI of Mn was greater than one). Excluding Mn, the non-carcinogenic and carcinogenic risk index values of the other six heavy metals were within acceptable ranges. Previous studies have also shown that industrial transportation and production have had a significant impact on the heavy metal content of dust fall in the desert steppe.

Heavy metal pollution characteristics and health evaluation of farmland soil in a gold mine slag area of Luoyang in China

The characteristics of eight heavy metals (lead, zinc, copper, nickel, chromium, cadmium, mercury and arsenic) in the surface soil of the historical slag area of the Au ore dressing plant in the South-West of Luoyang City were investigated and evaluated in terms of a pollution index, potential ecological hazards and health risks. The results showed that the average amounts of the heavy metals Pb, Zn and As in the soils of plots S3, S5, S7, S12 and S18 exceeded the soil pollution risk screening values. The Mero comprehensive pollution index in plots S7, S12 and S18 was greater than 3, indicating severe pollution. The severe pollution plot integrated the potential ecological risk index (RI) of each sampling point, which was in the order of RIS12 > RIS18 > RIS7 > RIS5 > RIS3. Among the heavy metals, Cd poses the greatest threat to ecological and human health. The effects of heavy metals in soil on the single non-carcinogenic health risk index (HQ) and the non-carcinogenic total risk index through three exposure pathways were in the order of HQHg < HQCu < HQNi < HQZn < HQCd < HQCr < HQPb < HQAs < 1, which meant that the adult and child total carcinogenic risk (TCR) and individual carcinogenic health risk indices were above the maximum acceptable human health level recommended by the USEPA (10-6). TCRAs and TCRCd accounted for 75.65% and 23.94% of the adult TCR, respectively. TCRAs and TCRCd accounted for 75.93% and 23.97% of the child TCR, respectively. Overall, the TCR of children was greater than that of adults. In summary, the soil in the historical slag area of the Au ore dressing plant constitutes a serious threat to the surrounding ecological environment and to residents. Keywords: historical slag area, heavy metals, pollution assessment, health assessment, farmland soil, ecological hazard DOI: 10.25165/j.ijabe.20211405.6536 Citation: Wang H, Zhang H, Xu R K. Heavy metal pollution characteristics and health evaluation of farmland soil in a gold mine slag area of Luoyang in China. Int J Agric & Biol Eng, 2021; 14(5): 213–221.

Evaluation and Sources of Heavy Metal Pollution in the Surface Soil of the Qaidam Basin

To understand surface soil heavy metal pollution characteristics, and the spatial distribution and sources of pollution in the main sedimentary features of the Qaidam Basin, a total of 129 topsoil samples(0-10 cm) were collected within a 25 km radius. The concentrations of As, Ba, Cr, Mn, Nb, Ni, Pb, Ti, Zn, Zr, and ten kinds of heavy metals were determined, the degree of contamination and potential sources quantitatively analyzed based on enrichment factors(EFs), the ground accumulation index(Igeo), and the absolute principal component-multiple linear regression(APCS-MLR) receptor model. The results showed that the surface soils of the Qaidam Basin have experienced pollution from ten kinds of heavy metals since the 1960s, with varying degrees of enrichment. As and Pb represent probable point source pollutants, and the basin as a whole shows negligible to low levels of pollution. The APCS-MLR analysis showed that heavy metal pollution derives from two sources, natural factors and anthropogenic(transportation) sources. Specifically, As, Cr, Mn, Nb, Ni, Ti, Zn, and Zr are associated with natural sources, while Ba and Pb are associated with both natural and anthropogenic sources.

Characteristics of heavy metal pollution in soils of a typical copper smelting site in China

During copper smelting, discharge of waste gas, waste water and waste residue has resulted in heavy metals pollution in soils. In a typical copper smelting site in China, arsenic pollution was the most serious, which could be found in soils within 6 m. All the measured heavy metals including Cu, Pb, As, Cd, Zn, Hg, Ni, Cr exceeded background concentrations in the study area. Key contamination areas of the site distributed nearby the uncontrolled emission source and under the leakage area of waste water and waste residue. This study is of great significance to the soil management and control of copper smelting industry.

