灾害观测

本文应用系统科学和信息科学讨论了灾害系统的能达性、能控性与能观性。根根系统能观性原理及量测科学的基本原则,讨论了灾害观测系统应注意的一些问题。     

Effects of relative humidity and PM2.5 chemical compositions on visibility impairment in Chengdu, China

To better understand the potential causes of visibility impairment in autumn and winter in Chengdu, relative humidity(RH), visibility, the concentrations of PM_(2.5) and its chemical components were on-line measured continuously in Chengdu from Nov. 2016 to Jan. 2017.Six obvious haze episodes occurred in Chengdu, with the total time of haze episodes accounted for more than 90% of the total observation period, and higher NO_2 concentrations and RH were related to the high particle concentrations in haze episodes. The visibility decreased in a non-linear tendency under different RH conditions with the increase of PM_(2.5) concentrations, which was more sensitive to RH under lower PM_(2.5) concentrations. The threshold concentration of PM_(2.5) got more smaller with the increase of RH. During the entire observation period, organic matter(OM) was the largest contributor(31.12% to extinction coefficient(bext)), followed by NH_4NO_3 and(NH_4)_2SO_4 with 28.03% and 23.01%, respectively.However, with the visibility impairment from Type I(visibility 10 km) to Type IV(visibility ≤ 2 km), the contribution of OM to bextdecreased from 38.12% to 26.77%, while the contribution of NH_4NO_3 and(NH_4)_2SO_4 to bextincreased from 19.09% and 20.20% to 34.29% and 24.35%, respectively, and NH_4NO_3 became the largest contributor to bextat Type IV. The results showed that OM and NH_4NO_3 were the key components of PM_(2.5) for visibility impairment in Chengdu, indicating that the control of precursors emissions of carbonaceous species and NH_4NO_3 could effectively improve the visibility in Chengdu.     

改性污泥基生物炭的性质与重金属吸附效果

为提高污泥基生物炭在高钙溶液体系中对重金属阳离子的吸附能力,将Fe₂O₃、MnO₂、ZnO与市政污泥以质量比1 ∶10（以过渡金属元素质量计）混合共热解,制备改性生物炭;表征改性生物炭的组成、官能团分布和表面性质,考察其对典型重金属阳离子Cd²⁺的吸附效果.过渡金属氧化物可促进污泥的热解,改性生物炭的H/C原子比均低于0.31,碳链裂解脱氢更彻底.改性生物炭中Fe、Mn保留较好,分别主要以单质和氧化物形态存在;而Zn流失较多.改性生物炭中的孔隙以介孔为主,平均孔径约3.8 nm,比表面积在50 m²·g^-1以上.初始浓度约200 mg·L^-1的Cd²⁺溶液中,Ca²⁺初始浓度从0 mg·L^-1升高到约200 mg·L^-1,Fe改性生物炭对Cd²⁺的吸附容量从43.17 mg·g^-1降至27.88 mg·g^-1,但仍较未改性生物炭高10 mg·g^-1以上,在含钙溶液体系中表现出了对Cd²⁺更强的吸附性能.Fe₂O₃较MnO₂和ZnO对市政污泥基生物炭吸附重金属的强化效果更好.     

In situ preparation of g-C3N4/polyaniline hybrid composites with enhanced visible-light photocatalytic performance

The graphic carbon nitride/polyaniline (g-C₃N₄/PANI) hybrid composites were successfully synthesized by a facile in situ polymerization process under ice water bath. The photocatalytic activities of the g-C₃N₄/PANI composites were evaluated by using oxytetracycline (OTC) as model pollutants. The optimal g-C₃N₄/PANI composite (5%PANI: the g-C₃N₄/PANI hybrid with 5 wt.% of PANI) showed an enhancement degradation rate of 5-fold compared to that of conventional g-C₃N₄ under simulated-sunlight irradiation. In addition, the 5%PANI demonstrate significantly photocatalytic evolution H₂ rate (163.2 μmol/(g?hr)) under the visible light irradiation. Furthermore, based on the results of optical performance and electrochemical testing, a possible mechanism was proposed, indicating that the incorporation of PANI into the traditional g-C₃N₄ can effectively tune the electronic structures, improve the photo-generated electrons-holes separation and enhance extensive absorption of visible light. Such a g-C₃N₄/PANI hybrid nanocomposites could be envisaged to possess great potentials in practical wastewater treatment and water splitting.     

Restoration processes of pollution zones in Hanjiang River

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国家级公益林生态效益价值核算

对国家级公益林生态效益的研究是当前制定森林生态补偿政策方面的一个研究热点。构建了国家级公益林生态效益的评估体系,并运用市场价值法、影子价格法等多种方法对国家级公益林的生态效益进行了实物量与价值量评估。结果表明,国家级公益林面积为9.38×1011m2,其生态服务功能的实物量总计为29566.69亿t,提供的生态效益总价值为261179.86亿元,单位面积价值为27.85元/(m2.a)。国家级公益林的生态效益巨大,平衡兼顾其生态效益有助于促进生态保护的协调。     

Comparison between urban Toronto PM and selected materials: aerosol characterization using laser ablation/ionization mass spectrometry (LAMS)

