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[Objective] Feasibility study of applying writing paper as sealing materials in oyster mushroom’s cultivation was conducted in or¬der to provide theoretical basis for increasing the safety of oyster mushroomproducts. ' Method】 The experiments and production demonstration were carried out by setting 2 treatments, ie. treatment Awith writing paper as sealing materials and treatment Bwith newspapers! CK) ,and the growth of mycelium, number and fresh weight of fruiting bodies, cost and economic returns as well as heavy metal contents in fruiting bodies were investigated and evaluated. ' Result】 The growth rate of mycelium was 0. 97 cm/d of treatment A, which was significantly higher than that of treatment B (% < 0 . 05 , the same as below), and the average number and fresh weight of fruiting bodies per bag (total of the first flush and second flush, hereafter) were 43.47 ,257. 59 g,5. 57 more and 11 . 7 g higher than that of treatment B, respectively. The results showed that the heavy metal content of Pb, Cd, Hg and As in fruiting bodies of both treatment A and Bwas lower than the limits (1 . 000, 0. 200 ,0. 100,0. 500 mg/kg, respectively) set by both national food safety ytandard and national aaricultural standard for green food mush¬ room, and the content of Pb, Cd, Hg, As of treatment A was only 0. 001, 0. 085 , 0.002 and 0. 037 mg/kg, which was far more lower tlian the safety limits mentioned above, respectively. Besides, Cr was not found in the fruiting bodies of treatment A. The results indicated that the oyster mushroom of treatment A was much safer than that of treatment B. Compared to treatment B， the cost per bag of sealing materials and their processing increased by 0.002 yuan， while the output valiae increased by 0. 140 yuan, thus the eco¬nomic retiams per bag of treatment A was 0. 138 yuan higher than that of treatment B. The results of production demonstra¬tion showed that，when compared witli treatment B，treatment A could shorten the period of spawn running by 3 days and shorten the average harvesting time of the first and second flush by 3 and 4 days, respectively, besides, treatment Acould increase thefresh weight per bag by 24. 00 gin total. ' Conclusion】 Based on the in¬crease of mycelium ’ s growth rate, number and fresh weight of fruiting bodies, economic returns, as well as decrease of heavy metal contents, it is recommended that writing paper could be applied instead of newspapers as sealing materials in oyster mushroom5 s production [ABSTRACT FROM AUTHOR]

Under prolonged high-intensity utilization, the issue of heavy metal pollution in China’s facility soil has become pronounced, necessitating the urgent development and deployment of eco-friendly, efficient, and cost-effective remediation technologies. As pivotal strategies for soil improvement, four categories of root zone regulation techniques—encompassing water and fertilizer management, gas and nutrient enrichment, amendment application, and microenvironment modulation—can significantly diminish heavy metal concentrations and bioavailability in facility soil, mitigate crop uptake of these contaminants, and foster their transformation and stabilization within the soil matrix, thereby mitigating the risks posed to ecological systems and human health. Notably, amendment-based technologies have garnered considerable attention and adoption due to their efficiency, cost-effectiveness, ease of application, diversity, and minimal equipment requirements. To further advance and optimize the application of root zone regulation technologies in facility soil, this paper outlines a research trajectory centered on the intricate interactions between these technologies and polluted facility soil-crop systems. It advocates for the establishment of long-term research frameworks to evaluate the efficacy of various root zone regulation approaches, with a particular emphasis on investigating the functional microbial communities within facility soil. Additionally, it underscores the importance of enhancing the integration of water and fertilizer management practices to systematically explore and devise the most effective strategies for mitigating heavy metal contamination in facility soil, thereby ensuring sustainable agriculture and safeguarding public health. [ABSTRACT FROM AUTHOR]

This paper provides an introduction to groundwater PRE technology, in situ bioremediation technology, and in situ chemical oxidation technology. It also presents a summary of the core-shell structure and physical and chemical preparation methods of nZVI. Furthermore, it discusses the mechanism by which nZVI degrades heavy metals, non-metallic inorganic substances, halogenated organics, and antibiotics in groundwater through processes such as adsorption/reduction, precipitation etc. The interaction mechanism between nZVI and microorganism coupling system is described along with an analysis of the promoting and inhibiting effects that nZVI has on microorganisms. Additionally, the research progress on removing groundwater pollutants using coupling systems is discussed. Finally, the future research focus for coupling technologies is proposed. [ABSTRACT FROM AUTHOR]

This paper introduces the preparation materials and methods of hydroxyapatite, as well as the meehanism of repairing contaminated soil, and focuses on the research progress in three aspects: The remediation effect of hydroxyapatite on heavy metal contaminated soil, the improvement of soil microbial community structure and the enhancement of soil enzyme activity, and analyzes the application advantages of hydroxyapatite. The future synthesis and application direction of hydroxyapatite are proposed. [ABSTRACT FROM AUTHOR]

[Objective] In view of the absorption and enrichment of heavy metals in agricultural solid waste by earthworms. [Method]This paper regulates the concentrations of Pb, Cr and Cd by adding exogenous heavy metal salts, studies the changes of the physicochemical properties and the total amount of heavy metals in the bait, and analyzes the influence of the concentrations of Pb, Cr and Cd in the bait on the enrichment of heavy metals by earthworms. [Result]The results showed that: after vermicomposting, the contents of TN, TP were significantly increased (P<0. 05), the contents of TK and organic matter were significantly decreased (P< 0. 05), and pH value was not significantly changed (P>0. 05). The concentrations of Pb, Cr and Cd decreased in different degrees compared with those before treatment. The enrichment coefficients of earthworms on Pb, Cr and Cd were 0. 18, 0. 55 and 17. 97, respectively. [Conclusion] Studies have shown that earthworms have different levels of absorption and enrichment of Pb, Cr and Cd in agricultural solid waste. [ABSTRACT FROM AUTHOR]

This paper comprehensively discusses the pathways of heavy metals into the plant root epidermis, the short-range transport pathway through the horizontal transport of coplanar and plasmodesmata, and the long-range transport pathway through the xylem and phloem for loading and unloading. The transport of heavy metal ions by the coplanar pathway is slow, while the transport of heavy metal ions by the extra plastid pathway has low resistance to migration and high rate. Cell wall adsorption and resolution are en-dogenous factors affecting the transport of heavy metal ions into the root xylem via the cytoplasmic ectodomain pathway, but the development of the Casparian strip and suberin in the root cortex, which constitute the ectodomain barrier, can block the ectodomain pathway of heavy metal ion migration to the xylem. Plant transpiration and root pressure provide the driving force for the long-distance transport of heavy metal ions in the xylem and are related to the transpiration rate of plants. The mechanism of plant detoxification and tolerance to heavy metals is mainly induced by the production of metallothionein, the formation of phytoch-elating pep tides (PCs) in stressed plants and the regionalization of heavy metals by vesicles. [ABSTRACT FROM AUTHOR]

This paper mainly reviews the methods and pros and cons of chemical reduction, ball milling and green preparation of nZVI, summarizes the modification research of nZVI composites and the application progress of heavy metal removal in recent years, and expounds the adsorption mechanism of nZVI composites for heavy metal ions, mainly adsorption, reduction, complexation, co-precipitation and synergy. The shortcomings of nZVI modified materials and heavy metal removal are pointed out, and the future research trend of nZVI removal of heavy metals is prospected, in order to provide reference for the application research of nZVI modification and removal of heavy metals. [ABSTRACT FROM AUTHOR]

