硫酸根自由基高级氧化技术对污染场地多环芳烃的修复效果研究

硫酸根自由基高级氧化技术(sulfate radical(SO₄^·–)based advanced oxidation processes,SR-AOPs)是一种被广泛应用于降解土壤有机污染物的原位氧化修复技术。然而,关于SR-AOPs降解土壤多环芳烃(polycyclic aromatic hydrocarbons,PAHs)的报道相对较少。本研究以南京某炼钢厂附近土壤作为试验样本,通过设置不同比例混合体系的过硫酸钠(Na₂S₂O₈)和亚铁离子(Fe²⁺)以及反应不同时间,探究SR-AOPs对土壤中16种PAHs的修复效果以及最佳技术方案。结果表明:Na₂S₂O₈和Fe²⁺的配比会显著影响土壤PAHs的降解效果,当两者比例达到10︰1时,即Na₂S₂O₈用量为5 mmol/g,Fe²⁺     

“绿色革命”以来大气CO2浓度升高对C3作物营养品质的影响

自20世纪60年代"绿色革命"以来,育种技术和农耕技术的发展促进了农作物产量的大幅提升,然而作物的营养品质出现下降趋势。在相似的遗传背景下,大气CO₂浓度升高会使单位体积农作物产品的营养元素含量下降,因此"绿色革命"至今,农作物产品的营养元素下降可能受大气CO₂浓度升高影响。通过植物生长箱模拟"绿色革命"初期和目前的大气CO₂浓度水平(310μmol/mol和400μmol/mol),针对主要C₃作物水稻、小麦和大豆,研究"绿色革命"以来大气CO₂浓度升高对其籽粒的C、N、Fe、Zn元素含量的影响,结果表明:CO₂浓度升高对3种作物籽粒的C元素含量几乎没有影响,变化幅度在±1.5%之间;籽粒的N、Fe、Zn元素含量普遍呈现下降趋势,但均未达到显著水平。     

湘西植烟土壤有机质和全氮时空变异特征研究

为揭示湖南省湘西州烟区土壤有机质(SOM)和全氮(TN)的时空变异特征和为合理施用有机肥和氮肥提供科学依据,采用经典统计学、地统计学和GIS等方法,对湘西州2000年和2015年植烟土壤SOM和TN时空变异特征进行了研究。结果表明:2015年SOM和TN平均含量较2000年分别增加了5.03g/kg和0.31g/kg,增幅分别达21.39%和21.99%,SOM和TN含量的最小值变小,变异系数、最大值和极差变大,Moran’sI指数标准化Z值下降,块金效应增加;SOM和TN含量"低""适宜"等级面积分别下降了3.42%、37.73%和2.04%、44.43%,"高""极高"等级面积分别增加了32.21%、8.94%和35.67%、10.80%。表明湘西植烟土壤SOM和TN含量和变异同时增加,SOM和TN空间自相关性减弱,随机变异性增强。植烟土壤SOM与TN含量表现出极显著的正线性相关,SOM的矿化释放是TN的一个主要来源。     

Seasonal Variations of Nitrogen Isotopic Ratios of Ammonium and Nitrate in Precipitations Collected in the Yahiko–Kakuda Mountains Area in Niigata Prefecture,Japan

Water, Air, & Soil Pollution - Precipitation was collected from May 15, 2001 to November 18, 2002, at the mountain top (620 m a.s.l.) and mountain foot (47 m a.s.l.) of the...     

Diversification of maize (Zea mays L.) through teosinte (Zea mays subsp. parviglumis Iltis & Doebley) allelic

Genetic Resources and Crop Evolution - Zea mays ssp. parviglumis is the progenitor of maize and assume to have tolerance against various biotic and abiotic stresses. It...     

Biodegradation of High Concentrations of Benzene and Diesel in a Fixed-Film Reactor

Water, Air, & Soil Pollution - The degradation of benzene in groundwater at concentrations as high as 2,000 mg L?1 was studied using a four-column trickling-flow fixed-film...     

Genome size,ploidy levels,and development of novel SSR primer to evaluate genetic diversity of Corylopsis Siebold & Zucc. germplasm collections

Genetic Resources and Crop Evolution - Corylopsis Seibold & Zucc. is a genus of flowering shrubs with few cultivars and little information on genome size, ploidy levels, and genetic...     

Photochemical Degradation of Organic Pollutants in Solutions of Soil Humic Acids

Eurasian Soil Science - Chernozem humic acid (HA) fractions with nominal molecular sizes (MS) >100, 30–100, 5–30 and <5 kDa were obtained, using a combination of...     

