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Soil heavy metal pollution is one of the hottest topics in soil environmental research. There are a large number of small abandoned metal mines in China. Due to the lack of timely restoration and treatment, the heavy metal concentration in the soil within these mining areas often exceeds the local background levels, facilitating pollution spread to other natural factors such as precipitation, resulting in a wider extent of continuous contamination. This paper investigates the current status of heavy metal pollution in an abandoned small lead-zinc mine, particularly examining the concentrations of 10 specific heavy metals (V, Cr, Ni, Zn, As, Cd, Hg, Pb, Cu, Co) in soil samples. Additionally, it explores the extent of contamination caused by these heavy metals within the area. Besides, principal component analysis and positive matrix factorization model (PMF) were adopted to determine the sources of these heavy metals. The risk assessment of the pollution status was also carried out. The provision of a scientific basis for mining area management under similar conditions holds significant importance. The results indicate a significant positive correlation among the majority of these 10 heavy metals in soil. The presence of these heavy metals in the soil within the concentrator and tailings reservoir area primarily stems from mining operations, construction activities, and discharges from the power system. Hg, Pb, Zn, and As in the surrounding agricultural land mainly come from the heavy metal spillover from the mining area. Furthermore, the area is plagued by severe contamination from As and Pb. The Nemerow comprehensive index method has confirmed substantial pollution in both the concentrator and tailings reservoir. Additionally, there exists a substantial ecological risk ranging from moderate to high. [ABSTRACT FROM AUTHOR]

High concentrations of heavy metals in the environment will cause serious harm to ecosystems and human health. It is urgent to develop effective methods to control soil heavy metal pollution. Phytoremediation has advantages and potential for soil heavy metal pollution control. However, the current hyperaccumulators have the disadvantages of poor environmental adaptability, single enrichment species and small biomass. Based on the concept of modularity, synthetic biology makes it possible to design a wide range of organisms. In this paper, a comprehensive strategy of "microbial biosensor detection - phytoremediation - heavy metal recovery" for soil heavy metal pollution control was proposed, and the required steps were modified by using synthetic biology methods. This paper summarizes the new experimental methods that promote the discovery of synthetic biological elements and the construction of circuits, and combs the methods of producing transgenic plants to facilitate the transformation of constructed synthetic biological vectors. Finally, the problems that should be paid more attention to in the remediation of soil heavy metal pollution based on synthetic biology were discussed. [ABSTRACT FROM AUTHOR]

The objective of this paper is to elucidate the environmental capacity of heavy metal in soils of an urbanization gradient zone of Urumqi City, a total of 88 surface soil samples were thereby collected from the typical gradient zone including urban, suburban, rural and wasteland areas, and heavy metal contents of Cd, Hg, As, Pb, Cu, Ni, and Zn in soils were measured, and the characteristics and spatial distribution pattern of the environmental capacity of soils was analyzed based on the GIS and the method of comprehensive environmental index (PI). As a result, the investigation showed that heavy metal contents in topsoil of the urbanization gradient zone along the areas of urban, suburban, rural and wasteland differed in a certain degree, and Hg had been evidently enriched in soils of all the areas of the gradient zone; the mean PIs of heavy metals in soils of the urbanization gradient zone were arranged in order of decreasing magnitude: rural> suburban>wasteland> urban, the relevant environmental capacity of all the areas being mediocre. As to the spatial pattern, individual environmental capacity index of each single heavy metal in soils of those areas was different, and low PI mainly distributed in the urban area, which indicated a significant impact of urbanization on soil environmental capacity. The dynamic annual capacity and static annual capacity of each heavy metal were in order of decreasing magnitude: Zn> Ni> Pb> Cu> As> Hg> Cd. In addition, the dynamic annual capacity of heavy metals in soils of each arear of the gradient zone showed a trend 20 a > 40 a > 60 a > 80 a > 100 a. The aver-age dynamic annual capacity of every kind of heavy metal in soil of each gradient zone area was greater than the static annual capacity in fixed number of years, and as a whole, the environmental capacity of soils tended better. [ABSTRACT FROM AUTHOR]

Toxic pollutants of industrial origin can be dangerous for professionals who come into contact with them at work, and also for the people who live near the sources of environmental hazards. There is a known relationship between the soil pollution with heavy metals and the morbidity of the population. This paper reports a study of the soil pollution with ions of heavy metals in the Turkestan region, Kazakhstan. The study found technogenic geochemical anomalies of various size, intensity and origin in the soils of the Turkestan region. The distribution of lead, copper, barium, zinc, molybdenum, phosphorus and arsenic was mapped based on the ecological and geochemical survey of the upper soil layer. The most polluted city is Kentau, where concentrations of Pb, Mo, Cu, Zn, As, Cd, Mn, Cr, Ni in the soil exceed the allowable level. The cause of pollution is erosion that occurs in the areas of technogenic waste storage. In some communities, the concentration of only one metal exceeded its MAC or the Clarke number, for example, only scandium exceeded its Clarke number by 1.1 in Lenger and only exceeded its Clarke number by 2.75 in Sholakkorgan. [ABSTRACT FROM AUTHOR]

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Contamination by heavy metals is a significant issue worldwide. In recent decades, soil heavy metals pollutants in China had adverse impacts on soil quality and threatened food security and human health. Anthropogenic inputs mainly generate heavy metal contamination in China. In this review, the approaches were used in these investigations, focusing on geochemical strategies and metal isotope methods, particularly useful for determining the pathway of mining and smelting derived pollution in the soil. Our findings indicate that heavy metal distribution substantially impacts topsoils around mining and smelting sites, which release massive amounts of heavy metals into the environment. Furthermore, heavy metal contamination and related hazards posed by Pb, Cd, As, and Hg are more severe to plants, soil organisms, and humans. It's worth observing that kids are particularly vulnerable to Pb toxicity. And this review also provides novel approaches to control and reduce the impacts of heavy metal pollution. Hydrometallurgy offers a potential method for extracting metals and removing potentially harmful heavy metals from waste to reduce pollution. However, environmentally friendly remediation of contaminated sites is a significant challenge. This paper also evaluates current technological advancements in the remediation of polluted soil, such as stabilization/solidification, natural attenuation, electrokinetic remediation, soil washing, and phytoremediation. The ability of biological approaches, especially phytoremediation, is cost-effective and favorable to the environment. [ABSTRACT FROM AUTHOR]

Based on the bibliometrics analysis, this paper firstly identifies that the research focus of humic acid-based material immobilization field is on immobilization remediation effect and remediation mechanism.Based on the two research focuses identified, the heavy metals in soil were classified into those in the form of cations（e.g.Cd, Pb, Hg, etc.) and those in the form of oxygen anions（e.g.As and Cr),and the immobilization effects and immobilization mechanisms of humic acid and humic acid-based materials on soil heavy metals were systematically reviewed.Humic acid and humic acid-based materials have highly effective to immobilize soil heavy metals, and their immobilization mechanisms mainly include complexation, ion exchange, electrostatic interaction, redox and co-precipitation with introduced modified materials.This review further points out the shortcomings of humic acid-based materials in immobilization remediation technology in terms of practical applications and provides an outlook on future research directions, in order to provide scientific references for in situ immobilization remediation of heavy metal contaminated soils. [ABSTRACT FROM AUTHOR]

