Influence of amendments on soil arsenic fractionation and phytoavailability by Pteris vittata L

Increasing availability of soil arsenic is of significance for accelerating phytoremediation efficiency of As-polluted sites. The effects of seven amendments, i.e., citrate, oxalate, EDTA, sodium polyacrylate (SPA), phosphate rock (PR), single superphosphate (SSP), and compost on fractionation and phytoavailability of soil As were investigated in lab culture experiment. The results showed that the addition of PR, SPA, EDTA or compost to soils significantly increased the concentration of NaHCO₃-extractable As over a 120 d incubation period compared with the control (amendment-free) soil. Then, the four amendments were selected to add to As-contaminated soil growing Pteris vittata. It was concluded that As accumulation by the fern increased significantly under the treatments of PR and SPA by 25% and 31%, respectively. For As fractionation in soil, SPA increased Fe-As significantly by 51% and PR increased Ca-As significantly by 18%, while both the two amendments reduced occluded-As by 16% and 19%, respectively. Adding PR and SPA in soil increased the activities of urease and neutral phosphatase resulting from the improvement the fertility and physical structure of the soil, which benefits plant growth and As absorption of P. vittata. The results of the research revealed that both PR and SPA were effective amendments for improving phytoremediation of As-contaminated sites by P. vittata.     

垃圾填埋场加速稳定化表征指标的相关性分析

加速稳定化表征指标是生物反应器填埋技术评价的重要内容。通过垃圾填埋室内模拟实验,研究不同运行工况下垃圾挥发性固体(VS)、生物可降解物(BDM)、纤维素(C)和纤维素/木质素(C/L)等组分指标的动态变化规律及其对加速稳定化进程的指示作用,进而探寻各指标之间的相关性,进一步筛选确定垃圾填埋场加速稳定化进程的核心表征指标。结果表明,垃圾组分VS、BDM、C和C/L的衰减符合一级反应动力学,其动态变化能够较为灵敏地指示渗滤液回灌和通风供氧对垃圾稳定化的显著加速作用,可作为垃圾填埋场加速稳定化进程的表征指标。VS、BDM、C和C/L相互之间具有良好的正线性相关性。BDM和C/L适宜作为垃圾填埋场加速稳定化进程的核心表征指标。     

《中国21世纪议程》:迎接挑战的战略抉择与实践探索

制定《中国21世纪议程》是中国发展必然的战略选择,是中国履行环发大会精神的重要举措。近20年来,我国立足基本国情,积极推进《中国21世纪议程》的实施,探索实践中国特色的可持续发展道路,做出了巨大努力,在发展经济、消除贫困、节约资源、保护环境等领域取得了举世瞩目的成就,对全球可持续发展做出了重要贡献。随着世情国情的深刻变化,我国进一步实施可持续发展战略面临着新的挑战,发展中不平衡、不协调、不可持续的问题依然严峻,发展的任务仍然十分艰巨。我们应该坚持以科学发展观为统领,坚定不移地走中国特色的可持续发展之路,充分把握全球绿色技术创新迸发的历史机遇,切实加快经济发展方式的转变;坚持共同但有区别责任的原则和合作共赢的理念,积极参与全球可持续发展治理,促进世界的可持续发展、和谐发展。     

猪场生物发酵床垫料卫生研究

通过选择有3个采用发酵床养猪模式的猪场,采集不同使用年限、不同深度及饲养不同阶段猪舍的发酵床垫料,通过测定水分、总N、总P、可溶性盐、黄曲霉毒素B1(AFB1)、枯草芽孢杆菌和大肠杆菌数目、Cu和Zn含量(全重金属及有效态重金属)评估垫料的卫生学状况.并将垫料与土壤以不同比例混合,研究对植物生长及Cu、Zn在植株中残留影响.研究表明,发酵床垫料随着深度增加,垫料的水分含量逐渐降低,温度逐渐升高,大肠杆菌、枯草芽孢杆菌数量减少.随着发酵床使用年限的延长,总N随垫料使用时间延长而变低,而总P含量随时间延长而增加,但变化均不显著(P＞0.05);Cu、Zn、Pb、可溶性盐含量都呈现显著的增加(P＜0.05).在1年、2年、3年期的垫料中AFB1均有检出,含量均小于10 μg/kg.种植实验结果显示,土壤添加垫料后,Cu、Zn含量随着添加比例增加而增加,植物中残留量随着垫料添加比例的增加而增加.因此在处理发酵床垫料时,要综合考虑其对环境及食品安全的影响.     