Evaluating heavy metal pollution and potential risk of soil around a coal mining region of Tai’an City, China

Monitoring the spatial distribution characteristics of heavy metal pollution and evaluating its potential risks in the soil is essential for promoting regional socioeconomic development and maintaining the safety of the ecological environment. In this study, a representative coal mining region in Tai’an City, Chinas was selected as the study area, eight typical heavy metal elements (HMEs), i.g. Cu, Pb, Zn, Cd, Cr, As, Hg, Ni in the topsoil (0–20 cm) of 59 randomly generated sample sites were measured and monitored through sampling, testing and statistical analysis, and their spatial distribution patterns were analyzed accordingly. The single factor pollution index（SFPI) method, comprehensive pollution index (CPI) method and potential ecological hazard index (PEHI) method were employed to systematically computed and analyzed the single factor, comprehensive pollution and potential ecological risks of the selected HMEs in the soil. Results found that: (1) the average measured content of these elements all exceeded the referenced background value. The Cr element pollution was the lowest (3.39%), while the pollution of Ni, Cd and Hg elements were the highest (86.44%, 83.05 % and 81.36%, respectively). (2) The comprehensive pollution level was above mild pollution at all sample sites, and the comprehensive pollution was mainly ranged in the mild pollution level (59.32%); The moderate pollution level of comprehensive potential ecological risk accounted for 64.41%, and the spatial distribution was annular from northwest to southeast. (3) The values of potential ecological risk index indicated that Hg and Cd were the main pollution elements in this coal mining region, and Cd had the highest pollution rate. The findings of this study can be used to evaluate the pollution in other coal regions, and provide reference for the decision-making of soil heavy metal pollution control.

Assessment of heavy metal pollution and water quality characteristics of the reservoir control reaches in the middle Han River, China

The systematic and scientific assessments on heavy metal pollutions and water quality characteristics are greatly important to protecting the river and coastal eco-environment. In this paper, sediment size, organic matter, total nitrogen, total phosphorus, and heavy metal contents were analyzed by collecting surface sediments and surface water in the reservoir control reach of the middle Han River. Besides, sediment enrichment factor and sediment pollution index were used to evaluate the heavy metal pollution, and enrichment analysis and redundancy analysis were applied to analyze the sources of heavy metals in sediments. The results show a low heavy metal content in the surface water, and the water quality is graded as a Good level. The average enrichment factor of Cd in surface sediments reached 4.63. Zn and Cu also showed significant enrichment in the tributary sediments, whose content far exceeded the background value of soil elements. Thus, the potential ecological risk of heavy metals was at a medium level. Statistical analysis and enrichment factors showed that the accumulation of heavy metals in sediments was affected by pollutant input and reservoir regulation, and it was urgent to conduct an integrated regulation of the heavy metals in river sediment. This study provided an insight into the understanding of feasible assessment for heavy metal contaminated sediment.

Research of Pollution Characteristics of Heavy Metals in Soil of Typical Closed Zinc Smelting Enterprises in Qinling Mountains

Research of Pollution Characteristics of Heavy Metals in Soil of Typical Closed Zinc Smelting Enterprises in Qinling Mountains

Physicochemical properties and heavy metal pollution characteristics and correlation analysis of sludge landfill

ABSTRACT Heavy metal content and speciation of sludge, physicochemical properties of sludge, and the correlation between heavy metal content and speciations were investigated in this work. Results demonstrated that organic matter content of sludge ranged from 158.4 to 474.5 g kg−1, total nitrogen content from 9.95 to 27.45 g kg−1, total phosphorus content from 22.72 to 41.45 g kg−1, and total potassium content from 5.04 to 11.20 g kg−1. The sludge contains high content of organic matter, phosphorus and potassium and low content of nitrogen, it indicated that the sludge has a big prospect of agricultural use, and it could improve and increase soil fertility. Cu and Zn content exceed the agricultural use standard. Heavy metal speciations analysis indicated that Cu mainly exists in oxidizable speciation; Zn and Cd mainly exist in exchangeable and reducible speciation; Mn and Pb mainly exist in residual speciation; Cr, Ni, As and Hg mainly exist in oxidisable and residual speciations. These results indicated that Zn and Cd migration and bioavailability are strong in the environment, whereas Cu, Cr, Ni, As and Hg are weak. Mn and Pb are most stable in the sludge in these heavy metals. The correlation analysis indicated that heavy metal content and physicochemical properties obtained a positive correlation, such as with the heavy metal content, and total carbon, total nitrogen, ammonia nitrogen content obtained a positive correlation with heavy metal content, heavy metal had the same source and synergistic effect, and heavy metal content obtained a positive correlation with speciation in the sludge sample.

