基于土壤酶活性变化的铅污染土壤修复基准

近年来,污染土壤修复技术发展很快,而污染土壤修复标准的建立则相对迟缓。为了推进我国该领域的工作,对铅胁迫下土壤酶活性（如过氧化氢酶,磷酸酶,脲酶）随时间的变化进行了研究,以确定棕壤土中铅的土壤修复基准。结果表明：土壤中的铅能够刺激土壤中过氧化氢酶活性的增加,但随着土壤铅浓度的增加,这种刺激作用逐渐减小。土壤过氧化氢酶活性不宜作为铅污染土壤的生物标记物。土壤磷酸酶活性没有一致的变化规律,土壤磷酸酶活性不能作为铅污染土壤的生物标记物。在整个实验时间范围内,土壤脲酶活性与土壤中铅的浓度具有明显的剂量-效应关系（P〈0.01）,土壤脲酶活性可以作为铅污染土壤生物标记物。以土壤脲酶抑制率降低25%为依据,确定棕壤中铅的土壤修复基准为94mg·kg-1,以土壤脲酶抑制率降低45%为依据,确定棕壤中铅的土壤修复基准为178mg·kg-1。     

Diurnal vertical migration of Cochlodinium polykrikoides during the red tide in Korean coastal sea waters

The diurnal vertical migration of Cochlodinium polykrikoides (C. polykrikoides), which caused a red tide in the Korean coastal waters of the East Sea/Sea of Japan in September 2003, was examined by determining the time-dependent changes in the density of living cells in relation to the depth of the water column. The ascent of this species into the surface layer (depth of water 2 m) occurred during 1400-1500. The descent started at 1600 and a high distribution rate (86%) at 15-20 m was observed at 0300. During the ascent, the cells were widely distributed at each depth level from 0600 hr and at 0800-1100, the cells were primarily distributed in the middle layer (0-6 m). The concentration of dissolved inorganic nitrogen was generally < or = 2.86 micromol l(-1), but at 1400-1500, the concentration in the surface layer reduced to < or = 0.14 micromol l(-1). Moreover, the concentration gradually increased as the depth increased to > or = 5 m. These results showed that the nutrient-consumption rate associated with the proliferation of C. polykrikoides during a red tide is more influenced by the inorganic-nitrogen resources ratherthan the inorganic-phosphorus compounds.     

Rainfall-human-spatial interactions in a salinity-prone agricultural region of the Western Australian wheat-belt

To explore the complexity of temporal and spatial dynamics of an agricultural landscape under various external and internal driven scenarios, SimKat, an agent-based model, has been developed with the simulation computer program CORMAS. This model combines simplified bio-physical processes of land cover, regional dry-land salinity changes, rainfall impact on productivity, farm profitability and the complexity of land-use decisions of individual farmers in a dry-land agricultural catchment (no irrigation). In this model, simulated farmers formulate individual decisions dealing with land-use changes based on the combined performance of their past land cover productivity and market returns. The willingness to adapt to market drivers and the ability to maximize returns vary between farmers. In addition, farmers in the model can demonstrate various attitudes towards dry-land salinity mitigation as a consequence of experiencing and perceiving salinity on their farm, in the neighborhood or across the entire region. Consequently, farmers can adopt land cover strategies aimed at reducing dry-land salinity. Aggregating the simulated individual behavior of farmers combined with historical rainfall and market price records, reproduced similar aggregated trends of land-cover changes, regional salinity change and farm number decline as observed in the last 20 years in the subject region (Katanning, Western Australia). Using the model in an initial exploratory study on the impact of rainfall variability and change highlighted the importance of average rainfall decline and the widespread willingness of farmers to adapt perennial vegetation in their farming systems to combat regional dry-land salinity. Rainfall decline, as one of the observed consequences of climate change in this region, can also lead to prolonged sequences of dry seasons in the future. Adaptation by farmers to sequences of dry and wet seasons, rather than an average trend in rainfall, seems to be critical for farm survival in this region. Intensifying cropping during wet seasons to maximize farm returns can increase vulnerability in subsequent periods of dry seasons, in particular where alternative income from pasture and sheep production has been lost in the adaptation process.     

钢管再生混凝土框架抗震破坏机制与性能水准研究

为了研究钢管再生混凝土框架的抗震破坏机制与性能水准,以100%为再生粗骨料取代率,进行了两榀圆、方钢管再生混凝土柱-钢筋再生混凝土梁框架试件的拟静力试验。实测试件的破坏特征与机制、荷载—位移滞回曲线和荷载—应变滞回曲线等,探讨钢管再生混凝土框架试件基于性能设计的性能水准的确立准则。结果表明:试件呈现出"强柱弱梁、强剪弱弯、强节点,弱构件"的抗震破坏机制。荷载—位移滞回曲线基本对称,呈现出比较饱满的梭形。试件破坏时,柱顶钢管纵向应变均小于屈服应变,柱底钢管纵向应变达到了0.01左右,试件变形能力良好。试件KJ-1和KJ-2梁端的纵向钢筋应变均超过了屈服应变,仅试件KJ-1箍筋应变达到了屈服应变。荷载—钢管横向应变滞回曲线沿着受拉应变轴呈螺旋式发展。基于钢管再生混凝土结构性能设计,划分五档性能水准,确立了水平位移角和损伤指标限值。     