Isitu passivation repair technology for heavy metals is a promising processing technology. This technology mainly adds exogenous remediation agents to the contaminated soil, and undergoes a series of reactions such as adsorption, ion exchange, precipitation, oxidation-reduction and other heavy metal ions to convert heavy metals into a more stable form and fix them in the soil, thereby preventing heavy metals from passing through plant roots migrate to the upper part of the ground to achieve the purpose of repairing the soil. This paper systematically expounds the effect and repair mechanism of passivation technology, deeply analyzes the types of passivation materials, and further puts forward the problems to be solved in passivation repair technology from the practical application, and prospects for future research directions. [ABSTRACT FROM AUTHOR]

Combined with the existing research, the research progress of biochar remediation of heavy metal pollution is reviewed. This paper focuses on the mechanism of biochar immobilization of heavy metals in soil, the effect of biochar on the absorption of heavy metals by plants, the research results of the application of biochar in field engineering, and the risks and shortcomings o£ biochar as a soil improver. Finally, it is hoped that on the premise of meeting safe production, the popularization of biochar should be promoted in agricultural production, rather than limited to scientific research. Start the life cycle assessment of biochar and establish a biochar life cycle database to provide a comprehensive and effective scientific basis for the future use of biochar. [ABSTRACT FROM AUTHOR]

As greenhouse horticulture continues to increase in South Korea, the effects of metal(loid)s from wastewater discharges on stream sediments were analyzed. A total of 106 samples were analyzed for cadmium (Cd), boron (B), copper (Cu), nickel (Ni), lead (Pb), zinc (Zn), chromium (Cr), manganese (Mn), and iron (Fe). The coefficient of variation (CV) of the metal(loid)s components was 96.58% for Mn, 93.40 for Zn, 62.47 for B, 58.90 for Pb, and 58.14 for Cd, suggesting anthropogenic sources. Correlation analysis suggested a cumulative source for Cd-Zn and B, and cluster analysis suggested an anthropogenic source for Cu, Pb, B, and Mn. The contamination factor (CF) suggested the need to trace the source of contamination to Pb (3.21 ± 1.89) and B (1.33 ± 0.83) and EF to Pb (3.30 ± 1.81) and B (1.44 ± 0.94). The analytical results identify anthropogenic sources of Pb, B, and Cd. The high contamination of Cd suggests the influence of mining areas, and Pb suggests the influence of traffic, fertilizers, pesticides, and fossil fuels in greenhouses, in addition to the influence of mines. B confirmed the impact of the facility's vegetable wastewater and suggested the need to further examine the cumulative impact of Mn, Fe, etc. By utilizing the facility horticulture wastewater for ecological restoration and other agricultural uses, we aim to prevent stream sediment pollution and realize a sustainable agricultural environment. [ABSTRACT FROM AUTHOR]

Tea plant [Camellia sinensis (L.) O. Kuntze] is one of the important foliar cash crops in China, and its root system absorbs heavy metal (HM) elements enriched in the soil and transports them to the over ground part. In order to ensure the safety of the soil ecological environment and tea raw materials in the tea production area, the HM contents of soil and tea plant leaves in Suzhou tea plantations were detected, the relationship between HMs and soil physicochemical properties was analyzed, and the ecological risk of HMs in tea plantation soils was evaluated by using relevant detection techniques and evaluation models. The results showed that the average pH of tea plantation soils around Tai Lake in Suzhou was within the range suitable for the growth of tea plants. The pH, soil organic matter, total nitrogen, available phosphorus and available potassium of tea plantation soil satisfying the requirements of high quality, high efficiency and high yield ('3H') tea plantation accounted for 47.06%, 26.47%, 8.82%, 79.41% and 67.65%, respectively. Site 2 fully met the requirements of '3H' tea plantation. In addition, the contents of cadmium (Cd) and mercury (Hg) were extremely variable, and the average contents exceeded the background value of soil in Jiangsu Province, but the HM contents of tea leaves all met the pollution-free standard, and the HM contents of tea leaves around Tai Lake in Suzhou were generally at a safe level. The composite ecological risk index ranged from 0.05 to 0.60, and 32 of the 34 sample sites (except site 21 and site 23) are the most suitable agricultural land for tea plantations. [ABSTRACT FROM AUTHOR]

The pollution of agricultural soil by heavy metals is a significant environmental issue that has a serious impact on human health and food security. This study focused on investigating the presence of heavy metal pollution in sewage-irrigated soils in Taiyuan city. A total of 110 soil samples were analyzed for the presence of As, Hg, Cd, Pb, Cr, Cu and Zn. The results showed that the concentrations of these metals ranged from 0.06 to 26.74 mg/kg for As, 0.00 to 0.84 mg/kg for Hg, 0.03 to 0.69 mg/kg for Cd, 44.32 to 100.09 mg/kg for Pb, 9.85 to 42.19 mg/kg for Cr, 13.38 to 53.72 mg/kg for Cu, and 42.77 to 145.47 mg/kg for Zn. The average concentrations of these metals were found to be below the risk values specified in the "Soil environmental quality (GB15618-2018)", except for As and Cd in three sampling points in Xiaodian District. The heavy metal pollution in these areas can be attributed to various sources, such as industrial activities, the use of fertilizers and pesticides, and the irrigation process. According to the geo–accumulation index, the agricultural soil in the Taiyuan irrigation area was found to be uncontaminated by Zn, Cr, Cu, and As, and lightly contaminated by Cd, Hg, and Pb. The Nemerow Pollution Index indicated that the soil at all sampling points exhibited a slight level of pollution. Moreover, the ecological risk assessment indicated that all heavy metals posed a slight level of pollution. The findings of this study provide a scientific basis for the development of effective policies and measures for soil environmental protection and pollution control. [ABSTRACT FROM AUTHOR]

Purpose: Heavy metal pollution is of major concern due to its potential threat to ecosystem safety and human health. To give a valuable insight into the status of heavy metal pollution in a sewage irrigation region in northwest China, this paper thoroughly studied the spatial distribution and possible source of heavy metals in soils under different land uses. Materials and methods: Soil samples were collected from arable lands (maize field, orchard, and paddy field) and nonarable lands (village and barren hill) from a sewage irrigation region, northwest China. The concentrations of Cd, Cr, Cu, Mn, Ni, Pb, and Zn in the soils, together with soil pH, soil organic matter (SOM), and soil particle size distribution, were detected. GIS-based approach was employed to construct the spatial distribution maps of heavy metals, and multivariate analysis was used to identify their possible source. Results and discussion: Although elevated concentrations of Zn, Pb, and Cu are detected, Cd is the priority pollutant in the soils. Land use, location, and SOM are crucial factors affecting metal distribution in the soils. Metal concentrations in different land uses arrange in the order of orchard > paddy field/maize field > village > barren hill. The area within the basin of Dongdagou stream presents the most pollution, whereas the northeast side far from the stream is the least. Irrigation water both from Dongdagou stream and the Yellow River are deemed as primary sources of Cd, Zn, Pb, and Cu. Besides, agrichemical application particularly contributes to metal accumulation in orchard soils, and Cd and Zn partially derive from atmospheric deposition. Nickel and Mn predominately originate from the soils. Conclusions: When studying metal pollution in soils, land use should be taken into account because of its important roles in determining metal concentrations. In the study area, arable lands are more likely to be polluted by Cd, Zn, Pb, and Cu than nonarable lands via sewage irrigation; moreover, agrichemical application and atmospheric deposition also should be held responsible for metal accumulation in the soils. [ABSTRACT FROM AUTHOR]

