Effect of ambient-level gas-phase peroxides on foliar injury, growth, and net photosynthesis in Japanese radish (Raphanus sativus)

To investigate the effects of ambient-level gas-phase peroxides concurrent with O₃ on foliar injury, photosynthesis, and biomass in herbaceous plants, we exposed Japanese radish (Raphanus sativus) to clean air, 50 ppb O₃, 100 ppb O₃, and 2-3 ppb peroxides + 50 ppb O₃ in outdoor chambers. Compared with exposure to 100 ppb O₃, exposure to 2-3 ppb peroxides + 50 ppb O₃ induced greater damage in foliar injury, net photosynthetic rates and biomass; the pattern of foliar injury and the cause of net photosynthetic rate reduction also differed from those occurring with O₃ exposure alone. These results indicate for the first time that sub-ppb peroxides + 50 ppb O₃ can cause more severe damage to plants than 100 ppb O₃, and that not only O₃, but also peroxides, could be contributing to the herbaceous plant damage and forest decline observed in Japan's air-polluted urban and remote mountains areas.     

Comparative study on the characteristics of fly ash and bottom ash geopolymers

This research was conducted to compare geopolymers made from fly ash and ground bottom ash. Sodium hydroxide (NaOH) and sodium silicate (Na(2)SiO(3)) solutions were used as activators. A mass ratio of 1.5 Na(2)SiO(3)/NaOH and three concentrations of NaOH (5, 10, and 15M) were used; the geopolymers were cured at 65 degrees C for 48 h. A Fourier transform infrared spectrometer (FT-IR), differential scanning calorimeter (DSC), and scanning electron microscope (SEM) were used on the geopolymer pastes. Geopolymer mortars were also prepared in order to investigate compressive strength. The results show that both fly ash and bottom ash can be utilized as source materials for the production of geopolymers. The properties of the geopolymers are dependent on source materials and the NaOH concentration. Fly ash is more reactive and produces a higher degree of geopolymerization in comparison with bottom ash. The moderate NaOH concentration of 10 M is found to be suitable and gives fly ash and bottom ash geopolymer mortars with compressive strengths of 35 and 18 MPa.     

Iron improving bio-char derived from microalgae on removal of tetracycline from aqueous system

Novel magnetic carbonaceous bio-char was hydrothermal prepared from microalgae under different loadings of iron and its structures and surface chemistry were characterized with Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and nitrogen adsorption-desorption isotherm (BET). The morphology of bio-char changed from sheet to particle as iron loading increased and its surface area also increased. When 3.0 g of dried microalgae and 6.0 mmol iron salt ((NH₄)₂SO₄·FeSO₄·6H₂O) were mixed and treated, the obtained bio-char possessing the highest amount of oxygen-containing functional groups resulted in the best adsorption performance on tetracycline (TC). This adsorption process was fitted to Langmuir adsorption isotherm and the maximum adsorption capacity was 95.86 mg/g, which is higher than other bio-char reported. The iron loading contributed to the higher adsorption capacity of bio-char, which may be due to three factors, the high surface area, more hydrogen bonding, and bridging effects of the structural Fe for TC. Our data suggest that bio-char may have more important role in stabilization of pollutants in the environment.     

Physicochemical and biological quality of soil in hexavalent chromium-contaminated soils as affected by chemical and microbial remediation

Chemical and microbial methods are the main remediation technologies for chromium-contaminated soil. These technologies have progressed rapidly in recent years; however, there is still a lack of methods for evaluating the chemical and biological quality of soil after different remediation technologies have been applied. In this paper, microbial remediation with indigenous bacteria and chemical remediation with ferrous sulphate were used for the remediation of soils contaminated with Cr(VI) at two levels (80 and 1,276 mg kg^?1) through a column leaching experiment. After microbial remediation with indigenous bacteria, the average concentration of water-soluble Cr(VI) in the soils was reduced to less than 5.0 mg kg^?1. Soil quality was evaluated based on 11 soil properties and the fuzzy comprehensive assessment method, including fuzzy mathematics and correlative analysis. The chemical fertility quality index was improved by one grade using microbial remediation with indigenous bacteria, and the biological fertility quality index increased by at least a factor of 6. Chemical remediation with ferrous sulphate, however, resulted in lower levels of available phosphorus, dehydrogenase, catalase and polyphenol oxidase. The result showed that microbial remediation with indigenous bacteria was more effective for remedying Cr(VI)-contaminated soils with high pH value than chemical remediation with ferrous sulphate. In addition, the fuzzy comprehensive evaluation method was proven to be a useful tool for monitoring the quality change in chromium-contaminated soils.     

