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In order to explore the effects of sludge combined with peat application on the soil of the wasteland in mining areas, in this study, a total of 10 treatments were set up, including single sludge application ( 5%, 10%, and 15%), single peat application ( 5%, 10%, and 15%), sludge and peat combined application ( sludge 5% + peat 10%, sludge 10% + peat 10%, and sludge 15% + peat 10%), and blank control. The effects of different sludge and peat application rates on soil organic matter, total nitrogen, available phosphorus, available potassium, pH, moisture content, polyphenol oxidase and sucrase activities in the wasteland soil were studied by planting ryegrass in pots. The results showed that compared with the control, single application of sludge, single application of peat, and combined application of sludge and peat in the soil of the wasteland in the mining area could increase the content of organic matter, total nitrogen, available phosphorus, and the activities of polyphenol oxidase and sucrase. Sludge application by 15% and peat treatment alone could significantly increase the content of available potassium in soil. Sludge application by 15%, peat application by peat alone, and sludge and peat combined treatment could significantly increase soil moisture content. The results of TOPSIS analysis showed that the comprehensive improvement effect of sludge application on the soil of mine wasteland was better than that of sludge and peat combined application. Among them, compared with the control, soil organic matter, total nitrogen, available phosphorus, available potassium, water content, polyphenol oxidase activity and sucrase activity increased by 151.10%, 495.37%, 1130.83%, 39.71%, 115.04%, 78.98%, and 109.58%, respectively, and the comprehensive effect of soil improvement on mine wasteland was better than that of other treatments. In summary, 15% of sludge alone could be recommended as a soil improvement technology for wasteland in mining areas. [ABSTRACT FROM AUTHOR]

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To explore the effects of nitrogen (N) and phosphorus (P) nutrient gradients on morphological characteristics and biomass of fine root (≤2 mm) of plant surface layer (0-10 cm) in new coastal reclamation areas, Ligustrum lucidum was used as the test material and the fertilization method of ingrown soil cores (volume 196.25 cm³) was used to conduct nitrogen and phosphorus addition experiments on the soil core of the soil surface layer (0-10 cm) of L. lucidum. Suppose the fertilization gradient was 0, 1, 3, 5, 7, 9, 11, 13, 15, 17, 20 g per hole. The effects of N and P nutrients on the functional traits of fine roots in the soil surface were studied. The results were as follows: (1) Compared with the control, when 3 g N was applied, the length, surface area, volume, root length density, root surface area density, and biomass of fine roots increased significantly, with the increases of 62.39%, 120.87%, 169.97%, 59.19%, 106.99% and 102.75%, respectively; when 5-11 g N was applied, the above indicators gradually decreased. When the amount of N was applied greater than 11 g, no root grew. (2) When 3 g P was applied, the total length, surface area, volume, root length density, root surface area density and biomass of the root system significantly increased, with the increases of 77.37%, 111.15%, 147.50%, 73.87%, 97.88% and 98.05%. When the amount of P was applied greater than 5 g, the above indicators of fine roots gradually decreased, but there was no rootless situation. Fertilization caused significant changes in the morphological indicators and biomass of fine roots, and plants improved the ability to acquire soil nutrients by changing the structure of fine roots. Therefore, applying 3 g of Nor P respectively to the surface soil 1 m away from the trunk significantly can promote the growth of fine roots of L. lucidum. [ABSTRACT FROM AUTHOR]

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In the ecological restoration of acid mining, aim to solute the problem of accurate amounts of soil matrix improvement materials, this article used an abandoned land in a metal mine in Guangdong as the research object. Based on the analysis of soil acid potential, it uses the "improvement of the in-situ soil matrix + direct vegetation" technology to comprehensively govern it. The potential acid production of soil, thereby accurately calculating the addition of soil in situ improvement materials, so that the soil improvement effect is effective for a long time,laying a solid foundation for the stable, safe, and self-maintained vegetation system in the later period. [ABSTRACT FROM AUTHOR]