The use of wastewater irrigation may contribute to the metal accumulation, and reduction of nutrient level of vegetables, which would then have an adverse effect on human health. Therefore, in the present study we investigated heavy metals contamination and its impact on nutrient quality of vegetables and health risk. The study was conducted from the agricultural fields of Varanasi distinct during the period from March 2022 to June 2023 and all the laboratory work was carried in the department of Botany, Banaras Hindu University. Heavy metal concentrations in water, soil, and vegetable samples were measured using an atomic absorption spectrophotometer. The physiochemical property (pH), daily intake of metal, metal pollution index and health quotient were also calculated according to the published protocols. All heavy metal were found in higher concentrations in the wastewater irrigated soil that control site. The Lohta site had the highest concentration of heavy metals in the vegetables, followed by Dinapur, and least at control site (BHU). The highest concentration of metals (Cu, Zn, and Pb) were found in the leafy vegetables (S. oleracea & A. esculentus) whereas lowest in fruity vegetables (P. vulgaris). The rise in the Metal Pollution Index (MPI) also provided evidence for the greater metal content of these vegetables. The S. oleracea was found to have the highest DIM (0.061 g/g) while P. vulgaris had the lowest (0.007 g/g). HQ values of these metals were found greater than one (>1) for both children and adults on the ingestion of the vegetables of wastewater irrigated sites. Further, nutrient contents (Na, Mg, Ca) were also declined in the vegetables of wastewater irrigated site when compared to control site. These findings suggest that the consumption of such vegetables leads to compromised health and might be associated with severe health risk in the human. [ABSTRACT FROM AUTHOR]

This study aims to solve the problem of cadmium heavy metal ion pollution caused by the abuse of chemical fertilizers and activities such as mining, which pose a serious threat to the plant growth environment. We successfully synthesized DMAPAA (N-(3-(Dimethyl amino) propyl) acrylamide)/DMAPAAQ (N, N-Dimethyl amino propyl acrylamide, methyl chloride quaternary) hydrogels via free radical polymerization. Subsequently, we conducted experiments on this hydrogel for growing vegetables under cadmium stress conditions in aqueous solutions and soil. The cadmium capture capacity of DMAPAA/DMAPAAQ hydrogels under different cadmium ion concentrations and pH values was evaluated by using inductively coupled plasma optical emission spectrometry (ICP). The research results show that under the condition of pH = 7.3, the cadmium capture capacity of DMAPAA/DMAPAAQ hydrogels is the greatest. We used the Langmuir model to fit the adsorption data, and the correlation coefficient was as high as 0.96, indicating that the model fits well. The application of the hydrogels promoted the growth of vegetables in soil under cadmium stress conditions. The results showed that when the added amount of hydrogel was 4%, the dry weight of the vegetables was the largest. In addition, when the added amount of cadmium was 500 mg/kg and the added amount of hydrogel was 4%, the absorption of cadmium by the vegetables decreased to an undetectable level. In summary, the hydrogel successfully synthesized in this study can be effectively used to immobilize cadmium ions in soil while positively promoting the growth and yield of vegetables. This achievement has practical significance for solving the problem of heavy metal ion pollution. [ABSTRACT FROM AUTHOR]

The paper reports the spatial distribution and contamination level of heavy metals (Co, Cr, Cu, Mn, Ni, Pb, Zn and V) in urban topsoil from the interior area of the second ringroad of Xi'an city, China, based on X-ray fluorescence spectroscopy measurements. Geostatistical analysis shows that Co, Cu, and Pb have similar spatial distribution patterns. Heavy traffic density mainly contributed to the high concentrations of Co, Cu and Pb. The spatial distribution of Cr coincides with the industrial activity, whereas the spatial distribution of Zn differs from other heavy metals. The high concentrations of Zn coincide with heavy traffic and high population density. For Mn, Ni and V, natural factors are important in controlling their distribution. The calculated geoaccumulation indices indicate that urban topsoil inside the Xi'an second ringroad was uncontaminated by Cr, V, Mn and Ni, while Pb, Cu, Co and Zn are classified as uncontaminated to moderately contaminated with means of 0.64, 0.46, 0.26 and 0.21, respectively. The Nemero synthesis pollution index of these heavy metals revealed that the topsoil inside Xi'an second ringroad has been heavily contaminated due to anthropogenic activity. [ABSTRACT FROM AUTHOR]

The dismantling and disposal of electronic waste (e-waste) in developing countries is causing increasing concern because of its impacts on the environment and risks to human health. Heavy-metal concentrations in the surface soils of Guiyu (Guangdong Province, China) were monitored to determine the status of heavy-metal contamination on e-waste dismantling area with a more than 20 years history. Two metalloids and nine metals were selected for investigation. This paper also attempts to compare the data among a variety of e-waste dismantling areas, after reviewing a number of heavy-metal contamination-related studies in such areas in China over the past decade. In addition, source apportionment of heavy metal in the surface soil of these areas has been analysed. Both the MSW open-burning sites probably contained invaluable e-waste and abandoned sites formerly involved in informal recycling activities are the new sources of soil-based environmental pollution in Guiyu. Although printed circuit board waste is thought to be the main source of heavy-metal emissions during e-waste processing, requirement is necessary to soundly manage the plastic separated from e-waste, which mostly contains heavy metals and other toxic substances. [ABSTRACT FROM AUTHOR]

Goa, a biodiversity hotspot, is also a major iron ore producing state in India. This study investigated total heavy metal (HM) contamination in 65 georeferenced soil samples through inductively coupled plasma atomic emission spectrophotometer (ICP-AES) for assessing risk of mining activity on agricultural soils. The mean concentrations of copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), chromium (Cr), cadmium (Cd), manganese (Mn), iron (Fe) and cobalt (Co) were 125.60, 75.60, 96.40, 51.20, 69.30, 25.77, 2091, 162638 and 21.20 mg kg−1, respectively. Lower pH, higher organic carbon (OC) and fine-textured soil augmented metal accumulation processes. Boxplot of geoaccumulation index (Igeo) values indicated that lead (Pb) metal had more variation in the study area. Mean Igeo values of metals in descending order are Fe (4.24) > Mn (3.08) > Cu (2.84) > Co (2.47) > Pb (1.85) > Cd (0.7) > Zn (0.58) > Ni (0.45) > Cr (0.16). Mean values of modified degree of contamination (mCdeg) (10.4) and pollution load index (PLI) (6.19) revealed high contamination with deteriorating soil quality. Combined approach of correlation, principal component (PC) and cluster analysis indicated the source of origin by describing association of metals with Fe. PC biplot showed that impact of mining was more on lowland agro-ecosystem rather than natural due to slope factor which led to clogging of pores by mining overburden mixed soil deposition from uphill as evidenced from the presence of waterlogged fallow lands. Fuzzy k-mean clustering yielded three contamination zones (CZs) of low (CZ2), moderate (CZ1) and high (CZ3) degree of contamination. The CZs-based site-specific land management plan might lead to a sustainable ecosystem through coexistence of both mining and agricultural activity by arresting contamination and restoring fallow lands. [ABSTRACT FROM AUTHOR]

