Accumulation Of Metals In Soils Research Articles

Accumulation of heavy metals in soil and Chelidonium majus L. in the urban environment

Accumulation of heavy metals in soil and Chelidonium majus L. in the urban environment

Analysis of the spatiotemporal fields of chemical soil pollution as a basic component of urban ecosystems

The soil is a depositing medium and an indicator of geochemical load. The fulfillment of important ecosystem functions by urban soils ensures the ecological safety of urban ecosystems as a whole. The purpose of the work is to forecast soil pollution as a basic component of the urban ecosystem with a high level of technogenic load. The calculation of the spatio-temporal fields of chemical pollution of soils in the city of Kolchugino, Vladimir region, was carried out using a balance model based on ecological and analytical data utilizing the results of area surveys of soils and snow cover. The content of heavy metals of hazard classes 1 and 2 in soil and snow samples (solid and liquid phases) was determined by atomic absorption method according to standard methods. The analysis of spatio-temporal fields of soil contamination for each heavy metal is performed on the basis of map diagrams constructed using the INTEGRO GIS software-technological complex. Taking into account aerotechnogenic intake, an assessment of the degree of accumulation of heavy metals in soils and their time to reach the critical level is given. In the soils of Kolchugino, an excess of sanitary and hygienic standards (gross forms) is revealed for all the metals studied. Analysis of the data of spatio-temporal fields of soil pollution with heavy metals in the city of Kolchugino showed that the established level of soil pollution exceeding the MPC is primarily associated with the past economic activity of non-ferrous metallurgy enterprises and will remain at the same level in the near future.

Unlocking the secrets of soil microbes: How decades-long contamination and heavy metals accumulation from sewage water and industrial effluents shape soil biological health

Heavy metals contamination is posing severe threat to the soil health and environmental sustainability. Application of industrial and sewage waste as irrigation and growing urbanization and agricultural industry is the main reason for heavy metals pollution. Therefore, the present study was planned to assess the influence of different irrigation sources such as industrial effluents, sewage wastewater, tube well water, and canal water on the soil physio-chemical, soil biological, and enzymatic characteristics. Results showed that sewage waste and industrial effluents affect the soil pH, organic matter, total organic carbon, and cation exchange capacity. The highest total nickel (383.71 mg kg−1), lead (312.46 mg kg−1), cadmium (147.75 mg kg−1), and chromium (163.64 mg kg−1) were recorded with industrial effluents application. Whereas, industrial effluent greatly reduced the soil microbial biomass carbon (SMB-C), soil microbial biomass nitrogen (SMB-N), soil microbial biomass phosphorus (SMB-P), and soil microbial biomass sulphur (SMB-S) in the winter season at sowing time. Industrial effluent and sewage waste inhibited the soil enzymes activities. For instance, the minimum activity of amidase, urease, alkaline-phosphatase, β-glucosidase, arylsulphatase and dehydrogenase activity was noted with HMs contamination. The higher levels of metals accumulation was observed in vegetables grown in soil contaminated with untreated waste water and industrial effluent in comparison to soil irrigated with canal and tube well water. The mean increase in soil microbial parameters and enzyme activities was also observed in response to the change in season from winter to spring due to increase in soil mean temperature. The SMB-C, SMB-N, SMB-P and SMB-S showed significant positive correlation with soil enzymes (amidase, urease, alkaline-phosphatase, β-glucosidase, arylsulphatase and dehydrogenase). The heavy metals accumulation in soil is toxic to microorganisms and inhibits enzyme functions critical for nutrient cycling and organic matter decomposition and can disrupt the delicate balance of soil ecosystem and may lead to long-term damage of soil biological health.