In order to study the influence of reclamation of open-pit coal mine dump on soil physical properties, the dump platform of Heidaigou open-pit mine in Zhungeer Banner, Ordos City, Inner Mongolia Autonomous Region, was as the research object. The difference of physical properties in 0-60 cm soil layer among natural landform (ZR), unreclaimed dump (WF) and 5-year reclaimed dump (FK) in mining area were analyzed, the effects of reclamation on soil physical properties of dump were studied by variance analysis and principal component analysis. The results showed that the soil bulk density and gravel content of unreclaimed dumps were significantly higher than those of reclaimed dumps and natural landforms, while the soil moisture content, saturated moisture content and field water holding capacity were lower than those of reclaimed dumps and natural landforms, among which the field water holding capacity was significantly different from those of reclaimed dumps and natural landforms. The correlation analysis and regression equation fitting analysis showed that the gravel content in soil affected soil bulk density and water holding capacity. Reclamation made the soil bulk density and gravel content decrease, and the soil moisture content, saturated water content and field water holding capacity increase. With the increase of soil depth, the soil unit weight, moisture content and saturated moisture content of the dump showed an increasing trend, while the field water holding capacity and gravel content showed a decreasing trend. The comprehensive scores of the 40-60 cm soil of 5-year reclaimed dump, 40-60 cm soil of natural landformand 20-40 cm soil of 5-year reclaimed dump were ranked as 1st, 2nd and 3rd, respectively, which indicated that the reclamation of the dump could improve the soil and optimize the soil texture. The depth of soil improvement by plants could reach 60 cm soil layer in the case of 5 years of reclamation of the dump. Above results provided certain guiding for reclamation work in mining area. [ABSTRACT FROM AUTHOR]

Gannan area in Jiangxi province, is famous as the "Rare Erath Kingdom" because ol the high reserves ol ionic type rare earth. However, the in-situ leaching ol rare earth resulted in the amounts ol ammonia nitrogen remained in the mine, and then caused the excessive ol ammonia nitrogen in surlace water or ground water. In order to explore the leasibility ol leaching and remediation of residual ammonia nitrogen in the in-situ leaching ol ionic rare earth mines in southern Jiangxi, column experiments were used to simulate the in-situ leaching ol soil. The shear resistance ol soil alter leaching with calcium lignosullonate(C2q H24 CaOi0 S2), magnesium sul!ate(MgSO4) and water was analyzed. The inlluence ol dilierent concentrations ol eluent and dilierent leaching speeds on the leaching ellect of ammonia nitrogen were investigated. To screen the elution ellect of dilierent elution methods on the residual ammonia nitrogen ol rare earth tailings and their ellects on the properties ol different bound ammonia nitrogen, pH and organic matter in soil. The results showed that the optimal elution concentrations ol C2Q H24CaOio S2 and MgSOd were 8 g/L; at the leaching rate of 1 mL/min, the leaching efficiency ol ammonia nitrogen Irom tailing soil was 78. 33% and 92. 16%, respectively. Eluent reached the direct discharge standard ol rare earth tail water at the 10th pore volume and the 8th pore volume lor C20 H24 C3O10S2 and MgSOq, respectively. Compared with the direct water leaching, C20 H24 CaOi°S2 and MgSOd mainly eluted exchangeable ammonia nitrogen Irom soil. The pH and organic matter of soil alter C2q H24 CaOi0 S2 leaching were more conducive to the subsequent ecological restoration ol soil. Alter screening by dilierent leaching methods, the compound leaching with a concentration ratio ol C20 H24 CaOi0 S2 and MgSO4 ol 1 : 1 had signilicant effects on soil ecological restoration and in-situ leaching ammonia nitrogen elution. The research result showed that the leaching and remediation ol residual ammonia nitrogen in the in-situ leaching ol ionic rare earth mines in southern Jiangxi can utilize the combined leaching of C20 H24CaOiQS2 and MgSO4, which can also increase the shear resistance of soil and reduce the risk of mine soil collapse. [ABSTRACT FROM AUTHOR]