Laser ablation/ionization mass spectrometry (LAMS) of particulate matter (PM) was undertaken on-line in order to extend and contrast PM characterization. Qualitative on-line LAMS results for certified materials and Toronto source materials demonstrated the versatility and limitations of the technique. The observation of organic and inorganic components of certified materials verified the proper working condition of the in-house on-line LAMS. Organic and inorganic components of Toronto source materials were also observed with the on-line LAMS. Common components identified from both types of materials were Na, Al, Ca, Fe, and K. Other recognized components were compared with marker elements reported for some common PM emission sources. An in-house off-line LAMS was used to analyze urban Toronto PM deposited on glass substrates, while the on-line LAMS analyzed individual urban Toronto PM particles that were introduced directly into the instrument. Scanning electron microscopy (SEM), X-ray spectrometry and inductively coupled plasma atomic emission spectrometry (ICP-AES) were used for confirmatory purposes. Organic and inorganic components of urban Toronto PM at their typical ng/m3 concentrations were successfully observed in mass spectra using both off-line LAMS and on-line LAMS. Identified ions unique to each analyzed material were compared to identified ions of urban Toronto PM. The ability of LAMS to analyze individual respirable PM particles (viz. < 2 microns), both for inorganic trace elements and for organic components, greatly extended our capability to characterize PM and also to achieve estimates of concentration contributions of each material.     

Accumulation of perchlorate in aquatic and terrestrial plants at a field scale

Previous laboratory-scale studies have documented perchlorate ClO(-)(4) uptake by different plant species, but less information is available at field scale, where ClO(-)(4) uptake may be affected by environmental conditions, such as distance to streams or shallow water tables, exposure duration, and species. This study examined uptake of ClO(-)(4) in smartweed (Polygonum spp.) and watercress (Nasturtium spp.) as well as more than forty trees, including ash (Fraxinus greggii A. Gray), chinaberry (Melia azedarach L.), elm (Ulmus parvifolia Jacq.), willow (Salix nigra Marshall), mulberry [Broussonetia papyrifera (L.) Vent.], and hackberry (Celtis laevigata Willd.) from multiple streams surrounding a perchlorate-contaminated site. Results indicate a large potential for ClO(-)(4) accumulation in aquatic and terrestrial plants, with ClO(-)(4) concentration in plant tissues approximately 100 times higher than that in bulk water. Perchlorate accumulation in leaves of terrestrial plants was also dependent on species, with hackberry, willow, and elm having a strong potential to accumulate ClO(-)(4). Generally, trees located closer to the stream had a higher ClO(-)(4) accumulation than trees located farther away from the stream. Seasonal leaf sampling of terrestrial plants indicated that ClO(-)(4) accumulation also was affected by exposure duration, with highest accumulation observed in the late growing cycle, although leaf concentrations for a given tree were highly variable. Perchlorate may be re-released into the environment via leaching and rainfall as indicated by lower perchlorate concentrations in collected leaf litter. Information obtained from this study will be helpful to understand the fate of ClO(-)(4) in macrophytes and natural systems.     

Allozyme polymorphisms and heavy metal levels in the green-lipped mussel Perna viridis (Linnaeus) collected from contaminated and uncontaminated sites in Malaysia

It has been widely reported that heavy metal contamination in coastal waters can modify the allozyme profiles of marine organisms. Previous studies have recorded elevated metal concentrations in sediments and mussel tissues off Peninsular Malaysia. In the present study, horizontal starch gel electrophoresis was carried out to estimate the levels of allelic variation of the green-lipped mussel, Perna viridis, collected from one contaminated and three relatively uncontaminated sites off Peninsular Malaysia. Fourteen polymorphic loci were observed. In addition, the concentrations of cadmium, copper, lead, mercury and zinc were determined in the sediments and in the soft tissues of the mussels. Mussels from contaminated site, evidenced by high metal pollution indices (MPI) of the sediment and the mussel tissues, showed the highest percentage of polymorphic loci (78.6%), while those collected from the uncontaminated sites had lower MPI of the sediment and mussel tissue, and exhibited lower percentages of polymorphic loci (35.7-57.1%). The population from the contaminated site showed the highest excess of heterozygosity (0.289) when compared to that of the populations from the three uncontaminated sites (0.108-0.149). Allozyme frequencies at the phosphoglucomutase (PGM; E.C. 2.7.5.1) locus also differed between the contaminated and uncontaminated populations. Previous studies have shown that exposure to heavy metals can select or counter-select for particular alleles at this locus. The present results suggest that allozyme polymorphism in P. viridis is a potential biomonitoring tool for heavy metal contamination but further validation is required.     

建设生态文明的重要举措——《让不堪重负的江河休养生息》述评

让江河湖泊休养生息，就是要实行最为严格的污染物排放总量控制制度，以水环境容量确定发展方式和发展规模；就是要尊重自然规律，充分发挥水生态系统的自我修复能力，逐步改变环境恶化状况；就是要综合运用工程的、技术的、生态的方法，加大治理水环境的力度，促进水生态系统尽快步入良性循环的轨道；就是要充分运用法律、经济和必要的行政手段，既要形成严格排放、合理开发的强大压力，又要形成主动治理水环境的积极动力，用高效的办法解决长期积累的环境问题。