Toxicity of hexyl to<Emphasis Type="Italic">F. candida and E. crypticus</Emphasis>

Aim, Scope and Background  Hexyl is along with TNT a possible pollutant of ammunition contaminated soils. To assess the ecological risk of a pollutant biotests are obligatory to gain information of the effects on the habitat function of the contaminated soil. The effect of Hexyl was investigated using the standardised biotests for the springtailFolsomia Candida and the enchytraeidEnchytraeus crypticus. Method  The tests with Hexyl were performed in spiked standard soil (Lufa 2.2). The toxic endpoints were mortality (short-term test, exposure time 7 days) and reproduction rate (long-term test, exposure time 28 days). The effect on the reproduction was further investigated by transferring animals from contaminated soil material onto uncontaminated substrate. Then the number of offspring was determined for the collembola and the cocoon- and hatching rates for the enchytraeid. Results. The mortality of the collembola was not influenced by Hexyl, but the number of offspring was significantly reduced. On the bases of these data the influence of the contaminant on the fertility of the adults itself was investigated. Therefore a reproduction test was performed with adult springtails transferred from contaminated onto uncontaminated soil material. It was shown that the fertility of the adults was not affected by Hexyl indicating a strong lethal effect on the juveniles. In case of the enchytraeid the mortality as well as the reproduction was affected. The surviving enchytraeids turned yellow and rigid in the mortality tests. They were also reduced in size compared to individuals in the uncontaminated control soil material. Thus the cocoon and hatching rates of worms transferred from contaminated soil material onto agar-agar was further investigated. Indeed, the reproduction (both cocoon production and juvenile hatching) was affected by the contaminant. However, the effect was not as strong as might have been suggested by their change in colour and size. A rapid recovery of the worms was observed, too. Conclusion  Hexyl is toxic for the two terrestrial invertebrates, although in comparison to other explosives tested it is less toxic than TNT, but more toxic than the other explosives such as Hexogen (RDX) and Octogen (HMX) or TAT, the end product of the microbial reduction of TNT. So far, all these substances have only been tested with the luminescent bacteriaVibrio fischeri, for which Hexyl and TNT were classified as very toxic to aquatic organisms. With earthworms (Eisenia fetida andEisenia andrei) only TNT, Hexogen and Octogen have been investigated. TNT was also the most toxic of these substances. Outook  Hexyl is one of the main pollutants of ammunition-contaminated sites and has to be considered as a toxic compound. Therefore an assessment of its full ecological impact is necessary and should include tests with animals from different trophic levels as well as biotests with plants and microorganisms.     

Regulation of Contaminated Soils in Spain - A New Legal Instrument (4 pp)

Background, Aims and Scope   This paper presents the new Spanish regulation on contaminated soils and its scientific basis. The regulation offers a regulatory framework for establishing industrial activities which may result in soil contamination, and presents the methodology for setting the generic reference levels of organic pollutants.Legal Framework   The Spanish regulation on contaminated soils is derived from the waste legislation and covers 101 industrial activities, as well as facilities handling significant amounts of hazardous chemicals (over 10,000 kg per year) or fuel (300,000 l fuel per year or storing 50,000 l fuel at any time). The regulatory framework includes initial declarations and a tiered system for selecting those soils requiring a proper site-specific risk assessment.Scientific Basis   The regulation is risk based, and covers human and environmental risks. The human health risk assessment focuses on chemical analysis; the selection of relevant exposure routes is associated to the soil uses. The environmental risk assessment includes chemical analysis and direct toxicity testing, and covers three main ecological receptors: Soil organisms, associated aquatic systems and terrestrial vertebrates. Low-risk threshold concentrations are established as generic reference levels; if exceeded, a site-specific risk assessment is required. The detection of a very high level of acute toxicity of soil or leachates led to the declaration of the soil as contaminated due to the capacity for contaminating the adjacent areas.Conclusion   Overall, the Spanish regulation offers a balance for combining regulatory needs, proper scientific basis and practicability. The use of European risk assessment protocols and the European legal framework would facilitate the pan-European extrapolation of this approach. The inclusion of direct toxicity testing as a legal method for classifying a soil as contaminated is considered a key element.     

~(137)Cs在土壤中的污染行为与钾盐的防治效果

本研究结果表明 ,在污染水平相同的情况下 ,不同土壤对春小麦吸收137Cs有很大影响 ,植株中137Cs的比活度相差几十倍。在同一种土壤、不同污染水平下 ,春小麦对137Cs的吸收与土壤中137Cs的污染水平呈正相关。在137Cs污染的土壤上施用钾盐可以降低春小麦植株对137Cs的吸收。防治效果与钾盐施用量有关 ,本试验结果为土壤阳离子代换量 1 / 3 0的量施用效果最好 ,使植株中的137Cs比活度降低 84 74%～88 89% ,与不施钾盐的对照组的差异十分显著     

成品油管道运营问题分析及其解决方法

针对兰成渝输油管道投产运行以来出现的问题进行了分析,并从输油计划的编制、混油的形成与处理以及管道内部杂质的处理三个方面对成品油顺序输送管道进行了总结和归纳,提出了成品油管道建设和运行的意见和建议.     

