基于叶经济谱理论的行道树与土壤重金属关系的评价方法

道路系统作为城市生态系统的重要组成部分,承担着生态廊道的重要职能。植物与环境间有着密切而复杂的联系,城市道路的土壤重金属直接影响着植物生长。本研究选取了泰兴市位于不同功能区的5条城市道路进行土壤重金属污染综合评价,同时选取各研究区域共有的10种典型的行道树为实验材料,对引起叶经济谱性状变化的土壤重金属环境进行研究,并提出针对重金属污染的行道树适应性评价方法,以及道路植物配置优化策略。

生物有机肥在重金属污染土壤植物修复中的效应研究

在我国现代社会经济快速发展的推动下,各个行业的整体发展规模愈发壮大。而在农业生产、工业制造以及交通运输等活动时常会引发土壤重金属污染问题,尤其是在农业种植过程当中施用有机肥和生物炭,重金属污染土壤当中的有机物质含量就会逐步提升,而土壤当中的钾含量以及酸碱值会出现不同程度的下降。有机肥的有机物质往往含量较高,肥力维持周期较长,其中富含了大量的氮磷钾等农作物生长必要微量元素,同时也能为农作物提供镁、锌、铁、锰、硼等微量元素,提高农作物的成活率。与此同时,通过生物碳材料的应用,也能为农作物提供极为丰富的矿物质,发挥出强大的离子吸附能力,借此来对土壤进行改良。针对受重金属污染土壤开展农业种植改良工作,相关种植人员可采用有机肥和生物炭,有效达成改善土壤理化性质、提高土壤肥力和微生物活性的目标,进而提升农作物的品质,为社会各界提供更为优质的农产品。

基于c语言对土壤表层重金属污染物扩散的分析

为了系统的分析与确定某一区域中土壤表层重金属污染物的迁移规律。本文基于c语言中传递闭包确定最小点基的方法和dijkstra算法进行计算，基本确定重金属污染源的位置及其在表层可能的扩散路径。为该区的土壤污染防治及环境治理建立了理论基础．也对改善区域土壤重金属污染提出了科学方法。

土壤污染程度分析及迁移规律的优化模型

本文根据题中给出的已知数据,对城区五个功能区的8种重金属元素(As、Cd、Cr、Cu、Hg、Ni、Pb、Zn)的浓度及分布范围,利用matlab软件中插值计算法和绘图功能,绘出了重金属元素在该城区的空间分布图.再运用变异系数值法初步估算出了每个功能区8种元素的变异系数值分析功能区重金属浓度超标情况,进而选用地累积指数法作优化模型,定量分析该城区内不同区域重金属的污染程度.根据采样的现有数据,分析了重金属在土壤中的传播特性,分析了重金属污染物在进入土壤环境系统后的迁移规律,阐述了土壤中重金属传播规律.

Impact of Urbanization on Shanghai's Soil Environmental Quality

Heavy metal contents in the soils in the Baoshan District of Shanghai were monitored to evaluate the risk of soil environmental quality degradation due to rapid urbanization and to reveal the ways of heavy metal accumulation in soil during rapid urban sprawl. It was found that the soils in this district were commonly contaminated by Pb, Zn and Cd. Evaluated with a geo-accumulation index (Igeo), the rate of Pb contamination in soils was 100% with 59% of these graded as moderate-severe or severe; Zn contamination reached 59% with 6% graded as moderate-severe or severe; and Cd contamination was over 50%, with one site graded as moderate-severe and another severe-extremely severe. Metal contamination of soils around the Shanghai metropolis was mainly attributed to traffic, industrial production, wastewater irrigation and improper disposal of solid wastes. Because of continuing urbanization, the cultivated land around the metropolis should be comprehensively planned and carefully managed. Also the soil environmental quality of vegetable production bases in this area should be monitored regularly, with vegetables to be grown selected according to the degrees and types of soil contamination.

