有效微生物菌与水生植物联合净化珍珠蚌养殖废水

以无有效微生物(EM)菌与水生植物的珍珠蚌养殖水体(NSE)作为对照组,对EM菌(EM)、苦草+菹草(VP)、水芹菜+水葱(OS)、苦草+菹草+EM菌(VPE)以及水芹菜+水葱+EM菌(OSE)净化珍珠蚌养殖废水的效果进行了对比研究。实验结果表明,EM、VP、OS对珍珠蚌养殖水体N、P均有较好的净化效果,VPE与OSE去N、P效果更佳。净化28 d后5组合中VPE对NH4+-N的去除效果最好,去除率达98.79%;OSE对NO2-N与TN的去除效果最佳,去除率分别达88.09%和91.53%;TP的去除率VPE最高,达91.75%;而COD的去除率以VP最高,达94.97%,效果好于VPE与OSE;EM池水体DO质量浓度第8天达到峰值(9.88±0.61)mg/L,VP、OS、VPE与OSE均在第16天左右达到峰值。实验数据还表明,EM净化水体效果与VP、OS、VPE和OSE均存在显著性差异,对照组NSE对水体的净化效果不明显。     

天然及CaCl2改性沸石对四环素的吸附

通过静态吸附实验研究了水中四环素在天然和CaCl2改性沸石上的吸附行为及机制。实验表明,天然沸石对四环素具有吸附能力,CaCl2改性可以提高沸石对四环素的吸附能力。天然和改性沸石对四环素的吸附符合拟二级动力学模型,颗粒内扩散不是吸附过程的主要控制步骤。Freundlich和Dubinin-Radushkevich(D-R)等温吸附模型可以较好地描述实验所用2种沸石对四环素的吸附行为,D-R等温方程拟合结果显示吸附过程包含离子交换作用。通过对天然和改性沸石吸附四环素前后溶液中主要阳离子浓度变化分析证实了该吸附过程包含离子交换作用。实验研究了pH值变化对沸石吸附四环素的影响,当pH=3～5时,天然和改性沸石对四环素的吸附量均随pH值的增加而急剧下降,而pH=5～10时,天然和改性沸石对四环素的吸附量变化均不明显,推测可能是离子交换作用和化学沉淀吸附作用所致。另外,实验还初步探索了溶液离子强度对沸石吸附四环素的影响情况,随着溶液中Na+和Ca2+离子强度的增加,吸附量先急剧降低随后趋向平稳,进一步说明了沸石对四环素的吸附过程不是由单一机制控制的。     

Coarsening of extracellularly biosynthesized cadmium crystal particles induced by thioacetamide in solution

A novel coarsening route for extracellularly biosynthesized cadmium nanocrystals was investigated for the first time. In this process, the white rot fungus Coriolus versicolor was employed to take up cadmium ions and synthesize extracellular cadmium crystal particles. The coarsening of the particles was induced by thioacetamide under certain conditions. Scanning electron microscopy showed that the formed cadmium crystal particles were coarsened from about 100 nm to 2-3 μm. The corresponding energy-dispersive X-ray spectra confirmed the presence of proteins in the particles. The maximum removal efficiency of Cd(II) increased from 17% to 87%, and the corresponding sorption capacity of biomass increased from 4 to 24 mg g⁻¹ with the completion of the coarsening process. The properties of the coarsened particles were also examined using X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD analysis of fungal mycelial pellets embedded with the coarsened particles confirmed the formation of cubic crystalline cadmium sulfide particles. The TEM results suggest that the coarsened particles were composed of clusters of several smaller particles. The changes in the functional groups on the biomass surface were studied through Fourier transform infrared spectroscopy. Based on the results above, a possible mechanism for the formation and coarsening of cadmium crystal particle is also discussed.     

SCR反应器内各关键部件对系统压力损失特性影响的研究

选择性催化还原(selective catalytic reduction,SCR)脱硝反应器的关键部件对系统压力损失特性的影响非常明显.针对某电厂1×300 MW锅炉机组的SCR脱硝反应器,采用数值模拟和实验研究的方法研究了各关键部件对系统压力损失特性影响.通过研究确定了SCR反应器的最优设计方案,即关键部件1设计为...     

Traffic noise exposure of high-rise residential buildings in urban area

Noise pollution is a major factor of environmental complaints in many cities, which has significant impacts on human health. As a dominating source of environmental noise, the impact of road traffic noise is increasing. Residents living in high-rise buildings along the main road are severely affected by traffic noise. In order to assess the noise level of urban area along the main road in Guangzhou, three buildings were selected to conduct traffic noise measurements, and the questionnaire about traffic noise impact on human being was completed. Through the questionnaire, around 70% of participants consider the traffic noise has negative effect, and about 60% of participants consider the noise has moderate or much higher impact on physical comfort. Around 65% of participants consider the noise had moderately or much higher impact on their psychological comfort. By analyzing the measured data, all of the measured noise levels in three buildings exceed the recommended limit of 55 dB (A) in the daytime and 45 dB (A) in the night for residence, and the exceeded value can be up to 16 dB (A). By comparing the fitting curve of noise level transfer function on each floor relative to the reference floor, the quadratic polynomial was selected to plot the transfer function rather than cubic polynomial.

