Organophosphate pesticides an emerging environmental contaminant: Pollution,toxicity,bioremediation progress,and remaining challenges

Organophosphates(OPs) are an integral part of modern agriculture; however, due to overexploitation, OPs pesticides residues are leaching and accumulating in the soil, and groundwater contaminated terrestrial and aquatic food webs. Acute exposure to OPs could produce toxicity in insects, plants, animals, and humans. OPs are known for covalent inhibition of acetylcholinesterase enzyme in pests and terrestrial/aquatic organisms, leading to nervous, respiratory, reproductive, and hepatic abnormaliti...     

Field assessment of straw pellet combustion in improved heating stoves in rural Northeast China

Straw pellets are widely promoted and expected to be a cleaner alternative fuel to unprocessed crop residues and raw coal in rural China.However,the effectiveness of these dissemination programs is not well evaluated.In this?eld study,emission characteristics of burning straw pellets,raw coal,and unprocessed corn cobs in heating stoves were investigated in a pilot village in Northeast China.Emission measurements covering the whole combustion cycle (ignition,?aming,and smoldering phases) shows th...     

大金山岛常绿阔叶林和落叶阔叶林中小型土壤动物群落特征

于2017年秋季(10月)和冬季(12月)及2018年春季(3月)和夏季(6月)分别对大金山岛8个植物群落中小型土壤动物群落进行调查,共捕获5门14纲23个类群土壤动物8 506只,优势类群分别为线虫纲(66.06%)、蜱螨亚纲(17.95%)和弹尾纲(11.15%),其余为稀有类群(4.84%)。常绿阔叶林中小型土壤动物4季平均密度和类群数均高于落叶阔叶林,且2种林型间类群数差异显著(P0.05),而这2种植被类型夏季中小型土壤动物密度均显著高于其他3季(P0.05);常绿阔叶林秋季中小型土壤动物类群数显著高于春、冬2季(P0.05),而落叶阔叶林表现为秋季显著高于其他3季(P0.05)。在垂直分布上,2种植被类型中小型土壤动物密度均表现出明显的表聚型,其0～5 cm土层密度分别占0～20 cm土层总密度的68.68%和66.94%。常绿阔叶林Shannon-Wiener多样性指数和Margalef丰富度指数均高于落叶阔叶林,且常绿阔叶林秋季这2个指数均显著高于其他3季(P0.05);落叶阔叶林秋季中小型土壤动物Margalef丰富度指数显著高于其他3季(P0.05)。由Pearson相关性分析可知,中小型土壤动物总密度以及线虫纲、蜱螨亚纲和弹尾纲密度均与土壤有机质含量呈正相关,与土壤pH呈负相关。     

Catalytic oxidation of CO over Pt/Fe3O4 catalysts: Tuning O2 activation and CO adsorption

• Strong metal-support interaction exists on Pt/Fe₃O₄ catalysts. • Pt metal particles facilitate the formation of oxygen vacancies on Fe₃O₄. • Fe₃O₄ supports enhance the strength of CO adsorption on Pt metal particles. The self-inhibition behavior due to CO poisoning on Pt metal particles strongly impairs the performance of CO oxidation. It is an effective method to use reducible metal oxides for supporting Pt metal particles to avoid self-inhibition and to improve catalytic performance. In this work, we used in situ reductions of chloroplatinic acid on commercial Fe₃O₄ powder to prepare heterogeneous-structured Pt/Fe₃O₄ catalysts in the solution of ethylene glycol. The heterogeneous Pt/Fe₃O₄ catalysts achieved a better catalytic performance of CO oxidation compared with the Fe₃O₄ powder. The temperatures of 50% and 90% CO conversion were achieved above 260°C and 290°C at Pt/Fe₃O₄, respectively. However, they are accomplished on Fe₃O₄ at temperatures higher than 310°C. XRD, XPS, and H₂-TPR results confirmed that the metallic Pt atoms have a strong synergistic interaction with the Fe₃O₄ supports. TGA results and transient DRIFTS results proved that the Pt metal particles facilitate the release of lattice oxygen and the formation of oxygen vacancies on Fe₃O₄. The combined results of O₂-TPD and DRIFTS indicated that the activation step of oxygen molecules at surface oxygen vacancies could potentially be the rate-determining step of the catalytic CO oxidation at Pt/Fe₃O₄ catalysts. The reaction pathway involves a Pt-assisted Mars-van Krevelen (MvK) mechanism.     

上海市生态资产核算体系研究

自然资源资产是具有商业或交换价值的自然环境要素,是人类生存与发展的基础。生态资产是自然资源资产的重要组成部分,提供各种产品和服务。以生态资产为研究对象,从存量和流量两个方面构建核算体系,并以上海市为案例,探讨了生态资产核算体系的核算方法,评价了上海市2013年的生态资产状况与价值总量。结果显示,存量核算方面,林地的质量等级主要为中,占林地总面积的45.62%;河流的质量等级主要为劣,占总长度的54.65%。2013年生态资产流量总价值量为5 002.76亿元,其中,直接产品价值为866.12亿元,间接服务价值为4 136.64亿元。结果表明,生态资产核算体系体现了生态资产对区域社会经济发展的支撑作用,可以用来定量评估和核算区域的生态资产状况及其变化特征,可以为区域的生态系统管理与绩效考核提供科学依据。     

Transverse approach between real world concentrations of SO2, NO2, BTEX, aldehyde emissions and corrosion in the Grand Mare tunnel

