Heavy metal accumulation by poplar in calcareous soil with various degrees of multi-metal contamination: implications for phytoextraction and phytostabilization

The object of this study was to assess the capacity of Populus alba L. var. pyramidalis Bunge for phytoremediation of heavy metals on calcareous soils contaminated with multiple metals. In a pot culture experiment, a multi-metal-contaminated calcareous soil was mixed at different ratios with an uncontaminated, but otherwise similar soil, to establish a gradient of soil metal contamination levels. In a field experiment, poplars with different stand ages (3, 5, and 7 years) were sampled randomly in a wastewater-irrigated field. The concentrations of cadmium (Cd), Cu, lead (Pb), and zinc (Zn) in the poplar tissues and soil were determined. The accumulation of Cd and Zn was greatest in the leaves of P. pyramidalis, while Cu and Pb mainly accumulated in the roots. In the pot experiment, the highest tissue concentrations of Cd (40.76 mg kg^?1), Cu (8.21 mg kg^?1), Pb (41.62 mg kg^?1), and Zn (696 mg kg^?1) were all noted in the multi-metal-contaminated soil. Although extremely high levels of Cd and Zn accumulated in the leaves, phytoextraction using P. pyramidalis may take at least 24 and 16 years for Cd and Zn, respectively. The foliar concentrations of Cu and Pb were always within the normal ranges and were never higher than 8 and 5 mg kg^?1, respectively. The field experiment also revealed that the concentrations of all four metals in the bark were significantly higher than that in the wood. In addition, the tissue metal concentrations, together with the NH₄NO₃-extractable concentrations of metals in the root zone, decreased as the stand age increased. P. pyramidalis is suitable for phytostabilization of calcareous soils contaminated with multiple metals, but collection of the litter fall would be necessary due to the relatively high foliar concentrations of Cd and Zn.     

上海市某污染场地土壤异位化学氧化修复方案设计

上海市某钢材剪切厂生产过程中机油泄漏等原因导致遗留场地被石油烃(C10～C40)和苯并(a)芘污染.在对场地开展污染状况调查和风险评估的基础上,确定了场地修复工程量和修复方案.采用过硫酸盐氧化+生石灰活化的异位化学氧化技术对污染场地土壤进行修复,确定过硫酸钠和生石灰的添加量都为1.5％(质量分数),根据实际情况控制在1...     

西部大开发与公民环境意识

提高公民环境保护意识,是西部大开发形势的需要。通过对目前新疆环境形势的分析,指出环境问题给社会经济和人民生活带来的严重影响;并就提高公民环境保护意识提出的有效方法和措施进行探讨。     

Mapping loci that control lateral spike development in Tibetan barley by bulked segregant analysis (BSA)北大核心CSCD

Fertility of lateral spikelets determines the two-rowed or six-rowed spikes of barley (Hordeum vulgare L.), which results in significantly different grain yields. The change in row type from two-rowed to six-rowed shows remarkable domestication characteristics. The Qinghai-Tibet plateau has abundant resources of wild and cultivated barley, and is considered one of the centers of domestication and genetic diversity of cultivated barley. In order to obtain a primary understanding of the genetic basis of lateral spike development regulation and the domestication process in cultivated Tibetan barley, an F2 segregation population was constructed by crossing the two-rowed wild barley accession ZYM0083 with the six-rowed landraces Linzhiheiliuleng. Genetic analysis showed that the row type was controlled by a single gene. Using the specific-locus amplified fragment sequencing (SLAF-seq) technology and bulked segregant analysis (BSA), two DNA pools from 22 two-rowed spike individuals and 22 six-rowed spike individuals of the F2 population were constructed and sequenced. A total of 456 691 SLAF tags were obtained. By adopting the ED and SNP index for association analysis, three candidate regions with a 53.84-Mb interval and containing 536 genes were obtained. Four-hundred thirteen, 189, and 160 annotated genes were acquired by GO, KEGG, and COG libraries, respectively. Loci that control lateral spike development in Tibetan barley were primarily mapped by SLAF-seq, and the results presented in this study will facilitate the fine mapping and cloning of target genes. © 2018 Science Press. All rights reserved.     

