Evaluation Of Heavy Metal Pollution Research Articles

In situ measurement of the three-dimensional distribution of labile copper in sediment pore water using a microneedle sensor with nanoporous structure

Conventional ex situ analytical methods for sediment pore water are susceptible to disruptions in the speciation equilibrium of metals due to changes in external conditions. This study introduced an innovative in situ method for detecting the three-dimensional distribution of labile copper (CuLabile) in sediment pore water with high spatial resolution using a highly stable microneedle electrochemical sensor. The sensor featured a nanoporous tip structure and embedded gold nanomaterials with excellent electrocatalytic performance. The nanoporous structure could prevent the nanomaterials from falling off because of friction during the in situ detection process in sediments. The sensor exhibited good detection performance under different salinity conditions with a detection limit of 0.2nM. Vertical and three-dimensional distributions of CuLabile in sediment pore water were successfully obtained using the in situ microneedle sensor. The results showed that the concentration of CuLabile was in the range of 5.2–43.5nM, with a maximum value at a depth of approximately 4cm, while there was almost no difference in the horizontal direction of a specific sediment sample column. Furthermore, this functional sensor could be extended to the in situ detection of other labile metals in sediment pore water. Environmental implicationCopper is a typical heavy metal pollutant that can disrupt the normal physiological functions of enzymes when its concentration exceeds a certain threshold, causing serious damage to aquatic organisms, ecosystems and human health. This study introduces an innovative in situ method for detecting the spatial distribution of labile copper in sediment pore water using a functional microneedle sensor. This method can avoid the disruption of copper speciation equilibrium during the extraction process of pore water and is helpful for the convenient and accurate evaluation of heavy metal pollution in sediments.

Metal-organic framework membrane-based probe for on-site and sensitive detection of Cr(VI) in groundwater using a portable system

Groundwater sources are often contaminated by heavy metal ions such as hexavalent chromium (Cr(VI)) produced by various industrial processes, which can accumulate in the human tissues through drinking of water, resulting in serious health hazards. For this reason, on-site and sensitive detection of heavy metals in contaminated groundwater is essential for effective heavy metal pollution evaluation. Here, we develop a carboxymethyl cellulose (CMC)-metal–organic framework (MOF) fluorescence sensing membrane and couple with portable laser-induced fluorescence spectrometers (LIFs) for on-site detection of trace Cr(VI) in groundwater. The membrane was prepared using coordination assembly approach between flexible CMC and MOF and subsequent vacuum-assisted filtration. The CMC-MOF membrane exhibits very sensitive behaviour to Cr(VI) with a detection limit as low as 3.72 ppb, lower than the World Health Organization defined action level (50 ppb). Density functional theory calculations show that the formation of coordination bonds between CMC and MOF results in the excellent stability of the CMC-MOF membrane, and Cr(VI) simultaneously binds to two nitrogen atoms in MOFs, enabling CMC-MOF membrane to enrich and be on-site detection of trace Cr(VI) in contaminated groundwater by portable LIFs. This work provides an approach for on-site and highly sensitive assessment of heavy metal in contaminated groundwater.

Analysis and Evaluation of Heavy Metal Pollution in Farmland Soil in China：A Meta-analysis

In this study, a Meta-analysis was used to investigate the pollution status of eight farmland soil heavy metal elements (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in China. Meanwhile, their spatiotemporal changes and differences between different types of cultivated land were explored. The research data were chosen from 449 relevant literature data collected by CNKI and Web of Science from 2005 to 2021, and the Meta-analysis used a weighted method based on "sampling numbers", "study area", and "standard deviation". The results showed that the national average values of the eight heavy metal elements in Chinese farmland soil were ω(As)11.00 mg·kg-1, ω(Cd)0.350 2 mg·kg-1, ω(Cr)62.91 mg·kg-1, ω(Cu)28.87 mg·kg-1, ω(Hg)0.135 1 mg·kg-1, ω(Ni)28.91 mg·kg-1, ω(Pb)34.67 mg·kg-1,and ω(Zn)90.24 mg·kg-1. Compared with their background values, all elements except As accumulated to some extent, and Cd and Hg accumulated the most, exceeding their background values by 177.9% and 340.3%, respectively. The research results indicated that Cd and Hg were the main pollution elements in farmland soil in China, and their accumulation was mainly influenced by human activities. In terms of their temporal and spatial changes, the Yunnan-Guizhou Plateau and the eastern coast were the most concentrated areas of pollution cases, and the pollution center shifted from the middle reaches of the Yangtze River to the southwest over time. The accumulation of heavy metals in farmland soil was affected by crop planting types, and the accumulation of heavy metals in vegetable and paddy soil was significantly greater than that in other cultivated land types.