A survey of yield differences between transgenic and non-transgenic crops

In the current survey, there was no clear evidence that GM (genetically modified) crops are higher yielding than those conventionally bred<fnoteref rid="fn1">1</fnoteref>. Furthermore, there were no trials to support valid comparisons of yield per se. This article investigates GM crop yields, introducing the importance of hybrid vigour and a non-stress environment for higher percentage heritability selection and therefore more productive conventional plant breeding and improved crops. GM technology and crops are compared with proven plant breeding methods, with respect to hybrid vigour and the economic viability of both systems. These proven methods of plant breeding are (1) traditional landrace cropping, (2) conventional Mendelian breeding and (3) Isolection Mendelian breeding, and are also considered historically.     

Patterns of morpho-phenological and genetic variation of Brachypodium distachyon (L.) P.Beauv. complex in Tunisia

Genetic Resources and Crop Evolution - The genus Brachypodium is generally considered taxonomically difficult because of the high levels of phenotypic variation and frequent...     

Morphology and genetic diversity of Marrubium cuneatum Russell and M. parviflorum Fisch. & C.A. Mey

Genetic Resources and Crop Evolution - Marrubium parviflorum Fisch. & C.A. Mey. and Marrubium cuneatum Russell, are naturally distributed in various parts of Iran. It is difficult to...     

Environmental conditions,and phenolic compounds potential in the leaves of Vitis tiliifolia Humb. & Bonpl. ex Schult.

Genetic Resources and Crop Evolution - The wild vine Vitis tiliifolia (Humb & Bonpl. Ex Schult.). is found in Mexico, Central América, and the Caribbean region. In the Veracruz State,...     

Application of Different Extraction Methods for the Quality Control of Water

The determination of chlorocarbons in drinking wateris described. The chlorocarbons studied include:tetrachloromethane, 1,1,1-trichloroethane, tribromomethane,bromodichloromethane, dibromochloromethane. Three methods ofsample preparation were compared: liquid-liquid extraction(LLE), purge & trap (P&T) and direct aqueous injection (DAI).The samples of drinking water were taken from Toruń (Poland):local sources, municipal water intake, drilled wells. Theobtained data allowed to create the map of chlorocarbonscontamination for Toruń town. Repeatability, linearity anddetection limits of LLE, P&T, DAI were evaluated forhalocarbons under investigation.     

Design and Performance of Pilot-Scale Constructed Wetland Treatment Systems for Treating Oilfield Produced Water from Sub-Saharan Africa

Pilot-scale constructed wetland treatment systems (CWTSs) were designed and built to decrease concentrations of constituents of concern in water simulated to match characteristics of water produced from specific oilfields in sub-Saharan Africa. The oilfield produced water has low ionic strength (704?C1,370?mg?L^?1 total dissolved solids) and contains Fe, Mn, Ni, Zn, and oil and grease (O&G). To treat these constituents, biogeochemical pathways were targeted in the design of two subsurface flow (SSF) CWTS series planted with Phragmites australis and a free-water surface (FWS) series planted with Typha latifolia. These systems were designed for prevailing conditions at the sub-Saharan site studied. Concentrations of O&G, Fe, Mn, Ni, and Zn in outflow from the SSF series met use criteria for irrigation and livestock watering. For the FWS series, outflow concentrations of O&G, Fe, and Mn met use criteria for irrigation and livestock watering, and Ni concentrations met use criteria for livestock watering. Both SSF and FWS series were effective in reducing concentrations of O&G in the produced water investigated with >98% efficiency. The high-removal efficiency is attributed to achieving aerobic conditions in the wetland cells. Both SSF and FWS series reduced concentrations of Fe and Mn but with a wider range of efficiency compared with O&G removal. The removal of Ni and Zn could be increased by the addition of organic matter, such as plant detritus, to wetland cells to promote reducing conditions and dissimilatory sulfate reduction.     

Clay mineral source tracing and characterisation of Burdekin River (NE Australia) and flood plume fine sediment

Journal of Soils and Sediments - The purpose of this study is to define the relative contributions of fine (<10 μm) suspended sediment from tributaries within the Burdekin...     

Genetic diversity and population structure in a regional collection of Kersting’s groundnut (Macrotyloma geocarpum (Harms) Maréchal & Baudet)

Genetic Resources and Crop Evolution - Kersting’s groundnut (Macrotyloma geocarpum (Harms) Maréchal & Baudet) is an important source of protein and essential nutrients that...     

