农业废弃生物质盐浸提液淋洗镉锌污染土壤

为了寻找成本低廉、环境友好、高效的重金属Cd和Zn淋洗剂,选取雅安市汉源县矿区污染土壤作为供试土壤,采用浓度0.3%KCl盐溶液提取金针菇菌渣(FVr)、茶树菇菌渣(AAr)、花生壳(AHL)和甘蔗皮(SOr)4种农业废弃生物质材料所得浸提液作为淋洗剂,通过恒温振荡淋洗实验探讨上述淋洗剂不同浓度、pH和时间条件下对污染土壤中镉(Cd)和锌(Zn)的淋洗效果。结果表明,4种生物质材料盐浸提液对Cd的淋洗率依次为FVr> SOr> AHL> AAr;对Zn的淋洗率则依次为SOr> FVr> AHL> AAr。随浓度上升,除FVr盐浸提液对土壤Cd和Zn的淋洗率呈线性增加外,其余盐浸提液对其淋洗率呈幂函数增长趋势。随pH增加,FVr和AAr、AHL和SOr盐浸提液对Cd和Zn的淋洗率分别呈对数、幂函数下降趋势(P<0.01)。随淋洗时间延长,4种生物质盐浸提液对土壤Cd和Zn的淋洗率变化均呈对数增加趋势(P<0.01)。综合淋洗率和土壤性质的变化,FVr与SOr盐浸提液在浓度为7%,pH为3的条件下持续振荡淋洗1 h可达到最佳淋洗效果,其对Cd的淋洗率分别为76.38%和49.54%;对Zn的淋洗率分别为29.24%和30.75%。FVr和SOr是具有一定潜力的重金属污染土壤修复生物质材料。

锌镉污染区植物根际与非根际土壤微生物区系研究

本文研究锌镉污染的区植物根际与非根际土壤微生物区系,为污染土壤生物修复提供理论基础。现场采样和室内培养分析的结果表明,污染区内土壤重金属锌镉含量大大超过土壤环境质量标准。植物根际土壤中锌镉含量低于非根际土壤锌镉含量,污染区根际与非根际土壤微生物区系组成发生了明显变化,土壤三大类微生物细菌、真菌、放线菌的数量均显著降低。微生物数量与土壤全锌、镉都呈显著的负相关,锌对微生物的抑制作用比镉显著。

真菌LP-20对金属矿土壤镉锌的固定化作用研究

采用真菌分离纯化的方法从某重金属污染土壤中筛选分离出一株能够耐受并吸附二价镉、锌离子（Cd（Ⅱ）、Zn（Ⅱ））的真菌菌株LP-20。考察不同修复时间以及土壤p H值对固定化效率的影响。固定化效率以反应前后的镉锌有效态含量（利用TCLP提取液提取法测定）变化衡量。根据ITS（Internal transcribed spacer）r RNA基因测序结果,菌株LP-20属于Trichoderma spirale。LP-20对于Cd（Ⅱ）的固定效果普遍优于Zn（Ⅱ）,并且对Cd（Ⅱ）的固定时间（10 d）少于对Zn（Ⅱ）的固定时间（20 d）。LP-20对于Cd（Ⅱ）和Zn（Ⅱ）的固定作用的最适宜p H范围为3~5。发现能够对土壤中镉锌离子具有良好固定化效果的真菌菌株对于发展土壤重金属污染的原位无毒无害化治理技术具有重要的实际意义。

骨炭和硫化钠联用修复镉-锌污染土壤

以湖南东江湖矿渣堆场土壤为研究对象,利用骨炭-硫化钠组合制剂修复矿区镉锌污染土壤,目的是探讨组合制剂修复重金属镉-锌复合污染土壤效果.采用美国固体废弃物毒性浸出程序（TCLP）评价修复效果,并对最佳处理组采用改进的BCR形态分析法进行分析.结果表明,与对照相比,骨炭-硫化钠使土壤中TCLP浸提态Cd和Zn分别降低了15.88％ ～ 58.82％和7.91％ ～ 73.60％,同时土壤pH提高了0.26～3.00个单位,且当投加4％骨炭和2％硫化钠时对土壤中镉和锌稳定效果达最佳;最优处理组镉的酸可提取态下降了4.8％ ～11.5％,锌的酸可提取态下降了4.3％～12.7％.因此,骨炭-硫化钠组合制剂能有效修复镉锌复合污染土壤.

Effects of Red Mud on the Remediation of Pb, Zn and Cd in Heavy Metal Contaminated Paddy Soil

[Objective] To study the remediation efficiency of red mud on Pb, Zn and Cd in the heavy metal contaminated paddy soil of mine area, to clarify its remediation mechanism and fertilizer efficiency on heavy metal contaminated soil. [Method] The soil incubation experiment was conducted to study the effect of red mud on the pH values and electrical conductivity （EC）, and the remediation efficiency of red mud on lead （Pb）, zinc （Zn） and cadmium （Cd） in heavy metal contaminated soil. [Result] Red mud addition reduced the content of exchangeable Pb, Zn and Cd in the soil significantly. Compared with the control, when incubated for 30, 60 and 90 d with the red mud dosage of 4% （W/W）, the exchangeable Pb content was decreased by 39.25%, 41.38% and 50.19%; exchangeable Zn content was decreased by 49.26%, 57.32% and 47.16%; and exchangeable Cd content was decreased by 19.53%, 24.06% and 25.70%, respectively. The application of red mud had significant impact on the share of Pb, Zn and Cd contents in five forms, and different amounts of red mud application all reduced the proportion of exchangeable Pb, Zn and Cd to the total Pb, Zn and Cd. In addition, the proportion of exchangeable Pb, Zn and Cd to total Pb, Zn and Cd decreased with the increasing amount of red mud addition. [Conclusion] The study provided references for reasonable application of red mud and reduction of heavy metal pollution in paddy soil.