Evaluation of Heavy Metals Pollution in the Sediments of Diyala River Lower Reaches, Eastern Iraq

Investigating the heavy metals in soil is important to the life of humans and living organisms. Diyala River Lower Reaches was chosen due to the changes in environmental characteristics that took place in recent years. Twelve sediment samples were collected from four different sites. The physical, and chemical properties and the concentrations of nine heavy metals were indicated. The results showed that the average concentrations of arsenic, copper, chromium, cobalt, iron, manganese, nickel, lead, and zinc are 8.5, 45.7, 538.5, 12.2, 5.07, 991.7, 183.5, 16.07, 136.5 ppm, respectively. They reflect contamination with arsenic, chromium, and nickel, while they are free of lead, and zinc contamination, according to the Environmental Protection Agency's (EPA) sediment quality guidelines. The measured contamination indices (the enrichment factor (EF), contamination factor (CF), degree of pollution (Cdeg), geographical accumulation index (Igeo), and pollution load index (PLI)), reflected high contamination factor for arsenic and chromium, and medium for manganese, nickel, lead, and zinc, while low for copper and cobalt. Based on all the results in all sampling sites indicate the presence of heavy element contamination in the sediments of the Diyala River Lower Reaches.

Analysis of Heavy Metal Pollution Evaluation and Correlation of Farmland Soil and Vegetables in Zhaotong City

A farmland area in Zhaotong City was taken as the research object， and the method of point-to-point collaborative sampling was used to collect farmland soil and vegetables in Zhaotong and test the content of six heavy metals， namely As， Pb， Cu， Zn， Cd， and Cr. The geo-accumulation index and potential ecological risk index were used to evaluate the heavy metal pollution of soil. The health risk model was used to evaluate the risk to the human body imposed by vegetables. The results showed that Cu， Zn， Pb， Cd， and Cr pollution existed in the research area. Compared with the risk screening value of farmland， the over-standard rates were 34.35%， 6.87%， 2.29%， 80.15%， and 6.11%， respectively； Pb， Cd， and Cr were found in vegetables. Compared with the pollutant limit in food， the over-standard rates were 6.87%， 15.27%， and 36.64%， respectively. According to the soil pollution evaluation， Cd in the soil showed a strong ecological risk， and other heavy metals in the soil showed a mild ecological risk. The human health risk evaluation model showed that both non-carcinogenic risk and carcinogenic risk were out of the acceptable range and had a greater influence on children. Correlation analysis showed that As in the soil had an antagonistic effect on Cu and Zn absorption by vegetables， whereas Cr in the soil could promote Cu and Zn absorption by vegetables.

Characteristics and evaluation of heavy metal pollution in a soil–wheat system of an arid oasis city in northwest China

In this paper, the Cu and Ni accumulation and contamination levels in agricultural soils and wheat around a smelter in Jinchang City in northwest China were investigated with a combination of field investigations and indoor analytical tests, using a soil–wheat system as the study area. The average Cu and Ni contents in the soil were 119.50 mg kg–1 and 123.40 mg kg–1, respectively, both of which exceeded the local soil background values. The Cu and Ni contents in 46.15% o and 26.92% of sampling sites, respectively, exceeded the screening values for soil contamination risk in agricultural land in China. The average Cu content in different parts of wheat was in the order of roots (24.22 mg kg–1) > leaves (20.11 mg kg–1) > husks (5.51 mg kg–1) > grains (4.05 mg kg–1) > stalks (3.74 mg kg–1). Furthermore, the average Ni content ranked as leaves (24.64 mg kg–1) > roots (21.12 mg kg–1) > husks (6.95 mg kg–1) > stalks (1.75 mg kg–1) > grains (0.38 mg kg–1). The health risk evaluation showed that with average hazard index values of 0.88 for adults and 1.04 for children for Cu and Ni in wheat grain, wheat in this region is unlikely to pose a health risk to adults but may pose a lesser health risk to children. The Ni bio–concentration and translocation factors in the husk and leaves of wheat were greater than those of Cu and smaller than those of Cu in the other parts of wheat. The results of this study provide basic data for the remediation of heavy metal contamination in local agricultural soils.