The basic discuss in detail the adsorption behavior of microplastics on heavy metals and the key environmental influences in the water environment, systematically summarize the latest research progress of the composite toxic effects on various organisms by the composite pollution formed by microplastics and heavy metals, and put forward the outlook of the future related researches. The adsorption capacity of heavy metals by microplastics is related to pH, temperature, dissolved organic matter and salinity, and the composite pollution formed by the two has both synergistic and antagonistic toxic effects on aquatic organisms, plants and animals. The purpose of this paper is to provide some reference for assessing the environmental behavior and ecological risk of the composite pollutants of microplastics and heavy metals, as well as to provide some reference for future related research. [ABSTRACT FROM AUTHOR]

In the case study of the pollution control over the heap leaching cyanide residue left by historical gold mines in arid areas of western China. Based on a thorough analysis of climate, hydrogeology, and the characteristics of heap leaching cyanide residue pollutants, in-situ closure operation is employed to verify the pollution control effect over the pollutant such as heavy metals in heap leaching cyanide residue. The paper in detail describes the in-situ sealing and isolation scheme, control and monitoring scheme, and auxiliary schemes. After implementation, the environmental pollution risks are effectively controlled, and the peripheral environment is evidently improved, achieving anticipated engineering goals. The control technology can provide references for the pollution control of heap leaching cyanide residue generated from similar gold mines. [ABSTRACT FROM AUTHOR]

The research on the physiological response of aquatic insects to the chemical-induced toxic pollutants has become a cross-over research hotspot in the field of entomology and environmental science in recent years. In this paper, the research progress of the physiological response of the enzymatic activity and the expression level of some genes in the larvae or adults of aquatic insects, such as Diptera, Odonata Ephemeroptera T Trichoptera Coleopter a, etc., to the three chemical-induced toxic pollutants of heavy metals, organic pesticides and microplastics was reviewed. Then, it was pointed out that the research object should be expanded in the future research, and the interaction law and mechanism between the proteins and enzymes in aquatic insects and the pollutants should be deeply studied, which could not only promote the water quality monitoring and environmental protection, but also provide theoretical support for the artificial breeding of the aquatic resource insects. [ABSTRACT FROM AUTHOR]

Many forming hypotheses of AGS, such as self-condensation hypothesis, extracellular polymer (EPS) hypothesis, nucleus induction hypothesis and selective driving pressure hypothesis, are briefly reviewed. The forming process of AGS was compared when the conditions of controlling matrix composition, coagulant, EPS, colony distribution and operating parameters were different. The application of AGS technology in domestic and industrial wastewater, such as nitrogen and phosphorus removal of wastewater, organic wastewater and heavy metal wastewater treatment, has been studied. This paper looks forward to the future development trend of this technology, with a view to providing some reference for future scholars in this field. [ABSTRACT FROM AUTHOR]

Objectives: The pollution of heavy metal has become increasingly serious in recent years. The accumulation of heavy metals in the soil will be a threat to ecological balance and human health. Therefore, we need to obtain heavy metal content in soil quickly and accurately. Methods: This paper proposes a method to combine field and laboratory spectra to construct a mechanism estimation model of soil lead (Pb). Firstly, direct standardization (DS) algorithm was employed to eliminate the influence of environmental factors on the field spectra. Secondly, in order to enhance the diversity of the samples, the laboratory spectra were introduced to joint modeling. Finally, the characteristic spectra of iron oxide were extracted for modeling to increase the model rationality. Results: This method was validated by the spectra of 70 soil samples from Xiong'an farming area in Hebei province. The accuracy R² of model established by full-band field spectra without DS correction was only 0.220 0. However, the accuracy R² of model established by the pro⁃ posed method in this paper reached 0.914 6.Conclusions: It indicates that the model for estimating Pb content can be significantly improved by removing the influence of environmental factors on the field spectra, extracting the iron oxide characteristic spectra of the combining field spectra with laboratory spectra. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to explore the spatial correlation and influencing factors of Se and heavy metal elements in soil. [Method] Taken Yuanzhou district as the research area, 162 topsoil samples were collected, and the soil pollution degree of Cd, Hg, AS, Pb and Cr was evaluated by ground accumulation index method, the spatial correlation between Se and heavy metals was analyzed by bivariate Moran index. Based on the geographic detector, ten factors such as soil property, distance, NDVI and terrain were selected as independent variables, and bivariate local Moran index was used as dependent variable to explore the spatial correlation and influencing factors between Se and heavy metal content in soil. [Result] (i) The average Se content of soil samples in the study area was 0.5, and the whole soil samples were in the selenium rich level. The ratio of the average heavy metal content to the soil background value of Jiangxi province was Cd, Hg, Cr, Pb and As in descending order, and the ratios were 4.20, 1.88, 1.59, 1.29 and 1.16 times, respectively; As and Pb were in a pollution-free state, Hg and Cr were in a mildly polluted state, and Cd was in a moderately polluted state, the average content of all heavy metals except Cd was lower than the screening value of soil pollution risk; (ii) There were significant differences in spatial clustering between Se and 5 heavy metals, among which Se had strong spatial correlation with Cd, Hg and Cr; (iii) Through factor detection, it was found that total nitrogen (TN), available potassium (AK), pH, organic matter (SOM), distance from water source and distance from railway had the most significant explanatory power for spatial clustering of Se and heavy metal elements; (iv) Interaction detection showed that the interaction between soil properties and other factors was the dominant influencing factor for spatial clustering of Se and heavy metal. [Conclusion] The research results can provide scientific and technological support for safe and reasonable utilization of selenium-rich soil resources, soil remediation and selenium-rich agriculture in Yuanzhou district. [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]

[Objective] The study aimed to identify the characteristics of heavy metal pollution in the dam soil in the loess ruins and gully are- as and conduct ecological health risk assessment. 【Method] In the paper, the loess remnant gully area was selected as the research object in the Xi' aogou check dam in Xiangning county, Shanxi province. 70 soil samples of 0 -20 cm were collected in August, 2021. The content of Cd, Cu, Pb and Zn, Ni, As, Hg, Cr were determined. ArcGIS 10. 4 was used to interpolate the distribution of soil heavy metals in space, and the single factor index (P;), Nemerow comprehensive index (P), and potential ecological risk index (RI) were used to eval- uate the distribution of eight soil heavy metal elements and the risk level. The PMF model was used to analyze the source of heavy metals of the soil. 【Result】 (i) The contents of eight soil heavy metals in the soil surface of the study area did not exceed the soil pollution risk control standards in agricultural land, but the average content values of Cd, Pb, Zn, As, and Hg were higher than the soil background values in Shanxi province, while the mean values of Cd, Pb, Zn, and Hg were higher than the soil background values. Cd, Cu, Pb, As, and Hg were relatively higher near villages and traffic roads when compared with the other sampling point. They showed a band-like distribution with higher content in the north and south and lower in the middle. (ii) The single factor index method showed that Cd and Hg were the most pol- luted when compared with the other heavy metals. The Nemerow comprehensive index method indicated that the Xi'aogou check dam was slightly polluted. (iii) The potential ecological risk index of a single index showed that Cd and Hg belonged to medium risk, while the others were low risk, which indicated that Hg and Cd had the highest ecological risk in Xi'aogou check dam soil. (iv) The PMF model indicated that there were 5 pollution sources in the Xi'aogou dam land soil, namely agricultural sources, livestock and poultry breeding sources, traffic sources, atmospheric deposition sources, and natural sources with the contribution rate of 22.71%, 24. 22%, 19. 10%, 16.63%, and 18.32%, respectively. And agricultural sources and livestock and poultry breeding sources contributed the most. 【Conclusion] Human activ- ities have already affected the content of heavy metals in dam soil to a certain extent. More attentions should be paid to the potential soil heavy metal pollution caused by Cd and Hg in the future. [ABSTRACT FROM AUTHOR]

