显像管玻壳铅尘在大气中的迁移扩散规律和污染特征

以石家庄市显像管玻壳厂排放的铅尘为研究对象，通过在该玻壳厂周围土壤表层布点采样，较系统地研究了铅尘在大气中的迁移转化规律及其污染特性。研究结果表明，用高斯模式能成功地预测铅尘在大气中的迁移扩散规律。     

Transformation of lead compounds in the soil-plant system under the influence of Bacillus and Azotobacter rhizobacteria

ABSTRACT

The study was aimed at the migration and transformation of lead compounds in the rhizosphere, its accumulation in plants under the influence of the rhizosphere bacteria. For experiment, soil samples of the technogenous ecosystem contaminated differently by lead have been selected for plant growing. The samples were subdivided into control soil and the soil, inoculated by Azotobacter and Bacillus rhizobacteria. Lead concentrations have been analysed in easily exchangeable, carbonate, organic and Fe hydroxide-associated fractions as well in chelate forms and fulvic and humic acids. In soils, inoculated by rhizobacteria, there is an increased mobilisation of lead due to its decrease in humic acids and increase in fulvic acids. On technogenic soil, rhizobacteria initiate the immobilisation of Fe-hydroxide-bound, chelate-bound lead in the rhizosphere as well as lead occurring in roots. As a results, there is a decreased lead uptake by upper parts of plants. There is also a correlation between increasing soil alkalinity and increasing Pb accumulation in the roots of plants. The results of the experiment helped to understand more about the mechanisms of Pb compound behaviour under the influence of rhizobacteria that can be used for developing biotechnologies related to soil bioremediation and crop production.     

Influence of fertilizer and sewage sludge compost on yield and heavy metal accumulation by lettuce grown in urban soils

Previous research has demonstrated that many urban soils are enriched in Pb, Cd and Zn. Culture of vegetable crops in these soils could allow transfer of potentially toxic metals to foods. Tanya lettuce (Lactuca sativa L.) was grown in pots of five urban garden soils and one control agricultural soil to assess the effect of urban-soil metal enrichment, and the effect of soil amendments, on heavy metal uptake by garden vegetables. The amendments included NPK fertilizer, limestone, Ca(H₂PO₄)₂, and two rates of limed sewage sludge compost. Soil Cd ranged from 0.08 to 9.6 mg kg^–1; soil Zn from 38 to 3490 mg kg^–1; and soil Pb from 12 to 5210 mg kg^–1. Lettuce yield on the urban garden soils was as great as or greater than that on the control soil. Lettuce Cd, Zn and Pb concentrations increased from 0.65, 23, and 2.2 mg kg^–1 dry matter in the control soil to as high as 3.53, 422 and 37.0 mg kg^–1 on the metal-rich urban garden soils. Adding limestone or limed sewage sludge compost raised soil pH and significantly reduced lettuce Cd and Zn, while phosphate fertilizer lowered soil pH and had little effect on Zn but increased Cd concentration in lettuce. Urban garden soils caused a significant increase in lettuce leaf Pb concentration, especially on the highest Pb soil. Adding NPK fertilizer, phosphate, or sludge compost to two high Pb soils lowered lettuce Pb concentration, but adding limestone generally did not. On normally fertilized soils, Pb uptake by lettuce was not exceptionally high until soil Pb substantially exceeded 500 mg kg^–1. Comparing garden vegetables and soil as potential sources of Pb risk to children, it is clear that the risk is greater through ingestion of soil or dust than through ingestion of garden vegetables grown on the soil. Urban dwellers should obtain soil metal analyses before selecting garden locations to reduce Pb risk to their children.     

Lead content of urban soils in China

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离子交换树脂吸附Cd(Ⅱ)和Pb(Ⅱ)的研究

采用静态法和动态法对阳离子交换树脂吸附Cd(Ⅱ)、Pb(Ⅱ)的行为进行了研究。考察了pH值、流速、吸附时间等条件对吸附效果的影响,优化了树脂洗脱再生的最佳条件。实验结果表明,732型强酸阳离子交换树脂能够有效地吸附废水中的Cd(Ⅱ)和Pb(Ⅱ)。对比两种交换方式,动态法具有操作简单、效率高、可连续运行等特点,具有较高的实用价值。     

流动注射在线萃取石墨炉原子吸收法测定芦荟中的铅

以APDC/MIBK为萃取系统 ,流动注射在线液 液萃取石墨炉原子吸收光谱法测定芦荟样品中痕量铅 ,对萃取条件 ,流路参数及共存组分的干扰等均进行了探讨。本法的测定精密度 (RSD)为 3 .74% ,检出限 (3σ)为 3 .2× 1 0 - 1 2 g ,加标回收率为 93 %～ 99%。测定结果令人满意。     

铅对泥鳅的致毒效应

铅作为环境重金属激素之一 ,对水生生物泥鳅具有明显的致毒效应。毒性实验揭示 ,铅可导致泥鳅发生各种生理、生殖反应 (甚至死亡 ) ,并诱发泥鳅血红细胞和卵细胞畸形 ,破坏血红细胞和卵细胞的正常生长 ,降低细胞的存活率 ,影响泥鳅的正常生理、生殖功能 ,显示较强的雌激素活性     

红壤性水稻土铅环境容量研究

以湖南省桃林铅锌矿区为试验区,通过水稻盆栽、田间小区、大田、农田地表径流和淋溶等试验以及土壤酶和微生物试验,研究土壤铅对土壤-作物(水稻)、土壤-微生物和酶、土壤-水体三体系的各种效应,得到各单体系中铅的临界含量并确定了红壤性水稻土中铅的临界含量,通过铅的平衡试验,建立了土壤铅环境容量数学模型,得出红壤性水稻土的铅环境容量。     

Simultaneous adsorption of As(Ⅲ) and Pb(Ⅱ) by the iron-sulfur codoped biochar composite:Competitive and synergistic effects

Simultaneous elimination of As(Ⅲ) and Pb(Ⅱ) from wastewater is still a great challenge.In this work,an iron-sulfur codoped biochar (Fe/S-BC) was successfully fabricated in a simplified way and was applied to the remediate the co-pollution of As(Ⅲ) and Pb(Ⅱ).The positive enthalpy indicated that the adsorption in As-Pb co-pollution was an endothermic reaction.The mechanism of As(Ⅲ) removal could be illustrated by surface complexation,oxidation and precipitation.In addition to precipitation and com...     

Alkaline leaching of metal melting industry wastes dseparation of zinc and lead in the leach solution

In this work, a thorough examinations on the extractability of zinc and lead present in the steelmaking dusts using alkaline leaching process and the effectiveness of the zinc and lead separation in the resultant leaching solutions using sulfide precipitation method were made. It was found that only about 53% of zinc and over 70% of the lead could be leached out of the dusts, while the other 47% of zinc and 306 of lead were left in the leaching residues. The zinc and lead in the resultant leaching solution can be effectively and selectively separated. When the weight ratio of sodium sulfide (M. W. = 222-240) to Pb was kept at 1.8, the lead in the solution could be precipitated out quantitatively while all the zinc was remained in the solution. The zinc left in the solution can be further recovered by the addition of extra sodium sulfide with a weight ratio of sodium sulfide to the zinc over 2.6. The resultant filtrate can be recycled to the leaching of dust in the next leaching process.