Impact of Heavy Materials Accumulation in Soil Using Inductively Coupled Plasma Mass Spectrometry

The formation of heavy metals in the soil greatly damaged the crops and caused many health issues near the region of Shikarapara.The issue of heavy metal accumulation in soil has become a significant concern with wide-reaching implications for the environment, agriculture, and public health.Heavy metals, including lead, cadmium, mercury, and arsenic, find their way into soil primarily through human activities such as industrial processes, mining, agricultural practices, and waste disposal. Once introduced, these metals can severely disrupt soil quality, potentially leading to decreased fertility, hindered plant growth, and alterations in microbial ecosystems. Furthermore, heavy metals can leach into groundwater, posing risks to water quality and aquatic life. The soil from shikarapara is taken along with few other places near to the shikarapara to find heavy metals accumulation using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Result has shown that heavy metals like lead, zinc, manganese, mercury, Iron, cadmium, copper and arsenic are present in the soil samples. Particular measures must be considered to regulate this pollution.

Heavy Metals in Foods and Beverages: Global Situation, Health Risks and Reduction Methods.

Heavy metals are chemical elements with a toxic effect on the human body. The expansion of industries has led to significant increasing levels of these constituents in the environment. Intensive agriculture can also lead to an increased concentration of heavy metals as a result of using different fertilizers and pesticides. Heavy metal accumulation in soil and plants represents a serious issue because of the potential risks to consumers. There are several methods available for the removal of these toxic components from different substrates (chemical precipitation, electrodialysis, coagulation and flocculation, photocatalytic removal, and adsorption-based processes), but most procedures are expensive and difficult to perform. Thus, more research is needed on the development of low-cost methods in foods. This work represents a review on the heavy metal presence in different food substrates (such as fruits and vegetables, milk and dairy products, meat and meat derivatives, oils, and alcoholic beverages) and provides an overview of the current situation worldwide, taking into account the fact that risks for human health are induced by the intensification of industry and the high degree of pollution. Considering that the toxicological quality of food affects its acceptability, this work provides valuable data regarding the actual situation on the proposed topic.

A Comparative Study on the Bioavailability and Soil-to-Plant Transfer Factors of Potentially Toxic Element Contamination in Agricultural Soils and Their Impacts: A Case Study of Dense Farmland in the Western Region of Saudi Arabia

Soil and aquatic pollution by heavy metal (Pb, Cr, Cu, Fe, Zn, and Ni) ions has become one of the prime problems worldwide. Thus, the purpose of the current study is to conduct hydrogeological research and quantify the main trace metals in the edible vegetables, soil, irrigation water, pesticides, and fertilizers in the farmland near Jeddah city, Saudi Arabia. Samples of soil, water, and plants such as coriander (Coriandrum sativum), dill (Anethum graveolens), parsley (Petroselinum crispum), and arugula (Eruca sativa) were collected, acid-digested, and analyzed using an inductively coupled plasma–optical emission spectrometer (ICP–OES). The levels of the elements in soil were determined in the order of Fe > Zn > Cu > Cr > Ni > Pb, whereas the sequence in plants was Fe > Cr > Zn > Pb> Ni > Cu, and in water, the order was Pb > Fe > Cu > Zn> Ni = Cr. In soil, the levels of Fe, Cr, and Pb were higher than the recommended values set by the World Health Organization (WHO) and the Food Administration Organization (FAO). In soil, Pb and Zn uptake increased with an increase in the availability of both elements, whereas in plants, Zn and Pb uptake occurs primarily through the plant roots, and some specific proteins facilitate metal transport and movement across the membrane. In soil, the root cell walls first bind to metal ions, which are taken up across the plasma membrane. The levels of the investigated elements in water and vegetables samples were below the permissible limits set by the FAO and within the allowable limits in the available pesticides and fertilizers. The transfer factor (TF) of metal absorption from soil to plant (TFsoil-plant) and from irrigated water to plant (TFwater-plant) in the study area was determined, followed by correlation and statistical treatment according to the date. The TF values were used to assess the metal levels in collected plant, soil, and water samples. The computed values of TF implied that plant leaves and soil were safe from the risk of heavy metals. Water irrigation causes heavy metal accumulation in soil and vegetables, with varying concentrations. The results of this study revealed no abnormal metal accumulation due to irrigation and no health risks to consumers.