[Objective] The paper provides references for the prevention of heavy metal pollution and the protection of cultivated soil environ- ment through exploring the content characteristics and the risk of heavy metals elements of paddy soil in Chongqing. 【Method】230 paddy soil samples were collected from 7 major and typical rice-growing regions in Chongqing, and the pH and the content of 5 heavy metal elements in- cluding Cd, Hg, As, Pb and Cr in paddy soil samples were analyzed. The Nemero pollution index evaluation method and the land accumula- tion index evaluation method were used to analyze the degree of pollution, and compared with the background value of heavy metals in Chongqing soil and the risk screening value of agricultural land soil. The characteristics of heavy metal pollution in Chongqing paddy soil were analyzed and evaluated. Then, the possible sources of heavy metal pollution in soil were explored through Pearson correlation analysis and cluster analysis. 【Result】 The average contents of Pb, Cd, Cr, As and Hg in the paddy soil of the research area were 25.4, 0.312, 66. 8, 4.71 and 0.0827 mg/kg, respectively. Through the analysis of single factor pollution index and Nemero pollution index evaluation methods, 19.57% of the paddy soil sites in the study area were in the state of Cd light pollution, 0.43% was in the state of Hg medium pol- lution, and the remaining points were in the state of no pollution. According to Geo-accumulation index, the paddy soil was lightly polluted by Cd, while the remaining heavy metal elements were at a non-polluted level. However, there were very few soils with extremely high ground accumulation index of Hg (4.03, belonging to the level of strong to extremely strong pollution). It was found that the content of Cd and Hg elements exceeded the background value of Chongqing soil, 2. 84 times and 1.38 times of the background value, respectively, with a cumulative effect; The content of Pb, Cr, As elements was slightly lower than the background value of Chongqing soil, and there was basi- cally no enrichment. The average content of heavy metals in the surveyed paddy soil was lower than the corresponding agricultural land soil risk screening value. Correlation and cluster analysis showed that heavy metal pollution mainly originated from soil formation processes and human factors. [Conclusion] The paddy soil in Chongqing is generally in a clean state, but there is a risk of Cd and Hg contamination. [ABSTRACT FROM AUTHOR]

This article reviews the research status of sewage irrigation and reclaimed water irrigation, points out the potential risk of local deterioration of the irrigation water meeting Chinese standard, and suggests that further optimization of local irrigation water.The paper summarizes the research status of purification of domestic irrigation water process and the substrate adsorption, suggests to increase and deepen the research of conventional purification processes and the development of conventional substrates, and to increase and deepen the research and development of small devices and structures, and composite and modified substrates. [ABSTRACT FROM AUTHOR]

To explore adsorption behavior of heavy metals by microplastics in water environment, this paper comprehensively analyzed the relevant public researches in recent years, including the distribution of microplastics, adsorption behavior of heavy metals by microplastics, the toxic effects of heavy metals adsorbed by microplastics on aquatic organisms, and the main influence factors of adsorption behavior.Then, the future research should focus on the response relationship between environmental factors, the surface characteristics of microplastics and the adsorption behavior of heavy metals by microplastics, and the transport process of microplastic and heavy metals in aquatic food web.It provides a theoretical basis for the study of environmental behavior and biological effects of interaction between microplastics and heavy metals in water environment. [ABSTRACT FROM AUTHOR]

The living environment of animals， plans and human beings has been seriously threatened by soil heavy metal pollution， so it’s urgently needed for cheap and efficient materials and methods to reduce their flow and migration. In this paper， soil column experiment was conducted to study the stabilization effect of hydroxyapatite（HAP)and the mixture of hydroxyapatite and fly ash （HAP+FA） on lead（Ⅱ)and cadmium(Ⅱ)in contaminated soil. It is indicated that the soil pH increased slightly with the addition of HAP and HAP+FA, and the concentration of heavy metals in the leachate was shown in this order: CK（without stabilizer） ＞ HAP+FA＞ FA. The migration of heavy metals in the soil treated with stabilizer was lower than that without stabilizer treatment. The stability efficiency of HAP was 7.5% and 2.79% higher than that of HAP+FA in lead-contaminated soil with initial concentration of 400mg/kg and 800mg/kg， respectively， and 2.5% and 0.51% higher than that of HAP+FA for cadmium-comtaminated soil with initial concentration of 400mg/kg and 800mg/kg， respectively. The stability efficiency of HAP for lead and cadmium is slightly higher than that of HAP+FA, and there was a better efficiency for the same concentration of lead of the same amount of stabilizer. [ABSTRACT FROM AUTHOR]

Soil heavy metal pollution in China is serious, threatening people ' s health and causing huge economic losses. The commonly used remediation technologies for heavy metal contaminated soil are based on physical, chemical and biological methods and their combination. This paper introduces the forms and sources of heavy metals in soil and the mechanism, influencing factors, advantages and disadvantages of commonly used remediation technologies, and compares the applicability of commonly used remediation technologies from three aspects : remediation cost, remediation time and long-term effect, so as to provide some reference for scholars in this field to develop remediation schemes for heavy metal contaminated soil in practical engineering applications. [ABSTRACT FROM AUTHOR]

In order to reduce the environmental impact caused by the migration of heavy metals in electrolytic manganese residue to water, this paper added calcined dolomite sand to electrolytic manganese residue to solidified Mn2+, and analyzed the microstructure and microstructure of dolomite sand before and after calcination by XRD, BET and SEM methods. The stabilization effect of calcined dolomite sand on Mn2+ in electrolytic manganese residue at different dosage was analyzed and evaluated. The results show that with the calcination temperature increasing from 600 °C to 800 °C, the dolomite sand gradually decompositions to form alkaline oxides such as CaO and MgO. The specific surface area, pore volume and pore size of calcined dolomite sand increase continuously, which are 1.16 ~ 3.96 times, 1.7 ~ 4.18 times and 1.99 ~ 16.12 times of uncalcined dolomite sand, respectively. When 10% calcined dolomite sand at 800 °C is added to electrolytic manganese residue, the stabilization efficiency of Mn2+ is 99. 95%, and when 30% calcined dolomite sand at 700 °C is added, the stabilization efficiency of Mn2+ is 99.85%, and the concentration of Mn2+ is as low as 1.66 mg/L. The stabilization effect of calcined dolomite sand on Mn2+ in electrolytic manganese residue is mainly that Mn2+ is solidified in the form of MnO2 and MnOOH. The calcined dolomite sand at 700 * 800 °C can be used as an effective stabilizer to solidified Mn2+ in electrolytic manganese residue. [ABSTRACT FROM AUTHOR]

