典型城市河流底泥溶解性有机质与重金属响应机制研究

应用三维荧光光谱(EEMs)结合平行因子(PARAFAC)分析、典范对应分析(CCA)和结构方程模型(SEM),以沈阳市建城区黄泥河、新开河、满堂河为研究对象,测定河流底泥营养盐和重金属浓度,检测溶解性有机质(DOM)三维荧光光谱,研究城市河流底泥DOM与重金属响应机制。总氮(TN)和总磷(TP)的平均浓度均为新开河>黄泥河>满堂河,TP平均浓度均大于650 mg/kg,根据US EPA底泥分类标准属于重度污染。基于相关性分析,黄泥河Cu、Ni、Cr具有同源性,新开河As、Cd和Hg具有同源性,满堂河As和Zn具有同源性。基于PARAFAC分析,DOM含有5个荧光组分,即陆源类腐殖质(C1)、类富里酸(C2和C3)、类胡敏酸(C4)和类色氨酸(C5)。C1的丰度占总丰度的30.31%,C2和C3占37.76%,显示陆源类腐殖质和类富里酸为DOM的主要组分。黄泥河与新开河DOM受外源影响较大,而满堂河受内源影响较大。CCA分析表明:C3、C5、Cr和Pb是影响黄泥河底泥的特征因子,Hg是影响新开河底泥的特征因子,TP、As和Zn是影响满堂河底泥的特征因子。基于SEM分析,TN、TP、C1、C2、C3和C5对重金属的权重分别为25.46%、22.16%、17.52%、15.42%、9.11%和10.33%,表明TN和TP是3条河底泥重金属的主要影响因子。营养盐对重金属的路径系数为-0.18,重金属对Hg、As、Zn、Cd路径系数分别为-2.83、-1.69、-1.91和-3.24,表明它们具有同源性;此外,DOM与重金属路径系数为0.11,重金属对Pb和Cr的路径系数为1.58和1.00,表明DOM与Pb和Cr具有同源性。     

慢速可生物降解有机物的转化特性及利用

通过对西安市城市污水处理厂碳源赋存特性和生物降解性分析,探明了西安市城市污水厂碳源的分布特性。西安市污水厂原水中颗粒态COD占总COD的65%左右,以慢速可生物降解有机物为主,是污水厂进水碳源的主要组成部分。分析评价了慢速可生物降解有机物的转化特性与利用潜力,结果表明,在好氧和厌氧2种条件下慢速可生物降解有机物会发生水解发酵作用,在8 h内转化率分别达到58%和65%。其中第1小时为慢速可生物降解有机物的限速阶段,降解缓慢。从第2~4小时降解转化速率显著提高,此后速率逐渐平缓。慢速可生物降解有机物水解产物主要有挥发性脂肪酸(VFAs)、多糖和蛋白类等易于直接被微生物利用的物质。与此同时,也会产生一些腐殖质类的难降解有机物,并在处理过程中会引发其结构改变,趋于生物可利用。     

基于响应曲面法的环境因素对生活污水三维荧光光谱的影响

采用响应曲面法（RSM）研究温度（10~35℃）、pH（3~11）、稀释倍数（1~10）及交互作用对生活污水溶解性有机物（DOM）三维荧光光谱特性的影响规律。研究表明：生活污水DOM主要含有类色氨酸蛋白质、类酪氨酸蛋白质和类富里酸荧光峰;响应曲面分析表明,温度、pH、稀释倍数其交互作用对于类色氨酸蛋白质荧光强度的影响强弱顺序为：稀释倍数 > pH > 温度、pH-稀释倍数 > 温度-pH > 温度-稀释倍数,其中温度-pH和温度-稀释倍数对其荧光强度的影响为拮抗作用,pH-稀释倍数为协同作用;对于类酪氨酸蛋白质,单因素影响顺序为：pH > 稀释倍数 > 温度,其他情况与类色氨酸蛋白质相似;对于类富里酸,温度、pH、稀释倍数及其交互作用对其影响规律与对类色氨酸蛋白质的相似,但交互作用类型与类色氨酸蛋白质情况相反。     

基于易回收的磁性碳纳米管催化湿式氧化处理垃圾渗滤液中的DOM

采用液相化学沉淀法制备了易于回收的磁性碳纳米管催化剂,应用于催化湿式氧化实验处理垃圾转运站渗滤液。结果表明,在反应温度为200 ℃,n(COD)∶n(H₂O₂)=1∶1.8,时间为60 min,催化剂添加量为0.1 g·L⁻¹的最佳条件下,垃圾渗滤液的COD去除率达到86.38%。出水可溶解性有机物(DOM)的紫外和三维荧光分析表明,实验对芳香族化合物和腐殖质的去除效果良好,可生化性提高。磁性碳纳米管在外加强磁场作用下30 s内便可实现快速分离,重复5次使用回收率可达90%。     

安全生产是企业领导者的首要工作

本文结合鞍钢多年安全生产工作实践,从企业领导者的角度,阐述了安全生产在企业中的地位、作用及重要性,提出了一把手安全生产负责制的对策及实施方法,这对于提高企业领导者的安全素质,搞好企业的安全生产工作具有重要的指导作用。     

Sediment organic matter and meiofauna community response to long-term fish-farm impact in the Ligurian Sea (Western Mediterranean)

Quantitative and qualitative changes in meiofauna community structure were investigated to assess the impact of a fish farm, which was operating continuously for 15 years (La Spezia Gulf, W Mediterranean). Sediment samples were collected in June, July, September, October 2000 and February 2001 for the analysis of phytopigments (chlorophyll-a and phaeopigments), the biochemical composition of organic matter (proteins, carbohydrates and lipids) and related to meiofaunal parameters.