The properties and sources of soil heavy metals (Pb, Zn, Cu, Cd, As, Hg, Cr, and Ni) need to be comprehensively analyzed to take effective steps to control and reduce soil pollutants. In this research, 416 soil samples were collected on a large scale in China. Two receptor models (PCA/MLR and PMF) were utilized to identify pollutant sources and quantify the contributions. The means of soil heavy metals (Zn, Cu, As, Hg, Cr, and Ni) were lower than the corresponding screening values and intervention values. Cd was greater than the intervention value, while Pb was between the screening value and the intervention value. Source apportionments suggested that mine sources were the most polluted (64.28%), followed by traffic sources (38.98%), natural sources (11.41–39.58%), industrial sources (9.8–18.65%), and agricultural sources (2.79–14.51%). Compared to the PCA/MLR model, the PMF model had a better effect in evaluating soil heavy metal pollution. It gave corresponding weights according to the data concentration and its uncertainty, which made the result reasonable. The ecological risk assessment indicated that Cd posed a significant risk, while Hg caused a mild risk and the other six heavy metals posed a low risk. The spatial distribution of ecological risk suggested that severe risk points were mainly distributed in the central area, while high-risk points were distributed in the southern region. The SRI method was developed to link pollution sources and their potential ecological risks and indicated better applicability to the PMF model. The study findings could provide guidelines for monitoring the main sources and reducing the pollution of soil heavy metals. [ABSTRACT FROM AUTHOR]

Repeated visiting, i.e., sampling and analysis at two or more temporal points, is one of the important ways of monitoring soil heavy metal contamination. However, with the concern about the cost, determination of the number of samples and the temporal interval, and their capability to detect a certain change is a key technical problem to be solved. This depends on the spatial variation of the parameters in the monitoring units. The “National Multi-Purpose Regional Geochemical Survey” (NMPRGS) project in China, acquired the spatial distribution of heavy metals using a high density sampling method in the most arable regions in China. Based on soil Cd, Hg, and Pb data and taking administrative regions as the monitoring units, the number of samples and temporal intervals that may be used for monitoring soil heavy metal contamination were determined. It was found that there is a large variety of spatial variation of the elements in each NMPRGS region. This results in the difficulty in the determination of the minimum detectable changes (MDC), the number of samples, and temporal intervals for revisiting. This paper recommends a suitable set of the number of samples ( n r ) for each region under the balance of cost, practicability, and monitoring precision. Under n r , MDC values are acceptable for all the regions, and the minimum temporal intervals are practical with the range of 3.3–13.3 years. [ABSTRACT FROM AUTHOR]

The research was carried out during the period of 2020-2022 in the south-eastern part of Romania on a reddish preluvosoil. Two types of slag from the metallurgical industry were applied, namely furnace slag and converter slag in doses of 1 t/ha, 3 t/ha and 5 t/ha. Taking into consideration the chemical composition of these materials and the fact that they contain elements such as Ca, P, Zn, Ni, Fe, Mg, they can be used to neutralize the acidic reaction of soils and for a better utilization of nutrients by crop plants. The research analyzed the effect of these materials on the chemical properties of the soil, on the soil's reaction, the soil's humus content and content in elements, as well as their influence on the production of maize, wheat and peas, while also taking into account the content in macroelements and heavy metals found in the soil and crop plants. The obtained results demonstrated that the application of these materials in the established doses of 1, 3 and 5 tons/ha led to significant increases in the production of maize, wheat and peas without the risk of accumulation of heavy metals in the soil and in the crop plants. [ABSTRACT FROM AUTHOR]

Evaluating the variation in heavy metal concentrations in soil caused by anthropogenic activities in heavily contaminated areas is of great significance. The degree of heavy metal pollution in soil is primarily assessed by different indices with different standards and reference elements. However, these methods cannot be used to evaluate the degree of heavy metal pollution caused by anthropogenic activities. In this study, Zhuzhou, China was selected as the contaminated area, and Yueyang, China was selected as the background area, where geological and climatic conditions are similar to those of Zhuzhou, China. The concentrations of As (6.6-23.6 mg/kg), Cd (0.125-0.757 mg/kg), Cu (33-75 mg/kg), Hg (0.032-0.202 mg/kg), Pb (17-108 mg/kg), and Zn (74-122 mg/kg) in the vertical soil profiles in the contaminated area were higher than those in the background area (ranging 1.7-20.7, 0.085-0.210, 21-47, 0.030-0.105, 17-38 and 32-88 mg/kg, respectively). K2O/Al2O3, SiO2/Al2O3, and the weathering leaching coefficient (ba) showed little difference, suggesting that the weathering degree of soil in these two areas was similar. The weathering degree of soil governs the geochemical behavior of heavy metals and reference elements. According to the prediction models for heavy metal concentrations and organic carbon, K2O/Al2O3, and SiO2/Al2O3 in the soil profiles from the background area, the increase in heavy metal concentrations in the topsoil in the contaminated area was depicted. The heavy metal concentrations in topsoil were obviously affected by anthropogenic activities. This study provides a case study for evaluating the impact of anthropogenic activities on heavy metals in soil. [ABSTRACT FROM AUTHOR]

Soil pollution in China is one of most wide and severe in the world. Although environmental researchers are well aware of the acuteness of soil pollution in China, a precise and comprehensive mapping system of soil pollution has never been released. By compiling, integrating and processing nearly a decade of soil pollution data, we have created cornerstone maps that illustrate the distribution and concentration of cadmium, lead, zinc, arsenic, copper and chromium in surficial soil across the nation. These summarized maps and the integrated data provide precise geographic coordinates and heavy metal concentrations; they are also the first ones to provide such thorough and comprehensive details about heavy metal soil pollution in China. In this study, we focus on some of the most polluted areas to illustrate the severity of this pressing environmental problem and demonstrate that most developed and populous areas have been subjected to heavy metal pollution. [ABSTRACT FROM AUTHOR]

Determining the factors that affect the heavy metal components of soil can reveal the source of and to prevent and control heavy metal pollution in soil. After sampling, screening, testing, and other steps, the amounts of various heavy metals in 975 sampling points were obtained. The heavy metal data were associated with eight different environmental factors, and the impact of each factor on the heavy metal components of soil in Xiangzhou District was studied by means of categorical regression. The research result and analysis shows that the way land is used, and industrial production and soil type are the key elements that impact the dispersion of heavy metals in the soil in Xiangzhou District. At the same time, the interaction among factors such as the slope, the traffic distance, the way the land is used, and the soil type can affect the lead, cadmium, and mercury contents of the soil. Analysis and research of the hot spots of heavy metals in the soil found a good spatial correlation between the heavy metal distribution in the soil and some factors, such as soil parent material, industrial activities, and population density. Some hot spots of heavy metal pollution correspond to indicators such as population density and industrial activities. Although categorical regression is less used in heavy metal research, it is an appropriate method to find out factors affecting the heavy metal contents of soil, which can provide a new perspective for future researchers. [ABSTRACT FROM AUTHOR]