Seeds Treatment and Nanotechnology -Review

Sustainable future in agriculture, encourage us to find more environmentally ecofriendlyalternatives,the seed is a fundamental component of sustainable production ,as approximately 90% of ourfood crops are grow from seed.Agriculture is facing challenges due to changing environmental conditions such as salinity,heavy metalaccumulation in soil,weeds and climate changes .etc....all of these factors affect seed germination leadingto abnormal seed dormancy,non-viability ,reduce water absorption in addition to seedling development,andcrop production.Seed treatment by agrochemical play a role in preserving seed quality against biotic and a bioticstresses,they often have negative impacts on the environment.As a result ,adoption green chemistrytechnologies(Nanoagrochemicls) is an adequate solution.In this article,we will attempt to spot light on various used for seed treatment.Additionally,we will examinethe advantages and disadvantages of each method,with the objective of applying seed treatment techniquesand assessing their effectiveness in promoting agro-production development,particularly in Africancountries.Furthermore,we will explore the adoption of nanotechnology as a solution to improve the quality ofagricultural products.

The environmental assessment of soil chemical properties irrigated with treated wastewater under arid ecosystem of Al-Ahsa, Saudi Arabia

PurposeThe present study focused on examining the effect of treated wastewater (TWW) on soil chemical properties. Also, efforts were made to compare the soil chemical properties under TWW irrigation with that under groundwater (GW).Design/methodology/approachDuring the years 2021 and 2022, surface and subsurface soil samples were randomly collected in triplicate by using an auger fortnightly at two depths (20 and 40 cm) from the selected spot areas to represent the different types of irrigation water sources: TWW and GW. Samples of the GW and the TWW were collected for analysis.FindingsThis study examines the impact of TWW on soil characteristics and the surrounding environment. TWW use enhances soil organic matter, nutrient availability and salt redistribution, while reducing calcium carbonate accumulation in the topsoil. However, it negatively affects soil pH, electrical conductivity and sodium adsorption ratio, although remaining within acceptable limits. Generally, irrigating with TWW improves most soil chemical properties compared to GW.Originality/valueIn general, almost all of the soil’s chemical properties were improved by irrigating with TWW rather than GW. Following that, wastewater is used to irrigate the soil. Additionally, the application of gypsum to control the K/Na and Ca/Na ratios should be considered under long-term TWW and GW usage in this study area in order to control the salt accumulation as well as prevent soil conversion to saline-sodic soil in the future. However, more research is needed to thoroughly investigate the long-term effects of using TWW on soil properties as well as heavy metal accumulation in soil.

Mapping heavy metals accumulation in conventional rice farming system at Banyumas Regency of Central Java, Indonesia

Rice grains produced in the conventional system are a prime source of heavy metal exposure in the human body leading to various health problems. The objective of this study was to assess heavy metals concentration in soil and rice grain under the conventional rice farming system in Banyumas, Indonesia, the pollution index, and the bioaccumulation factor. There were thirty-seven samples collected based on soil type, elevation, and irrigation system. The heavy metals level in soil ranged from 2.7 to 39.92 ppm of Pb, 0.11 to 3.01 ppm of Cd, and 4.79 to 61.32 ppm of Cr. Pb and Cr accumulation levels were below the maximum permissible concentration (MPC). A different result in Cd exceeded the MPC in 56.75% of sampling sites. Rice grain showed a high accumulation in Pb (6.85 ppm) and Cr (5.73 ppm) that exceeds the maximum standard. Cd exceeded 24.32% of sampling sites with an average of 0.54 ppm. The Pollution Index (PI) was medium in Cd and low in Pb and Cr. The Bioaccumulation Factor (BAF) of heavy metals in rice was Cd>Pb>Cr with averages of 0.64, 0.53, and 0.30, respectively. A high correlation resulted in Pb and Cd in soils and rice grains. Remediation is must done to reduce the heavy metals accumulation in soils and rice grains for environmental and health safety to prevent further contamination.