Source Appointment and Assessment of Heavy Metal Pollution in Surface Dust in the Main District Bus Stops of Tianshui City

In this study, a PMF model was used to identify the sources and pollution level of heavy metals in the surface dust of a bus station. On the basis of the traditional heavy metal pollution evaluation methods, the Hakanson toxicity response coefficient was used to modify the traditional weight. The matter-element extension theory was introduced to reflect the toxicological properties and hazard degree of the heavy metals, and the matter-element extension model was established to evaluate the pollution level of heavy metals in the surface dust of the study area. The results were compared with Igeo, PN, and RI. ① Except for Co and V, the other heavy metals were higher than the Gansu soil background values by 1.29-9.30 times. The points of Cu and Pb exceeded the rate by 100%, and Cr, Ni, and As exceeded the rate by 96.15%, 94.23%, and 96.15%, respectively. ② PMF showed that source 1 was a natural source, and its contribution rate to V was 32.12%. Source 2 was natural-traffic pollution sources, contributing 51.50% and 33.37% to Cu and Co, respectively. Source 3 was a construction waste pollution source, with contribution rates of 45.06% and 44.70% for Cr and Ni, respectively, and source 4 was a coal-traffic mixed source, with contribution rates of 49.89% and 75.25% for As and Pb, respectively. ③ The matter-element evaluation results showed that the surface dust of the bus stops was mainly class IV (moderately polluted), and 13% of sample points were still clean, 37% were moderately polluted, and 25% were slightly and heavily polluted. The results of this method were quite different from the PN results and were more consistent with the RI results, indicating that its evaluation results were more sensitive and can be used for heavy metal pollution assessment.

Evaluation of Heavy Metal Pollution in Commonly Consumed Mollusc (Crassostrea gasar) from Elechi Creek, River State, Nigeria and the Health Risk Implications

Marine biotas are used to assess potential adverse human health risks associated with consuming protein-rich aquatic organisms. Heavy metal content of Mangrove oysters (Crassostrea gasar) was evaluated between January and June 2022 in 3 stations. Six heavy metals (copper, cadmium, zinc, lead, arsenic and iron) were determined using standard methods. Target Hazard Quotient (THQ) and Hazard Index (HI) were used for the non-carcinogenic assessment while Target Cancer Risk (TR) was used for the carcinogenic assessment of the potential human health risk of consuming the oysters. The heavy metal values recorded were Cu (473.2 – 596.7 mg/kg), Cd (2.33 – 3.84 mg/kg), 209.02 – 246.41 mg/kg), Pb (6.16 – 12.07 mg/kg), As (0.012 – 0.016 mg/kg) and Fe (1609.0 – 1846.0 mg/kg). All the heavy metals were above the acceptable limits except arsenic. Stations 2 and 3 had relatively higher values; attributed to anthropogenic activities. The THQ and HI values were less than 1 in all the metals and stations while TR for Pb and arsenic were within the negligible range in all the stations. However, Cd was unacceptable among the children in station 2. Station 3 had relatively higher values while the children were more vulnerable to both non-carcinogenic and carcinogenic risks. In conclusion, the consumption of oysters from Elechi Creek is considered safe based on acceptable levels of the THQ, HI and TR; though Cd-TR for children (Station 2) was unacceptable.