As a by product of municipal sewage treatment, municipal sludge contains a lot of organic matter and rich nutrients such as nitrogen, phosphorus and potassium, but also contains a variety of heavy metals. After mining, the mine soil is poor and barren, therefore, a large amount of guest soil and timely fertilization are needed in ecological restoration. This paper investigates the amount of sludge products added to the guest soil by detecting the chemical composition of the guest soil, calculation, experiment, and expert argumentation. Based on the effective control of heavy metal content, the goal of utilizing and treating the urban sludge to save soil costs is achieved, which is also verified through engineering practice. The results show that it is feasible to use sludge products in improving the soil quality of the abandoned mine land. The application of sludge products not only meets the soil pollution requirements, but also enhances soil fertility to a certain extent, with good ecological restoration. The innovation is that sludge products can replace part of the substrate materials for mine restoration, and generally save about 10% 30% of soil cost. In addition, the fertilizer cost can also be reduced. Moreover, the sludge products containing about 50% water reduces the water requirement of vegetation growth and the cost of labor and equipment for irrigation during the maintenance process. Therefore, this study can be used as a reference for similar engineering practice in the future. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to screen leguminous plants suitable for improving the soil of bauxite mine reclaimed soil and provide a reference basis for sustainable agricultural development in mining areas. [Method] Seven legumes, including Sesbania cannabina, Vicia sativa, Astragalus sinicus, V. villosa, Medicago sativa, Stylosanthes guianensis and Coronilla varia, were planted in the reclaimed soil of the Pingguo bauxite mine in Guangxi, and the biomass, presence of root nodules, nutrient content, nitrogen fixation efficiency, biological nitro- gen fixation, soil nutrients, calcium and magnesium ion content, total aluminum and active aluminum content of each legume were determined. The legumes suitable for planting in bauxite mine reclamation soil were screened through principal component analysis, and a partial least squares path model (PLS-PM) was established to explore the factors that affected the biological nitrogen fixation of legumes in bauxite mine reclamation soil. [Result] Among the seven legumes, A. sinicus had the highest below-ground biomass(1.961 g/pot) and above-ground bio-mass (0.344 g/pot), C. varia had the lowest below-ground biomass (0.387 g/pot) and above-ground biomass (0.099 g/pot) while Sesbania had the highest N(7.98% ), P(2.999 g/kg), and K(19.828 g/kg) contents. In terms of nodulation, only Sesbania, A. sinicus, and C. varia had root nodules, while the rest of the legumes did not nodulate. Among the three nodulated legumes, S. cannabina had the highest nitrogen fixation efficiency (80.01%) and biological nitrogen fixation (0.077 g/pot). Principal component analysis of three leguminous plants based on evaluation factors including plant nutrient content, biomass, biological nitrogen fixation, and nitrogen fixation efficiency as evaluation factors showed that comprehensive score of S. cannabina repens was the highest (2.30 points). PLS-PM pathway analysis showed that the biological nitrogen fixation of legumes in bauxite mine reclamation soil was directly influenced by plant nutrient content and soil active aluminum and pH, soil nutrients, and types of plants indirectly influenced the biological nitrogen fixation of legumes by affecting plant nutrient content and soil active aluminum. [Conclusion] S. cannabina, A. sinicus, and C. varia are capable of nodulating and improving the pH, available K, ac- tive aluminum, organic matter content, and biological nitrogen fixation of the reclaimed soil in bauxite mines. Based on the comprehensive e- valuation, S. cannabina is considered as the most suitable legume plant for planting in the reclaimed soil of bauxite mines and can be promo- ted and applied as a legume plant for nitrogen fixation and soil improvement in bauxite mining areas. [ABSTRACT FROM AUTHOR]

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Mineral resources are considered significant material sources for economic and social development. However, during mining processes, various toxic pollutants, such as heavy metals, are released into the soil environment, which pose serious threats to the ecological environment and human health in mining areas. In addition, intricate geology, geomorphology, and changes in soil physicochemical properties, as well as complex processes comprising the migration and transformation of pollutants, complicate the remediation of soil environments. Given the lack of existing technology, such as inadequate soil remediation, we analyzed the recent achievements in the remediation of contaminated soils in mining areas and introduced the basic concept of land restoration. Moreover, we introduced the theoretical and experimental research status of five types of typical treatment technologies for heavy metals, including extraction, passivation, nanotechnology, combination, and new concept techniques in detail; subsequently, we also described the advantages and limitations of the application of existing remediation techniques. This study aims to provide directions for future research on soil pollution control, treatment technologies, and remediation practices in mining areas. [ABSTRACT FROM AUTHOR]

In order to explore the effects of different organic fertilizers on nitrogen mineralization and related enzyme activities in reclaimed soil under the same nitrogen level, in this experiment, the reclaimed soil of coal mine was taken as the research object, and five treatments were set at 300 mg/kg nitrogen level by indoor aerobic culture method : no fertilization （CK）, chemical fertilizer, chicken manure, pig manure, and cow manure. The changes of net nitrogen mineralization, nitrification rate and related enzyme activities in different treatments within 0-126 days were analyzed. The results showed that the content of ammonium nitrogen in the soil of each fertilization treatment decreased first and then was stabilized with the prolongation of incubation time, while the content of nitrate nitrogen increased first and then was stabilized with the prolongation of incubation time. The net nitrogen nitrification and mineralization rates of the soil in the treatment of no fertilization did not change much during the entire incubation period, while the net nitrogen nitrification and mineralization rates in the chemical fertilizer, chicken manure, and pig manure treatments showed a downward trend with the incubation time, and cow manure showed the opposite trend. The order of the contents of ammonium nitrogen, nitrate nitrogen, the net nitrogen nitrification rate, and mineralization rate of each treatment: chemical fertilizer > chicken manure > pig manure > cow manure > no fertilization, and there were significant differences among the treatments. Compared with chemical fertilizer, application of organic fertilizers significantly increased soil urease, protease, and asparaginase activities, but had little effect on glutaminase activity, but chemical fertilizer treatment inhibited glutaminase activity. In summary, the application of chemical fertilizer and organic fertilizers could promote the mineralization of nitrogen in soil, and organic fertilizers could also improve the activity of nitrogen transformation related enzymes in soil compared with chemical fertilizer. [ABSTRACT FROM AUTHOR]