Characteristics of Some Heavy Metals in Acid Sulfate Topsoils, Eastern Australia

Forty-five acid sulfate topsoil samples (depth < 0.5 m) from 15 soil cores at 11 locations along the New South Wales coast, Australia, were selected to investigate the chemical behavior of Zn, Mn, Cr, Co and Pb in these soils. The amount of HCI-extractable Mn was much smaller than the mean value of the total Mn documented for other soils. This may be attributed to enhanced mobilization of Mn from the soils under the extremely acidic and seasonally flooded conditions encountered in the investigated soils. The pH-dependency of soluble Zn and Mn was strongly affected by the availability of acid reactive Zn and Mn compounds. There were fairly good relationships between soluble Zn and acid reactive Zn compounds, and between soluble Mn and acid reactive Mn compounds. Soluble Zn and soluble Mn concentrations were important controls on exchangeable Zn and Mn concentrations, respectively. In contrast to the suggestion by other authors that adsorption of Co was closely associated with Mn oxides present in soils, the exchangeable Co in the investigated acid sulfate soils was not clearly related to the abundance of Mn minerals. In addition to the fact that there are few Mn minerals present in the soils, this might also be because the availability of canon exchange sites on the crystal surfaces of Mn oxides was reduced under extremely acidic conditions.

Effect of Heavy Metal Pollution on Potassium Behavior in Typic Udic Ferrisol

The indirect influence of heavy metal contamination of soil on nutrient availability, an important aspect of soil quality, may need to be taken into consideration when determining overall effects of heavy metals. A laboratory experiment was performed to study the effects of combined pollution of Cu, Ph, Zn and Cd on soil K status as indicated by chemical fractions, adsorption-desorption and quantity/intensity (Q/I) relationship of K in a Typic Udic Ferrisol (generally called red soil), by employing uniform design and single factor design. Compared to the control, content of exchangeable K was decreased, but that of soluble K increased in the samples contaminated with heavy metals. Due to heavy metal pollution, potassium adsorption was reduced by 5% to 22%, whereas the desorption percentage of adsorbed K increased by 2% to 32%. The Q/I curves shifted downward, potassium buffering capacity (PBCK) decreased, and equilibrium activity ratio values (ARoK) increased with increasing heavy metal pollution. These influences followed the sequences of Ph>Cu>Zn and combined pollution>single one. Displacement of K from canon exchange sites and decrease in soil CEC due to heavy metals should be responsible for the changes of soil K behaviours. The findings suggest that heavy metal pollution of soil might aggravate the degradation of soil K fertility by decreasing K adsorption and buffering capacity and increasing desorption.

Effect of Amendments on Growth and Element Uptake of Pakchoi in a Cadmium, Zinc and Lead Contaminated Soil

A pot experiment was carried out to study the effects of two amendments, limeand calcium magnesium phosphate, on the growth and Cd, Pb, Zn, Cu, Mu, Fe, N, P and K uptake ofpakchoi (Brassica chinensis) in a Cd, Pb and Zn polluted acid soil in the southern part of China.The growth of pakchoi was apparently improved by lime and calcium magnesium phosphate application,the uptake of Cd, Pb, Cu and Zn by pakchoi was significantly depressed and the symptom caused byheavy metals pollution was eliminated. Meanwhile, the absorption of N, K and Mn was also inhibitedby these amendments. Soil pH was the main factor controlling the uptake of the heavy metals bypakchoi. This suggests that lime and calcium magnesium phosphate could be used as effectiveamendments for eliminating the toxicity of heavy metals to the vegetable and inhibiting theirabsorption by the crop.

Growth,Cadmium and Zinc Accumulation of Ornamental Sunflower (Helianthus annuus L.) in Contaminated Soil with Different Amendments

Use of ornamental plants for phytoremediation of metal-contaminated soil is a new option. A pot experiment was carried out to assess the effect of application of amendments, i.e., swine manure, salicylic acid （SA） and potassium chloride （KC1）, on the growth, uptake and translocation of cadmium （Cd） and zinc （Zn） of ornamental sunflower （Helianthus annuus L.） grown on a contaminated soil. The three amendments increased sunflower height, flower diameter, and biomass. Manure significantly decreased Cd and Zn concentrations in sunflower, and thus decreased the bioaccumulation coefficient （BCF） of Cd and Zn. However, using of KC1 markedly increased Cd concentrations in sunflower and the BCF of Cd. Additionally, both swine manure and KC1 application increased Cd and Zn translocation from root to aboveground part. Swine manure and salicylic acid reduced the Cd/Zn ratios in flower of sunflower, while KC1 significantly increased the Cd/Zn ratios. Correlation analysis demonstrated that the Cd/Zn ratio in the root of sunflower was affected by K/Na ratio in root and soil available potassium （K） concentration. Ornamental sunflower could be grown as an alternative plant in the Cd- and Zn-contaminated soil with KC1 application to get the balance between environmental and economic interests.