Quantitative and Predictive Evaluation of Heavy Metal Pollution in Bay Ecosystems of Northern China: Characteristics, Accumulation, and Risk Assessment

Quantitative and Predictive Evaluation of Heavy Metal Pollution in Bay Ecosystems of Northern China: Characteristics, Accumulation, and Risk Assessment

The Evaluation of Heavy-Metals Pollution in Soil Based on a Comprehensive Connection Cloud Model

The Evaluation of Heavy-Metals Pollution in Soil Based on a Comprehensive Connection Cloud Model

Lead induced structural and functional damage and microbiota dysbiosis in the intestine of crucian carp (Carassius auratus).

Lead (Pb) is a hazardous pollutant in water environments that can cause significant damage to aquatic animals and humans. In this study, crucian carp (Carassius auratus) were exposed to waterborne Pb for 96 h; then, histopathological analysis, quantitative qPCR analysis, and 16S high-throughput sequencing were performed to explore the effects of Pb on intestinal bioaccumulation, structural damage, oxidative stress, immune response, and microbiota imbalance of C. auratus. After Pb exposure, the intestinal morphology was obviously damaged, including significantly increasing the thickness of the intestinal wall and the number of goblet cells and reducing the depth of intestinal crypts. Pb exposure reduced the mRNA expressions of Claudin-7 and villin-1 while significantly elevated the level of GST, GSH, CAT, IL-8, IL-10, IL-1, and TNF-α. Furthermore, 16S rRNA analysis showed that the Shannon and Simpson indices decreased at 48 h after Pb exposure, and the abundance of pathogenic bacteria (Erysipelotrichaceae, Weeksellaceae, and Vibrionaceae) increased after Pb exposure. In addition, the correlation network analysis found that Proteobacteria were negatively correlated with Firmicutes and positively correlated with Bacteroidetes. Functional prediction analysis of bacteria speculated that the change in intestinal microbiota led to the PPAR signaling pathway and peroxisome function of the intestine of crucian carp was increased, while the immune system and membrane transport function were decreased. Finally, canonical correlation analysis (CCA) found that there were correlations between the intestinal microbiota, morphology, antioxidant factors, and immune factors of crucian carp after Pb exposure. Taken together, our results demonstrated that intestinal flora dysbiosis, morphological disruption, oxidative stress, and immune injury are involved in the toxic damage of Pb exposure to the intestinal structure and function of crucian carp. Meanwhile, Pb exposure rapidly increased the abundance of pathogenic bacteria, leading to intestinal disorders, further aggravating the damage of Pb to intestinal structure and function. These findings provide us a basis for the link between gut microbiome changes and heavy metal toxicity, and gut microbiota can be used as biomarkers for the evaluation of heavy metal pollution in future.

Evaluation of Heavy Metal Pollution in Rice (Oryza sativa L.) Fields of Bafra Plain

Heavy metals are naturally present in the soils in trace quantity. Besides, some soils include these elements at high levels resulting from the weathering of minerals or human activities. Contamination of these metals has been of great concern in the environment interrelatedly with their toxicity, persistence and non-degradability. So, this article aimed to evaluate heavy metal pollution by using several pollution indices contamination factor (CF), degree of contamination (CD), pollution load index (PLI), summarization of the sources of heavy metals, and change of these metals along soil depth. For this purpose, 10 coordinated soil samples were taken from 0-20 cm and 20-40 cm depths in the rice fields of Bafra Plain in Samsun-Türkiye. In these samples, some physico-chemical soil characteristics (texture, pH, electrical conductivity, organic matter and lime content, available phosphorus and cation exchange capacity) and heavy metal contents Zinc (Zn), copper (Cu), nickel (Ni), cobalt (Co), cadmium (Cd), chromium (Cr) and lead (Pb) were determined. According to the results, metal contents were determined between 39.79-58.44 mg kg-1, 32.15-68.31 mg kg-1, 75.68-132.6 mg kg-1, 11.95-18.02 mg kg-1, 0.001-0.278 mg kg-1, 61.88-102.5 mg kg-1, and 9.942-14.67 mg kg-1 for Zn, Cu, Ni, Co, Cd, Cr and Pb, respectively. While Cd content was higher at 0-20 cm depth, Cr, Ni and Zn values were higher at 20-40 cm. Cu, Pb and Co values did not show significant change with depth. Average CF values for heavy metals were determined as Ni>Pb>Cr>Cu>Cd>Zn>Co. Degree of contamination values varied between 4.922-7.848 and PLI values varied between 0.946-1.028. In all elements, CF and CD values were classified in the group of low and moderate contamination. Besides, significant relationships were found between soil physicochemical properties, heavy metal concentrations and pollution indices.

