Content: Study on the evaluation method of bioavailability of heavy metals in contaminated soil —— Taking heavy metal pollution in coal mining area as an example, Liu Yurong has a master's degree in heavy metal pollution in soil; Biological utilization; Plant indication method; Extractant; Institute of Geochemistry, Chinese Academy of Sciences; Taking the soil contaminated by heavy metals in Wangjiazhai coal mine area of Shuicheng County, Guizhou Province and its surrounding lead-zinc smelting frozen soil area as an example, the activity and bioavailability of heavy metals were studied by total amount method, chemical speciation analysis method and plant indication method respectively, and different methods for evaluating the bioavailability of heavy metals were compared. The feasibility of various methods for this kind of polluted soil was tested. The results show that the total amount method 1 can be used to predict the potential environmental effects of heavy metals in coal gangue weathered soil, but the evaluation of lead-zinc smelting wasteland is limited, because a considerable part of heavy metals in lead-zinc smelting wasteland come from atmospheric deposition. With the change of time, its total content will definitely change. 2. In the experiment, we used Tessier's five-step continuous extraction method to analyze the occurrence state of heavy metals, and found that the speciation distribution of each element was very different. 3. Comparing the extraction results of the two methods, it is found that the heavy metal forms analyzed by the three-step extraction method can basically represent the analysis results of the five-step extraction method, and can also represent the analysis results of no residual heavy metals between phases in the soil. And the operation steps are more economical and simple. Therefore, we think that the three-step extraction method is more suitable for analyzing the combined forms of heavy metals in soil. 4. Six single extractants were selected for extraction, and the results showed that all extractants had good extraction ability for cadmium. Acidic reagents have high extraction rate of zinc, strong ability to form complexes with copper and lead, and are easy to be extracted by complexing agents.

Study on heavy metal pollution dose in soil, toxic effect of vegetables and its control technology: root elongation test; Heavy metal pollution in soil; Food safety; Lime; Northwest A&F University of Food Science; The effects of different concentrations of Cu, Zn and Pb on early root elongation of Chinese cabbage, cabbage, radish, onion, tomato and cucumber were studied in three typical soils, namely yellow soil, cinnamon soil and red soil, in order to clarify the inhibitory and toxic effects of different heavy metals and their dosage on vegetable root growth. Studies show that tomatoes are most sensitive to copper, zinc and lead in yellow soil. Chinese cabbage is the least sensitive to the toxicity of copper, zinc and lead. Tomato and Chinese cabbage are the most sensitive in red soil, while cucumber and radish are the least sensitive. Onion is the most sensitive to the toxicity of copper, zinc and lead, while cucumber is not sensitive. Different heavy metals have different inhibitory effects on vegetable growth, and vegetables are most sensitive to copper toxicity, followed by zinc and lead soil. The available forms of heavy metals are negatively correlated with the root length of vegetables. Under the same concentration of copper, zinc and lead, the comparison of three soils shows that. Different aging times of heavy metals in yellow brown soil > cinnamon soil have different effects on the root length of vegetables, but the root length tends to increase with the aging time. The content of available heavy metals in the soil of vegetable planting area increases with the increase of the concentration of added heavy metals in the soil. The aging trend of heavy metals in soil changes with its concentration. When the concentration is high, it will age rapidly within 0 ~ 30 days. The longer it takes to achieve stable aging, the stronger the toxic effect of different aging time on vegetables, which is 2 days. 180d is the weakest. It can be seen that the toxicity of heavy metals to vegetables will decrease with the aging time in soil, and the effective forms of heavy metals in soil are positively correlated with the amount of heavy metals absorbed by vegetables. , Cu>= 0.952 & lt*>, r<, zn>= 0.998 & lt*> Applying lime to the soil polluted by heavy metal Cul00 can effectively reduce the effective content of heavy metals in the soil, increase the biomass of vegetables and reduce their absorption of heavy metals. - 1 & gt； At the same time, the total amount of copper in Chinese cabbage decreased by 6 1. 1%, zinc 250 decreased by 55.0%, zinc 500mg-kg was more than leaves, and the distribution of Cu was roots.