Heavy metals in groundwater and soil are toxic to humans. An accurate risk assessment of heavy metal contamination can aid in environmental security decision making. In this study, the improved ecological risk index (RI) is used to comprehensively investigate the influence of heavy metals in soil and groundwater within electroplating factories and their surrounding regions. In the non-overlapping area, the RI of soil and groundwater is computed individually, and in the overlapping area, the greater RI of soil and groundwater is employed. Two typical electroplating factories are used to examine the heavy metal distribution pattern. The heavy metal concentrations are compared between Factory A, which is in operation, and Factory B, which is no longer in operation, in order to analyze the heavy metal concentrations and associated ecological risks. Heavy metals continue to spread horizontally and vertically after Factory B was closed. Heavy metal concentrations in groundwater surrounding Factory B are substantially greater, and the maximum concentration exists deeper than in Factory A. Because Cr, Cu, and Hg in soil contribute significantly to the RI, the primary high RI region is observed at Factory A and the region to the southwest. The RI of Factory B demonstrates a broad, moderate risk zone in the west and southwest. [ABSTRACT FROM AUTHOR]

In this study, soil and total suspended particles samples (TSP) were collected from different soil layers in four functional areas of Urumqi City, Northwest China, and electric heating plate digestion and inductively coupled plasma-optical emission spectrometry (ICP-OES) were used to determine the mass fractions and spatial distribution of six heavy metals. The aim was to determine the effects of human activities on the urban soil and atmosphere and provide a theoretical basis for environmental protection and management in Urumqi. The results showed that: (1) The average mass fractions of Cr, Cu, Mn, Ni, Pb, and Zn were 129.24, 42.445, 691.70, 48.705, 31.36, and 126.5 mg kg−1, respectively; the average mass fractions of Cr, Zn, Ni, and Cu exceeded the limit of the national soil standard; the pollution indexes were 1.44, 1.27, 1.22, and 1.21, respectively. (2) The heavy metal contents of surface soils are higher in the industrial, traffic, and cultural and educational areas than in the clean park area; in the vertical section, the heavy metals in the industrial, traffic, and culture and education areas show a weak epimerism, and the soil in the park area shows a good primitivity. (3) The ratios of the highest to lowest concentration of heavy metals in TSP can be ranked as follows: Pb (9.75) > Mn (2) > Ni (1.48) > Cr (1.36) > Cu (1.32) > Zn (1.17). (4) The correlations of heavy metals between the soil and TSP are significant, indicating that dry and wet deposition significantly affect the heavy metal content of the soil. [ABSTRACT FROM AUTHOR]

This geochemical study reports the concentrations, spatial distributions, and sources of heavy metals in soil samples from southern Konya. The investigation focused on topsoil (0–20 cm; n = 65), two soil profile (20–100 cm; n = 5), bedrock (n = 12) and stream sediment (n = 4) samples. A total of 70 soil samples were collected and in some samples determined to be enriched in Cd (5.38 ppm), Co (86.4 ppm), Cr (342 ppm), Cu (647 ppm), Fe (6.82%), Ni (755 ppm), Mn (2850 ppm), Zn (529 ppm) and As (89.8 ppm) relative to maximum allowable heavy metal concentrations in Turkey's soil. The heavy metals accumulated and enriched in stream sediments are mainly Cr, Ni, Co. The samples of soil profiles collected from different depths show commonly geogenic and partially anthropogenic effects. According to calculated geoaccumulation index (Igeo), enrichment factor (EF), and contamination factor (Cf) to evaluate possible metal enrichment in soil, the enrichment of heavy metals in the study area shows in the decreasing order of As > Ni > Cd > Co > Cr > Cu > Mn. The topsoil samples have CIA (Chemical Index of Alteration; 4.34–68.27) and CIW (Chemical Index of Weathering; 4.36–74.37) values ranged indicative of low–medium weathering. The 87Sr/86Sr and εNd values ranged from 0.705341 to 0.707491 and − 0.62 to − 4.95 in topsoil samples suggesting their bedrock sources. Lead isotopic data (207Pb/206Pb = 0.816–0.852; 208Pb/206Pb = 2.000–2.242) of the topsoil and profile soil samples show mostly geogenic (natural), partially anthropogenic sources. Ni, Cr, Co, and Cu enrichments in soils and stream sediments are related extremely with weathering of ophiolitic rocks and partially with traffic and agricultural activities (fertilization, irrigation, etc.), while As and Cd enrichments in soils are related commonly with weathering of volcanic rocks and partially with similar human activities. The geochemical results of heavy metals, Pb and Sr–Nd isotope analyses indicate that the most important source of high amounts of As, Cd, Co, Cr, Ni, Cu, Mn in some of soils in southern Konya is dominantly geological materials (natural resources) and rarely human activities (anthropogenic). [ABSTRACT FROM AUTHOR]

X-ray fluorescence (XRF) is widely used to rapidly detect heavy metals in soil. Spectra processing has been an important research topic to improve accuracy. In this study, 80 soil samples were analyzed by XRF under indoor conditions, where different preprocessing and quantitative analysis methods were compared in terms of prediction accuracy. Denoising algorithms were used to preprocess the soil spectra before establishing prediction models for As, Pb, Cu, Cr, and Cd in soil. The influence of denoising methods on the prediction effects of different models was compared and discussed. The results on five heavy metal spectra show that the proper spectral preprocessing method can effectively improve the prediction performance of the model. The multilayer perceptron model provides promising analysis and modeling for the five metal elements. The determination coefficients (R2) of the models were 0.857, 0.976, 0.977, 0.995, and 0.886, respectively. The proposed method provides the potential to support accurate quantitation by XRF analysis. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we compare linear regression with tree regression for analysis of the influence of soil properties on the sorption and retention of added Cd, Cu and Pb by 20 soil horizons typical of cropped soils in Galicia (N.W. Spain); our measure of sorption/retention capacity was K r, a recently introduced adimensional parameter. Sorption and retention of Cd was depressed by the presence of Cu and Pb. The soil parameters that were most associated, overall, with differences in Cd, Cu and Pb sorption and retention were cation exchange capacity (CEC), pH and Mn oxides’ content. Tree regression, which can take into account variation on both global and local scales, afforded better-fitting models than linear regression, which only reflects global tendencies; but for coherent interpretability of tree regression results it is just as important to avoid overfitting as in the case of linear regression. [Copyright &y& Elsevier]