Role of mi RNA in Phytoremediation of Heavy Metals and Metal Induced Stress Alleviation.

Anthropogenic activities have contributed hugely in enhancing various types of environmental toxicity. One of these is higher accumulation of toxic heavy metals in soil and plant tissues. Although many heavy metals act as essential component for the growth and development of plants when present in low concentrations but at higher concentrations it becomes cytotoxic. Several innate mechanisms have evolved in plants to cope with it. In recent years the mechanism of using miRNA to combat metal induced toxicity has come to fore front. The miRNA or the microRNA regulates different physiological processes and induces a negative control in expressing the complementary target genes. The cleavage formation by post-transcriptional method and the inhibition of targeted translational mRNA are the two main procedures by which plant miRNAs function. The heavy and enhanced metal accumulation in plants has increased the production of different kinds of free radicals like reactive nitrogen and oxygen which damage the plants oxidatively. Several plant miRNA are capable of targeting and reducing the expression of those genes which are responsible for higher metal accumulation and storage. This can reduce the metal load and hence its negative impact on plant can also be reduced. This review depicts the biogenesis, the mode of action of miRNA, and the control mechanisms of miRNA in metal induced stress response in plant. A detailed review on the role of plant miRNA in alleviation of metal induced stress is discussed in this present study.

Тяжёлые металлы в почвах различных функциональных зон урбанизированных территорий: оценка содержания и экологического риска

In order to analyze heavy metal pollution of urbanized soils of the city of Vladimir, the selection and study of soil samples was carried out. Soil samples were analyzed for lead, zinc, copper, nickel, manganese, cobalt and chromium. The obtained indicators were compared with the maximum permissible concentrations and background values. The regularities between the proximity of the studied sites to industrial enterprises and the concentration of heavy metals in the soil are established. The coefficients of accumulation of heavy metals in soils have been calculated and metals that are priority pollutants with the highest accumulation coefficient have been identified. By calculating the total accumulation index of heavy metals, the territory of the city is differentiated by the degree of danger. The calculation of such indicators as: the general pollution index PLI, the indicator of potential environmental risk PERI, the Nemerow pollution index (NPI). It has been established that lead, arsenic and zinc are priority pollutants. The use of various calculated parameters of pollution allowed us to reveal a more detailed picture of the spatial distribution of heavy metals in the soils of urban landscapes under the influence of a strong anthropogenic load. Despite the differences in the calculation of the indices, a high correlation was found between the values of the total pollution index (Zc), the Nemerow pollution index (NPI) and the potential environmental risk index (PERI). The degree of soil contamination of various functional zones according to the indicator of potential environmental risk and the general pollution index PLI increases in the following series: zones of multi-storey buildings < zones of green spaces < zones of transport infrastructure < zones of low-rise buildings < industrial zones.

Effect Of Phytoremediation On The Geotechnical Properties Of Heavy Metal Contaminated Soil

<p>The accumulation of heavy metals in soils increases rapidly due to various natural processes. Heavy metal pollution changes the geotechnical properties of soil and poses a serious threat to human health and ecosystems, so soil pollution remediation is particularly important. Phytoremediation is an environmentally friendly approach that can be used as a successful mitigation measure to restore heavy metal-contaminated soils cost-effectively. The plants extract and remove elemental contaminants or reduce their bioavailability in soil and improve the geotechnical properties. In this study, we are conducting a pot experiment with Amaranthus by adding Zn salt as a contaminant and determining the rate of removal of metal.</p>

Ecological Risk and Migration Patterns of Heavy Metals in Soil and Crops in the Lead-Zinc Mining Area in Guizhou, China

