湖南南岭草地植被类型的数量分类、排序及其合理利用

湖南南岭山区的地带性植被是常绿阔叶林,由于不合理的利用,森林遭受严重破坏而出现了大面积的草山,面积约1497.2万亩(99.8万ha),占土地总面积的1/4强。本文运用二元指示种分析TWINSPAN和无倾向对应分析DCA的数学方法对草地植被进行分类与排序。利用48个样方和150个植物种的资料进行计算,在第4级水平上划分出12个主要草地植被类型,其中将近似的类型合并成10个类型。在第1级水平上明显地将海拔1000m以上的与600m以下的分成2大组;在其它水平上则根据其他不同生态因子(岩性、pH值等)将出现的区别种逐级分开。所得结果与定性分类基本相同,说明该方法是适用于亚热带草地分类的。 不同类型在开发利用上有很大差异,高海拔的植被类型应以造林或封山育林为主,并可适当发展木本药材;在平缓的山原上虽可开辟人工草地发展畜牧业,但必须要防止水土流失,坡度在25。以上的应封育;15—20°的地方可以发展林业与畜牧业;在海拔300—600m的丘陵岗地类型上可以发展薪炭林、经济林;在海拔300m以下,水源充足的地方可以发展果木林(柑桔等),缓坡丘陵地类型可建立人工草地,但应与林业相结合,在农区可进行粮草轮作。总之,应该建立人工生态系统,以提高经济效益和生态效益。     

Microbial characteristics associated with six different organic wastes undergoing anaerobic decomposition in batch vial conditions.

In this study, the biodegradation characteristics of six plant-based wastes were compared in anaerobic batch vial systems. The highest gas accumulation and methane (CH4) concentrations (approximately 70%) were observed in samples containing copy paper, newspaper and box paper materials, whereas the lowest were observed in samples containing wood and leaves. In samples containing steamed rice and fruit, the methanogenic activity was inhibited, which resulted in acid accumulation. The high biodegradation activity of newspaper samples was also associated with high adenosine triphosphate levels and dehydrogenase activity. No significant differences were, however, observed in the dehydrogenase activity of the samples. High bioluminescence was observed in samples with high biodegradation activities, indicative of low toxicity.     

磺酰脲类除草剂在环境中的光降解研究——水溶液中的光解动力学

以汞灯为光源,研究了甲黄隆,苯黄隆,氯黄隆,氯嘧黄隆,苄嘧黄和胺苯黄隆６种磺酰脲类除草剂在水液中的光解动力淡。结果表明,５种磺酰的降解呈一级动力学反应;体系的ＰＨ值对降解速率影响不明显,光强的影响较明显著;Ｈ２Ｏ２丙酮和溶解有机质均可促进磺酰光解;党妥氧对该类除草剂光解的影响表现为光氧化与淬灭２种作用的竞争。     

内蒙阿拉善地区植物与土壤元素背景值特征及其相互关系

内蒙阿拉善地区植物、土壤的元素背景特征及其相互关系的研究结果表明：５３种植物的９种元素（Ｚｎ、Ｃｕ、Ｎｉ、Ｐｂ、Ｃｄ、Ｃｏ、Ｃｒ、Ｖ、Ｍｎ）背景含量有很大差异．不同生活型植物背景值也各异，总的规律为：Ｍｎ＞Ｚｎ＞Ｖ＞Ｃｕ＞Ｎｉ＞Ｃｒ＞Ｐｂ＞Ｃｏ＞Ｃｄ；同种植物的元素含量在不同群落中有明显差别，但都在同一个数量级．土壤９种元素的背景含量均以Ｍｎ含量最高，其次为Ｚｎ和Ｖ，Ｃｄ的含量最低；不同上类各剖面各种元素的垂直分布规律为底层或表层的元素含量高于中间各层．土壤元素背景值都高于植物背景值，前者一般为后者的２～２０倍．植物对元素的吸收系数以Ｃｄ最大，Ｃｒ最小．土壤元素含量与有机质含量的相关性因土类不同而异：沙土的有机质含量最低，只有Ｚｎ含量与有机质相关性显著；而盐土的有机质含量最高，有Ｃｏ、Ｃｄ、Ｍｎ、Ｎｉ、Ｃｒ、Ｚｎ６种元素含量与之显著相关．     