Post-contentious politics and Iran's first ecovillage

The existing scholarship on alternative institutional designs around environmental issues mostly focuses on ideals, goals and practices of these designs. It remains unclear under which circumstances these initiatives emerge and expand. Moreover, those scholars who address the emergence and expansion of these initiatives focus on examples which are located in advanced industrialised societies. It remains unclear why and how these alternative institutions emerge in non-industrialised societies and countries which have not gone through the same growth path as their advanced industrialised counterparts. Consequently, transformative implication of these initiatives for broader social change in non-advanced industrialised societies has not been explored. In this paper, I show that in Iran the emergence of these alternative designs should be understood within the context of post-contentious politics. I present original research on a cooperative that embraces an alternative lifestyle and whose aim is to create Iran's first ecovillage. This case study discusses one kind of response to the contraction of space for civil society and environmental non governmental organisations in Iran. The paper adds to our understanding of the interplay between democratisation processes and environmental activism.     

Residual tembotrione and atrazine in carrot

Carrot (Daucus carota L.) is a vegetable crop that is grown throughout the year across various regions of Brazil in rotation or in succession to other cultures. Herbicide residual effect has emerged as a concern, because of the possibility of carryover. Thus, the objective of this study was to evaluate the effect of tembotrione and atrazine residues – in mixture and isolated – on carrot planted in succession to corn. The experiment was designed in randomized blocks with five replications. Treatments consisted of tembotrione (50.4 g ha^?1), tembotrione (100.8 g ha^?1), tembotrione + atrazine (50.4 g ha^?1+ 2 L ha^?1), tembotrione + atrazine (100.8 g ha^?1+ 2 L ha^?1), and atrazine (2.00 L ha^?1) applied eight months before carrot seeding, plus a control treatment with no herbicide application. Investigated variables were shoot dry mass, productivity, and classification of carrot roots. The presence of atrazine and tembotrione decreased dry mass in the area, and only tembotrione reduced total root productivity. Thus, there is a carryover effect to tembotrione application that reduces the dry matter accumulation of shoot and total productivity, and an atrazine + tembotrione (100.8 g ha^?1) mixture reduces the total productivity after application of these herbicides to soil.     

不同质量浓度黄莒蒲和狭叶香蒲对铜绿微囊藻的化感作用

分别采用黄菖蒲（IrispseudacorusL．）、狭叶香蒲（TyphaangustifoliaL．）和铜绿微囊藻（Microcystisaeruginosa）共生培养的实验方法研究了不同质量浓度黄菖蒲、狭叶香蒲对铜绿微囊藻的化感作用。结果表明,黄菖蒲在质量浓度大于10g／L时对初始密度为1．0×10^7ind／mL的铜绿微囊藻具有较好的抑制作用,表现为黄菖蒲质量浓度为10、20和40g／L时,第15天对铜绿微囊藻的抑制率分别为30．1％、51．8％和84．0％;狭叶香蒲在质量浓度大于20g／L时对铜绿微囊藻有明显的抑制作用,表现为狭叶香蒲质量浓度为20g／L和40g／L时,第15天对铜绿微囊藻的抑制率分别为34．2％和77．7％,实验过程中,铜绿微囊藻叶绿素a含量逐渐减少,而藻密度、SOD活性及MDA含量先增加后逐渐降低,表明经过一段时间持续地化感胁迫,黄菖蒲和狭叶香蒲可以诱导铜绿微囊藻产生氧化胁迫,导致细胞结构严重损伤和叶绿素大量分解,从而强烈抑制铜绿微囊藻的生长。     