This paper reviews the application of silica nanomaterials in the field of heavy metals, and mainly introduces the progress and development trend of mesoporous silica nanomaterials, functional group modified silica nanomaterials and composite silica nanomaterials. Silica nanomaterials have the advantages of low cost, high specific surface, good stability and multiple modification ways, which are important development direction of heavy metal pollution control. This work also analyzes the future development trend and potential value of silicon dioxide nanomaterials, and puts forward some opinions and suggestions on the solutions to the technical problems still existing in the application of silicon dioxide nanomaterials in the field of heavy metals. [ABSTRACT FROM AUTHOR]

The direct or indirect discharge of industrial wastewater leads to the high degree of pollution of heavy metals in Chinese natural water resources. The removal of heavy metals sewage is a problem that is exigent to be solved. However, existing heavy metal removal methods are generally found to be too complicated or expensive. Because the waste concrete particles contain cement hydration products and unhydrated cement particles, which have a certain activity and a high specific surface area. This paper tries to use the waste concrete particles as the adsorption material of water polluted by heavy metals. Through the heavy metals leaching test, it is found that the heavy metal leaching capacity is related to the particle size of the waste concrete. The larger the particle size is, the smaller the heavy metal leaching capacity is. Based on the test data and the discharge threshold requirements of the National Comprehensive Sewage Discharge Standard, the optimal selected particle size of the waste concrete particle material is finally determined. Then, by the static adsorption test, the effect of the adsorption time, the adsorbent dosage and the initial mass concentration of heavy metal on the adsorption of heavy metals copper and lead in waste concrete are mainly investigated. The result shows that the adsorption time, waste concrete dosage and initial concentration of heavy metal copper and lead will affect the adsorption properties of waste concrete. With the increase of adsorption time, the adsorption of two heavy metals copper and lead shows a trend of increasing first and then stabilizing. In the first 100 min, the adsorption of copper and lead quickly reached the equilibrium. With the increase of the initial mass concentration of copper and lead, the removal rate of the two heavy metal gradually decreases, and the adsorption capacity gradually increases and then stabilizes. When the initial mass concentration is less than 150 mg/L, the adsorption capacity for heavy metal copper is positively correlated, while heavy metal lead is positively correlated at the initial mass concentration of 200 mg/L. However, with the increase of waste concrete dosage, the removal rate of the two heavy metals copper and lead increases first and then stabilized. The adsorption of heavy metals copper and lead on waste concrete conforms to the Langmiur isothermal adsorption model, and the maximum adsorption capacity obtains 40.75 and 86.73 mg/g respectively; the pseudo-second-order kinetic model is more suitable for describing the adsorption process of heavy metals copper and lead on waste concrete, which indicating that the adsorption rate is controlled by chemisorption. Compared with other common adsorbent materials, the maximum adsorption capacity of heavy metals lead and copper on the waste concrete is much higher than natural zeolite and palygorskite, while the maximum adsorption capacity of heavy metal copper is lower than activated carbon. However, based on the price, the recycling price of waste concrete is still far lower than the market price of activated carbon even if the processing cost caused by crushing. This also reflects that the waste concrete has good adsorption capacity for the heavy metals copper and lead, which can be used as an adsorption material to treat the wastewater containing heavy metals copper and lead. [ABSTRACT FROM AUTHOR]

Heavy metals in tailings leachate are an important source of environmental pollution in tailings ponds, and rainfall and the soaked time in rainwater are the key factors affecting the leaching of heavy metals. Based on this, this paper discusses the leaching law of heavy metals in tailings under different liquid solid ratios. Two experimental methods, static leaching and dynamic leaching, were used to simulate the tailings with different particle sizes, and the change of leaching concentration of heavy metals (Cu, Mn, Zn) in tailings samples were analyzed. The results show that: under the simulated conditions of pH = 5. 4, the leaching concentration of heavy metals in static leaching decreases with the increase of liquid solid ratio. The leaching degree of heavy metals in tailings with different particle sizes is: fine particle size is better than medium particle size, and coarse particle leaching is minimal. The effects of liquid solid ratio on leaching concentrations of different heavy metals is as follows: manganese>copper>zinc. Under dynamic leaching, the leaching concentration of heavy metals shows an obvious downward trend with the increase of leaching amount, and there are two stages of rapid decline and slow decline. The fitting of the mathematical model of heavy metal release showed that the release of heavy metals was a complex process, and the release kinetics of Cu and Zn fitted well with the double constant rate equation; the release process of manganese was better described by the modified Elovich equation. [ABSTRACT FROM AUTHOR]

Plant green synthesis of nanometer zero-valent iron (FeNPs) has attracted much attention in the field of environmental remediation due to its environmentally friendly synthesis method, simple operation and excellent yield of zero-valent nanometer iron.In this paper, the mechanism (reduction, adsorption) of the removal of Cr(Ⅵ) from water by plant green synthesis of nano-iron and the influencing factors (pH value, temperature, initial concentration) in the removal process are summarized. Finally, the scientific problems existing in the removal of Cr(Ⅵ) by FeNPs are proposed and the application prospect of the green synthesis of FeNPs in environmental remediation is prospected. [ABSTRACT FROM AUTHOR]

This paper takes the surface soil around a non ferrous metal tailings reservoir in Baotou City，Inner Mongolia as the research object. A total of 44 soil sample collection points are arranged around the tailings reservoir to detect the contents of heavy metals Cu，Pb，Zn，Cr and Cd in the samples. The heavy metal pollution index，USEPA health risk assessment model，correlation analysis，cluster analysis? and principal component analysis were used to study the soil heavy metal pollution degree, health risk and soil heavy metal sources* The results show that the average content of the five heavy metals is higher than the background value of Hetao area， especially Pb，Zn，Cd are 3. 64,2. 36,3, 25 times of the background value? respectively. The evaluation result of heavy metal pollution is that the study area is dominated by Pb，Zn and Cd pollution，but the pollution range is relatively small. The result of the health risk assessment is that the five heavy metals in the soil in the study area This paper takes the surface soil around a non ferrous metal tailings reservoir in Baotou City，Inner Mongolia as the research object. A total of 44 soil sample collection points are arranged around the tailings reservoir to detect the contents of heavy metals Cu，Pb，Zn，Cr and Cd in the samples. The heavy metal pollution index，USEPA health risk assessment model，correlation analysis，cluster analysis? and principal component analysis were used to study the soil heavy metal pollution degree, health risk and soil heavy metal sources* The results show that the average content of the five heavy metals is higher than the background value of Hetao area， especially Pb，Zn，Cd are 3. 64,2. 36,3, 25 times of the background value? respectively. The evaluation result of heavy metal pollution is that the study area is dominated by Pb，Zn and Cd pollution，but the pollution range is relatively small. The result of the health risk assessment is that the five heavy metals in the soil in the study area. [ABSTRACT FROM AUTHOR]