An accumulation of heavy metals in soil poses a risk to the ecological environment and human health. In this study, the concentrations of heavy metals in soil and crops were examined in a lead-zinc mining area in Guizhou Province, China. The distribution and sources of heavy metals were analyzed using GIS spatial mapping. The potential ecological risks of heavy metals were assessed using the potential ecological risk index (RI), and the human health risk assessment method recommended by the United States Environmental Protection Agency (USEPA) was used to quantify the health risk of residents exposed to heavy metals in the soil around lead-zinc mines. According to the results, the average of concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in the soil were 58, 7.9, 175, 64, 0.461, 65, 1539, and 2513 mg·kg-1, respectively, which were significantly higher than the background values in Guizhou Province. It was found that the As, Cd, Cu, Hg, Pb, and Zn concentrations were extremely irregular in the soil and that the concentrations decreased significantly with the distance to the smelters, which were greatly disturbed by human activities. Comprehensive evaluation of soil heavy metals using the potential ecological risk index revealed that the risks of soil heavy metals were pole-strength and strong levels, and Cd constituted the primary ecological risk factor. A total of 22% and 10% of the corn samples contained Pb and As above the heavy metal pollution thresholds in the national food safety standards. According to human health risk assessments, heavy metals in the soil present potential non-carcinogenic risks to adults or children, and pose a potential carcinogenic risk to children. Soil pH was an important controlling factor affecting the bioavailability, migration, and accumulation of Cd in soil-crop systems. This study provides data and theoretical support for the prevention and control of soil pollution in lead-zine mining areas.

Distribution Characteristics, Ecological Risks, and Source Identification of Heavy Metals in Cultivated Land Under Non-grain Production

The purpose of this study was to explore the distribution characteristics and potential ecological risks of soil heavy metal pollution of cultivated land under non-grain production. Taking a typical area around Hangzhou Bay as an example, 254 topsoil samples (0-20 cm) of cultivated land were collected, and the content of eight soil heavy metals in four different cultivated land use types, including grain, seedlings, vegetables, and fruits, was analyzed. The ecological risk was assessed by the Nemerow pollution index and the potential ecological risk index, and the PMF model was used to identify the source of soil heavy metals in the study area. The results showed that the average contents of As, Cr, Cd, Cu, Hg, Ni, and Zn were all higher than the soil background value, except for Pb, but were lower than the national risk control standard for soil contamination of agricultural land. Non-grain production had a significant impact on the accumulation of heavy metals in soil. The content of heavy metals in nurseries and orchards was relatively high, followed by vegetable fields, and the lowest in grain fields. The Nemerow index showed that the cultivated land in the study area was in a light pollution level as a whole, and the single-factor pollution risks of Hg, Cd, and As were relatively high. The potential ecological risk levels of heavy metals in different cultivated land use types were:nurseries>orchards>vegetable fields>grain fields. The PMF results showed that the main sources of soil heavy metals in the study area were mixed sources of industrial emissions (36.8%), natural parent material sources (28.4%), atmospheric deposition sources (21.4%), and agricultural activity sources (13.4%). In conclusion, the increase in the application of chemical fertilizers and pesticides was the direct reason for the increase in soil heavy metal content caused by non-grain production of the cultivated land, whereas the industrial and mining emissions and atmospheric deposition accelerated the increase in soil heavy metal content in the study area.

Assessment of Some Heavy Metals in Cereal Samples from Bayo and Hawul Local Government Areas, Borno State, Nigeria

Bayo and Hawul local government areas are known for large production of cereal for consumption and commercial purposes, and uses tones of agrochemicals to increase yield. Long-term use of agrochemicals result in accumulation of heavy metals in soil and subsequent absorption by plant, hence the need to asses level of heavy metals in the cereal samples (sorghum and maize). Atomic Absorption Spectroscopy (AA-6800 SHIMADZO) was used to determine concentration of heavy metals in cereal samples collected from agricultural locations in Bayo and Hawul local government areas. When compared with joint safety limit of WHO/FAO, the levels of heavy metals in cereal samples were higher in most of the agricultural locations. The average daily dose (ADD) of the heavy metals computed for cereal samples were above the tolerable daily intake. The levels of heavy metals exposure due to consumption of cereals were above the acceptable risk levels (ILCR > 10-4 ), suggesting an individual developing cancer over a lifetime is of high probability. There is potential health risk for humans through the consumption of the studied cereal as revealed by high values of hazard quotient (HQ). Moreover, hazard indices (HI) of all the metals due combined non-cancer effects in the study were greater than one (1), suggesting potential health risk. As, Cd and Pb show consistency through consumption of the studied cereal samples and should be given priority to public health concern because of health risk associated with these heavy metals

Bacterial and fungal diversities examined through high-throughput sequencing in response to lead contamination of tea garden soil.

