Exogenously applied oxalic acid assists in the phytoremediation of Mn by Polygonum pubescens Blume cultivated in three Mn-contaminated soils

• The OA supply significantly increased the water-extractable Mn in all soils. • All OA supply levels promoted plant growth in unexplored soil. • Low OA supply level promoted plant growth in explored and tailing soils. • OA amendment increased the Mn concentrations and total Mn in P. pubescens. • P. pubescens experienced less Mn stress in unexplored soil than in the other two soils. The current study evaluated the effects of oxalic acid (OA) application on the growth and Mn phytoremediation efficiency of Polygonum pubescens Blume cultivated in three different manganese (Mn)-contaminated soils sampled from an unexplored area (US), an explored area (ES) and a tailing area (TS) of the Ertang Mn mine, South China. The supplied levels of OA were 0 (control), 1 (low level), 3 (medium level), and 9 (high level) mmol/kg, referred to as CK, OA1, OA3 and OA9, respectively. The results revealed that the average water-extractable Mn concentrations US, ES and TS amended with OA increased by 214.13, 363.77 and 266.85%, respectively. All OA supply levels increased plant growth and Mn concentrations in US. The low OA supply level increased plant growth in ES and TS; however, contrasting results were found for the medium and high OA supply levels. Plant Mn concentrations and total Mn increased in ES and TS in response to all OA supply levels. Total Mn in the aerial parts increased by 81.18, 44.17 and 83.17% in US, ES and TS, respectively; the corresponding percentages for the whole plants were 81.53, 108.98 and 77.91%, respectively. The rate of ·O₂⁻ production and malondialdehyde (MDA) concentrations increased in response to OA amendment, especially the medium and high OA supply levels in ES and TS. In general, antioxidant enzymes might play a vital role in alleviating Mn stress in plants cultivated in US, while non-enzymatic antioxidants might be the main factor for plants cultivated in ES and TS.     

电动力学修复铜污染土壤的研究

采用电动力学方法修复重金属污染土壤。研究中采用高岭土模拟铜污染土壤,电化学装置的电压强度为0.5 V/cm,通过在阴阳极室加入不同的缓冲液来确定铜的迁移效果。结果表明在阴极室加入乙酸作为缓冲液可以有效提高铜的迁移效果,在阳极加入柠檬酸能够有效的与铜形成络合物达到更好的迁移效果。     

Cd对不同形态漆酶修复DDT污染土壤的影响

研究了重金属Cd对游离漆酶和同定化反胶团漆酶修复土壤有机氯农药DDT污染的影响.结果表明.游离漆酶对土壤中DDT各组分均有不同程度降解,且均随着cd浓度的增大而降低,含量越高的组分降解率越高.受到Cd污染的影响也越大(P,P'-DDT>P,P'-DDD>0.P'-DDT>P,P'-DDE);当Cd浓度分别为0、0.5、1和2 mg·kg-1时,游离漆酶对土壤中DDT总量的降解率分别为50.68%、32.50%、14.92%和13.40%.固定化反胶团漆酶比游离漆酶能更有效地降解DDT,DDT降解率在无Cd和有Cd存在时(Cd浓度为0.5 mg·kg-1)分别提高20%和30%左右.     

甘蓝和油菜对镉污染土壤的修复研究

通过土培盆栽试验研究了甘蓝和油菜对土壤中重金属镉的吸收及生物净化作用。以及添加螯合剂对油菜富集镉的影响。实验结果表明：甘蓝对于高浓度镉污染土壤的修复作用并不明显,油菜对于镉污染土壤的净化作用较显著,但添加螯合剂对于提高修复水平效果并不显著。因此油菜较适宜作为镉污染土壤的修复植物,但添加螯合剂对植物修复的作用要视情况而定,不可盲目添加。     

生物炭修复与改良矿区重金属污染土壤的研究进展

概述了生物炭制备的关键影响因素及对矿区重金属污染土壤修复与改良作用的研究进展，在此基础上分析了生物炭修复与改良矿区重金属污染土壤的机理，提出了开展生物炭在实际矿区污染场地的长期性与稳定性行为研究，以及探讨生物炭与不同土壤改良剂的优化组合等建议。     

