电催化氧化技术处理制革综合废水

选择DSA电极中的钛基掺硼金钢石膜电极(Ti/BDD),用于制革综合废水的电催化氧化处理研究,考察了在不同的电流密度、电压、电解质、pH值和电解时间等因素对COD去除率和电流效率的影响。结果表明,控制电流密度为30mA/cm2,电压为8.0 V,电解质(NaCl)浓度为2.0 g/L,pH为4.0,电催化氧化处理2 h后,废水的COD和NH4+-N的去除率分别达到了83.6%和90.3%,BOD/COD为0.45,比能耗为35.34 kWh/kg COD,电流效率为37%。     

Distribution and ecological risk assessment of organochlorine pesticides in surface sediments from the East Lake,China

Organochlorine pesticides (OCPs) are ubiquitous pollutants, and their presence in urban lakes is a concern for human and ecological health. Surface sediments in the East Lake, China, were collected in winter 2012 and summer 2013 to investigate concentrations, distribution patterns, possible sources, and potential ecological risks of OCPs in this area. The total concentrations of 14 OCPs ranged from 6.3 to 400 ng g^?1 dry weight (dw) with an average concentration of 79 ng g^?1 dw. The mean values of hexachlorocyclohexanes (HCHs) (α-, β-, γ-, and δ-HCH) and dichlorodiphenyltrichloroethanes (DDTs) (p,p’-DDE, p,p’-DDD, and p,p’-DDT) were 36 and 7.6 ng g^?1 dw, accounting for 45 and 10 % of the total OCPs, respectively. The concentrations of OCPs in sediment samples collected in winter were significantly higher than those in summer, especially the HCHs, of which in winter were two times greater than summer. Composition analyses indicated that DDTs and endosulfan were mainly from historical contribution. Historical use of technical HCH and new input of lindane were probably the source of HCHs in the East Lake. Most sampling sites of HCHs and DDTs were found to have the potential ecological risk based on levels specified in the sediment quality standards.     

基于环境一号卫星高光谱数据的太湖富营养化遥感评价模型

采用环境一号卫星高光谱数据直接监测太湖富营养化状态的方法较多光谱影像监测有着更高的精度优势,对内陆水环境监测具有一定的意义。利用2009年4月地面实测高光谱数据模拟环境一号卫星星上数据,结合确定的太湖富营养化状态遥感评价的水质因子,构建富营养化状态评价模型,并采用实测数据和环境一号卫星高光谱影像数据对模型的精度和适用性进行验证。研究结果表明：（1）选用叶绿素a作为富营养化遥感监测的水质因子监测太湖富营养化状态与综合营养指数法相比,平均相对误差为597%;（2）采用模拟的环境一号卫星高光谱影像数据结合三波段模型与采用地面实测数据评价结果之间的相关系数r=0855,平均相对误差为919%;（3）结合环境一号卫星高光谱影像对2010年5月2日太湖进行富营养化监测评价,结果显示太湖水体整体成中营养状态,存在1129%的监测水域出现轻度富营养化状态     

面源磷负荷改进输出系数模型及其应用

传统的输出系数模型是模拟较大流域面源污染的有效手段,但它假设同一土地利用类型的输出系数相同,忽视了营养物径流和截留过程中其他流域特征对输出系数空间分布的影响,难以为流域分区管理提供依据。在传统输出系数模型基础上,引入产污因子（CI）和截留因子（RI）,校正地形、降雨、植被缓冲带对面源磷流失空间格局的影响。用改进输出系数模型模拟滇池流域面源磷负荷并将模拟结果应用于流域管理。结果表明,改进的输出系数模型能更好地模拟面源磷污染的空间格局,识别出面源总磷的关键风险区--湖滨平原地带以及与入滇河流邻近的山谷、台地。以2008年滇池流域面源总磷的模拟结果（3525 t）为基准,若单位面积磷肥施用量减少20%,面源总磷负荷将减少86%;若环湖公路内侧全部实现退耕还林或还草,面源总磷负荷将减少60%;若同时实施减少磷肥施用量和环湖公路内退耕两项措施,面源总磷负荷将减少130%     

Biodegradation of beta-cypermethrin by a novel Azoarcus indigens strain HZ5

A novel strain HZ5 was isolated from the activated sludge of a pesticide manufacturer in Hangzhou, which was capable of degrading beta-cypermethrin (beta-CP). Based on its physiological characteristics and analysis of 16S rDNA gene, strain HZ5 was identified as Azoarcus indigens, which was a new genus that can degrade beta-CP effectively. Strain HZ5 could degrade beta-CP over a wide range of temperature (20 to 40°C) and pH (5.5 to 9.0), and the optimal temperature and pH were 30°C and 7.0. The highest degradation rate was approximately 70% of 50 mg/L beta-CP within 144 h at pH 7.0 and 30°C in MSM. An additional carbon source could enhance the biodegradation of beta-CP. Studies on biodegradation of the beta-CP showed no significant enantioselectivity. During the process, two main intermediate metabolites were produced by strain HZ5 and determined as 3-phenoxybenzaldehyde and 3-phenoxybenzoic acid by gas chromatography-mass spectrometry (GC-MS) analysis. The results indicated that strain HZ5 may have potential application in bioremediation of beta-CP polluted environment.     