Several studies have indicated that the heavy-metal content in tea is increasing gradually. Researchers examining the soil of more than 100 tea gardens in China have observed that lead content was higher in some soils. The effect of lead contamination on soil microorganisms in tea gardens was studied to determine the effect of lead on the essential functions of microorganisms in a tea garden soil ecosystem. Previous studies on pot experiments adopted the method of adding a single instance of pollution, which failed to comprehensively simulate the characteristics of the slow accumulation of heavy metals in soil. This study designed with two pollution modes (multistage and single instance) determined the content of soil lead in different forms according to the European Community Bureau of Reference extraction procedure. The community structure, species diversity and functional abundance of soil bacteria and fungi were examined by high-throughput sequencing. We observed that the content of four forms of lead was higher in the multistage contamination mode than in the single instance contamination mode. The effects of lead contamination on bacteria differed significantly (p < 0.05), and the abundance and diversity of bacteria were higher in the multistage contamination mode than in the single instance contamination mode. The community structure of fungi was more affected by lead than was that of bacteria. The content of each lead form was the environmental factor most strongly affecting soil bacteria and fungi. The predicted main function of the bacterial community was amino acid transport and metabolism, and the trophic mode of the fungal community was mainly pathotroph-saprotroph. This study revealed changes in soil microorganisms caused by different forms of lead and contamination methods in tea garden soil and provide a theoretical basis for examining the effects of lead contamination on soil microorganisms.

Partial Purification of Glutathione S-transferase Enzyme From the Seed of Mallow (Malva Slyvestris L.) and Investigation of the Inhibition Kinetics of Some Heavy Metals.

Glutathione S-Transferase (GST) enzyme is abundant in mammals, insects, fish and microorganisms, as well as in various tissues of these species, particularly in tissues exposed to xenobiotics from the environment. As a result, the enzyme execute detoxifying function by scavenging a diverse range of xenobiotics, such as chemotherapeutic medicines, environmental carcinogens and endogenous compounds. In this study, GST enzyme was partially purified from mallow (Malva slyvestris L.) seed for the first time and the kinetic parameters were determined. The optimum ionic intensity was found in 400 mM Tris-Buffer, optimum pH: 7.0, and optimum substrate concentration was determined as 0.2 mM. One of the biggest reasons for deterioration of ecological balance in nature is heavy metal accumulation in soil, air and water which becomes a major threat to the vital activities of living things. In this study, inhibitory effects of Cd+ 2, Ag+, Zn+ 2 and Fe+ 3 heavy metals, which are common in nature, on mallow seed glutathione S-transferase enzyme were investigated. Each heavy metal showed micromolar inhibitory effects on enzyme activity. IC50 values of the metals were calculated as 60.93, 74.602, 178.22 and 369 µM, respectively.

Heavy metals accumulation in soil and uptake by barley (Hordeum vulgare) irrigated with contaminated water

Impacts of nine heavy metals (Cd, Cr, Cu, Ni, Pb, K, Fe, Mn, and Zn) contamination in irrigation water on the soil, shoots, and roots of barely were investigated. Due to freshwater shortages, the use of available and inexpensive urban wastewater with input from local industrial factories containing heavy metals in irrigation is still practiced in the Middle East including Palestine. Barely was grown in plastic pots filled with sandy soil irrigated with simulated treated wastewater during two growing seasons. The metal treatments investigated include one, three, nine, and 15 multiples of the average metal content of treated effluent. Results showed that (i) Barley showed similar growth responses but different metal uptake patterns, (ii) Cd, Fe, Pb, and Zn in roots and shoots of barley were higher than WHO permissible levels, (iii) all metals accumulated in the soil had lower content than WHO permissible levels, (iv) The average value of enrichment factor (EF) for most heavy metals used was around unity indicating poor enrichment to soil and translocation to roots and shoots, (v) The highest Translocation factor (TF = 57.8) and Bioconcentration Factor (BCF = 126.8) was observed for K indicating its role in enhancing barley's tolerance to drought and its effectiveness in using barley in phytoremediation, and (vi) Barley growth and development and soil quality parameters were significantly affected by repetitive and increased irrigation with wastewater containing heavy metals.