中国台湾地区土壤及地下水污染整治管理与经验

中国台湾地区土壤及地下水污染整治基金管理会自2001年成立以来,不断完善管理架构和管理体系,发布相关领域的法律法规、行政规则和公告,有效运行污染整治基金的财务筹措和使用等经济管理机制。开展了一系列行之有效的预防、监测、调查、评估等管理工作,为污染场地的识别和筛选奠定了坚实的基础。对于污染场地的整治工作,采用标准和风险评估相结合的验收方式,推行场地可持续利用的绿色修复技术。重点研究台湾地区土壤及地下水污染整治工作的管理政策、模式和措施,总结相关经验,为中国土壤及地下水污染防治工作提供借鉴和参考。     

土壤镉污染修复方法及生物修复研究进展

土壤镉污染主要由人为活动引起,镉在土壤环境体系中存在复杂多变的形态,文章介绍了土壤镉污染对生物体的危害性及其修复方法,综述了生物修复技术处理镉污染土壤的研究进展,并提出了展望。     

Removal of Cr(VI) from simulative contaminated groundwater by iron metal

The Cr(VI) removal from simulative contaminated groundwater using zero-valent iron (Fe⁰) filings, Fe⁰ powder and nanoscale Fe⁰ in batch experimental mode was studied. Cr(VI) is a primary pollutant of some soils and groundwater. Zero-valent iron, an important natural reductant, could transform Cr(VI) to Cr(III) which is much less toxic and immobile. The Cr(VI) removal percentage was 87% at a metal to solution ratio of 6 g l⁻¹ for commercial iron powder (200 mesh) in 120 min, and 100% Cr(VI) was removed when the metal to solution ratio was 10 g l⁻¹. The results demonstrates that the Cr(VI) removal percentage was affected apparently by pH, the amount of Fe powder and the reaction temperature. The Cr(VI) removal percentage with nanoscale Fe⁰ was much higher than those with Fe⁰ filings or Fe⁰ powder at the same reaction time. Electrochemical analysis of the reaction process led to the conclusion that the Cr(VI) trended to form Cr(III) hydroxide under the reaction conditions. The kinetics analysis showed that Cr(VI) reduction by Fe⁰ could be described as a pseudo-first-order kinetics model.     

Olive oil mill wastewater for soil nitrogen and carbon conservation

In this work the application of two levels of N fertilizer (NH₄NO₃) dissolved in water or olive oil mill wastewater (OOMW) diluted 10 or 20 times in water, has been studied in relation to the properties of two soils (Loam and Silt-Clay-Loam). Also, the effect of irrigation water bubbled with CO₂ (Dissolved Inorganic Carbon, DIC) was studied. Nitrate N, ammonium N, total N, organic C (OC), and CaCO₃ contents were determined in the soil as well as pH, electrical conductivity (EC), oxidation–reduction potential (ORP), and absorbance at 250 and 360 nm.     

Comparison of Microscopic and Macroscopic Modeling Approaches for Subsurface Contaminant Transport

The practice of contaminant transport and remediation has shown significant progress in recent years. However, despite the significant progress made, remediation efforts are often delayed by extremely long breakthrough curve tails that render efforts to bring the level of contaminants below the regulatory standards inefficient. One hypothesis is that these long tails are due to the reservoir-like slow diffusive processes in soil micropore zones. This study compares the effects of micropores at macroscopic and microscopic levels and establishes a link between these approaches for validation and calibration purposes. The link between macroscopic and microscopic levels is established through comparisons and testing of the two models while incorporating appropriate scale and boundary effects. Despite the differences in conceptual approaches and simulation time, the two approaches rendered meaningful results. The link helps forecast the effects of micropore zone transport processes in the subsurface efficiently and thus allows development of numerical tools that could contribute towards more efficient remediation design.