     

Effects of straw returning and feeding on greenhouse gas emissions from integrated rice-crayfish farming in Jianghan Plain,China

Great efforts have been devoted to assessing the effects of straw managements on greenhouse gas (GHG) emissions, global warming potential (GWP), and net economic budget in rice monoculture (RM). However, few studies have evaluated the effects of straw managements on GHG emissions and net ecosystem economic budget (NEEB) in integrated rice-crayfish farming (RC). Here, a randomized block field experiment was performed to comprehensively evaluate the effects of aquatic breeding practices (feeding or no feeding of forage) and straw managements (rice straw returning or removal) on soil NH₄⁺–N and NO^?₃–N contents, redox potential (Eh), CH₄ and N₂O emissions, GWP, and NEEB of fluvo-aquic paddy soil in a rice-crayfish co-culture system in Jianghan Plain of China. We also compared the differences in CH₄ and N₂O emissions, GWP, and NEEB between RM and RC. Straw returning significantly increased CH₄ and N₂O emissions by 34.9–46.1% and 6.2–23.1% respectively compared with straw removal. Feeding of forage decreased CH₄ emissions by 13.9–18.7% but enhanced N₂O emissions by 24.4–33.2% relative to no feeding. Compared with RM treatment, RC treatment decreased CH₄ emissions by 18.1–19.6% but increased N₂O emissions by 16.8–21.0%. Moreover, RC treatment decreased GWP by 16.8–22.0% while increased NEEB by 26.9–75.6% relative to RM treatment, suggesting that the RC model may be a promising option for mitigating GWP and increasing economic benefits of paddy fields. However, the RC model resulted in a lower grain yield compared with the RM model, indicating that more efforts are needed to simultaneously increase grain yield and NEEB and decrease GWP under RC model.

     

贵阳市冬季PM_(2.5)中典型重金属元素的化学形态分析与健康风险评价

为了更准确地研究重金属的生物有效性和对环境与人体的潜在生态危害,采用改进BCR法分析了贵阳市冬季PM_(2.5)中Cu、Mn、Co、Cd、Pb这5种重金属元素的化学形态,并评价了它们的生物有效性和健康风险。结果表明:不同重金属元素形态分布存在差异,Cu主要是弱酸溶态,其次是可氧化态;Mn主要是弱酸溶态,其次是残渣态;Co没有检测出可还原态,而在其他3种形态分布比较平均;Pb和Cd绝大部分都是弱酸溶态。生物有效性系数(K)分析结果表明:重金属生物有效性强弱顺序为CdPbMnCuCo,其中Cd和Pb的K0.8,属于生物可利用性元素;Mn、Cu、Co的K值在0.4~0.7之间,属于潜在生物可利用性元素。健康风险评价表明:成人的致癌风险比儿童大,尤其Cd对成年人存在潜在的致癌风险,且成年男性高于成年女性;Mn存在潜在非致癌风险,且对儿童的风险最大。     

Time series analysis of ambient air pollution effects on daily mortality

Although the growths of ambient pollutants have been attracting public concern, the characteristic of the associations between air pollutants and mortality remains elusive. Time series analysis with a generalized additive model was performed to estimate the associations between ambient air pollutants and mortality outcomes in Shenzhen City for the period of 2012–2014. The results showed that nitrogen dioxide (NO₂)-induced excess risks (ER) of total non-accidental mortality and cardiovascular mortality were significantly increased (6.05% (95% CI 3.38%, 8.78%); 6.88% (95% CI 2.98%, 10.93%), respectively) in interquartile range (IQR) increase analysis. Also, these associations were strengthened after adjusting for other pollutants. Moreover, similar associations were estimated for sulfur dioxide (SO₂), particulate matter with an aerodynamic diameter of <10 μm (PM₁₀), and total non-accidental mortality. There were significant higher ERs of associations between PM₁₀ and mortality for men than women; while there were significant higher ERs of associations between PM₁₀/NO₂ and mortality for elders (65 or elder) than youngers (64 or younger). Season analyses showed that associations between NO₂ and total non-accidental mortality were more pronounced in hot seasons than in warm seasons. Taken together, NO₂ was positively associated with total non-accidental mortality and cardiovascular mortality in Shenzhen even when the concentrations were below the ambient air quality standard. Policy measures should aim at reducing residents’ exposure to anthropogenic NO₂ emissions.     

山东省资源环境承载力综合评价与区域差异研究

为准确分析区域资源环境承载力的整体状况及区域内部差异,推进经济社会发展与资源环境承载力相协调,以山东省为研究对象,构建包含人口、经济、资源与环境因素的区域资源环境承载力评价指标体系,以2014年山东省统计数据为基础,对全省和17个地级市资源环境承载力进行评估。结果表明:粗放型经济增长方式和资源环境本底脆弱导致山东省资源环境承载力不高,综合发展指数为0.33;17个地级市资源环境承载力序参量可分为4种类型,呈现出北部南部的空间分布特征,产生区域差异的原因主要有区位和自然条件因素、产业结构、技术水平、人才资源、经济发展水平等。