The exploitation of mineral resources leads to the destruction of land resources, the ecological environment, and even affects the sustainable development of the regional economy. Land reclamation, especially soil amelioration, has become an important part of ecological restoration in mining areas in China. Soil amelioration has become the primary challenge of land reclamation in mining areas because of the poor soil structure and fertility of the reclaimed land, as observed in waste storage yards. This highlights the importance of soil amelioration in mine land reclamation. The amelioration principles and techniques were comprehensively analyzed based on the soil amelioration status of mining areas in China and abroad as well as on the basis of the characteristics of soil in reclaimed mining land in China. According to the existing problems in the research and application of soil amelioration, combined with the green, stable, and sustainable development orientation of mine ecological restoration the development direction of soil amelioration in mining area was put forward. This provides reference for soil improvement and ecological restoration of mining reclaimed land in the future. [ABSTRACT FROM AUTHOR]

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Copyright of Industrial Minerals & Processing / Huagong Kuangwu yu Jiagong is the property of Industrial Minerals & Processing Editorial Office 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.)

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This study aims to explore the effects of different vegetation blanket covers on the nutrient and enzyme activities of open-pit coal mine soils in arid areas. The research object was taken as the Dafeng mine in Ningxia Helan Mountains Nature Reserve. Three vegetation blanket covers were set as straw, straw-coir, and coir. Some parameters were measured, including the organic carbon, total nitrogen, total phosphorus, urease, protease, and alkaline phosphatase, as well as the peroxidase and ecological stoichiometric ratios of the mine soils. The results showed that: 1) The vegetation blanket covered with different materials increased the organic carbon and total nitrogen content of the surface layer of the soil. Specifically, the maximum content was achieved in the soil covered by the coir vegetation blanket. By contrast, there was no significant change in the total phosphorus content, and the organic carbon. Among them, there was the total nitrogen, and total phosphorus content of the soil from 10 to 20 cm. Only the organic carbon content of straw-coir vegetation blanket cover soil decreased with the increasing soil depth in the vertical direction. There was no change in the organic carbon, total nitrogen, and total phosphorus of the rest of the vegetation blanket-covered soil, as the soil depth increased. 2) The vegetation blanket cover with different materials increased C/P and N/P ratios. The maximum was also the soil covered by the coir vegetation blanket. There was no significant change in the C/N. Moreover, there was no change in the C/N, C/P and N/P, as the soil depth increased. 3) The urease and alkaline phosphatase activities of the vegetation blanket-covered soil were significantly higher than those of the bare ground. The soil from 0 to 10cm was greater than that from 10 to 20cm. There was no change in the protease activity with the depth of the soil layer. Furthermore, the catalase activity was significantly higher only in the soil from 0 to 10cm of the coir vegetation blanket than in the soil from 10 to 20 cm. 4) The correlation between soil enzyme activity and environmental factors showed that the total phosphorus of soil and C/N were the main influencing factors to govern the enzyme activity, whereas, the N/P and the total nitrogen of soil were the main factors to drive the enzyme activity. The nutrient content of the soil surface layer increased after the three vegetation blankets were mulched, which also increased the C/P and N/P of the soil surface layer, thus promoting surface soil enzyme activity. In addition, there was a significant positive correlation (P<0.01) among the four enzyme activities. The coir vegetation blanket was more capable to provide soil nutrients, compared with the straw and straw-coir vegetation blankets. The redundancy analysis of soil enzyme activities and environmental factors showed that the total soil phosphorus of soil and C/N were the main influencing factors to govern the enzyme activities, while the N/P and the total nitrogen of soil were the main factors driving the enzyme activities. Consequently, the vegetation blankets cover increased the nutrients in the surface layer of the soil. At the same time, the enzyme activity was also promoted in the surface soil. The findings can provide a strong theoretical basis to implement the ecological restoration of vegetation blankets for the open-pit coal mine soil in arid areas. [ABSTRACT FROM AUTHOR]