Characteristics of Heavy Metal Pollution and Ecological Risk Evaluation of Indoor Dust from Urban and Rural Areas in Taiyuan City During the Heating Season

The presence of heavy metals in indoor dust is a world-wide concern owing to its negative impact on humans. In this study, we collected indoor dust samples from urban and rural residential areas during the heating season in Taiyuan City. We then identified the concentrations of 11 heavy metals (Cd, Co, Cr, Pb, Mn, Ni, Cu, Zn, V, As, and Hg) using inductively coupled plasma-mass spectrometry. Based on the concentrations, we categorized the pollution levels of indoor dust using the geo-accumulation index and the pollution load index. We further identified the sources of heavy metals using the enrichment factor and principal component analysis. Finally, we evaluated the potential ecological risks of heavy metals via the potential ecological index. The results illustrated that ① with the exception of Co, Mn, and V, the mean concentrations of Cd, Cr, Cu, Ni, Pb, As, Zn, and Hg in indoor dust were higher than the soil background values of Shanxi Province. There was a significant difference (P<0.05) in the concentrations of Co, Cr, Cu, Mn, Ni, and Hg between the urban and rural areas. ② Overall, the pollution degree of heavy metals in indoor dust was identified as moderate in the urban area of Taiyuan City, but slight in the rural area. The indoor dust sample in the urban area was not contaminated by Co, Mn, and V. However, it was slightly polluted by As, Ni, and Hg. In addition, it was close to moderately polluted by Cd, Cr, Cu, Pb, and Zn. In the rural area, the pollution degrees of all the metals, except for Hg and V, in indoor dust were lower than those in the urban area. ③ The As, Cd, Cu, Pb, Zn, and Hg in indoor dust for both urban and rural areas might have mainly originated from anthropogenic sources. The pollution sources were mainly transportation and industry in the urban area and coal combustion and indoor smoking in the rural area. The Co, Cr, Mn, Ni, and V in indoor dust in Taiyuan City might have mainly originated from natural sources. ④ The ecological risk of heavy metal pollution in indoor dust for both the urban and rural areas of Taiyuan City was relatively high, with integrated ecological risk indexes of 359.43 and 471.02 in the urban and rural areas, respectively. In addition, Cd and Hg were the largest contributors.

Spatial Distribution Characteristics of Heavy Metals in Surface Soil of Xilinguole Coal Mining Area Based on Semivariogram

Heavy metal pollution is a major environmental problem facing humankind. Locating the source and distribution of heavy metal pollutants around mines can provide a scientific basis for environmental control. The structure effect and random effect of a semivariogram can be used to determine the reason for spatial differences in the heavy metal content in surface soil, and the coefficient of variation and regression analysis can be used to confirm that the verification accuracy meets the geostatistical requirements. According to the maximum difference method, the content of heavy metals in the surface soil of the mining area is higher than that of the surroundings, and Cu and Zn levels are higher than the background values for Inner Mongolia. In the present case, Zn, Mn, Pb, Cr, Ni, and Cu levels exceeded the background values for the surroundings of the study area by 65.10%, 53.72%, 52.17%, 46.24%, 33.08%, and 29.49%, respectively. The results show that human activities play a decisive role in the spatial distribution of heavy metals, leading to their spatial distribution in the form of “core periphery”. This distribution pattern was significantly affected by the slope, NDVI value, and the distance from the mining area, but the spatial distribution of Pb was significantly related to high-grade roads. The research methods and conclusions have reference significance for the sources and spatial distribution characteristics of heavy metal pollution in similar mining areas and provide a target for the prevention and control of environmental pollution in the study area.

Characteristics of Heavy Metal Pollution in Farmland Soil along the Lancang River in Lincang, Yunnan

Taking the farmland soil along the Lancang River in Lincang as the research object, through soil sampling test and analysis, using single factor evaluation method, Nemeiro comprehensive pollution index method and relative pollution index method, the heavy metals As, Cd, Pb and Zn pollution characteristics and causes in farmland along the Lancang River were analyzed. The results show that according to the national soil environmental quality standards, the Cd in the farmland along the Lancang River in Lincang seriously exceeded the standard on a large scale, followed by Pb and Zn, while As did not exceed the standard; the soil single factor pollution index is Cd>Zn>Pb>As. It shows that the relative pollution indexes of As, Cd, Pb and Zn in farmland soil all exceed the standard, and the exceeding rate is Pb>Zn>Cd>As. The pollution of heavy metals in the soil of the farmland along the Lancang River in Lincang is not only caused by mine development, but also related to its high background value. The pollution of heavy metals in farmland soil along the north river from upstream to downstream has changed significantly. The correlation between the pollution of As, Cd, Pb and Zn in the farmland along the Lancang River in Lincang is significant, the probability of homology is very high, and there is a danger of combined pollution of four heavy metals.