With regard to automotive traffic, a tunnel-type semi enclosed atmosphere is characterized by a higher concentration of gaseous pollutants than on urban traffic roads and highlights the gaseous effluent species having an impact on material degradation. Therefore, a transverse approach between air quality and its consequences upon the longevity of materials is necessary, implying better knowledge of tunnel atmosphere and a better understanding of material degradation inside a tunnel for operating administration. Gaseous pollutant measurements carried out in a road tunnel in Rouen (Normandy) give the real world traffic concentrations of experimental exposure conditions. The sampling campaigns, achieved in summer and winter include SO₂, NO₂, BTEX and aldehyde analyses. Effluent profiles in the upward and downward tubes have been established. The current work shows that SO₂, NO₂, formaldehyde, acetaldehyde, propanal and butanal must be considered in the degradation process of materials in a stuffy environment. As regards NO₂, its concentration depends on the modification of the automotive fleet. The total aldehyde concentrations indicate no particular trend between the two bores. Formaldehyde, acetaldehyde, propanal, butanal and acrolein species are the most abundant species emitted by vehicles and represent 90% to 95% of the total aldehyde emissions.     

Effect of CeO2 and Al2O3 on the activity of Pd/Co_3O_4/cordierite catalyst in the three-way catalysis reactions (CO/NO/CnHm)

The present article studies the effect of CeO₂ and Al₂O₃ on the activity of Pd/Co₃O₄/cordierite catalyst in conversion of NO, CO, C_nH_m. The catalysts were characterized by temperature programmed reduction with hydrogen, X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy. It is shown that the effect of CeO₂ on the properties of Pd/Co₃O₄/cordierite catalyst depends on preparation method. The catalyst obtained by co-deposition of cerium and cobalt oxides has higher activity in CO oxidation (CO + O₂ and CO + NO) and total hexane oxidation (C₆H₁₄ + O₂). Such phenomenon is probably caused by more than stoichiometric amount of formed oxygen vacancies, an increase in both mobility of surface oxygen and dispersity of components in the catalytic composition. It is demonstrated that CeO₂ addition promotes the SO₂ resistance of Pd/Co₃O₄/cordierite. The second support decreases the activity of Pd/Co₃O₄/cordierite catalyst in the reactions of CO and C₆H₁₄ with oxygen because of CoAl₂O₄ formation.     

pH-dependent leaching behaviour and other performance properties of cement-treated mixed contaminated soil

Portland cement has been widely used for stabilisation/solidification (S/S) treatment of contaminated soils. However, there is a dearth of literature on pH-dependent leaching of contaminants from cement-treated soils. This study investigates the leachability of Cu, Pb, Ni, Zn and total petroleum hydrocarbons (TPH) from a mixed contaminated soil. A sandy soil was spiked with 3000 mg/kg each of Cd, Cu, Pb, Ni and Zn, and 10,000 mg/kg of diesel, and treated with ordinary Portland cement (CEM I). Four different binder dosages, 5%, 10%, 15% and 20% (m/m) and different water contents ranging from 13%-19% dry weight were used in order to find a safe operating envelope for the treatment process. The pH-dependent leaching behaviour of the treated soil was monitored over an 84-day period using a 3-point acid neutralisation capacity (ANC) test. The monolithic leaching test was also conducted. Geotechnical properties such as unconfined compressive strength (UCS), hydraulic conductivity and porosity were assessed over time. The treated soils recorded lower leachate concentrations of Ni and Zn compared to the untreated soil at the same pH depending on binder dosage. The binder had problems with Pb stabilisation and TPH leachability was independent of pH and binder dosage. The hydraulic conductivity of the mixes was generally of the order, 10^-8 m/sec, while the porosity ranged from 26%-44%. The results of selected performance properties are compared with regulatory limits and the range of operating variables that lead to acceptable performance described.     

一种高架复合路补充安装声屏障车流条件确定方法

某一地面高架复合公路,通车初期由于车流量很小,相对沿线大型保护目标高架部分暂未安装噪声屏障,但相对原有设计增加了提高护栏、采用较低噪声路面、绿化带等有利于减小噪声影响的措施,现欲确定必须补充安装隔声屏障的车流条件。该后评价计算目标的确定,完全可以通过盲的试算确定,但由此需要的工作量将是极为繁重和庞大的。为了提高效率,本文提出一种半理论半经验的方法予以简化。     

Heavy metal phytoextraction by Sedum alfredii is affected by continual clipping and phosphorus fertilization amendment

Improving the efficacy of phytoextraction is critical for its successful application in metal contaminated soils. Mineral nutrition affects plant growth and metal absorption and subsequently the accumulation of heavy metal through hyper-accumulator plants. This study assessed the effects of di-hydrogen phosphates (KH₂PO₄, Ca(H₂PO₄)₂, NaH₂PO₄ and NH₄H₂PO₄) application at three levels (22, 88 and 352 mg P/kg soil) on Sedum alfredii growth and metal uptake by three consecutive harvests on aged and Zn/Cd combined contaminated paddy soil. The addition of phosphates (P) significantly increased the amount of Zn taken up by S. alfredii due to increased shoot Zn concentration and dry matter yield (DMY) (P<0.05). The highest phytoextraction of Zn and Cd was observed in KH₂PO₄ and NH₄H₂PO₄ treatment at 352 mg P/kg soil. The amount of Zn removed by phytoextraction increased in the order of 1st clipping<2nd clipping<3rd clipping, and for Cd extraction the order was 2nd clipping<1st clipping<3rd clipping. These results indicate that the application of P fertilizers coupled with multiple cuttings can enhance the removal of Zn and Cd from contaminated soils by S. alfredii, thus shortening the time needed for accomplishing remediation goals.