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Reclaimed Mine Soil (RMS) is the type of high compacted and nutrient exhausted soil, due to the mining and reclamation operations. The soil aggregate associated carbon (C), nitrogen (N), and isotope can be a platform to understand the pedogenic process of reclaimed mine soil. This study aims to monitor the soil aggregate recovery and Soil Organic Matter (SOM) formation. Different sorts of age chronosequence soil (0, 3, 12, 14, 17, 25, 28, and 32 a) were collected from the Robinia pseudoacacia L. forests in the Pingshuo opencast coal mine in China. Moreover, the soil was selected from adjacent and undisturbed Populus simonii forest as a reference (CK) as well. The wet-sieving method was used to separate the fractions of soil aggregate, and the aggregate-associated C, N, 13C, and 15N isotopes. The results showed that: 1) The proportion of >250-2 000 μm aggregate in the 32 a soil was 737.02% higher than that in the 0a soil, whereas, the proportion of 53-250 μm in the 32 a soil was 19.25% lower than that in the 0a soil, indicating that the reclamation operations destroyed the structure and stability of water-stable aggregate. Moreover, the mean weight diameter of soil aggregate in the 32 a soil was 133% higher than that the in 0a soil, indicating the excellent recovery of the structure and stability with the ages. 2) Soil aggregate associated C and N increased with the reclamation time. The >2 000 μm and >250-2 000 μm associated C and N were dominated in the total C and N. In addition, the aggregate-associated C, N, and C/N ratio increased with the time. Specifically, the large-size aggregate (>250 μm) associated C/N was significantly higher than that of the microaggregate (P<0.05). 3) The δ13C values were differed from -15.14‰--26.40‰, while the δ15N values were ranged from 1.13‰-10.87‰. More importantly, the δ13C values decreased with the time in the soil aggregate >2 000 μm, >250-2 000 μm, and lower than 53 μm, the δ15N values decreased in the >2 000 μm as well. The 13C isotopes were significantly enriched in the soil aggregate 53-250 μm and lower than 53 μm fractions, compared with the large-size aggregates (P<0.05). It infers that the soil C was incorporated into the RMS from the large-size to small-size aggregate fractions during the pedogenic process. 4) The proportion of the new C was accounted for over 80% of the total C in the soil aggregate >2 000 and >250-2 000 μm, without the significant temporal variation (P>0.05). However, the proportion of the new C increased significantly in the lower than 53 μm fraction over 17 years after reclamation, whereas the proportion remained stable after that, indicating the nearly saturated recalcitrance pool (<53 μm C) after 17-year reclamation. Overall, the reclamation operations significantly increased the proportions of small-size soil aggregates. However, the vegetation restoration can be expected to facilitate the recovery of aggregate structure, stability and aggregate associated C and N. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board 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.)

Taking the heavy metal pollution caused by metal mining as the starting point, this paper fully analyzes several commonly used typical heavy metal pollution remediation measures, obtains their advantages and disadvantages, and gives reasonable suggestions. It is concluded that a variety of remediation methods should be combined in the future remediation process of soil heavy metal pollution, so as to be able to repair contaminated soil more reasonably. [ABSTRACT FROM AUTHOR]

To study the characteristics of heavy metal pollution in the soil of a pyrite mine site and evaluate the potential risk of heavy metal pollution to human health, the pollution degree of the site was evaluated by a single factor pollution index and multi-factor comprehensive pollution index, the sources of pollutants were analyzed by principal component analysis and correlation analysis, and health risk assessment on excessive pollutants was conducted. The results showed that As, Hg, Pb, and Cr6+ in the site exceeded the standard to different degrees, the surface soil was moderately polluted and the deep soil was slightly polluted. Excessive pollutants As and Pb were mainly from pyrite, while Hg and Cr6+ were imported pollution. Health risks of As, Pb, Cr6+ and Hg in the site all exceeded the acceptable risk level, which has posed a threat to the health of employees of the enterprises on the site. [ABSTRACT FROM AUTHOR]