Evaluation and Source Analysis of Soil Heavy Metal Pollution in a Planting Area in Wanquan District, Zhangjiakou City

Taking the soil of a vegetable planting area in Wanquan District of Zhangjiakou City as the research object, 132 surface and 80 deep soil samples were collected to test and analyze the contents of eight heavy metals such as As, Cd, Cr, Hg, Cu, Ni, Pb, and Zn and the occurrence forms of Cr and Ni. By applying geostatistical analysis and the PMF receptor model and combining three heavy metal pollution evaluation methods, the spatial distribution characteristics of soil heavy metals in the study area, the degree of heavy metal pollution, and the distribution of Cr and Ni fugitive forms in the vertical layer were clarified, and the sources and contribution rates of soil heavy metal pollution were analyzed. The results showed that the average contents of Cd and Pb in surface soils were higher than the background values of soils in Hebei Province, and the spatial distribution characteristics of Cr, Ni, Cu, Cd, Pb, and Zn in surface soils were similar. The ground accumulation index method showed that the study area was mainly free of pollution, with a small number of lightly polluted sites, and most of them were polluted with Cd. The enrichment factor method showed that the study area was mainly free-weakly polluted, with medium pollution of all elements; the significantly polluted elements in the background area were As, Pb, and Hg, and the significantly polluted element in the key area was Cd. The potential ecological risk index method showed that the study area was mainly lightly polluted, with local distribution. The potential ecological risk index method showed that the study area was mainly lightly polluted, with a local distribution of "medium" and "strong" risk points, with "very strong" risk points for Hg in the background area and "very strong" risk points for Cd in the focus area. These three evaluation results indicated that the background area was dominated by Cd and Hg pollution, whereas the focus area was dominated by Cd pollution. The study on the fugitive morphology of vertical soil showed that Cr was dominated by the residue state (F4) and supplemented by the oxidizable state (F3), and the vertical direction was dominated by the surface aggregation type and supplemented by the weak migration type. Ni was dominated by the residue state (F4) and supplemented by the reducible state (F2), and the vertical direction was dominated by the strong migration type and supplemented by the weak migration type. The sources of heavy metals in the surface soil were divided into three categories; Cr, Cu, and Ni were mainly from natural geological background sources. The contributions of Cr, Cu, and Ni were 66.9%, 66.9%, and 76.1%, respectively. As, Cd, Pb, and Zn were mainly from anthropogenic sources, with contributions of 77.38%, 59.2%, 83.5%, and 59.5%, respectively. Hg was mainly from dry and wet atmospheric deposition, with a contribution of 87.8%.

Comparison of magnetic susceptibility probes relevantly used in soil contamination applications.

Magnetic susceptibility (MS) technology can achieve the efficient rough measurement, mapping, and pollution assessment of soil heavy metal concentrations in topsoil due to atmospheric dust contamination. However, previous studies of commonly used MS field probes (MS2D, MS2F, and MS2K) have not dealt with the range of magnetic signal detection and the attenuation characteristics of the signal with respect to distance. In this study, the vertical and horizontal measurement ranges of the MS2D, MS2F, and MS2K probes were explored through laboratory and field experiments, and the intensity of their magnetic signals was further compared and analyzed in the field. The results showed that the magnetic signal intensity of the three probes decreased exponentially with distance. The penetration depths of the MS2D, MS2F, and MS2K probes were 8.5, 2.4, and 3.0cm, respectively, and the horizontal detection boundary lengths of their magnetic signals were 32, 8, and 6.8cm, respectively. In the field surface soil MS detection, the magnetic measurement signals of the MS2F and MS2K probes showed a weak linear correlation with the MS2D probe (R2 of 0.43 and 0.50, respectively), while the MS2F and MS2K probes had a significantly better correlation (R2 = 0.68) with each other. In general, the MS2D probe and MS2K probe correlation had a slope close to unity, meaning MS2K probes had good mutual substitution. Furthermore, results of this study improve the effectiveness of the MS evaluation of heavy metal pollution in urban topsoil.