活性污泥的耐盐驯化培养

以某污水处理厂二沉池好氧污泥为接种污泥,采用逐步提高盐度和稳定盐度2种方法对活性污泥进行耐盐性驯化培养,考察驯化结果表明,前一种方法更有利于耐盐菌的培养。对比不同盐度情况下各项指标的去除效果得出:本实验污泥适宜盐度为1%。使用稳定进水盐度的方法,出水指标及各指标的去除率均低于逐步提高盐度法,且镜检结果表明大量微生物死亡。     

Influence of root-exudates concentration on pyrene degradation and soil microbial characteristics in pyrene contaminated soil

The effect of ryegrass (Lolium perenne L.) root-exudates concentration on pyrene degradation and the microbial ecological characteristics in the pyrene contaminated soil was investigated by simulating a gradually reducing concentration of root exudates with the distance away from root surface in the rhizosphere. Results showed that, after the root-exudates were added 15 d, the pyrene residue in contaminated soil responded nonlinearly in the soils with the same pyrene contaminated level as the added root-exudates concentration increased, which decreased first and increased latter with the increase of the added root-exudates concentration. The lowest pyrene concentration appeared when the root exudates concentration of 32.75 mg kg(-1) total organic carbon (TOC) was added. At the same time, changes of microbial biomass carbon (MBC, C(mic)) and microbial quotient (C(mic)/C(org)) were opposite to the trend of pyrene degradation as the added root-exudates concentration increased. Phospholipid fatty acid (PLFA) analysis revealed that bacteria was the dominating microbial community in pyrene contaminated soil, and the changing trends of pyrene degradation and bacteria number were the same. The changing trend of endoenzyme-dehydrogenase activity was in accordance with that of soil microbe, indicating which could reflect the quantitative characteristic of detoxification to pyrene by soil microbe. The changes in the soils microbial community and corresponding microbial biochemistry characteristics were the ecological mechanism influencing pyrene degradation with increasing concentration of the added root-exudates in the pyrene contaminated soil.     

Quantitative evaluation of environmental risks of flotation tailings from hydrothermal sulfidation–flotation process

Floatation tailings (FT) are the main by-products of the hydrothermal sulfidation–flotation process. FT (FT₁ and FT₂) were obtained by treating two different neutralization sludges (NS) (NS₁ and NS₂). This paper quantitatively evaluated the environmental risks of heavy metals (Zn, Cd, Cu, Pb, and As) in FT versus NS. The total concentration and leaching rates (R ₂) of heavy metals in FT were much lower than those in NS, demonstrating that the hydrothermal sulfidation–flotation process was able to effectively suppress the mobility and leachability of heavy metals. The BCR-three sequence leaching procedure of FT confirmed that all metals were transformed into more stable forms (residue and oxidizable forms) than were found that in NS. The potential ecological risk index indicated that the overall risks caused by heavy metals decreased significantly from 6627.59 and 7229.67 (very serious risk) in NS₁ and NS₂, respectively, to 80.26 and 76.27 (low risk) in FT₁ and FT₂, respectively. According to the risk assessment code, none of the heavy metals in FT posed significant risk to the natural environment except Zn (with low risk). In general, the risk of heavy metals in FT had been well controlled.     

贵州省自然灾害区域分异规律及分析方法研究

贵州省自然灾害严重，且种类多，区域差异明显。为了分析自然灾害区域分异规律，本文提出了灾害模数、灾害区域差异系数等概念，编制了贵州省灾害等级图。     

高层建筑火灾人员疏散和人员伤亡的模拟

基于建筑火灾全风网网络模型的基础上 ,结合紧急疏散模型 ,模拟火灾时期疏散时间和建筑物内人员滞留的情况 ,同时也可以模拟可能出现的伤亡情况 ,有助于高层建筑的疏散系统设计 ,为火灾的再现提供了一个有效的分析工具 ,也为高层建筑火灾的风险评价提供了理论数据     

基于WebGIS构建突发公共卫生事件应急指挥系统——以成都市为例

分析了成都市突发公共卫生事件应急指挥信息系统的需求，阐述了如何基于数字城市空间信息基础设施，利用网络地理信息系统技术（WebGIS）来整合数字城市信息化资源以及公共卫生专题资源，建设城市突发公共卫生事件应急指挥系统的总体设计和技术实现。