This paper reviews the different aging processes and mechanisms of MPs by domestic and foreign scholars, and the research progress on the change of pollutant adsorption capacity before and after aging. The toxicity after aging and the release behavior of its own additives on the environment were summa・ rized・ The formation process of biofilm on the surface of MPs and the interaction between biofilm and aging MPs were revealed・ Finally, based on the current research status of MPs and their aging, it is suggested that attention should be paid to the harm of aging microplastics to the environment and the combined toxicity of aging microplastics and heavy metals to animals and higher plants in the future. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimed to analyze the blocking effect of different blocking inhibitors on cadmium（Cd） and arsenic（As） in heavy metal contaminated rice fields and their effect on the yield of different varieties of rice, in order to provide a reference basis for the screening of rice varieties with low accumulation of heavy metals and the production of safe rice.【Method】Using the field test method, 16 Guangxi main planted late rice varieties were planted in the soil with high risk of heavy metal pollution, and two kinds of inhibitors, selenium-inhibitor and silicon-inhibitor, were tested for heavy metal control. The Cd and As contents in the rice samples of each variety were measured, and the blocking effects of different blocking agents on Cd and As and the yields of different varieties of rice were compared and analyzed.【Result】The Cd and As contents of the 16 rice varieties differed significantly, among which five varieties, namely, Shenliangyou 8386,Guang 8 you jinzhan, Fengtianyou 553,Guixiang 12 and Guang 8 you 169,had lower Cd enrichment ability, and four varieties, namely, Yexiangyou 703,Hengfengyou 666,Guang 8 you jinzhan and Yexiangyou lisi, had lower As enrichment ability. The yield of each rice variety sprayed with selenium-inhibitor and silicon-inhibitor was significantly improved, with an average yield increase of 6.5% and 5.4%,respectively, compared with the control（CK）. After spraying selenium-inhibitor and silica-inhibitor, the Cd content of rice of 16 rice varieties was lower than 0.200 mg/kg, and the average content was 0.119 and 0.125 mg/kg, respectively, which were significantly lower than that of CK（0.189 mg/kg）. The average contents were 0.119 and 0.125 mg/kg, which were 37.03% and 33.33% lower than those of CK（P<0.05）. The mean As contents of rice were 0.197 and 0.185 mg/kg, respectively, which were not significantly different（P>0.05） compared to CK（0.186 mg/kg）.【Conclusion】The test results show that there are significant differences in the adsorption capacity of different late rice varieties of rice for heavy metals Cd and As.Foliar spraying of selenium and silicon inhibitors in Cd-contaminated rice fields can significantly improve rice yield and also significantly reduce the Cd content of rice, but has no significant effect on reducing the As content of rice. The five low Cd accumulation rice varieties, namely Shenliangyou 8386,Guang 8 you jinzhan, Fengtianyou 553,Guixiang 12 and Guang 8 you 169,can be promoted and planted in local Cd contaminated rice fields, and the four low As accumulation rice varieties, namely Yexiangyou 703,Hengfengyou 666,Guang 8 you jinzhan and Yexiangyou lisi, can be promoted and planted in local As contaminated rice fields. [ABSTRACT FROM AUTHOR]

At present, there are many methods to govern heavy metal pollution, among which the joint governance of plants and bacteria has the advantages of low cost and high benefit, which has attracted extensive attention. Under heavy metal stress, many bacteria not only develop strong tolerance to heavy metals, but also promote plant growth by dissolving phosphorus, fixing nitrogen, dissolving potassium and secreting related metabolites. They can also enhance plant resistance to heavy metals by changing metal fluidity and inducing high expression of related genes. In this paper, the mechanism of bacteria-plants joint governance of heavy metal pollution was reviewed to provide reference for the application and research of bacteria-plants joint governance of heavy metal pollution. [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]

This paper summarizes the sources and water quality characteristics of wastewater with high ammonia nitrogen, and analyzes the effects of typical pollutants such as antibiotics, aromatic compounds, salinity and heavy metals on Anammox, including the changes of rritrogen removal performance, the structure of Anammox sludge (bacteria), the community structure and abundance of functional microorganisms, and the genes of microorganisms. The study of Anammox for the treatment of actual wastewater with high ammonia rdtrogen was also analyzed. The prospects were given for some problems that need to be improved in the study of the influence of typical pollutants on Anammox, in order to provide help for the application o£ Anammox in the treatment of wastewater with high ammonia nitrogen. [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]

[Objective] The present paper aimed to take the open-pit coal mining area in southern Karamari mountains as an example, the contents, enrichment characteristics and spatial distribution of heavy metals in typical desert plant Reaummuria soongorica（Rs）and surrounding soil were analyzed. The pollution status of six heavy metals, zinc, copper, chromium, lead, mercury and arsenic (Zn, Cu, Cr, Pb, Hg, As) was evaluated and their sources were explored. [Method] Mathematical statistics and GIS methods were used to analyze the enrichment characteristics and spatial distribution of heavy metals in bipachai, analyze the pollution sources and evaluate the potential ecological risk. [Result] The over-standard rates of Cr, Pb and As in soil samples were more than 70%, and the average values exceeded the background values of Changji. The over-standard rates of Hg in Rs samples were 23.08%. The enrichment coefficient (3.658) of Hg in Rs was much higher than that of other elements, indicating that Rs has a strong tolerance to Hg. Except for Pb, the retention rate of other elements was positive, indicating that there was a certain tolerance in the root of Rs. Zinc and copper mainly came from crustal sources, while other elements were affected by both human and natural factors, especially Hg, which was heavily affected by disturbance in mining area and seriously polluted. Potential ecological hazard assessment results showed that in soil and plant, Zn, Cu, Cr, Pb, As five elements were relatively light pollution, Hg pollution was more serious. The distribution of Cu, Cr and As in Rs was similar, which might come from same sources. The enrichment ability of Rs to As was related to the content of As in soil. [Conclusion] The content of elements exceeding the standard in the soil of the study area was low in Pipa. At the same time, Pipa had a certain tolerance and can be used as a dominant species for ecological restoration. [ABSTRACT FROM AUTHOR]

As an economical and effective soil remediation material, biochar can reduce the bioavailability of heavy metals through fixation and transformation of heavy metals in soil. Biochar combined with plant, animals, microorganism or other types of materials can not only improve the remediation efficiency, but also enhance the stability of the remediation effect of contaminated soil. In this paper, the effects of biochar single on soil physical and chemical properties and heavy metals were discussed, and the progress of its combination technology was reviewed, while the future development was prospected. [ABSTRACT FROM AUTHOR]

The source, treatment status and harm of incineration fly ash are briefly described, and the development status of solidification and stabilization technology is introduced. This paper mainly analyzes the effect of cement solidification method, chemical agent method, hydrothermal method and melting solidification method on heavy metals and their advantages and disadvantages, and introduce the treatment methods combining various solidification methods and other solidification treatment technologies. The existing problems of solidification and stabilization technology and the prospect of its development are described. [ABSTRACT FROM AUTHOR]