Soil Microbial Characteristics Under Long-Term Heavy Metal Stress:A Case Study in Zhangshi Wastewater Irrigation Area,Shenyang

Soil samples were collected from Zhangshi Wastewater Irrigation Area in the suburb of Shenyang City,China,an area with a 30-year irrigation history with heavy metal-containing wastewater.The chemical properties and microbial characteristics of the soils were examined to evaluate the present situation of heavy metal pollution and to assess the soil microbial characteristics under long-term heavy metal stress.In light of the National Environmental Quality Standards of China,the soil in the test area was heavily polluted by Cd and to a lesser degree by Zn and Cu,even though wastewater irrigation ceased in 1993.Soil metabolic quotient (qCO_2) had a significant positive correlation,while soil microbial quotient (qM) had a negative correlation with content of soil heavy metals.Soil microbial biomass carbon (MBC) had significantly negative correlation with Cd,but soil substrate-induced respiration (SIR),dehydrogenase activity (DHA),cellulase activity, and culturable microbial populations had no persistent correlations with soil heavy metal content.Soil nutrients,except for phosphorous,showed positive effects on soil microbial characteristics,which to a certain degree obscured the adverse effects of soil heavy metals.Soil Cd contributed more to the soil microbial characteristics,but qM and qCO_2 were more sensitive and showed persistent responses to heavy metals stress.It could be concluded that qM and qCO_2 can be used as bioindicators of heavy metal pollution in soils.

Science Letters:Gama-aminobiityric acid accumulation in Elsholtzia splendens in response to copper toxicity

A solution with different Cu supply levels was cultured to investigate gama-aminobutyric acid (GABA) accumulation in Elsholtzia splendens, a native Chinese Cu-tolerant and accumulating plant species. Increasing Cu from 0.25 to 500 ?mol/L significantly enhanced levels of GABA and histidine (His), but considerably decreased levels of aspartate (Asp) and glutamate (Glu) in the leaves. The leaf Asp level negatively correlated with leaf Cu level, while leaf GABA level positively correlated with leaf Cu level. The leaf Glu level negatively correlated with leaf GABA level in Elsholtzia splendens. The depletion of leaf Glu may be related to the enhanced synthesis ofleafGABA under Cu stress.

Heavy metal pollution and potential ecological risk in reclaimed soils in Huainan mining area

In order to determine the environmental quality condition of reclaimed soils inHuainan mining area, soil samples were collected from three representative mines, suchas Panyi Mine, Xinzhuangzi Mine and Datong Mine.The total concentration of Cd, Hg, Cu,Pb and As in the samples were analyzed.The potential ecological risk was used to evaluatethe heavy metals pollution.The investigation reveals that the reclaimed soils are contaminatedto a certain degree and the trace elements in coal gangue transferred to thesurface soil.The order of potential ecological risk is Cd>Hg>Cu>Pb>As; the pollution degreeof each sampling site is arranged in the following order: Xinzhuangzi Mine>DatongMine>Panyi Mine, and the multiform of heavy metals of potential ecological risk index is at357.35～484.62.

Evaluation on environmental quality for heavy metal elements of Xihe soil

According to "Environmental quality standard for soil" and using As,Cd,Cr,Cu,Hg,Ni,Pb,Zn elements as evaluation index,the author evaluated soil environmental quality in Xihe area of Shenyang.The results show that the soil in Xihe area is polluted rifely by heavy metal elements.The polluted areas are mainly distributed near the upstreams of Xihe River,Shenxin River and Shenliao irrigation canal.There exist large distinctions among the heavy metal elements to the pollution degree.Cd pollution area is the biggest and the most serious in pollution degree.

Remediation of Heavy Metal-Polluted Agricultural Soils Using Clay Minerals： A Review

Heavy metal contamination of agricultural soils poses risks and hazards to humans. The remediation of heavy metal-polluted soils has become a hot topic in environmental science and engineering. In this review, the application of clay minerals for the remediation of heavy metal-polluted agricultural soils is summarized, in terms of their remediation effects and mechanisms, influencing factors, and future focus. Typical clay minerals, natural sepiolite, palygorskite, and bentonite, have been widely utilized for the in-situ immobilization of heavy metals in soils, especially Cd-polluted paddy soils and wastewater-irrigated farmland soils. Clay minerals are able to increase soil pH, decrease the chemical-extractable fractions and bioavailability of heavy metals in soils, and reduce the heavy metal contents in edible parts of plants. The immobilization effects have been confirmed in field-scale demonstrations and pot trials. Clay minerals can improve the environmental quality of soils and alleviate the hazards of heavy metals to plants. As main factors affecting the immobilization effects, the pH and water condition of soils have drawn academic attention. The remediation mechanisms mainly include liming, precipitation, and sorption effects. However, the molecular mechanisms of microscopic immobilization are unclear. F^ture studies should focus on the long-term stability and improvement of clay minerals in order to obtain a better remediation effect.