典型喀斯特高原水库浮游植物与环境因子的关系

浮游植物的生长往往受多种环境因素共同作用,独特的地理特征也是影响其密度与群落结构变化的要素之一。为探索喀斯特高原水库浮游植物与环境因子的耦合关系,以贵州省典型喀斯特高原水库——阿哈水库为例,于2019年春(4月)、夏(7月)、秋季(10月)对水库各支流及库中心区域进行采样调查,探究了喀斯特水库基础水环境指标的量级、浮游植物群落组成、优势种变化及其密度的时空分布,进一步揭示浮游植物与环境因子的耦合关系,为喀斯特高原水库浮游植物研究以及水资源保护提供一定的科学依据。结果显示,阿哈水库浮游植物密度在3.95×10⁴-525.35×10⁴cells·L^?1,之间,以蓝藻、硅藻、绿藻、隐藻居多,伪鱼腥藻(Pseudoanabaena sp.)、水华束丝藻(Aphanizomenon flos-aquae)为主要优势种。单因素方差分析(One-way ANOVA)结果表明,浮游植物密度的季节性差异显著(P<0.01),呈夏季>春季>秋季的趋势。由一元线性回归分析可知,在春季,浮游植物密度与溶解氧、pH、钙离子浓度呈极显著线性相关(P<0.01),与透明度、氮磷比具有显著相关关系(P<0.05);然而,浮游植物密度仅与夏季的透明度关系显著(P<0.05),与秋季的所有环境因子均无显著相关关系(P>0.05)。由冗余分析(RDA)可知,影响春季浮游植物群落结构的主要环境因子为pH、钙离子浓度和总磷,夏季为透明度、总磷和氮磷比。秋季浮游植物群落结构可能受低温影响较大。     

Identification of iron and sulfate release processes during riverbank filtration using chemical mass balance modeling

Environmental Geochemistry and Health - Various hydrogeochemical processes can modify the quality of river water during riverbank filtration (RBF). Identifying the subsurface processes responsible...     

交联菌丝体吸附剂的制备及其对Cr^3＋的吸附特性

深入研究了交联菌丝体吸附剂的制备工艺及其对Cr^3＋的吸附特性。交联菌丝体吸附剂制备工艺简单，但在制备过程中，活化剂NaOH和交联剂的用量对吸附特性影响较大。与纯菌丝体吸附剂相比，交联菌丝体吸附剂表观吸附容量提高48％，达到49．83mg／g（pH=2．53，水溶液中的Cr^3＋浓度为600mg／L），同时其机械强度明显增强。交联菌丝体吸附剂对Cr^3＋的吸附特点是将沉淀法与吸附法相结合，将沉淀与吸附两过程合二为一，从而简化了处理工艺，降低了处理成本。     

喀斯特生态脆弱区的土地退化及生态重建 --以贵州省关岭县为例

我国西南喀斯特地区是世界上著名的脆弱生态区，土地退化严重，人地矛盾尖锐，区域发展可持续性差。对此区退化土地进行生态重建，是西部开发中十分紧迫的任务，本文以位于贵州喀斯特高原峡谷地带的关岭县为研究区，分析了喀斯特地区生态环境脆弱性的主要特点，土地退化的主要过程及生态，经济和社会系统驱动机制。在此基础上提出相应的生态重建对策，指出我国西南喀斯特地区可持续发展迫切需要外部的物质、技术，资金等投入扶持，而最终实现则需要立足于本地的生态重建和生态产业的良性发展。     

截污工程完成后武汉东湖自然净化速率探讨

根据几十年来武汉东湖水质监测资料和数据 ,在东湖截污工程完成后 ,没有新的污染物进入水体的前提下 ,对东湖水体通过自然净化恢复到健康状态所需要的时间进行了详细的数学推导和科学论证。结果表明 ,在不考虑地泥营养物质的情况下 ,东湖水体通过工业、农业、生活用水以及收获鱼类和高等植物造成的营养物的输出 ,只需要 3a左右的时间就能恢复。然而如果考虑地泥的影响 ,几十年沉积在地泥的营养物质持续向水体中释放 ,然后再通过用水及生物输出 ,东湖水质需要35a以上才能得到恢复。可见 ,截污后东湖在相当长的时间内还将处于富营养化状态 ,地泥是造成东湖长期富营养化的关键。解决东湖污染问题的关键是清除地泥 ,因此得出结论 :挖底泥后引入长江水源来加速东湖水体改善的最佳途径     

类羧酸对棕壤中与磷素转化有关的生物活性的影响

类羧酸是一种带有羧基的化工副产品，其主要成分是二羧酸和三羧酸，具有较强的络合能力，可以用作鳌合剂。通过室内恒温培养试验，研究了类羧酸对棕壤中与磷素转化有关的生物活性的影响。研究结果表明：土壤中性磷酸酶活性与土壤有机磷转化强度间存在显著直线相关关系。并且，施用类羧酸能增加土壤微生物生物量磷含量，增强土壤中有机磷化合物的水解，增加土壤有效磷的含量，从而改善土壤的供磷能力。