[Objective]The present paper aimed to provide reference for screening low accumulation Cd cabbage varieties, the enrichment pattern of Cd in different varieties of cabbage and the safe limit value of Cd in cultivated soil was studied. [ Method ] Through pot experiment, six varieties of cabbage 'Zhongqingmaye' 'Mayehuoguocai' 'Gaokang 100' 'Kangbingdamaye' 'Jiwopadibai' 'Houye zaoshu 5') were studied for their biomass changes, Cd content from edible fraction, enrichment characteristics and the correlation between different varieties of cabbage and soil Cd content under the conditions of Cd concentration of O (CK), 0. 3, 0 . 6, l. 2, 2.4, 4. 8 mg/kg, respectively. [Result] There was not toxicity observed in cabbage with increasing Cd concentration. The Cd enrichment coefficients of different cabbage edible parts were 'Zhongqingmaye' (1. 61) > 'Kangbingdamaye' (1. 3 8) > 'Hou ye zaoshu 5' (1. 3 0) > 'Gaokang 100' (1. 02) > 'Mayehuoguocai' (0. 76) > 'Jiwopadibai' (0. 64 ). The enrichment coefficient of ' Mayehuoguocai' and 'Jiwopadibai' were less than l. According to Logistic equation, the correlation between Cd content from edible fraction of cabbage and Cd concentration in soil was significant, as 'Zhongqingmaye '(0. 9981) > 'Mayehuoguocai' (0. 9979 ) > 'Gaokang 100' (0. 9976) > ' Kangbingdamaye' (0. 9968) > 'Jiwopadibai' (0. 9949) > 'Houye zaoshu 5' (0. 9949). The corresponding safety limit values of Cd in soil for different cabbages were 'Jiwopadibai' (0. 30 mg/kg) > 'Gaokang 100' (0. 24 mg/ kg) > 'Mayehuoguocai' (0. 17 mg/kg) > 'Hou ye zaos hu 5' (0. 12 mg/kg) > 'Kangbingdamaye' (0. 09 mg/kg) > 'Zhongqingmaye' (0. 06 mg/kg). [Conclusion] Based on the tolerance and enrichment capacity of cabbage to Cd in soil and the corresponding soil safety limit value, 'Mayehuoguocai', 'Jiwopadibai' and 'Gaokang 100' were the low accumulation varieties of Cd. [ABSTRACT FROM AUTHOR]

This paper reviews the production, harm and the current treatment of acid mine drainage (AMD), and mainly introduces the progress in the treatment of acid mine drainage by sulphate reducing bacteria (SRB) (anaerobic bioreactor technology, joint processing technology, microbial immobilization technology and in-situ microbial treatment technology). It is a promising method to treat acid mine drainage by sulphate reducing bacteria, with low cost, high removal rate of heavy metal ions and no secondary pollution. However, in the process of application, the low pH value of AMD makes it impossible for common microorganisms to survive. In this regard, we can domesticate SRB to make it have a lower pH tolerance value, or isolate eosinophilic aSRB, or apply biological H2S to treat AMD, so as to achieve the reuse of polluted acid wastewater while removing heavy metals. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to explore the effects of Cd stress on the absorption and transport of mineral elements in rice.[Method] 29 rice varieties were selected and treated with two groups (0,0.5 mg/kg). The contents of eight mineral elements (Ca, Fe, Zn, Mg, Cu, Mn, K,Na) in the upper and lower parts of rice were measured by atomic absorption flame spectrophotometer.[Result] In the underground part, compared with control group, the effect of Cd on Fe was shown to inhibit absorption; Zn, Mg, K and Na were resistant to Cd, and Zn was more resistant than Cu, and Cd was more competitive than Mn and Mg.Its Cd resistance and competitiveness were greater than that of Ca. Zhuzhen B and Japonica 7623 showed Cd tolerance among the eight mineral elements. [Conclusion] Zhuzhen B was the only rice variety that promoted the absorption of eight mineral elements after Cd stress; Liusha 1 was the least Cd-tolerant rice variety. [ABSTRACT FROM AUTHOR]

The distribution characteristics and environmental risks of heavy metals( HMs) As, Hg, Cr, Ni, Cu, Zn and Pb in surface water and sediments of Huixian wetland typical rivers, Cr, Ni, Cu, Zn and Pb in Eichhornia crassipes are investigated in this paper. Single factor pollution index and Nemoro comprehensive pollution index were carried out to evaluate the pollution characteristics of HMs in surface water and sediment. The geoaccumulation index and potential ecological risk index were utilized to evaluate the level of pollution and ecological risk of HMs in sediments. Bioaccumulation factor was adopted to assess the accumulation ability of Eichhornia crassipes. The content of HMs in summer badly polluted by HMs is significantly higher than that in autumn polluted by lightly HMs. Surface water quality classified to Ⅳ class in the two seasons was affected by the high content of Hg primarily. The sediments were lightly polluted by HMs in the two seasons, but the strong ecological risk rate of Hg is up to 95. 8%. The content of roots is generally higher than that in stems and leaves in the Eichhornia crassipes. The sequence of the ability of roots to absorb HMs from surface water and sediments is consistent as Zn>Pb>Cu(Ni)>Cr. [ABSTRACT FROM AUTHOR]

[Objective] In order to understand the content characteristics and ecological risk of heavy metals in agricultural soils in small-scale areas of karst regions, the present paper provides reference for the utilization of land function and the protection of cultivated soil environment. [Method] A total of 27 sites were laid on soil on agricultural land in the southwestern of Guizhou Province, samples of surface soil ( 0 - 20) cm were collected, and 8 heavy metal elements such as pH and Cd, Hg, As, Pb, Cr, Cu, Zn and Ni were analyzed and determined. The 'Soil Environmental Quality-Soil Pollution Risk Control Standard for Agricultural Land' (GB15618 - 2018) was used as the evaluation criteria to analyze its distribution characteristics, ecological risks and sources. [Result] The results showed that the soil pH in the study area was 5. 46 to 8. 07, and the average contents of heavy metals Zn, Cr, Pb, Ni, As, Cu, Cd and Hg were 154. 24, 153. 71, 64. 25, 61. 76, 50. 38, 49. 86, 0. 41 and 64. 25 mg/kg, respectively. The soil pollution index of agricultural land in the study area was 1. 68 and 1. 38, respectively. The hazard index (IR) value of 8 kinds of heavy metals was 69. 00, which was less than the limit of ecological hazard (IR = 150) . Cd and Pb, Hg and As, Cu, Zn, Ni, As and Cu, Zn, Ni, Cr, Cr and Cu, Zn, Ni, Zn and Ni have homology respectively, and there is compound pollution. The results of the main component analysis show that As, Hg, Cr, Cu, Zn, Ni have a higher load in the first main component, the variance contribution rate is 57. 565%, the content is mainly caused by the long-term application of heavy metal fertilizer; Cd and Pb have higher load in the second principal component, and their variance contribution rate is 80. 277%. The higher content is mainly due to the higher content in the parent material. [Conclusion] The soil pH of agricultural land in the study area is 5. 46 - 8. 07 which has been polluted by As and Cd to different degrees. Cr and Ni pollution is still clean range; Hg, Pb, Cu and Zn are in the clean range. The pollution level is slight ecological hazard [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to reveal the effects of soil heavy metal pollution on the safety of diversified utilization of mulberry and the possible health risks caused by ingestion of mulberry products in abandoned lead-zinc mining area [Method]Taking the mulberry garden which had been ploughed for 14 years in the abandoned small lead-zinc mining area as the research object, the pollution status of heavy metals in mulberry products was analyzed by single factor pollution index and Nemero comprehensive pollution index. The target hazard coefficient was used to evaluate the effect of heavy metals in mulberry products on possible human health. [Result] (i) Under different limit standards, the single factor pollution index of cadmium and lead in mulberry trees planted in the study area was less than 1. 00 as the utilization mode of mulberry leaf and mulberry leaf tea, except for severe pollution [Pi(lead) = 5. 29] of fresh leaf mulberry leaf, which belonged to the clean level. (ii) The comprehensive pollution index of cadmium and lead was severe pollution (P = 4. 33). As the utilization mode of traditional Chinese medicine mulberry leaf and mulberry leaf tea, the single factor pollution index was less than 1. 00, which be longed to the clean level. (iii) The comprehensive pollution index of branch bark, branch stem and root bark as products developed by traditional Chinese medicine was 0. 09 - 0. 36, which all belonged to the clean level. (iv) Although the hazard coefficients of single cadmium target of mulberry leaves, mulberry branches and mulberry roots were all less than 1. 00, the hazard coefficients of single lead target and lead-cadmium com- pound heavy metal pollution target were more than 1. 00. Mulberry leaves polluted by lead and cadmium combined with heavy metals for a long time would have a negative impact on human health, and the health risk of children was higher than that of adults, but there was no chronic toxic effect [Conclusion] In the study area, the lead of mulberry planted in lead-zinc mining area can not be used in the development of mulberry leaf vegetables, but can be used in the product development of traditional Chinese medicine and mulbeny leaf tea [ABSTRACT FROM AUTHOR]