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BACKGROUND: Rare earth resources are essential for a wide range of advanced technologies, which have received considerable attention in the world. Bayan Obo is the largest rare earth mine in the world. The study on the distribution characteristics of rare earth elements ( REEs) and heavy metal elements in the environmental media such as soil and plants in the Bayan Obo mining area can provide basic data for the investigation of the environmental status of the mining area and provide reference for its environmental restoration. OBJECTIVES: To investigate the distribution characteristics of REEs and heavy metal elements m vanous environmental media at different areas in the Bayan Obo mine. METHODS: Nine plant samples, six soil samples, one rock sample and one cow manure sample were collected from the Bayan Obo rare earth mine and surrounding areas. The contents of 15 rare earth elements and 8 heavy metal elements of these samples were determined by ICP - MS, which were used to study the behavior of elements and the variation rules in space. RESULTS: The results showed that the distribution patterns of REEs in rocks, soil, plants, and cow manure samples were similar: obvious enrichment of light - REEs and depletion of high - REEs. The richest rare earth element in soil and plant was Ce, reaching 49. 95% and 48. 55%, respectively. The spatial variation law of the total content of rare earth element in Limonium bicolor (Bag. ) Kuntze was consistent with the mineralization change of the three ore bodies: the main ore > the east ore > Dongjielegele ore. This indicated that the rare earth content of this plant was basically controlled by the minerality of the ore body, and it was more accurate to indicate the enrichment degree of rare earth in the growth environment. In addition, there was accumulation of Zn ( 465 - 778mg/kg), Cd ( 1.35 - 2. 23mg/kg), Pb (181 - 43lmg/kg) in the soil of the mining area. Some points of Cd and Pb were beyond the risk control value. CONCLUSIONS: The ore, soil, and plant samples in Bayan Obo all show the characteristics of Ce enrichment. Moreover, the rare earth content of plants is highly correlated with the ore body where it grows. The REE content characteristics among the three media show obvious inheritance and consistency. Special attention should be paid to the mining and agricultural activities in the main mining area in Bay an Obo because of the accumulation of Zn, Cd, and Pb in these mining areas. [ABSTRACT FROM AUTHOR]

BACKGROUND: Metal activity state measurement method is one of the effective means to find hidden ore. However, during the application of the method, it was found that the types of effective activity states of gold in different geochemical landscape conditions were not the same. Moreover, it was found that the conditions such as solid-liquid ratio, temperature and time during the extraction would have a significant impact on the active state extraction data. OBJECTIVES: To solve the problems of selective extraction and accurate determination of the active state of gold. METHODS: A comparative study of different experimental conditions and samples of different grain sizes for the active state extraction of gold from the Wangjiaping gold deposit in the Qinling area using ICP-MS analysis. RESULTS: The optimal extraction conditions for gold element water extraction state, clay adsorption state, organic binding state and iron manganese oxide state were determined. Solid-liquid ratio was 1∶5, the extraction time was 24 h, the extraction temperature was 35℃ and the sample size range was-80 mesh. The method detection limits for the four phase states of elemental gold were 0.03 ng/g for water extraction state 0.03 ng/g for clay adsorption state, 0.04 ng/g for organic binding state, 0.05 ng/g for iron manganese oxide state. The relative standard deviation (RSD) was 7.25%-9.02%. In the 23 rd line of the Wangjiaping gold deposit, the average content of the water extracted state gold was 0.19×10-9, the average clay adsorption state gold was 0.30×10-9, the average organic binding state gold was 11.16×10-9, and the average iron manganese oxide state gold was 0.20×10-9. CONCLUSIONS: The organic binding state is the main active phase state of gold in the soil of the mining area, and the abnormality of the organic binding state of gold is consistent with the position of the hidden gold ore body. [ABSTRACT FROM AUTHOR]

In this study, 225 topsoil samples were collected from different areas（natural background, agricultural planting, and mining areas）in Guizhou Province to systematically investigate the concentrations, distribution, and accumulation characteristics of heavy metals As, Cd, Cr, Cu, Hg, Pb, and Zn. Based on this, the potential ecological risk index（RI）and human health risk assessment were used to assess the ecological risk level and human health risk of heavy metal exposure in different areas. Results indicated that the concentrations of heavy metals in the topsoil of different regions in Guizhou Province were significantly different. Compared with the corresponding background value of soil in Guizhou Province, the accumulations of Hg, Zn, Cd, and As in agricultural planting area soil were significant. The mean concentrations of Hg, Zn, Cd, Pb, and As in the soil of mining areas were 52.55, 23.22, 16.32, 14.48, and 4.85 times of the soil background values of Guizhou Province, respectively. The geoaccumulation index（Igeo）values showed that the heavy metals in the soil of the natural background areas were uncontaminated, while the pollution from heavy metals in the agricultural planting areas were at uncontaminated or uncontaminated to moderately contaminated levels. The heavy metals contaminated levels were more prominent in the mining area, and the pollution of Hg, Zn, Cd and Pb reached moderately contaminated levels. especially in the mineral resources distribution areas, such as northwest Guizhou and Tongren areas. The RI results showed that the ecological risk levels of heavy metals in the soil of the mining area were considerably higher than those in agricultural planting areas and natural background areas. The ecological risks of heavy metals in the soil of mineral-resource concentrated-distribution areas were relatively high, with some samples were in high ecological risk levels. The potential ecological risk assessment of single heavy metal revealed that Hg, Cd, Pb, and As were the main risk factors in the soil of agricultural planting and mining areas, while Cr and Cu were in low risk levels. The health risk assessment results indicated that the non-carcinogenic risks existing in soils of agricultural planting and mining areas to adults were acceptable, but the carcinogenic risk could not be neglected. The non-carcinogenic and carcinogenic risks to children were evident. The overall human health risks in mining areas were higher than those in agricultural planting areas, and the human health risks for children were higher than those for adults. [ABSTRACT FROM AUTHOR]