Abstract: This paper describes in detail the tree regression models fitted, using the CART software package, to data on the sorption by 14 soils of Cd, Cr, Cu, Ni, Pb and Zn from solutions containing all six, and on the retention of these metals by the soils when subsequently exposed to metal-free medium. Pb, Cu and Cr were sorbed and retained to a greater extent than Cd, Ni and Zn, and the data for the former three metals were fitted better than those for the latter three, in keeping with previous indications that the influence of soil properties on the sorption and retention of Cd, Ni and Zn is limited by the presence of the more readily sorbed metals. Importance values suggest that the sorption and retention behaviour of Cr depends mainly on Fe/Al oxides, the organomineral fraction, sand and chlorite; that of Cu on CECe, organomineral content and haematite content; and that of Pb on CECe, haematite content and Mn oxides content. Although the behaviour of Cd, Ni and Zn depends on that of the more readily sorbed metals, it also appears to be influenced by silt content and various clay minerals (haematite in the case of Cd, mica in that of Ni, and quartz, gibbsite and chlorite in that of Zn). [Copyright &y& Elsevier]

The mining areas have faced severe pollution by caustic metals. In this study, heavy metals (Cu, Zn, Cr, Cd, Pb and Ni) in the soil of an extremely large iron mine pit from Ningwu-Luohe metallogenic belt, one of the seven iron ore areas in China was characterized. SiO2 was predominant soil mineral composition as 57.0 ± 1.3 %, followed by considerable Al2O3 (23.1 ± 2.5 %) and Fe2O3 (8.58 ± 1.2 %). Cu, Zn, Cr, Cd, Pb and Ni had the range of 7.62–237, 97.8–313, 1.73–43.8, 0.119–0.512, 5.13–44.7 and 7.87–23.9 mg/kg, respectively, wherein, Cu, Zn, Cr and Pb were likely to have relatively low concentration in the soil from the boom of mining pit. Comparatively, both Cu and Zn arose at the level of 1-fold higher than that of local background values, indicating that the soil from mining pit had been subjected to Cu and Zn accumulation. BCR (European Communities Bureau of Reference) sequential extraction analysis showed that these metals mainly existed in residual fraction, with averaged percentages of 42.0 ± 18 %, 70.3 ± 8.1 %, 76.6 ± 18 %, 30.2 ± 14 %, 52.5 ± 11 % and 61.0 ± 9.7 % for Cu, Zn, Cr, Cd, Pb and Ni, respectively. Geo-accumulation index indicates that the soil was moderately contaminated by Cu, practically uncontaminated or uncontaminated to moderately contaminated by Zn, while practically uncontaminated by Cr, Cd, Pb and Ni. There were just significant relationships between Zn and Cd and between Cd and Pb, indicating that Cd in the soil investigated possibly had at least two sources and for most of the elements the sources were different. The effects of pit depth and major soil composition on the distribution of trace metals varied depending on the element itself and its chemical forms. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Chronic kidney disease (CKD) in the North Central Province (NCP), Sri Lanka, is becoming a major cause of national burden with high mortality and morbidity. The origins of these kidney diseases are unknown, and the exact aetiology is not yet understood. Therefore, as an attempt to understand the effect of soil characteristics towards the disease, soil of surface (n = 25) and subsurface (50 cm depth, n = 25 of each) was collected from Horowpothana (HWP n = 50), Kabithigollawa (KBG n = 50), Medawachchiya (MWC n = 50) and Padaviya (PDW n = 50) of the NCP, where the highest number of patients is recorded. The soil samples were analysed using X-ray fluorescence for 22 major and trace elements, and the pH, electrical conductivity and oxygen reduction potential (ORP) for each sample were measured. The soil of all four villages mainly shows basic conditions. The high concentration of heavy mineral signatures in Horowpothana, Kabithigollawa, Padaviya and Medawachchiya could relate to high CKD patients in these four areas. The 50-cm soils of all four areas are in oxidized condition, while surface soil is in the anoxic condition. High fluctuation between surface and 50 cm may indicate high mobility of ions. According to the current study, P, F− and Fe2O3 ion could easily be mobilized into the groundwater of the area and thereby be related to the highest recorded CKD patients in these areas. Thus, as for the current study the heavy metals and elements that indicate the variations which causes health issues are Fe2O3, Pb, Zn, Cr, F−, Ti, Cu, Ni, V and Zr. [ABSTRACT FROM AUTHOR]

Cr heavy metal was observed in a soil sample collected around the rice mill of Bemetara district. The analysis is done by Atomic Absorption Spectrophotometer. The soil sample is collected from 50-4500 m distance. The concentration of Cr (III) is observed 94.330 mg/kg in 50 m and 41.780 mg/kg in 4500 m. Removal of Cr (III) heavy metal is also discussed. The accumulation of various heavy metals in bioadsorbent was confirmed by FTIR. It indicates the involvement of O-H (Hydroxyl) and =CH (alkenes) groups which are metal-binding chelate. Bioadsorbent was used for the removal of toxic heavy metals from industrial effluents. SEM and EDX are also used for the characterization of bioadsorbent. It is noteworthy that even at a maximum exposure time of heavy metal and biomass, the removal of heavy metal becomes higher. The result establishes the efficiency of C. sativum as a very good adsorbent to remove the heavy metals from the soil sample as it is economical for farmers. [ABSTRACT FROM AUTHOR]

The heavy metal pollution level in soils is heavily affected by the soil particle size distribution. However, the heavy metal loss during particle size extraction and the effect of calcite on the heavy metals removal in terms of the particle size are unclear. In this study, the distribution of heavy metals (Cu, Cd, Cr, Co, Ni, Zn, Pb, U, and V) was determined in five particle fractions (> 2, 2–0.25, 0.25–0.02, 0.02–0.002, and < 0.002 mm) of two soil and one sediment samples collected from the floodplain of Dongchuan, Yunnan Province, Southwest China. The sampled floodplain soils were mainly composed of gravel and sand fractions (> 97%). The concentrations of all nine heavy metals in the sampled soils and sediment increase significantly with decreasing particle sizes. The maximal loss rate of Cd and Cu reaches 54% and 8.6%, respectively, which should be considered in the process of particle size fraction extraction in soils. The removal amount and removal rate of heavy metals in solution by pure calcite ranks in the order of Pb2+ > Cu2+ > Cr6+, while the removal rate of Pb (93.13%) is much higher than that of Cu (24.56%) and Cr (10.71%), which increase with the calcite particle size decreasing. The stabilization of carbonate minerals in soils is crucial for heavy metal pollution control in floodplain soils with high carbonate concentrations in Dongchuan, China. [ABSTRACT FROM AUTHOR]

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As a major agricultural province in China, it is necessary to study the content of heavy metals in farmland soil and crop in Jilin Province and to evaluate the risks to ecology and human health. This study presented the work completed on 79 soil samples, 10 rice samples, 66 maize samples and 15 soybean samples collected from Jilin Province farmland and evaluated six heavy metals (Zn, Cu, Pb, Cd, Hg and As) concentrations. The results showed that the concentrations of the six heavy metals in farmland soil and crop samples from Jilin Province basically met the soil standards and food health standards of China. The agricultural soil pollution spatial distribution was the most serious in the south of Jilin Province and the lightest in the west. The non-carcinogenic risks faced by children eating crops were higher than those of adults, but the carcinogenic risks were lower than those of adults. Both of the two health risks to adults and children from eating crops were very limited. The results would help determine the heavy metals pollution in farmland soil in Jilin Province efficiently and accurately and helped decision makers to achieve a balance between production and environmental regulation. [ABSTRACT FROM AUTHOR]