Analysis and evaluation of heavy metal pollution in soil of molybdenum mine area and its surrounding farmland: heavy metal pollution in soil; Pollution intensity; Multi-metal compound pollution; College of Environmental Sciences; Northeast Normal University; In this paper, the heavy metal pollution in the soil of mines, concentrator, mineral transportation area and tailings mining area in Huludao molybdenum mine area of Liaoning Province was systematically studied. 80 samples of contaminated soil in this mining area and 60 samples of contaminated soil in farmland around the mining area were selected by HNO.

Heavy metals and so on

Determination of soil heavy metal activity by Donnan membrane, model simulation and in-situ pollution control: heavy metal activity; Concentration of free heavy metal ions; ECOSAT red mud; Heavy metal pollution in soil; Donnan membrane balance method; Institute of Geochemistry, Chinese Academy of Sciences; Soil is an important part of the natural environment and a valuable resource for human survival and development. However, in recent years, heavy metal pollution in China soil has become increasingly serious. Compared with other types of pollutants, heavy metal pollutants have a series of particularities, such as concealment, long-term and irreversibility. They become permanent pollutants in the soil and eventually enter the human body through the food chain, causing potential harm to human health. Therefore, it is of great significance to study soil heavy metal pollution and its control. In this paper, Donnan membrane equilibrium method, Donnan membrane technology and Ecosat equilibrium calculation model are introduced into the study of soil heavy metal activity in China for the first time, and the results obtained by the two methods are compared. Mutual verification has achieved good results. The influence of red mud from Guizhou aluminum plant on the concentration of free heavy metal ions in soil was discussed by combining two methods. Soil samples were collected in the cadmium-zinc mine area of Duyun, Guizhou. One paddy soil (hereinafter referred to as dam soil) located in the farmland under the tailings dam of the cadmium-zinc mine concentrator is heavily polluted, and the other paddy soil (hereinafter referred to as bridge soil) located in the farmland near the bridge in the upper reaches of the cadmium-zinc mine is lightly polluted.