[ Objective ] The present paper aimied to study the effects of cadmium stress on the physiological response of hydroponic seedlings of Cichorium endivia L. and the changes of leaf ultrastructure, so as to provide reference for the study of heavy metal stress in the cultivation process of C. endivia L. . [ Method ] Hydroponics method was used in plant factory, adding cadmium chloride concentration of O (CK), 0. 5 (low concentration), 1, 5, 10 mg/L ( high concentration) for culture. Total cadmium content, chlorophyll and carotenoid content, stress physiological indexes and ultrastructure of C. endivia L. were determined at 3 days of treatment. The growth indexes of C. endivia L. were measured at day 30. [ Results ] High concentrations of Cd significantly decreased fresh weight and plant height of C. endivia L seed lings, and increased seedling mortality. With the increase of cadmium ion concentration, the contents of malondialdehyde and free proline both showed a trend of first increase and then decrease, but they were always higher than that of the control. SOD enzyme activity decreased with the increase of total cadmium content in C. endivia L. seedlings. The activity of POD enzyme was firstly decreased and then increased, and reached the highest when cadmium chloride was added at the concentration of 10 mg/L. The structure and function of chloroplasts were destroyed after cadmium chloride was added. [ Conclusion ] C. endivia L. seedlings had certain tolerance to Cd through a series of self-regu lation, but high concentration of Cd significantly affects the physiological metabolism of C. endivia L. seedlings, causing dysregulation and metabolic abnormalities, and destroying the structure and function of chloroplasts. In the future, we could funher study the physiological re sponse of plants to heavy metal stress from the perspective of cell metabolism pathway. [ABSTRACT FROM AUTHOR]

Phytoextraction is an environmentally friendly and in-situ remediation technology for removal of heavy metals from contaminated soils, with the advantages of easy operation and economic benefits. Proper disposal of polluted plants after phytoextraction needs to be further scientifically studied and developed. This paper reviews the current disposal technologies for heavy metal-polluted plants, such as incineration, pyrolysis, and hydrothermal upgrading and discusses the advantages and disadvantages of each method. Future research on pyrolysis and hydrothermal upgrading technologies is envisioned, which may provide a strong basis and reference for rational selection and recycling of disposal technologies in practical applications. This would promote future research development of disposal technologies for polluted plants from phytoremediation of soil contaminated by heavy metals. [ABSTRACT FROM AUTHOR]

Tn recent years? heavy metal pollutants in water bodies have caused serious environmental problems. The concentration of heavy metal ions is low? and the adsorption method can deal with heavy metal pollution. The key to the adsorption method lies in the design and preparation of the adsorption material. Cellulose is a renewable high molecular polymer, which has the advantages of abundant reserves and wide sources. Tt has gradu- ally become a research hotspot in adsorbent materials. After modification? cellulose materials have good adsorption capacity for heavy metal ions. This paper introduces the simple physical modification of cellulose? direct chemical modification of cellulose? graft modification of cellulose and the effect of functional groups on the adsorption of heavy metal ions? and analyzes the adsorption effect of modified cellulose on heavy metal ions. Tn addition, the development of cellulose adsorbent materials is prospected. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to provide the scientific basis for rational land-use planning, soil resources conservation and pollution-free agricultural development in Luodian County, Guizhou. [Method] The effects of five typical land-use patterns (forestland, natural grassland, artificial grassland, cropland and abandoned farmland) on content and environment contamination of Cd, Cr, Pb, Ni, Hg and As in topsoil were evaluated by Nemerow comprehensive index, single-factor contamination index and Hakanson potential ecological hazard methods. [Result] The content of 6 heavy metals in topsoil was Cr > Pb > Ni > As > Cd > Hg and lower than the contamination background value of heavy metals in Guizhou overall. The topsoil Cd content was the highest in abandoned farmland and lowest in forestland. The topsoil Cr content was the highest in abandoned farmland and lowest in natural grassland. The topsoil Pb and Hg content was the highest in cropland and lowest in forestland. The topsoil Ni content was the highest in artificial grassland and lowest in natural grassland. The topsoil As content was the highest in natural grassland and lowest in cropland. The topsoil Cd, C.r, Pb and Hg content was high relatively and greatly influenced by human activity. Topsoil Cr had the same source as Ni, Hg and As. The topsoil As content was closely related to soil pH. The topsoil Cd and Cr content was closely related to soil cation exchange capacity (CEC) . The topsoil Pb, Hg and As content was closely related to soil organic matter (SOM). [Conclusion] Six heavy metals in topsoil do not cause soil contamination. The single-factor contamination index and potential ecological hazard index both are at the clean level. The pollution-free agriculture can be vigorously developed according to local soil nutrient, soil fertility and land-use pattern in Luodian County, Guizhou. [ABSTRACT FROM AUTHOR]

With the rapid development of industry and agriculture, pesticides and heavy metals entered the environment, resulting in the combined pollution in various environmental conditions. Many of the pesticide and heavy metals are persistent in the environment and toxic to environmental organisms, which will cause potential hazards to the ecological environment. In this paper, the current status of the combined pollution of pesticides and heavy metals in water and soil at home and abroad was reviewed. With respiration, enzyme activity, mortality and the development as the toxicological end points, the progress of ecological toxicological research of combined pollution of pesticides and heavy metals on soil microorganisms, plants and animals was described. Moreover, the ecotoxicology research on the combined pollution of pesticides and heavy metals has been prospected. This review aims to provide ideas for the study of combined pollution by combining the domestic and foreign literatures on the ecological toxicology of combined exposure of pesticides and heavy metals. And this review also included the outlook in the research field of combined pollution by analyzing the present research situation of combined exposure of heavy metals and pesticides at home and abroad. [ABSTRACT FROM AUTHOR]