Adsorption behavior of light green anionic dye using cationic surfactant-modified wheat straw in batch and column mode

An agricultural by-product, natural wheat straw (NWS), was soaked in 1 % cationic surfactant (hexadecylpyridinium bromide, CPB) solution for 24 h (at 293 K), and modified wheat straw (MWS) was obtained. Analysis of FTIR, XFR, and nitrogen element showed that CPB was adsorbed onto surface of NWS. Then, MWS was used as adsorbent for the removal of light green dye (LG, anionic dye) from aqueous solution. The experiment was performed in batch and column mode at room temperature (293 K). Sodium chloride (up to 0.1 mol/L) existed in solution was not favor of LG dye adsorption. The equilibrium data were better described by Langmuir isotherm, and adsorption capacity of q _m from Langmuir model was 70.01?±?3.39 mg/g. In fixed-bed column adsorption mode, the effects of initial LG concentration (30, 50, 70 mg/L) and flow rate (6.5, 9.0, 14.5 mL/min) on adsorption were presented. Thomas and modified dose–response models were used to predict the breakthrough curves using nonlinear analysis method, and both models can fit the breakthrough curves. Theoretical and experimental breakthrough curves were drawn and compared. The results implied that MWS can be used as adsorbent material to remove LG from aqueous solution.     

SO2 inhalation causes synaptic injury in rat hippocampus via its derivatives in vivo

SO₂ remains a common air pollutant, almost half of the world’s population uses coal and biomass fuels for domestic energy. Limited evidence suggests that exposure to SO₂ may be associated with neurotoxicity and increased risk of hospitalization and mortality of many brain disorders. However, our understanding of the mechanisms by which SO₂ causes harmful insults on neurons remains elusive. To explore the molecular mechanism of SO₂-induced neurotoxic effects in hippocampal neurons, we evaluated the synaptic plasticity in rat hippocampus after exposure to SO₂ at various concentrations (3.5 and 7 mg m⁻³, 6 h d⁻¹, for 90 d) in vivo, and in primary cultured hippocampal neurons (DIV7 and DIV14) after the treatment of SO₂ derivatives in vitro. The results showed that SYP, PSD-95, NR-2B, p-ERK1/2 and p-CREB were consistently inhibited by SO₂/SO₂ derivatives in more mature hippocampal neurons in vivo and in vitro, while the effects were opposite in young hippocampal neurons. Our results indicated that in young neurons, SO₂ exposure produced neuronal insult is similar to ischemic injury; while in more mature neurons, SO₂ exposure induced synaptic dysfunctions might participate in cognitive impairment. The results implied that SO₂ inhalation could cause different neuronal injury during brain development, and suggested that the molecular mechanisms might be involved in the changes of synaptic plasticity.     

Ti（Ⅳ）催化臭氧／过氧化氢预处理酸性难降解废水

在Ti（Ⅳ）和过氧化氢存在条件下,考察了臭氧化酸性苯乙酮溶液、硝基苯溶液和垃圾渗滤液（浙江衢州某垃圾填埋场）的预处理效能。结果表明,在pH2．86条件下,单独臭氧化处理对苯乙酮、硝基苯和垃圾渗滤液的COD去除率分别为10．1％、44％和28．6％。BOD,／COD值分别从原来的0．039、0．060和0．085提高到了0．130、0．158和0．174,仍属生化难降解废水。当体系加入Ti（Ⅳ）后,臭氧化苯乙酮和硝基苯的COD去除率分别达到了75．5％和65％,BOD;／COD则提高到了0．679和0．314,可生化性提升明显。对于垃圾渗滤液,只有当体系加入Ti（Ⅳ）和H22后,臭氧化COD的去除率达到66．6％,BOD、／COD提高至0．425。上述结果对酸性难降解废水的处理实际意义非常突出。     

Correlation of climatic factors and dengue incidence in Metro Manila, Philippines

Dengue is a serious public health problem in Metro Manila, Philippines. Increasing dengue incidence has been attributed to climate change; however, contradicting reports show inconclusive relationships between dengue and climatic factors. This study investigates temperature and rainfall as climatic factors affecting dengue incidence in Metro Manila from 1996 to 2005. Monthly dengue incidence and climatic data for Metro Manila were collected over a 10-y period (1996-2005). Climatic factors temperature and rainfall were linked with dengue incidence through regression analysis. A predictive model equation plots dengue incidence (Y) versus rainfall (X), which suggests that rainfall is significantly correlated to dengue incidence (r2 = 0.377, p < 0.05). No significant correlation between dengue incidence and temperature was established (p > 0.05). Evidence shows dengue incidence in Metro Manila varies with changing rainfall patterns. Intensified surveillance and control of mosquitoes during periods with high rainfall are recommended.     

Relationship of PCDD/Fs congener profiles between beef and raw milk in South Korea

The relationship between profiles of residual PCDD/Fs in beef and raw milk was examined by measuring concentrations and detected frequencies. Unrelated samples of beef and raw milk were collected from nine regions in South Korea. Congener-specific profiles of PCDD/Fs in beef and raw milk were very similar. PCDFs, particularly 2,3,4,7,8-PeCDF, 1,2,3,4,7,8-HxCDF, 1,2,3,6,7,8-HxCDF, and 2,3,4,6,7,8-HxCDF, were dominant congeners in both beef and raw milk suggesting that sources of contamination may not significantly differ nationwide. The profiles of PCDD/Fs in domestic beef and raw milk in this study were closer to the profiles of emission from metal industries although Korea imports over 75% of feedingstuffs. The ratios of PCDF/PCDD in TEQ concentration were more than 5 and 15 in beef and raw milk, respectively. The mean concentrations of PCDD/Fs in 60 samples of beef and 60 samples of raw milk were 0.80 pg WHO-TEQ/g fat and 0.65 pg WHO-TEQ/g fat, respectively. The residual profiles of PCDD/Fs in raw milk resembled that in beef although the congener profiles might change throughout the food chain. This indicated that monitoring of dioxins in milk could provide information for contamination of milk itself or other associated food.