Study on the Effect of Earthworms on the Migration and Transformation of Zinc and Lead in Soil-plant System; Feng Fengling has a master's degree in Earthworms; Heavy metal pollution in soil; Bioavailability; Ryegrass; Indian mustard; Phytoremediation; Soil pollution control; Shandong Normal University Environmental Science; With the aggravation of heavy metal pollution in soil, the treatment of heavy metal pollution in soil has become the focus of current research. As a new green biotechnology, phytoremediation technology has incomparable advantages over physical and chemical remediation methods, and has great potential in soil pollution control. However, the small biomass of hyperaccumulator plants and the low bioavailability of heavy metals in soil are the main limiting factors for the successful application of this technology. In order to improve the bioavailability of heavy metals in soil, although the "earthworm induction-phytoremediation" technology proposed in recent years has broad development prospects, most of the existing studies use heavy metal-tolerant plants, and the absorbed heavy metals accumulate in the roots of plants without moving to the aboveground parts of plants. Therefore, the absorption patterns of heavy metals by tolerant plants and hyperaccumulator plants are different. It is the key to the successful application of this technology to select hyperaccumulator plants and study the effect of earthworm on the migration and transformation of heavy metals in soil-plant system. In this paper, acidic brown soil, moist brown soil, hydrated brown soil and limestone cinnamon soil were used as test soils, and Zn2+0, 100 and 200 were added respectively. Using 400 mg kg-1or Pb2+0,200,400,800 mg kg-1to simulate soil pollution, earthworms inoculated Eisenia foetida, but not earthworms. The effects of earthworms on plant growth and bioavailability of heavy metals in soil were studied in order to reveal the chemical behavior mechanism of earthworms on heavy metals in soil-plant system and provide theoretical basis for the application and development of earthworms in phytoremediation technology. Heavy metal pollution in soil obviously inhibited the growth of earthworm. After planting ryegrass for one month, the weight of earthworm in each treatment decreased significantly, and the average growth rate in acidic brown soil was -6% ~-56%. The average growth rate is -7% ~-46% in moist brown soil and -9% ~-35% in cinnamon soil, and the growth rate of earthworm decreases with the increase of lead and zinc concentration in soil. After Indian mustard was cultivated for one month, the growth rate of earthworm was higher than that of ryegrass, with an average growth rate of +3% ~-25% in acid brown soil and +3% ~-25% in wet brown soil. The average growth rate of earthworm activity in cinnamon soil was +2% ~-29%, which promoted the growth of all Zn and Pb-treated tolerant plants and super-accumulated plants in the three soils. In cinnamon soil, earthworms can promote the growth of Indian mustard in all treatments, while in moist brown soil and acidic brown soil, earthworms can only promote its growth under the condition of low concentration of heavy metal pollution. The promotion of earthworms to plant growth is related to soil properties, heavy metal species and plant species. Whether planting Indian mustard or ryegrass, earthworm activities significantly reduced the pH value of zinc and lead-treated soil in cinnamon soil and wet brown soil, and significantly increased the pH value of zinc and lead-treated soil in acidic brown soil. Earthworms have no significant effect on the zinc content extracted from DTPA soil. The zinc content extracted by DTPA in acidic brown soil increased significantly. Only when the zinc concentration was 400 mg kg-1,earthworm activity significantly increased the content of DTPA-extracted zinc in moist brown soil planted with Indian mustard, and earthworm activity significantly decreased the content of DTPA-extracted zinc. The influence of earthworm activity on zinc content extracted by DTPA in cinnamon soil has no obvious regularity. Whether planting mustard or ryegrass, the influence of earthworm activity on the content of DTPA extracted lead in the three tested soils has no obvious regularity. The lead and zinc content in earthworm dung increased with the increase of lead and zinc concentration, and the lead and zinc content in earthworm dung living in three soils planted with ryegrass was higher than that in the corresponding mustard treatment. The total amount of zinc in earthworm manure is 1.02 ~ 1.9 1 times that of the corresponding treated soil. The zinc content extracted by DTPA in earthworm manure is 0.52 ~ 52.9 times that in soil, and the total lead content in earthworm manure is 0.87 ~ 8.25 times that in corresponding treated soil. The content of DTPA-extracted lead in earthworm manure is 0.77 ~ 3 1.8 times that in soil. Lead and zinc extracted from earthworm dung by DTPA are important sources of plant absorption. When the zinc concentration is 200 mg kg-1and 400 mg kg-1,the zinc content in cinnamon soil and ryegrass is significantly increased. Other treatments had no significant effect on earthworm activity, but significantly increased the Zn content absorbed by Indian mustard in cinnamon soil and acid brown soil. When the Pb concentration in moist brown soil was 400 mg kg-1and 800 mg kg-1,and the Pb concentration in acidic brown soil was 800 mg kg-1,earthworm activity significantly increased the Pb absorption of Indian mustard. Neither ryegrass nor Indian mustard can enrich Pb. Whether earthworm activity can improve the bioavailability of heavy metals is not only related to earthworm species, soil properties, heavy metal species and other factors, but also related to plant species. Statistical analysis of soil pH value, zinc and lead content in earthworm manure, and the relationship between available zinc and lead in soil and zinc and lead absorbed by plants shows that earthworms can affect soil pH value, thus affecting the bioavailability of heavy metals in soil, or increase the lead and zinc content in DTPA state by grinding, digesting and excreting heavy metals in soil after ingesting heavy metals. And secrete a large number of mucins complexed with heavy metals, which may be the main mechanism of earthworm improving the activity of heavy metals in soil. The above research shows that earthworm can survive in the soil polluted by heavy metals, has certain tolerance to heavy metals, and can still promote plant growth. Increasing the growth of plants Earthworms can activate heavy metals in soil through various mechanisms and improve their plant effectiveness, but the effect varies with soil properties. Although the effectiveness of earthworm activities on heavy metals varies from plant to plant, it is of great significance to improve the activity of heavy metals in soil or increase the absorption of plants by promoting plant growth.