Objective The present paper aimed to explore the effect of exogenous citric acid addition on the remediation of lead contaminated soil by three ornamental plants. [ Method ] In the present study, we used Iris tectorum, Hemerocallis fulva and Canna indica as the experimental materials to the pot experiment to study the effects of exogenous citric acid on the remediation of lead contaminated soil by three ornamental plants. Three species were treated with various concentrations of lead pollution. The control group (CK), without citric acid group (Wx 100 mg • kg-1, Wm ; 500 mg •kg-1-, Wg ; 1000 mg • kg-1 ); Added citric acid group (Tx ; 100 mg • kg-1, Tm; 500 mg • kg-1, Tg; 1000 mg • kg-1). Result] (i) Compared with the control, the addition of citric acid significantly reduced the pH value of the soil. (ii) The addition of citric acid significantly improved the growth of three ornamental plants. It increased the plant height, root length, growth and root-shoot ratio of the three plants, with the highest values of 1.43, 0.92 and 4.95, respectively. (iii) By comparing the lead contents in the aboveground and underground parts of the three ornamental plants, it could be seen that the addition of citric acid significantly promoted the lead accumulation in the aboveground parts of the three ornamental plants. Compared with the non-added citric acid, the difference be-tween the above-ground lead content of the added citric acid and the non-added citric acid was 0.15 —1.38, 0.23 —2.25 and 0.05 —0.35 mg • kgkg-1, respectively. Judging from the aboveground lead accumulation and transportation coefficient, the transportation capacity of the three ornamental plants can be significantly increased when citric acid was added. However, Hemerocallis fulva was inferior to Iris tectorum and Canna indica in enrichment effect due to its own growth characteristics. ( Conclusion]To sum up, all three ornamental plants could he used as lead contaminated soil remediation plants, and the addition of citric acid can effectively improve the remediation efficiency of the three ornamental plants on lead contaminated soil. [ABSTRACT FROM AUTHOR]

[Objective] Urbanization is currently one of the most significant features in China. In the progress of urbanization, some lands in the newly-built city that not developed currently are left for planting crops, while the change of land use poses new threat for farming, especially the soil heavy metal (SHM) pollution. In the present paper, taking Chenggong New District, Kunming as an example, we investigated the status of SHM pollution across 28 farmlands in Chenggong. [Method] The contents of soil Cu, Ni, Pb, and Zn were analyzed. Single factor pollution index (Cu, Ni, Pb, Zn), Nemerow integrated pollution index and Hankanson potential ecological risk index for each farmland were calculated. Spatial autocorrelation for each heavy metal was investigated based on Moran' s I. [Result] N emerow integrated pollution index ranged from 1. 39 - 3. 43, indicated the different extent of SHM pollution. The potential ecological risk index was small due to the low toxicological factors across the investigated heavy metals. The average Cu content was 2. 8 times for the background value and 1. 68 times for the national soil quality standard (II), besides, strong spatial autocorrelation and variation across the samples indicated the possible human influence. [Conclusion]These types of farmlands should be regulated and some heavy polluted lands should be prohibited for agricultural production to ensure the quality and safety of agricultural products. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to explore the absorption and enrichment of heavy metals cadmium( Cd) and lead( Pb) from jute in different growth stages in heavily polluted soil, and to provide reference for bioremediation of heavy metal pollution of soil and selection of vegetable jute plantation. [ Method] Four jute varieties were planted on soil heavily polluted by Cd and Pb. The contents of Cd, Pb in different growth stages ( seedling stage, flowering stage, mature stage) and different parts ( root, hemp skin, sticks, leaf ( seed) were determined by microwave-assisted digestion and inductively coupled plasma atomic emission spectrometry, the bio virus were determined at the same time. The bio concentration factor, transfer factor and accumulation in jute were analysed. [ Result The total biomass of Funong 4 at flowering stage and mature stage was 21. 53 and 26. 18 t/hm²,respectively, higher than that of the other 3 varieties. The contents of Cd and Pb in each part of the four varieties in all stage were ranked as root > leaves( seeds) > bast > sticks. With the change of growth stage the Cd content in root, bast, stickts of Guimacai2, Funong1,Funong4 and in bast, stickts of Guimacail were ranked as seedling stage> mature stage >flowering stage. The Ph content of each part in each growth stage were ranked as mature stage > flowering stage > seedling stage. The enrichment factor and transfer factor of Cd, Pb in the four varieties were less than 1. 000 at all the growth stage. The accumulation of Cd and Pb in four varieties showed ranked as mature stage> flowering stage> a seeding stage. The highest accumulations of Cd(50.160 g/hm² ) was Guimacail at the mature stage, while the highest accumulations of Pb ( 64. 025 g/hm2 ) was Funong1 at the mature stage. [ Conclusion] When four jute varieties were planted as vegetables, the heavy metal background value of the planting soil should be investigate thoroughly to ensure their food safety. The Guimacail could be popularized and applied as a soil Cd pollution remediation plant. [ABSTRACT FROM AUTHOR]

[Objective)Through monitoring the water and sediment in Chongqing section of Jialing River, the present paper aimed to understand the current situation of eutrophication of water, pollution status of heavy metal elements in water and sediment. [ Method J 4 monitoring points we set up in the Chongqing section of Jialing river and tested twice in May and August, Water monitoring indicator B included TP, TN, NH3-N, CODmn, SD, Chl. a, DO, pH, etc.; Monitoring indication for heavy metal elements included Cu, As, Pb, Cd, Hg and Zn. The national standard ( GB 3838-2002) was used to determine the type of water quality, the Carlson Comprehensive Nutritional Status Index ( TLl) we used to evaluate the eutrophication of water bodies, and the limiting factors affecting phytoplankton growth was determined by the nitrogen and phosphorus ratio( N/P) ; The geo accumulation index( Igeo) was used to quantify the concentration of heavy metals in the sediment. [ Result)The water quality of Chongqing section of Jialing river was between III-V water in dry season and III-IV water in wet season. The water was less polluted by heavy metal elements, except Hg which was a potential pollutant, all other heavy metal elements met the requirements of grade I surface water and met the requirements of China Fishery Water Quality Standard ( 1989) and domestic drinking water sanitation standard ( 2006 ) . The variation range of heavy metal elements in sediment was Luger than that in water, and the lgeo of As, Cd existed light pollution in the range of O - 2, Zn, Hg and Cu had almost no pollution. [ Conclusion) The water quality in Chongqing section of Jialing river was between 111-V, the degree of eutrophication was between moderate nutrition and mild eutrophication, the water was less polluted by heavy metal elements, and the sediment was polluted by heavy metal elements Cd, As and Pd. Phosphorus was the main nutrient limiting factor of phytoplankton. [ABSTRACT FROM AUTHOR]