Air concentrations of polybrominated diphenyl ethers (PBDEs) in 2002–2004 at a rural site in the Great Lakes

Atmospheric PBDEs were measured on a monthly basis in 2002–2004 at Point Petre, a rural site in the Great Lakes. Average air concentrations were 7.0 ± 13 pg m^?3 for Σ₁₄BDE (excluding BDE-209), and 1.8 ± 1.5 pg m^?3 for BDE-209. Concentrations of 3 dominant congeners (i.e., BDE-47, 99, and 209) were comparable to previous measurements at remote/rural sites around the Great Lakes, but much lower than those at urban areas. Weak temperature dependence and strong linear correlations between relatively volatile congeners suggest importance of advective inputs of gaseous species. The significant correlation between BDE-209 and 183 implies their transport inputs associated with particles. Particle-bound percentages were found greater for highly brominated congeners than less brominated ones. These percentages increase with decreasing ambient temperatures. The observed gas/particle partitioning is consistent with laboratory measurements and fits well to the Junge–Pankow model. Using air mass back-trajectories, atmospheric transport to Point Petre was estimated as 76% for BDE-47, 67% for BDE-99, and 70% for BDE-209 from west–northwest and southwest directions. During the same time period, similar congener profiles and concentration levels were found at Alert in the Canadian High Arctic. Different inter-annual variations between Point Petre and Alert indicate that emissions from other regions than North America could also contribute PBDEs in the Arctic. In contrast to weak temperature effect at Point Petre, significant temperature dependence in the summertime implies volatilization emissions of PBDEs at Alert. Meanwhile, episodic observations in the wintertime were likely associated with enhanced inputs through long-range transport during the Arctic Haze period.     

Porous carbon derived from waste corrugated paper board using different activators

Journal of Material Cycles and Waste Management - Porous carbon with a large specific surface area (maximum was 1600 m2/g) was successfully prepared from waste corrugated paper board. The plant...     

双酚类化合物污染现状和内分泌干扰效应研究进展

双酚类化合物(bisphenols, BPs)是合成碳酸聚酯、环氧树脂和聚丙烯酸酯等高分子聚合物的主要原料,在商业制造中广泛使用。经过度排放污染环境,并能通过食物链放大作用在动物和人体内蓄积。已经在水体、底泥、室内灰尘、食品以及动物和人体内检测到双酚A(bisphenol A, BPA)及其替代品或衍生物等多种BPs。BPs对性激素、甲状腺素和神经内分泌系统具有干扰效应,能影响机体生殖功能、性腺发育、神经行为和激素依赖性疾病的发展,已经成为危害人体健康的风险因子。多种BPA替代品的内分泌干扰效应甚至比BPA更强,但缺乏全面的内分泌干扰效应评估数据和对作用机制的深入研究。本文对BPs种类来源、污染现状及其内分泌干扰效应进行综述。     

Methods to control harmful algal blooms: a review

Environmental Chemistry Letters - The recent rise of red tide harmful algal blooms has induced ecosystem degradation, economic losses, and aquaculture damage, yet little is known on prevention and...     

High-performance Si-Containing anode materials in lithium-ion batteries:A superstructure of Si@Co–NC composite works effectively

To mitigate the massive volume expansion of Si-based anode during the charge/discharge cycles, we synthesized a superstructure of Si@Co–NC composite via the carbonization of zeolite imidazolate frameworks incorporated with Si nanoparticles. The Si@Co–NC is comprised of Si-nanoparticle core and N-doped/Co-incorporated carbon shell, and there is void space between the core and the shell. When using as anode material for LIBs, Si@Co–NC displayed a super performance with a charge/discharge capacity of 191.6/191.4 mA h g-1 and a coulombic efficiency of 100.1％ at 1000 mA g-1 after 3000 cycles, and the capacity loss rate is 0.022％ per cycle only. The excellent electrochemical property of Si@Co–NC is because its electronic conductivity is enhanced by doping the carbon shell with N atoms and by incorporating with Co particles, and the pathway of lithium ions transmission is shortened by the hollow structure and abundant mesopores in the carbon shell. Also, the volume expansion of Si nanoparticles is well accommodated in the void space and suppressed by the carbon host matrix. This work shows that, through designing a superstructure for the anode materials, we can synergistically reduce the work function and introduce the confinement effect, thus significantly enhancing the anode materials' electrochemical performance in LIBs.     

Respiratory exposure to PM2.5 soluble extract induced chronic lung injury by disturbing the phagocytosis function of macrophage

Environmental Science and Pollution Research - Exposure to airborne urban particles is a contributing factor for the development of multiple types of respiratory diseases; its pathological role as...