Date palm-magnetized biochar for in-situ stabilization of toxic metals in mining-polluted soil: evaluation using single-step extraction methods and phytoavailability

Mining activities provide a pathway for the entry and accumulation of various heavy metals in soil, which ultimately leads to severe environmental pollution. Utilization of various immobilizing agents could restore such contaminated soils. Therefore, in this study, date palm-derived biochars (BCs: produced at 300 °C, 500 °C and 700 °C) and magnetized biochars (MBCs) were employed to stabilize heavy metals (Cd, Pb, Cu and Zn) in mining polluted soil. Metal polluted soil was amended with BCs and MBCs at w/w ratio of 2% and cultivated with wheat (Triticum aestivum L.) in a greenhouse. After harvesting, dry and fresh biomass of plants were recorded. The soil and plant samples were collected, and the concentrations of heavy metals were measured after extracting with water, DTPA (diethylenetriaminepentaacetic acid), EDTA (ethylenediaminetetraacetic acid), and acetic acid. BCs and MBCs resulted in reduced metal availability and uptake, with higher fresh and dry biomass (>36%). MBCs showed maximum decrease (>70%) in uptake and shoot concentration of metals, as these reductions for Cd and Pb reached below the detection limits. Among all single-step extractions, the DTPA-extractable metals showed a significant positive correlation with shoot concentrations of tested metals. Thus, the synthesized BCs and MBCs could effectively be used for stabilizing heavy metals and improve plant productivity in multi-contaminated soils. However, future studies should focus on long term field trials to restore contaminated mining soils using modified biochars.

Ecological risk assessment and early warning of heavy metal cumulation in the soils near the Luanchuan molybdenum polymetallic mine concentration area, Henan Province, central China

The Luanchuan molybdenum polymetallic mine concentration area is rich in mineral resources and has a long history of mining. The environmental impact of long-term mining activities cannot be ignored. It is of great significance to study the ecological risk and the accumulation trends of heavy metals in the soil of mining areas for scientific prevention and control of heavy metal pollution. Taking the Taowanbeigou River Basin in the mine concentration area as the research object, the ecological pollution risk and cumulative effect of heavy metals in the soil of the basin were studied by using the comprehensive pollution index method, potential ecological risk assessment method and geoaccumulation index method. On this basis, the cumulative exceeding years of specific heavy metals were predicted by using the early warning model. The comprehensive potential ecological risk of heavy metals in the soil near the Luanchuan mine concentration area is moderate, and the single element Cd is the main ecological risk factor, with a contribution rate of 53.6%. The overall cumulative degrees of Cu and Pb in the soil are “none-moderate”, Zn and Cd are moderate, Mo has reached an extremely strong cumulative level, Hg, As and Cr risks are not obvious, and the overall cumulative risks order is Mo>Cd>Zn>Cu>Pb>Hg. According to the current accumulation rate and taking the risk screening values for soil contamination of agricultural land as the reference standard, the locations over standard rates of Cu, Zn and Cd will exceed 78% in 90 years, and the over standard rate of Pb will reach approximately 57% in 200 years. The cumulative exceeding standard periods of As, Cr and Hg are generally long, which basically indicates that these elements do not pose a significant potential threat to the ecological environment. Mining activities will accelerate the accumulation of heavy metals in soil. With the continuous development of mining activities, the potential pollution risk of heavy metals in the soil of mining areas will also increase.©2023 China Geology Editorial Office.