停输对混油量影响数值模拟研究

针对顺序输送管道在运行过程中的停输现象,建立了动量传递质量传递耦合的非稳态停输混油数学模型。利用PHOENICS 3.6软件进行停输过程数值模拟,通过算例分析了柴油前行、汽油后行在管道上下坡等工况下停输后的混油机理及不同工况条件下停输对混油量的影响。     

有机酸对土壤重金属的浸提效果研究

重金属污染土壤的原位淋洗修复既要实现对重金属的高效去除,还要尽量减少对土壤性质的破坏。以张士污灌区农田土壤为研究对象,利用振荡浸提技术对有机酸淋洗重金属污染土壤进行研究。结果发现：对重金属Cd、Pb、Zn的浸提率随着酒石酸、乙酸、柠檬酸、苹果酸的浓度升高而增加;4种有机酸对土壤重金属的浸提效果均是Cd〉Pb〉Zn;酒石酸在浓度为0.5mol/L时对土壤中重金属Cd、Pb、Zn的浸提效果最好,浸提率分别为99.39%、57.65%、43.52%。     

三种观赏植物对Cd污染土壤酶活性的影响

通过盆栽实验,系统研究了含羞草、白雪姬和树马齿苋对Cd污染土壤中土壤酶的修复作用。结果表明,脲酶、过氧化氢酶和磷酸酶的活性随着Cd浓度的上升不断下降,且均与Cd浓度呈显著负相关关系。3种观赏植物生长均能提高Cd污染土壤中脲酶、磷酸酶和过氧化氢酶的活性。白雪姬还能显著提高土壤蔗糖酶的活性。含羞草、白雪姬和树马齿苋对土壤酶的修复效果均表现为:脲酶>磷酸酶>过氧化氢酶>蔗糖酶,且白雪姬对土壤酶的修复效果显著高于其它两种观赏植物,说明白雪姬作为一种常见的观赏植物,在修复重金属Cd污染土壤方面具有很高的应用前景。     

环境材料对Pb、Cd污染土壤玉米生长及土壤改良效果的影响

为探索环境材料对种植于Pb、Cd污染土壤中的玉米生长、品质的影响, 以及对Pb、Cd重金属污染土壤的改良效应, 本文采用温室盆栽方法, 研究了不同环境材料[腐殖质类材料(HA)、高分子材料(SAP)、煤基复合材料(FM)及粉质矿物材料(FS)]及其复合处理对Pb-Cd复合污染土壤中玉米(Zea mays L.)生长、品质及根系土壤环境的影响。结果表明, 添加环境材料组合F22(FM+SAP)、F23(FS+SAP)及F32(HA+SAP+FS)能促进苗期玉米生长, 长势好于对照; 所有环境材料处理中玉米地上部粗灰分含量都低于对照, 添加单一环境材料对玉米地上部粗淀粉含量的提高效果高于对照、优于组合; 处理FM、F33(SAP+FM+FS)及F4(HA+SAP+FM+FS)对土壤中Pb固定效果显著, 抑制土壤中Pb向玉米体内迁移; 单一处理FM、FS及组合F33(SAP+FM+FS)对土壤重金属Cd固化效果明显, 抑制土壤中Cd向玉米体内迁移。环境材料的添加在一定程度上有助于土壤基本理化性质的改善, 促进土壤改良, 同时环境材料对阻止土壤重金属向植物体迁移有一定作用。     

Rice (Oryza sativa L.) seedlings enriched with zinc or manganese: Their impacts on cadmium accumulation and expression of related genes

Cadmium (Cd) contamination in paddy soils means that the rice produced there may be unsafe for human consumption. A hydroponic study was conducted to enrich rice seedlings with zinc (Zn) or manganese (Mn), and the uptake and transport characteristics of Cd in these Zn- and Mn-rich seedlings were subsequently investigated using a greenhouse pot trial. The results showed that hydroponic cultivation in 10–50 μmol L^-1 Zn (ZnSO₄·7H₂O) or 50–250 μmol L^-1 Mn (MnSO₄·H₂O) for 30 d had no significant impact on rice growth, while the accumulation of Zn and Mn was 7.31–18.5 and 25.4–47.7 times higher, respectively, than in the control (no Zn or Mn addition). The accumulation of Cd in the Zn- and Mn-rich rice plants was 26.3%–38.6% and 34.4%–44.5% lower than that in the control, respectively, and the translocation factors of Cd from roots to shoots also decreased by 23.3%–41.3% and 25.3%–37.0%, respectively, after transplanting to Cd-contaminated soils. Furthermore, the relative expression levels of OsIRT1 (Oryza sativa iron-regulated transporter 1) were downregulated by 40.1%–59.3% and 16.0%–25.9%, respectively, in the Zn- and Mn-rich seedling roots. This downregulation may indicate a possible mechanism contributing to the reductions in Cd absorption. Field experiments confirmed that the Zn- and Mn-rich seedlings produced brown rice (unpolished rice grains) with significantly decreased concentrations of Cd (34.2%–44.4%). This study provides an innovative method for reducing the food safety risks from rice grown on slightly to moderately Cd-contaminated paddy soils.     

间套轮作超积累植物技术模式修复Cd污染土壤的研究进展

我国农田土壤中Cd污染问题突出，其修复技术一直备受关注。基于超积累植物的植物提取技术是根治我国Cd污染农田土壤的热门修复技术，但单一的植物提取技术模式通常无法保障污染地区正常的农耕生产需求，故当地农户对该技术的接受程度普遍较低。为解决单一超积累植物修复技术在工程应用推广中的实际问题，提出“高效修复与安全生产”相结合的双赢策略，总结了前人对植物修复技术、超积累植物的概念由来及研究范围，综述了现阶段基于超积累植物的间、套、轮作修复模式的研究进展，统计比对了各种植物组合耕作模式对Cd污染农田土壤的综合治理效果，并对今后利用不同种植模式修复Cd污染农田土壤提出了研究展望。