In view of the influence of different soil types on the effect of chemical oxidation remediation, three typical soils in my country were selected to simulate the preparation of benzo [a] Pyrene contaminates the soil, using activated sodium persulfate in the reaction conditions: water-soil ratio 2:1, activator addition 10%, reaction temperature 25 ℃ Carry out chemical oxidation experiments. The effects of three soil types and their properties on the loading and oxidation effect of benzo[a]pyrene were explored. Research Form Ming: Among the three soil types, yellow sand soil has the worst loading capacity for benzo[a]pyrene, followed by purple soil, and black soil is the best. The degradation rate of benzo[a]pyrene in the soil after chemical conversion is the lowest in black soil, followed by purple soil, and highest in yellow sand; Cation exchange capacity and organic matter content in soil And the specific surface area is positively correlated with the loading rate of benzo[a]pyrene, and the pH value is negatively related to the loading rate of benzo[a]pyrene, and the square of the correlation coefficient is greater than 0.92, of which the content of organic matter and its specific surface area have a greater impact on the loading capacity of benzo[a]pyrene; the content of organic matter in the soil has a greater impact on its oxidation efficiency Fruit has the greatest impact. The higher the organic content, the lower the degradation rate of benzo[a]pyrene. The results of the study are useful for the repair of benzo[a]pyrene contaminated soil in different regions. The design of complex technical solutions has guiding significance. [ABSTRACT FROM AUTHOR]

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BACKGROUND: The large - scale mining of ion - type rare earth mines in southern Jiangxi and the unreasonable disposal of tailings and slag caused heavy metal lead content in the surrounding environment of the mining area to exceed the standard, destroying the ecological environment of the mining area. OBJECTIVES: Passivate the lead in the soil of the mining area to reduce its bioavailability and ecological risks. METHODS: Acid modification and organic modification of attapulgite, and passivation of lead - containing soil with unmodified attapulgite. RESULTS: After 50 days of cultivation, the modified attapulgite reduced the acid - extracted content of lead from 25. 69mg/kg to 7.42mg/kg, the residual content increased by 1. 38 times compared with the control group, and the TCLP extracted content decreased by 65. 70% compared to the control group, significantly reducing the bioavailability and ecological risk of lead. CONCLUSIONS: Compared with the natural attapulgite, the modified attapulgite has a better effect on the soil remediation of rare earth tailings. [ABSTRACT FROM AUTHOR]

[Objectives] The objective of this study was to explore the role of bacteria and different passivation agents in reducing the heavy metals uptake of vegetables and remediating heavy metal contaminated soil.[Methods] The cadmium-contaminated soil in a mining area in Nanjing was collected as potting test soil. In this pot experiment,biochar (B) and K-feldspar (K) were used as passivators in combination with the cadmium-resistant bacteria Bacillus halotolerans G20 strain to explore the effects of different treatments on the growth,Cd content and quality of lettuce (Lactuca sativa L. var. ramosa Hort.) in Cd-contaminated soil,as well as pH,organic matter content and Cd morphological changes of lettuce rhizosphere soils.[Results] Compared with the control,strain G20,biochar,K-feldspar and their combined bacteria agents could increase the above-ground dry weight and reduce the Cd content of lettuce. Among them,the Cd content in the above-ground tissue of lettuce treated with biochar combined bacteria agent (G20L+B) was significantly reduced by 53.1% to 0.15 mg·kg-1,which was lower than the national food safety limit. G20+B agent could increase the bacterial count (16.5%),pH value (0.3) and organic matter content of the lettuce rhizosphere soil (44.6%),reduce the effective Cd content (45.4%),reduce the toxicity of Cd to the lettuce,significantly increase the vitamin C content in the lettuce (32.9%),and reduce nitrite content (38.8%).[Conclusions] The biochar combined B.halotolerans G20 bacteria agent had the potential to repair moderately Cd-contaminated soil and to ensure the safe production of vegetables. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board 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.)