Evaluation of the suitability of integrated bone char- and biochar-treated groundwater for drinking using single-factor, Nemerow, and heavy metal pollution indexes.

The treatment of contaminated groundwater using integrated bone char and biochar beds has been studied. The bone char and biochar were made in a locally built double-barrel retort utilising cow bones, coconut husks, bamboo, neem trees, and palm kernel shells at 450°C and were graded into 0.05- and 0.315-mm sizes. Eight groundwater treatment experiments (BF2-BF9) were performed in columns with bed heights of 8.5-16.5cm to remove nutrients, heavy metals, microorganisms, and interfering ions from groundwater using bone char, biochar, and a combination of bone and biochar. The water samples were analysed for twenty-one water quality parameters including pH, total dissolved solids, conductivity, turbidity, fluoride, chloride, sodium, and potassium. The rest were total coliforms, faecal coliforms, total heterotrophic bacteria, Escherichia coli, manganese, and total iron. The effectiveness of the treatment processes was assessed using the Ghana standard authority and the World Health Organisation's recommended values for drinking water quality. The results were shared using a simplified single-factor index, Nemerow's pollution index, and a heavy metal pollution index with decision-makers as a technology for groundwater treatment in rural communities in Africa. Bone char was more effective in removing total heterotrophic bacteria than any of the other treatment agents tested. This is because of its compact nature and small particle size. The quality of water treated by BF3, BF5, BF6, BF7, BF8, and BF9 was fit for drinking based on the single-factor and heavy-metal pollution evaluation because they have the lowest level of pollution. However, Nemerow pollution analysis found only BF5 to be the most suitable for public use.

Principle Component Analysis Based Risk Evaluation Model for Heavy Metal Pollution in Soil in E-waste Incineration Sites in a Smart City

Abstract In order to improve the accuracy of risk evaluation of heavy metal pollution in soil in e-waste incineration sites, a risk evaluation model of heavy metal pollution in soil in e-waste incineration sites is designed. In this study, taking an e-waste incineration site as an example, the analytical materials and reagents are proposed, and the risk evaluation model of heavy metal pollution in soil in e-waste incineration site is established through the establishment of risk evaluation index, principal component analysis, and comprehensive evaluation so as to realize the risk evaluation of heavy metal pollution in soil in e-waste incineration site. The effectiveness of the evaluation model is verified, which proves that the model has higher evaluation accuracy and less evaluation time.

Analysis and Evaluation of Heavy Metal Pollution in Kosasthalaiyar River near Ennore Creek Using Geo Statistical Approach

<p>The increasing industrialization and urbanization in recent times has led to a significant increase in heavy metal pollution in soil and sediment. The present study aims to evaluate the heavy metal contamination (HmC) in surface sediments collected from the Kosasthalaiyar River located between latitudes 13°12′03″N and 13°16′34″N and longitudes 80°18′6″E and 80°19′56″E. Ten sampling locations were selected in the study area and samples of surface sediments were collected and analyzed for 16 geochemical and heavy metal parameters, including Silver (Ag), Aluminium (Al), Calcium (Ca), Cadmium (Cd), Chloride, Cobalt (Co), Total Chromium (Cr), Copper (Cu), Mercury (Hg), Manganese (Mn), Molybdenum (Mo), Nickel (Ni), Lead (Pb), Silica (Si), Titanium (Ti), and Zinc (Zn). The study aims to determine the potential environmental hazards of heavy metals in the sediment through calculation of the potential environmental hazard index (RI). Assess the impact of human activities on HmC in the surface sediments using four pollution indices: the Geo-accumulation index (Igeo), the Contaminant factor (CF), the degree of contamination (DC), the potential contamination index (PCI), and the pollution load index (PLI) and Conduct a human health risk assessment (HHRA) of heavy metals in the sediment. The study results will provide insight into the contamination levels and help inform measures for controlling pollution and promoting sustainability in the area.</p>