Effect of river-lake connectivity on heavy metal diffusion and source identification of heavy metals in the middle and lower reaches of the Yangtze River

Metal pollution poses a significant threat to ecological security and human health. Current research on the causes, sources and distribution of metal pollution in the Yangtze River plain is lacking. This study investigated the accumulation, risk, distribution, and sources of heavy metals in 62 lakes along the Yangtze River, and analyzed the relationship between river-lake connectivity, economic structure, population and metal diffusion. The mean concentrations of Cr, Cu, Hg, Zn, Cd, Pb and As in the surface sediments of these lakes were 90.8, 60.1, 0.06, 102, 0.89, 42.7, and 6.01 mg/kg, respectively. Most (99%) of the lake sediments were contaminated with Cd, and the lakes in the middle reach and southern bank of the Yangtze River had a higher ecological risk. Cr originated from the natural environment, whereas Zn, Cu, Pb, Cd and As were affected by human activities. The lakes disconnected from the Yangtze River had higher concentrations of Cu, Zn, Pb and As, while the lakes connected to the river had higher concentrations of Cd and Cr. This comprehensive analysis determined the pollution characteristics of heavy metals, illustrated the causes of non-point pollution in the Yangtze River plain, and showed that soil-water erosion is important in metal diffusion.

Study on Unconfined Compressive Strength of Zinc Contaminated Soil Solidified by Magnesium Phosphate Cement under Acid Rain

In this article, through the preparation of artificial contaminated soil in laboratory and simulated acid rain pollution to zinc magnesium phosphate cement (MPC for short) solidified soil erosion, the unconfined compressive strength characteristics of a single heavy metal (Zn) pollution under the above conditions was studied. In addition, water glass was added to improve the acid resistance of magnesium phosphate cement solidified soil. The effects of the mixing ratio of curing agent (MgO/KH2PO4, M/P for short), initial pH value by simulating acid rain, and the water glass content on the physical and mechanical properties of solidified zinc contaminated soil were analyzed. Studies have shown that when M/P=4, solidified soil contaminated by zinc has better solidification strength and solidification effect than M/P=6; adding water glass can increase the unconfined compressive strength of solidification of zinc contaminated soil by cement. 4% water glass content has a better effect to improve the strength of solidified soil; When the cement with M/P=4 has better engineering characteristics and acid resistance than that with M/P=6. Therefore, water glass can improve the engineering properties of solidified soil contaminated by zinc under sour environment effectively.

Heavy metal pollution characteristics and health risk evaluation of soil around a tungsten-molybdenum mine in Luoyang, China