BACKGROUND: As more and more countries pay greater attention to energy metals, the strategic position of lithium has been continuously improved. As a result, the research related to lithium deposits and lithium metal has been continuously carried out. Heavy metal pollution in the lithium mine has received attention in recent years. Under the circumstances, the content and distribution of heavy metals in lithium mines is worthy of further study. OBJECTIVES:To evaluate the level and safety of heavy metals in the Jiajika lithium mining area. METHODS:From 2016 to 2018, 68 root soil samples were collected from the Jiajika lithium mining area in Western Sichuan. The content of Cd, As, Pb, Cr, Cu, Ni and Zn in root soil sample were determined by inductively coupled plasma-mass spectrometry (ICP-MS). RESULTS:The results show that the average content of Cd, As, Pb, Cr, Cu, Ni and Zn in the root soils of Jiajika mining area was 0.13, 15.31, 25.47, 60.57, 16.12, 23.59, and 66.83mg/kg, respectively. None of the soil samples exceeded the latest published standard for agricultural land in August 2018. Soils from the tailings reservoir area of common deposits like Cu, Pb, Zn often had serious heavy metal pollution. The heavy metal content in Jiajika tailings reservoir was lower than the environmental standard limit, and the content of Cd, As and Cr in root soils from tailings reservoir areas was decreasing year by year during the three years after mining activity ceased. CONCLUSIONS:The heavy metals in the roots of the mineral processing factory and the tailings reservoir have certain enrichment due to the existence of anthropogenic sources, but they do not constitute a hazard and the waste has little environmental pollution. [ABSTRACT FROM AUTHOR]

[Objective] To screen the effective chelator which can enhance the absorption of heavy metals by Bidenspilosa L., the effects of chelators[glycol-bis-(2-aminoethylether)-N. N, N’, N’-tetraacetic acid(ETGA), nitrilotriacetic acid(NTA)and ethylene diamine disuccinate(EDDS)]on the uptake and accumulation of Cd, Pb, Cu and Zn with Bidens pilosa L. were investigated. [Method]Pot experiments was conducted to evaluate the effects of application ETGA, NTA and EDDS on the uptake and transportation of heavy metals(Cd, Pb, Cu and Zn)from contaminated mining area soil with Bidenspilosa L.. [Result] The results indicated that three chelators promoted the growth of Bidens pilosa L., and the order of effects was EDDS>EGTA>NTA. Judging from the unit content of root, stem and leaf tissue, EGTA, NTA and EDDS could promote the absorption of Zn in stem, Pb in root and Cu in root, stem and leaf of Bidens pilosa L.. Judging from the total absorption and accumulation of plants, EGTA had the best effect on absorption and accumulation of Zn, EDDS had the best effect on absorption and accumulation of Pb and Cu, and the effects of three chelators on absorption of Cd were not good in Bidens pilosa L.. The accumulation and transfer coefficients of Cu in leaves and stems of Bidens pilosa L. treated with EGTA were higher than the control, indicating that EGTA could effectively promote the accumulation and transportation of Cu in Bidens pilosa L.. [Conclusion] The chelators EGTA and EDDS did not significantly affect the absorption of Cd in Bidens pilosa L., and NTA not only reduced the absorption of Cd in Bidens pilosa L. but also did not significantly increase the absorption of Zn. All three chelators significantly increased the accumulation of Zn, Pb and Cu in Bidens pilosa L. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board 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.)

Copyright of Journal of Agricultural Science & Technology (1008-0864) is the property of Journal of Agricultural Science & Technology 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.)

In order to understand carbon dynamics in mine soil, the spatial variation of soil organic carbon (SOC) contents was investigated in two types of landscapes destroyed by coal mining, i. e. subsidence slope and ground fissure site from Jiaozuo mine area, China. It is found that the SOC contents in topsoil (0-10 cm) decreases and their spatial variability increases in both subsidence slope and ground fissure site in comparison with those in non-subsidence site. The SOC contents at all the layers of depth profile decrease, especially at the layers of 10-30 cm depth,where a decrease of 29%-38% in the SOC contents is observed. The depletion of SOC pool in the study area was estimated up to 20.8-47.3 t/hm². For the subsidence slope, the SOC contents in topsoil obviously decrease from upper slope to middle slope positions, and then gradually increased from middle slope to toe slope positions. At the middle,lower and toe slope positions of soil profiles,the SOC contents decrease linearly along with depth,but vary irregularly in those of the upper slope positions. The loss of SOC storages occurs on the whole subsidence slope,especially at the upper, middle and lower slope positions. The spatial variation patterns of SOC in the study area could be attributed to soil erosion, land-use, and fissure-induced leakage as well as the low input of crop biomass to mine soils. [ABSTRACT FROM AUTHOR]