Modeling Analysis of Heavy Metal Evaluation in Complex Geological Soil Based on Nemerow Index Method

To accurately understand soil environmental quality and improve the problem of the traditional method, which is that it has a single evaluation factor and cannot reflect the overall condition of the soil, a complex geological soil heavy metal evaluation modeling method based on the Nemerow index method is proposed. Index evaluation methods, ArcGIS technology, and a human health risk assessment were carried out to obtain the spatial distribution of heavy metals in the soil and the current status of pollution accumulation. The comprehensive pollution index (CPI) method, geo-accumulation index (GAI) method, and potential ecological hazard (PEH) index were adopted to analyze the pollution degree of soil heavy metals. On this basis, the Nemerow index method was used to establish a complex geological soil heavy metal evaluation model, and the standard Nemerow index was calculated to complete the evaluation of heavy metal pollution in complex geological soils. The research results showed that this method could make the evaluation factors obtain reasonable scores and obtain more reasonable soil evaluation results.

Evaluation of heavy metal pollution with uneven spatial sampling distribution based on Voronoi area density.

Ecological risk index and Voronoi diagram have been extensively used as a diagnostic guide for heavy metal pollution to support people in-depth analysis of the possibility of various contamination sources causing damage to social production, life, and the ecological environment. However, under the condition of uneven distribution of detection points, there are often situations where the Voronoi polygon area corresponding to a large degree of pollution is small or the area of the Voronoi polygon is great with a low level of pollution, and using the Voronoi area weighting or the Voronoi area density may ignore heavily polluted local areas. This study proposes the Voronoi density-weighted summation to accurately measure the concentration and diffusion of heavy metal pollution in the target area for the above issues. Then, we propose a contribution value method based on k-means to determine the number of divisions to ensure the prediction accuracy and computational cost at the same time. Moreover, applying local entropy deepens the understanding of local regional and overall system situations. Through four representative regions, the results show that the proposed whole scheme based on Voronoi diagram can effectively predict and evaluate the spatial distribution of heavy metal pollution, which provides a theoretical basis for comprehending and exploring the complex pollution environment.

Assessment of environmental and toxicity impacts and potential health hazards of heavy metals pollution of agricultural drainage adjacent to industrial zones in Egypt

The objectives of this study were to assess the environmental impact of industrial wastewater disposal in the El-Khadrawiya agricultural drain, Menoufia Governorate, Egypt, as well as the effect on water, soil, and plant qualities in the drain's extension area, which was primarily adjacent to the industrial zone. The analyses results of wastewater at El-Khadrawiya drain revealed that heavy metal concentrations in water samples exceeded WHO permitted limits. Heavy metal levels followed the following pattern: (Pb > Zn > Cr > Cd > Ni > As), where Heavy metal levels average were: (1.8492 > 1.7857 > 0.1815 > 0.1578 > 0.059 > 0.0048. Wastewater, soil and plant samples were analyzed using (PerkinElmer AAnalyst 400 Atomic Absorption Spectrometer A Analyst 400), Heavy metal pollution evaluation indicators: Target hazard quotient (THQ), Hazard index (HI), Chronic daily intake (CDI), Carcinogenic risk (CR), and Heavy metals pollution index (HPI)) showed that a majority of samples discovered values referring to carcinogenic health risks for the population. In contrast, the soil contamination indices followed the same trend, with the contamination factor (CF) indicating that the majority of samples exposed low to medium levels of pollution for (Ni, Cd, and Zn), while Pb and Cr were between high and very high, and the contamination degree (Cd) and modified degree of contamination (mCd) indicating that the majority of samples revealed the medium level of pollution, with the exception of one site with a high level of contamination. The bioaccumulation factor (BAF) revealed that heavy metal accumulation in plants exceeds the critical range. This study should be expanded to include additional agricultural regions with comparable conditions in order to provide environmental monitoring of present challenges and work toward solutions.