Heavy metal pollution in mining area soil and its impact on human health have been becoming one of the most important global environmental problems. This study investigated the heavy metals in the soil around the tungsten-molybdenum mining area in southwestern Luoyang, Henan Province, assessed the level of heavy metal pollution in the soil around the tungsten-molybdenum mining area, and quantified the risks of these pollutants to human health. To assess these potential threat levels, The pollution index, potential ecological hazards and health risk assessment methods recommended by the United States Environmental Protection Agency (USEPA) are applied. The results indicated that the average soil content of the heavy metals Zn, Cr, Cd and As exceeded the soil pollution risk screening value. The Nemerow comprehensive pollution index (PN) was greater than 3, which indicated severe pollution. The potential ecological risk index (RI) of each sampling point was integrated in the order $${\mathrm{RI}}_{\#7}$$ > $${\mathrm{RI}}_{\#6}$$ > $${\mathrm{RI}}_{\#5}$$ > $${\mathrm{RI}}_{\#3}$$ > $${\mathrm{RI}}_{\#4}$$ > $${\mathrm{RI}}_{\#2}$$ > $${\mathrm{RI}}_{\#1}$$ . Among the heavy metals, Cd posed the greatest ecological threat, accounting for 91.32% of RI. The effect of heavy metals in soil on the single non-carcinogenic health risk index (HQ) and non-carcinogenic total index (HI) through three exposure pathways, oral intake > skin contact > respiratory inhalation, was $${\text{HQ}}_{{{\text{Zn}}}} {\text{ < HQ}}_{{{\text{Cu}}}} {\text{ < HQ}}_{{{\text{Cd}}}} {\text{ < HQ}}_{{{\text{Pb}}}} {\text{ < HQ}}_{{{\text{Cr}}}} { < 1}$$ . The sum of $${\mathrm{HI}}_{\mathrm{Pb}}$$ and $${\mathrm{HI}}_{\mathrm{Cr}}$$ accounted for 92.96 and 92.98% of adults and children, respectively. In addition to the inhalation route $${\mathrm{CR}}_{\mathrm{Cd}}$$ , $${\mathrm{CR}}_{\mathrm{Cr}}$$ and $${\mathrm{CR}}_{\mathrm{Cd}}$$ in the study area were higher than the maximum acceptable human-level recommended by the U.S. EPA (10–6), and the CR and TCR were higher in children than in adults. Therefore, the heavy metal pollution of soils in the studied tungsten-molybdenum mine area was found to pose a serious threat to the surrounding ecological environment and residents’ health.

Multiple adsorption systems and electron-scale insights into the high efficiency coadsorption of a novel assembled cellulose via experiments and DFT calculations

In view of the characteristics of heavy metal and antibiotic compound pollution in the Pearl River Basin in Guangzhou. More scientifically modified cellulose, named HVUC, is characterized by multiple hydrophilic groups, long chains and large space and displays highly efficient adsorption of both Cd and sulfamethoxazole (SMZ) and good adaptability in a wide pH range and at high ion strength. Furthermore, the coadsorption mechanism was elaborated from multiple angles. Multiple adsorption experiments explained the competition and synergy effect in the adsorption process. The electrostatic potential maps indicated that HVUC had advantageous adsorption sites for both Cd and SMZ and that electrostatic interactions had the greatest impact on the adsorption of Cd and SMZ. The electron density and differential charge density images proved that Cd more easily overlapped electron clouds and transferred electrons with HVUC and that SMZ- and could act as a bridge for SMZ-. The equilibrium configuration indicated that the formation of Cd-SMZ- complexes led to the bending and folding of SMZ-, which was not conducive to overall adsorption when SMZ- was close to HVUC and could lead to the release of SMZ- when Cd was close to HVUC, which confirmed the proposed mechanism of complexation-decomplexation-complexation.

A spectral characteristic analysis method for distinguishing heavy metal pollution in crops: VMD-PCA-SVM

Exploring the characteristics and types of heavy metal pollution in crops has important implications for food security and human health. In this study, a method for distinguishing heavy metal-polluted elements in corn leaves was proposed. Based on the spectral data obtained from corn leaves polluted by Cu and Pb, the spectra were divided into four characteristic regions. Variational mode decomposition (VMD) was used to decompose the first-order differential spectrum, and the characteristic analysis was transformed from the spectral domain to the frequency domain. Each modal component was processed separately using principal components analysis (PCA) according to the different characteristic regions to obtain the main information on the pollution characteristics, and then a two-dimensional space was constructed to identify the differential characteristics of corn under Cu and Pb stress visually. Finally, the support vector machine (SVM) classifier was used to get the classification line model to distinguish Cu and Pb pollution. This method was named VMD-PCA-SVM. The results show that the method can highlight the spectral response characteristics of heavy metal pollution, which is expected to guide the rapid and non-destructive identification of heavy metal pollution in crops and the formulation of remediation strategies.

Heavy metal pollution characteristics and risk assessment of the soil of Lotus Pool influenced by JACW

During quite a long time, the Japanese Abandoned Chemical Weapons (JACW) has been a constant threat to the public safety and the environment. Because of the environmental corrosion, the chemical agents leaked from the JACW pollute the soil and water severely, especially the heavy metal chemicals. This paper demonstrated the analytical result of heavy metal pollution caused by JACW in the soil of Lotus Pool, where located in the Northeast of China. 10 typical soil samples were taken, in which 7 heavy metal elements were quantified by ICP-MS. By calculating the Nemerow Index and the ecological potential risk index, the pollution degrees and risk assessment of most sites were evaluated.