Orchids represent a unique group of plants that are well adapted to extreme conditions. In our study, we aimed to determine if different soil contamination and pH significantly change fungal and bacterial composition. We identified bacterial and fungal communities from the roots and the surrounding soil of the family Orchidaceae growing on different mining sites in Slovakia. These communities were detected from the samples of Cephalanthera longifolia and Epipactis pontica from Fe deposit Sirk, E. atrorubens from Ni-Co deposit Dobšiná and Pb-Zn deposit Jasenie and Platanthera bifolia by 16S rRNA gene and ITS next-generation sequencing method. A total of 171 species of fungi and 30 species of bacteria were detected from five samples of orchids. In summary, slight differences in pH of the initial soils do not significantly affect the presence of fungi and bacteria and thus the presence of the studied orchids in these localities. Similarly, the toxic elements in the studied localities, do not affect the occurrence of fungi, bacteria, and orchids. Moreover, Cortinarius saturatus, as a dominant fungus, and Candidatus Udaeobacter as a dominant bacterium were present in all soil samples and some root samples. Finally, many of these fungal and bacterial communities have the potential to be used in the bioremediation of the mining areas. [ABSTRACT FROM AUTHOR]

This study investigated the environmental impact of the operation of lignite‐fired power plants in Yunnan Province. Soil, water, vegetable plant, and bottom ash samples were collected from around three lignite‐fired power plants in the area and the contamination levels of Cr, Cu, U, Mn, Cd, Ba, Pb, Sb, Co, and Ni in the samples were measured by inductively coupled plasma‐mass spectrometry (ICP‐MS). These results showed the pollutants contents in the soils taken from around the three plants were similar. Ba, Mn, and Sb had the highest concentrations of 15492, 2417, and 281 mg/kg respectively, and rapidly migrated from ash to soil. The contents of the metals in four common vegetable plants grown in the area (pine, smilax, Artemisia apiacea, duchesnea) were also measured and found to be substantially less than those in the soils and ashes. The heavy metal concentrations in the plants and water were below the standard level. The running of the power plant thus only had negative impacts on the ambient soils, especially Ba and Mn pollution. [ABSTRACT FROM AUTHOR]

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sewage irrigation has been widespread in the water shortage area of eastern China and inevitably tends to result in heavy metal accumulation in soils. A total of 148 surface soil samples from five land-use types were collected in Longkou, a typical sewage irrigation area of China, and As, Cd, Cu, Pb, and Zn concentrations were determined. The Nemerow index method and improved fuzzy comprehensive evaluation method were used to examine the pollution status of heavy metals. The potential ecological risk was evaluated by the Hakanson model by adjusting the assessment threshold, and its spatial distribution was interpolated using geostatistical techniques. As, Cd, Cu, Pb, and Zn accumulated in different amounts in the five land-use types. Urban industrial land and mining land were moderately polluted, irrigated land was slightly polluted, orchards were minimally polluted, and bare land was at a safe level of pollution. Cd exhibited high percentages of strong and severe levels of potential ecological risks. For Cd, irrigated land, orchard, and bare land mainly presented moderate risks, whereas urban industrial land and mining land mainly presented high risks. The comprehensive ecological risk of the five heavy metals was at a severe level for all tested land-use classes except for bare land. [ABSTRACT FROM AUTHOR]

In this study, soil profiles of four active sawmill vicinity were investigated for physiochemical properties and heavy metals concentration. Particle size distribution of soil showed a preponderance of sand fraction, followed by clayed and silt, classifying the soil to be sandy loam. The pH values of study soil were slightly acidic to slightly basic region (5.8±0.02 to 8.1±0.04). This pH region is an indication that the soil will drained. Soil sample from control site (Mn = 5.20± 0.02, Cu = 8.10± 0.04, Cr = 2.51± 0.00) revealed low metal concentration than the soil collected from the sawmill vicinity. These results suggest that heavy metal concentration is from anthropogenic sources (sawdust and other wood waste materials). The risk assessment of the study soil determined in terms of mobility factor, contamination factor and ecological risk factor indicate that the soil is polluted with respect to these heavy metals, Mn, Cu and Cr. It was advocated that the federal and state ministry of environment should routinely monitor sawmill vicinity soil in order to ensure a reduction in the level of contamination by heavy metal. [ABSTRACT FROM AUTHOR]

Accumulation of heavy metals in agricultural soils due to human production activities—mining, fossil fuel combustion, and application of chemical fertilizers/pesticides—results in severe environmental pollution. As the transmission of heavy metals through the food chain and their accumulation pose a serious risk to human health and safety, there has been increasing attention in the investigation of heavy metal pollution and search for effective soil remediation technologies. Here, we summarized and discussed the basic principles, strengths and weaknesses, and limitations of common standalone approaches such as those based on physics, chemistry, and biology, emphasizing their incompatibility with large-scale applications. Moreover, we explained the effects, advantages, and disadvantages of the combinations of common single repair approaches. We highlighted the latest research advances and prospects in phytoremediation-chemical, phytoremediation-microbe, and phytoremediation-genetic engineering combined with remediation approaches by changing metal availability, improving plant tolerance, promoting plant growth, improving phytoextraction and phytostabilization, etc. We then explained the improved safety and applicability of phytoremediation combined with other repair approaches compared to common standalone approaches. Finally, we established a prospective research direction of phytoremediation combined with multi-technology repair strategy. [ABSTRACT FROM AUTHOR]

Analysis of soil samples around pristine and major gold-mining areas in Ghana was carried out for heavy metals as part of a larger soil contamination and metal background study. The surface soil samples were digested using microwave digester (aqua regia) and analyzed with ICP-MS for As, Cd, Hg, Zn, Co, Cu, Mn, Fe, Al, V, Cr, and Pb. The average concentrations (mg/L) for the metals ranged from 0.01 ± 0.01 (Cd) to 86,859.36 ± 47.07 (Fe) for the pristine sites, and 0.01 ± 0.01 (Cd) to 59,006.95 ± 79.06 (Fe) for the mining sites. Mercury was below the detection limit of the analytical instrument (0.029). The concentrations of heavy metals from this study were used to assess their contamination levels, and health risks. The results showed that, the metals ranked by severity of health risks as As > Pb > Cr > Cd. Principal component analysis (PCA) and cluster analysis showed two groupings with the PCA showing metals variability explained by 79.02%. Results from the PCA and Cluster analysis indicate anthropogenic sources of the metals which may be emanating from gold-mining activities. Results from multi-criteria ranking and pattern recognition employing PROMETHEE and GAIA revealed major contribution of the metals from the mining sites with metal variability explained by 72.83%. This is the first time a multi-criteria approach is employed to characterize heavy metal contamination in Ghana, and the study nevertheless brought to light the impact of mining on human health and the environment with implications for other mineral areas around the globe. [ABSTRACT FROM AUTHOR]