Sediment organic matter reached extremely high concentrations beneath the fish cages when compared to the control. Particularly lipids, carbohydrates and chlorophyll-a were significantly higher in fish-farm sediments. On a long-term basis meiofauna displayed adaptations in sediments beneath the cages resulting in an increase of density. Organic impact on meiofaunal community structure was evident in terms of an increase of the nematodes to copepods (Ne/Co) and nauplius to copepods (Na/Co) ratios in fish farm sediments. Cumaceans and kinorhynchs were encountered in control sediments, but disappeared in fish-farm samples. These data suggest that meiofauna is a sensitive tool for evaluating the effects of organic enrichment in fish farm impacted areas.     

Trace elements in coconut water—a preliminary study

Trace element analysis for five elements namely, Ba, Sr, Mn, Cr and Cd was carried out on both ash weight and dry weight basis for mine water and coconut water from Mangampeta barite area. The concentration of trace elements is strikingly different in the coconut water when compared with that of mine water. The coconut plant has the ability to control the presence of certain inorganic elements in its water, whatever be the amount of those elements present in irrigation water. Further, biogeochemical studies of coconut water may be of considerable importance in balneology.     

失效锂离子电池有机物真空脱除和浸出研究

文章采用真空蒸发热处理的方法脱除废弃失效的锂离子电池中的有机物,加热温度为220~500℃,真空炉内压力150Pa,恒温处理时间1h。除有机物被脱除外,当处理温度为280℃时形成了CoO和Li2CO3。温度升高至350℃时,主要的物相为LiCoO2、CoO、Co3O4和Co,以及少量Li2CO3。在超声场中将电极材料与铝、铜箔集流体分离,然后分别用含亚硫酸钠的硫酸溶液和氨性溶液处理电极材料。当用含亚硫酸钠的硫酸溶液浸出经280℃脱除有机物的电极材料时,钴元素基本被浸出。而用氨性溶液浸出经350℃脱除有机物的电极材料时,钴元素的浸出率很低。为了提高钴的浸出率,真空热处理的温度应介于280~350℃之间。     

The role of plant leaf attributes in linking land use to ecosystem function in temperate grassy vegetation

We tested predictions of the relative changes in plant leaf traits in response to land uses in Australian eucalypt grassy ecosystems. Predictions were determined from responses observed in European landscapes in relation to disturbances associated with agricultural land uses. We measured specific leaf area (SLA) and leaf dry matter content (LDMC) across five land uses: reference sites (closest to pre-European state), native pastures (unfertilized), fertilized pastures, sown pastures (cultivated and fertilized) and enriched grassland (previously fertilized, no longer grazed). Leaves were expected to have higher SLA and lower LMDC at sites with increasing fertility and/or disturbance.The predictions were confirmed, with SLA increasing progressively in land uses associated with (1) grazing; (2) grazing and fertilization; (3) grazing, fertilization and cultivation. Values for LDMC were closely (but inversely) correlated with those of SLA. For both traits, there were relationships with available soil phosphorus but not with soil total nitrogen. The positive correlation of SLA with phosphorus was not evident above 30 mg kg⁻¹, the recommended level of phosphorus for improved pastures.Results confirm patterns of leaf-trait response to disturbance that reflect fundamental constraints to plant survival in habitats with different levels of resources and disturbances. A conservative strategy for low productivity undisturbed habitats is associated with low SLA and high dry matter content in contrast to fertile disturbed habitats which select for high SLA and low dry matter content. The changes in leaf traits across land uses resulted from species substitution rather than variation within species across sites, and most notably the replacement of native by annual exotic species as land use intensifies.Recommended fertilization rates for pasture production convert the ground layer to plants with soft, digestible leaves, that are responsive to fertilizer and desirable for livestock production. However, fertilization also drastically reduces the diversity of native plants and annual plants tend to dominate. The trade-off associated with high production includes increased vulnerability to soil erosion, due to reduced plant cover and low persistence of cover. If alternative ecosystem values such as erosion control, water quality, salinity control and biodiversity persistence are required, incentives may be needed to offset the loss of production that can be gained from fertilizer application.     

Element and mineral characterization of dust emission from the saline land at Songnen Plain, Northeastern China

Recent observations of Asian dust storms show an eastern expansion of the source area to degraded lands, where dust emissions have been little studied. The dust concentrations over the saline land of the western Songnen Plain (SSL), Northeastern China, are circumstantially higher than those from the northwestern Chinese deserts. These concentrations are sensitive to the surface soil conditions and wind velocity on the ground. The dust samples collected during dust storm events on the SSL contain abundant Na, Mg, Al, K, Ca, Fe and Ti, as well as toxic elements such as Cu, V, Zn and Ba. Individual particle analysis reveals that fine saline particles (< 10 μm in diameter) on the saline land, consisting largely of carbonate, halite and sulfate together with lithogenic minerals such as SiO₂ and aluminosilicate, are eventually uplifted during the interval from spring to autumn. The predominantly fine saline particles uplifted from the SSL are likely transported eastward by the winter monsoon circulation and westerlies. Recent degradation of saline lands in Northeastern China would not only increase the frequency of dust storm events in the downwind area, but also might change the chemical composition of the Asian dust emissions.