北京市密云县潮河周边土壤中类二恶英PCBs分析评价

为了探讨密云水库上游流域可能给水库带来的非点源污染,本研究测定了入库河流潮河下游周边土壤中12种类二恶英多氯联苯(DL-PCBs)的含量水平。结果表明,ΣDL-PCBs的总含量水平为0.0039~0.0365 ng·g-1,其中PCB-118,115,77为12种DL-PCBs的主要成分,PCB-81,114,157均低于检出限。草地、林地和果园中ΣDL-PCBs的含量高于玉米地,表明研究区的DL-PCBs主要受大气沉降和河流沉积物的影响,受当地人类活动影响不大。与其他研究相比,采样区域的PCBs含量总体处于偏低水平,毒性当量处于中等水平。而毒性当量因子(TEF)较高的PCB-126与PCB-169,可能会对人类和生物产生危害,应给予足够的重视。     

低温下膜-生物活性炭工艺深度处理回用水的试验研究

开展低温下膜-生物活性炭工艺深度处理回用水的试验研究，探讨该工艺低温运行的可行性及作用机制。结果表明，采用HRT为3h的膜-生物活性炭反应器对回用水中有机物具有良好的去除效果，CODcr，UV254、UV410的去除率分别稳定在33％、35％、40％；对NH3-N的去除效果不明显，其平均去除率在15％左右，主要受原水浓度过高的影响。同时与其他工艺进行对比研究，结果表明，由于该工艺结合了膜分离、活性炭吸附、生物降解三者的综合作用而表现出明显的优势。     

基于腐蚀与盐堵塞问题的超临界水氧化研究进展

超临界水氧化(简称SCWO)以其特有的优点成为了引人注目的有机废水处理方法.在操作过程中,有机物与氧化剂呈现为快速的均相反应,在数分钟内便可完全氧化生成CO2和H20.尽管已建造了工业规模的SCWO装置并用于处理化学废水,但该技术所存在的设备腐蚀以及设备因盐沉积而堵塞的问题制约着该技术的推广应用.为解决上述问题,科技工作者对SCWO工艺进行了改进,并提出了多种新颖的SCWO反应器设计思想.综述了基于解决设备腐蚀与盐堵塞问题的SCWO研究进展,并对相关问题进行了讨论.     

Monitoring the genotoxicity of Lake Taihu, using two kinds of micronucleus tests

Mutagenicity of surface water in Lake Taihu was monitored by genotoxicological methods. The goal is to determine the situation concerning the contamination by mutagens, their distribution in the lake, and the potential effect on public health. In this study, the micronucleus test of Vicia faba root tip, a standard monitoring technique now in China, was carried out to make a preliminary screening of environmental mutagens in 39 representative sites of the lake. Highly significant differences in MCN permillage (average number of micronuclei per 1000 cells) and PI (pollution index) values were found among these sites. From the results, a rough distribution of the contamination could be obtained: mainly concentrated in the north-west area of the lake from several tributaries flowing into the lake. In order to provide further evidence, organic extracts from four entrances and one outlet of the five major tributaries were examined by the micronucleus test of human peripheral lymphocytes. The results were in accord with those of the micronucleus tests using Vicia faba. The tests also revealed that the intensity and mechanism of the pollutants were diverse in the different sources.     

The connection between urbanization and carbon emissions: a panel evidence from West Africa

Environment, Development and Sustainability - This study examined the nexus between urbanization and carbon emissions in West Africa. Second-generation econometric techniques that are robust to...     

超声-过氧化氢-氧化铜组合技术催化氧化水中苯酚

研究了超声-H2O2-CuO组合技术对苯酚的降解效果。考察了苯酚初始浓度、溶液温度及鼓入空气对苯酚去除率的影响。实验结果表明,与未鼓入空气时相比,连续鼓气时苯酚的降解效果较好;初始浓度低,苯酚去除率高;溶液温度从20℃上升到55℃时,苯酚去除率随温度升高而增大,温度对该过程的影响主要表现为对催化剂的影响而不是对超声作用的影响。高效液相色谱分析表明,苯酚降解的中间产物主要为对苯二酚、邻苯二酚及其他有机小分子物质,最终产物为草酸、二氧化碳和水。