Background: Meles River is one of the major Zn, Cr, Cu, Ni and Pb sources that enter Izmir inner Bay. However, the impacts of land uses on the river's catchment basin has not been investigated before. The study aims to exhibit the impacts of various land uses located on the catchment basin of the river. Cr, Cu, Pb, Ni and Zn concentrations were determined to present the current situation. In addition, the correlation analyses were performed in order to identify the metals' possible sources in the city. Methods: Soils and street dusts from the sites representing industrial, residential, and commercial areas and the roads in Meles River basin were sampled and heavy metal levels were determined by using the aqua regia digestion. The correlations among the analytical parameters and the factors loaded with clusters of parameters identified by Principal Component Analysis were used to describe the major sources of studied elements The contamination assessment was also done by using the geoaccumulation index (Igeo) and enrichment factor (EF) values. Results: Ni concentrations (average 697 mg kg−1) in soils were higher than the levels in street dusts (average 548 mg kg−1). Dust samples contained 131 mg kg−1 Pb, 179 mg kg−1 Cr, 347 mg kg−1 Cu, and 241 mg kg−1 Zn, while the average values of these metals were detected in lower levels in soils. The average values were found as 114 mg kg−1, 125 mg kg−1, 143 mg kg−1, and 129 mg kg−1, for Pb, Cr, Cu and Zn, respectively. The main component of soil heavy metals was determined as geochemical background enriched with long-term industrial depositions. Similarly, industrial emissions were found to be the major influence on the heavy metal levels in street dusts. Conclusions: Soil and street dust heavy metal levels are significantly affected by emissions from intense industrial activities and traffic emissions, and heavy metals are transported between these two matrices by exchanging masses between each other. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the levels of potential toxic metals; cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), zinc (Zn), and lead (Pb) in the wheat variety (Fsd-2008) irrigated by sewage water. Various indices were examined such as bioconcentration factor, enrichment factor and health risk index in order to better understand the transport and accumulation of metals through the food chain. Seeds of wheat variety were sown toward the end of October 2014 and flooded with different combinations of local sewage water and groundwater. Determination of metal concentration in soil and wheat samples was carried out by atomic absorption spectrophotometer. Analysis of mean metal concentration in soil that was irrigated by five different water treatments revealed that the mean concentration of Cd was less in the soil of treatment III, IV and V. Results also indicated that the mean concentrations of Cd, Cu and Cr increased and that of Ni and Pb decreased by sewage water irrigation. [ABSTRACT FROM AUTHOR]

Walnut is one of the most popular nuts worldwide and contains various mineral nutrients. Little is known, however, about the relationship between toxic heavy metals in walnuts and growth soil. In this study, we investigated the distribution, relationship, and risk assessment of five toxic heavy metals—lead (Pb), arsenic (As), chromium (Cr), cadmium (Cd), and mercury (Hg)—in walnuts and growth soil in the main production areas of China. The results showed that the main heavy metal pollution in walnut and soil was Pb and Cd. Regionally, positive relationships existed between heavy metals and the pH and organic matter of soil. In addition, we observed a notable uptake effect between walnut and growth soil. In this study, we found a significant correlation (r = 0.786, P < 0.05) between the bioconcentration factors and the longitude of the sampling areas. The risks (total hazard quotients) of five heavy metals toward children and adults by dietary walnut consumption were 46.8 and 56.2%, respectively. The ability to identify toxic heavy metal pollution in walnuts and growth soil could be helpful to screen suitable planting sites to prevent and control heavy metal pollution and improve the quality and safety of walnut. [ABSTRACT FROM AUTHOR]

Industrial processes, mining, weathering, and erosion release tin into the environment, which can be absorbed by vegetables. The research was undertaken to determine levels of tin in the perennial and annual vegetables:Allium ampeloprasumL,A. wakegiL,Artemisia dracunculusL,Coriandrum sativumL,Lepidium sativumL,Mentha arvensisL,Petroselinum crispumNyman Consp,Raphanus sativusL,Spinacia oleraceaL, andTrigonella foenum-graecumL and irrigation water and soil. Plant tissue, water, and soil samples were gathered from agricultural sites of Markazi Province, Iran. The highest tin levels were inT. foenum-graecum(454.110 ± 208.24 µg·kg−1) andS. oleracea(346.54 ± 156.14 µg·kg−1). Levels of tin in perennial and annual plants averaged 413.874 and 395.442 µg·kg−1, respectively, which were statistically similar. Mean concentration of tin in soil was 50.9205 ± 4.31 µg·kg−1and the mean concentration in water was 49.90 ± 0.4025 µg·kg−1, which were low. There were no differences in amounts of tin in the vegetables. Tin can accumulate in green leaves but all vegetables had levels of tin in edible parts of plants that were below the maximum acceptable limit for human consumption (<1 µg·g−1). [ABSTRACT FROM AUTHOR]

Guiyu is a well-known electronic waste dismantling and recycling town in south China. Concentrations and distribution of the 21 mineral elements and 16 polycyclic aromatic hydrocarbons (PAHs) collected there were evaluated. Principal component analyses (PCA) applied to the data matrix of PAHs in the soil extracted three major factors explaining 85.7% of the total variability identified as traffic emission, coal combustion, and an unidentified source. By using metallic or metalloid element concentrations as variables, five principal components (PCs) were identified and accounted for 70.4% of the information included in the initial data matrix, which can be denoted as e-waste dismantling-related contamination, two different geological origins, anthropogenic influenced source, and marine aerosols. Combining the 21 metallic and metalloid element datasets with the 16 PAH concentrations can narrow down the coarse source and decrease the unidentified contribution to soil in the present study and therefore effectively assists the source identification process. [ABSTRACT FROM AUTHOR]

Whole-cell bioreporters (WCBs) have attracted increasing attention during the last few decades because they allow fast determination of bioavailable heavy metals in contaminated sites. Various WCBs to monitor specific heavy metals such as arsenic and cadmium in diverse environmental systems are available. However, currently, no study on simultaneous analysis of arsenic and cadmium has been reported, even though soils are contaminated by diverse heavy metals and metalloids. We demonstrated herein the development of dual-sensing WCBs to simultaneously quantify bioavailable arsenic and cadmium in contaminated sites by employing the promoter regions of the ars and znt operons as separate metal-sensing domains, and egfp and mcherry as reporter genes. The dual-sensing WCBs were generated by inserting two sets of genes into E. coli DH5α. The capability of WCBs was successfully proved to simultaneously quantify bioavailable arsenic and cadmium in amended Landwirtschaftliche Untersuchungs und Forschungsanstalt (LUFA) soils, and then, it was applied to contaminated field soils collected from a smelter area in Korea. As a result, it was noticed that the bioavailable portion of cadmium was higher than that of arsenic while the absolute amount of bioavailable arsenic and cadmium level was opposite. Since both cadmium and arsenic were assessed from the same E. coli cells, the data obtained by using dual-sensing WCBs would be more efficient and convenient than that from comparative WCB assay. In spite of advantageous aspects, to our knowledge, this is the first report on a dual-sensing WCB for rapid and concurrent quantification of bioavailable arsenic and cadmium in contaminated soils. [ABSTRACT FROM AUTHOR]