The response of Chenopodium album L. and Abutilon theophrasti Medik. to reduced doses of mesotrione

Limited toxicity data are available for estuarine and marine species and the widely used pyrethroid insecticide, permethrin. This study determined acute effects of permethrin on survival, lipid peroxidation, acetylcholinesterase activity, and splenocyte proliferation for two fish species found in South Carolina estuaries; juvenile red drum (Sciaenops ocellatus) and adult mummichog (Fundulus heteroclitus). Juvenile S. ocellatus were significantly more sensitive than adult F. heteroclitus to permethrin exposure, with a 96-h LC50 value of 8 μg/L determined for red drum compared to 23 μg/L for mummichog. Lipid peroxidation activity of the liver increased in permethrin-treated fish compared to control animals after 24 h and decreased after 96 h. Permethrin had no effect on acetylcholinesterase activity of the brain at the concentrations tested. Permethrin exposure significantly inhibited splenocyte proliferation, indicating an immunosuppressive effect. Most of the effects of permethrin on fish cellular stress enzymes and survival occurred at concentrations much higher than those typically measured in the environment. However, inhibition of splenocyte proliferation in juvenile red drum occurred at approximately twice that of measured permethrin concentrations in surface water. These findings may prove useful to the future management and regulation of pyrethroid insecticide use near estuarine habitats.     

Dissipation of pendimethalin in the soil of field pea (Pisum sativum L.) and detection of terminal residues in plants

Dissipation of pendimethalin in the soil of field peas (Pisum sativum L.) at 0 to 110 days, and terminal residues in green and mature pea were studied under field conditions. Pendimethalin was applied as pre-emergence herbicide at 750, to 185 g a.i. ha^?1 in winter, in field peas. Dissipation of pendimethalin in the soil at 0 to 110 days followed first-order kinetics showing a half-life of 19.83 days averaged over all doses. Low pendimethalin residues were found in mature pea grain (0.004, 0.003, <0.001 μg g^?1), and straw (0.007, 0.002, <0.001 μg g^?1) at 750, 350 and 185 g a.i. ha^?1 treatments, respectively. The study indicated that residues of pendimethalin in green and mature pea were within the prescribed MRL limits.     

A fluorometric method to determine rainfastness,volatilization and photostability of glyphosate from glass slides,after application of vision® with two adjuvants

Abstract

A fluorometric method was developed to quantify glyphosate loss from glass surfaces after exposure to the natural forest environment. The method was based on the principle of converting glyphosate into glycine, followed by the fluorogenic labeling with o‐phthalaldehyde. A fluorometer (with λ _Ex = 360 nm / λ_Em =430 nm) was used to quantify the derivatized fluorogenic compound. Response was linear over the concentration range of 143, 286, 572, 858 and 1144 μg of glyphosate (acid equivalent, AE) per mL of the diluted Vision® formulation. Three end‐use mixtures of Vision® were prepared, each at a concentration of 28.6 g AE/L, without and with two adjuvants, Ethomeen® T/25 at 4.5 mL/L and Silwet^® L‐77 at 1.5 mL/L. Several dilutions of the end‐use mixtures were applied on glass slides without and with the coating of cuticular wax extracted from trembling aspen foliage. The slides were left for 5 days in a forest opening to determine rainfastness, volatilization and photostability of glyphosate. The residues were quantified using the method developed. Three calibration curves were required because Silwet decreased the fluorometric response of glyphosate, whereas Ethomeen increased it. The minimum detection limit was 143 μg of glyphosate/mL. Glyphosate was resistant to volatilization and sunlight‐mediated degradation, regardless of the presence of wax coating or the adjuvants. About 64% of the applied glyphosate was washed off after a 9.6 mm rainfall when no adjuvant was present. Both adjuvants provided some amount of rain‐protection to glyphosate, but Silwet reduced the washoff to a greater extent (46%) than Ethomeen (55%).