Regional Diversity of Mineralogical Composition of Solonetzes in Russia

Eurasian Soil Science - The quantitative and qualitative diversity of the clay fraction (<1 µm) from parent materials (BC and C horizons), albic (suprasolonetzic eluvial SEL)...     

Stability of desiccated rhizosphere soil aggregates of mycorrhizal Juniperus oxycedrus grown in a desertified soil amended with a composted organic residue

Adequate soil structural stability favours the establishment and viability of a stable plant cover, protecting the soil against water erosion in desertified Mediterranean environments. We studied the effect of soil drying-rewetting, inoculation with a mixture of three exotic arbuscular mycorrhizal (AM) fungi (Glomus intraradices Schenck & Smith, Glomus deserticola (Trappe, Bloss. & Menge) and Glomus mosseae (Nicol & Gerd.) Gerd. & Trappe) and addition of a composted organic residue on aggregate stabilisation of the rhizosphere soil of Juniperus oxycedrus. The AM fungi and composted residue produced similar increases in plant growth, independently of the water conditions. Under well-watered conditions, the highest percentages of stable aggregates were recorded in the amended soil, followed by the soil inoculated with AM fungi. Excepting microbial biomass C, the soil drying increased labile C fractions (water soluble C, water soluble and total carbohydrates), whereas the rewetting decreased significantly such C fractions. Desiccation caused a significant increase in aggregate stability of the rhizosphere soil of all plants, particularly in the amended and inoculated plants. In all treatments, the aggregates formed after soil drying were unstable, since, in the rewetting, they disappear, reaching the initial levels before soil drying. Our results suggest that the aggregation mechanisms developed by rhizosphere microbial community of the amended and inoculated plants under water stress can be particularly relevant in desertified soils exposed to long desiccation periods.     

Can Vegetal Biopolymers Work as Coagulant–Flocculant Aids in the Treatment of High-Load Cosmetic Industrial Wastewaters?

The aim of this work was to evaluate the role of three biopolymers used as coagulant?Cflocculant aids in the treatment of a high-load cosmetic industry wastewater (WW) located in Mexico. Discussion is based on a surface response methodology. When using guar, locust bean gum, and Opuntia mucilage, conductivity and turbidity removals as high as 20.1 and 67.8?% were found, respectively. Chemical oxygen demand (COD) removals as high as 38.6?% were observed. The maximum removal efficiency was found for mucilage, with 21.1?mg?COD/mg polymer. At the end of the process, pH was in the range of 5.8?C7.3 for an initial wastewater pH value of 5.6. The production of sludge was very dependent on the WW organic load. An analysis of some metal content in the sludges is presented. From the response surface analysis, it was observed that the parameter which strongly affected the removal of COD, turbidity, oil and greases (O&G), and the amount of sludge including their metal contents was the polymer dose. Only in the case of O&G removal was a combination of dose?Cwastewater organic load responsible for the removals. The values of R ² for the correlation process were between 0.5451 (O&G) and 0.7989 (COD). The p values for the different expressions were between 0.1985 (COD) and 0.7195 (O&G). The values of adequate precisior (AP) indicate how feasible it is to use the surface response analysis (AP?>?4). Most of the analysis indicated that AP?>?4, except in the case of the O&G removal analysis where AP?=?2.9.     

Examining the Effects of the Destroying Ammunition,Mines and Explosive Devices on the Presence of Heavy Metals in Soil of Open Detonation Pit; Part 2: Determination of Heavy Metal Fractions

As a result of the destruction of ammunition, mines, and explosive devices by the method of open detonation, the increased concentration of heavy metals is often recorded in the soil of military polygons, which is a serious ecological problem. However, in order to determine the potential risk of such locations to the environment, it is necessary to determine, in addition to the total content, the forms in which the metals are present. In this paper, a sequential extraction method was used to analyze the six fractions of five heavy metals (cadmium, lead, nickel, copper, and zinc) in the soil of the polygon for destruction of ammunition, mines, and explosive devices. Samples were collected from the place of direct detonation (so-called pits) and from the edge of the pit. The aim of this research is determination of metal speciation in order to obtain a better insight in their mobility and risk arising from this. The results showed that heavy metals are predominantly present in the residual, oxide, and organic fractions. Cd and Cu were also significantly present in the mobile fractions due to conducted activities on the polygon. To assess the potential environmental risk of soil, the risk assessment code (RAC) and individual (ICF) and global (GCF) contamination factors were used. According to the RAC, the mobility and bioavailability of the analyzed heavy metals decreases in the following order: Cd?>?Cu?>?Zn?>?Pb?>?Ni. ICF results show low to moderate risk, while GCF results show low risk in terms of heavy metal contamination in the examined area.