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1.
HCO3^-碱度对铜绿微囊藻生长与光合活性的影响   总被引:1,自引:0,他引:1  
研究了2.3 mM(ALK2.3)和12.4 mM(ALK12.4)HCO-3对铜绿微囊藻(Microcystis aeruginosa FACHB 927)生长与光合特性的影响.实验结果表明,ALK2.3显著抑制铜绿微囊藻的生长,至培养结束,与对照相比对生物量的抑制率为38%,ALK12.4条件下虽然至培养结束生物量没有显著变化,但碱度增加铜绿微囊藻生物量有一个快速的增殖期,之后其生长速率持续下降.碱度增加强烈抑制光合色素Chla的合成,ALK2.3和ALK12.4条件下对Chla含量抑制率分别为74%和56%.藻胆蛋白与叶绿素a的比值(PBP/Chla)在碱度增加的条件下有显著升高.HCO-3碱度增加,铜绿微囊藻的光合活性先降低之后逐渐恢复,至处理结束表现出低碱度(ALK2.3)促进光合活性,高碱度(ALK12.4)对光合活性影响不显著.说明HCO-3碱度增加对铜绿微囊藻有一定伤害作用,与高碱度(ALK12.4)相比,低碱度(ALK2.3)对细胞的伤害程度更大,随着细胞的增殖,碱度对细胞的伤害作用逐渐恢复,且低碱度下细胞恢复更快.暗示碱度可以作为水华控制的手段之一.  相似文献   

2.
研究了23 mM (ALK23)和124 mM (ALK124) HCO-3对铜绿微囊藻(〖WTBX〗Microcystis aeruginosa〖WTBZ〗 FACHB 927)生长与光合特性的影响。实验结果表明,ALK23显著抑制铜绿微囊藻的生长,至培养结束,与对照相比对生物量的抑制率为38%,ALK124条件下虽然至培养结束生物量没有显著变化,但碱度增加铜绿微囊藻生物量有一个快速的增殖期,之后其生长速率持续下降。碱度增加强烈抑制光合色素Chla的合成,ALK23和ALK124条件下对Chla含量抑制率分别为74%和56%。藻胆蛋白与叶绿素a的比值(PBP/Chla)在碱度增加的条件下有显著升高。HCO-3碱度增加,铜绿微囊藻的光合活性先降低之后逐渐恢复,至处理结束表现出低碱度(ALK23)促进光合活性,高碱度(ALK124)对光合活性影响不显著。说明HCO-3碱度增加对铜绿微囊藻有一定伤害作用,与高碱度(ALK124)相比,低碱度(ALK23)对细胞的伤害程度更大,随着细胞的增殖,碱度对细胞的伤害作用逐渐恢复,且低碱度下细胞恢复更快。暗示碱度可以作为水华控制的手段之一.  相似文献   

3.
城市生活垃圾焚烧(发电)是"减量化、无害化、资源化"终极环保处理的最重要和必要趋势。原始垃圾含水率高、发热值低、焚烧不完全,导致毒性物质产生,造成二次污染是制约焚烧处理的主要因素。通过将原始生活垃圾无须人工分选分拣,进行一系列的脱水、磁选、破碎、烘干、除臭杀菌和加入特制添加剂等高新技术处理,即可100%利用转化成污染少、热值高的环保再生燃料,解决焚烧产生的烟气、飞灰和二噁英的达标排放。该垃圾环保再生煤热值达15.42-16.29 MJ/kg,在焚烧时无需添加煤、油等燃料助燃,燃烧温度达1000℃以上,可供工业锅炉、砖厂使用,特别是与锅炉蒸汽发电工艺联合,获得更好应用效果。文中介绍了利用城市生活垃圾制造环保再生煤要解决的关键技术问题、技术路线、示范生产工艺流程和技术创新点,对垃圾环保再生煤的应用效果进行了总结评价。  相似文献   

4.
天气衍生品作为一项金融创新产品,为天气风险的管理和转移提供了新的途径.与传统衍生品不同的是,天气衍生品合约标的物是常见的天气变量,本身不具有资产价格,因此面临的并不是传统意义上的基差风险.天气衍生品的基差风险包括产品基差风险和空间基差风险,这些基差风险严重影响着天气衍生品的风险对冲效果,阻碍了市场发展,也是研究的重点与难点.相比产品基差风险因特定部门而异,空间基差风险具有不可避免的特点.依据反距离加权法,增加空间多样性构建天气衍生品组合,可用于对冲空间基差风险,但需要经验数据验证.研究表明,天气衍生品收益与假设收益的均方根误差(RMSE)能够很好的量化天气敏感企业遇到的天气风险,天气风险对冲效果可以通过RMSE的变化值进行度量;构建中国华东地区降雨量看跌期权交易,相较单一地区收益偏差,期权买方采用空间组合策略取得了更好的空间基差风险对冲效果.此外,研究结果发现,在构建天气衍生品空间组合时,组合中气象观测点的数目并不是越多越好,即较少的观测点个数即能显著降低天气风险对冲效果,这也为实践操作提供了便利.  相似文献   

5.
要成为化石能源的有效替代品,生物燃料必须能提供净能量收益,能产生环境效益,具有经济效率,且在大量生产的情况下不引起粮食危机。麻疯树作为第二代生物柴油的重要原料作物,在国内得到大力推广,但实际效率尚不清楚。基于将麻疯树种子油与化石柴油直接混合使用的技术选择,利用生命周期评估法分析了麻疯树种子油生命周期的经济、环境和能量效率。结果表明:(1)在当前产量和生产技术水平下,生产和使用麻疯树种子油的财务净现值为负,要促进麻疯树种子油的生产,需要每年为种子生产者提供8817 元/hm2以上的补贴,为榨油厂商提供268 元/L的补贴;(2)生产和使用每升麻疯树种子油可减少约13 kgCO2当量的温室气体排放,固碳价值为补贴生产提供了部分经济依据,但是仅考虑种子油和固碳的价值时,生产和使用麻疯树种子油尚不具有经济可行性;(3)当仅考虑种子油的能量产出时,只有当种子产量达到795 kg/hm2以上才具有能量效率;当把树枝和果壳等所包含的生物质能计算在内时,在较低种子产量的情况下,也具有显著的能量效率。敏感性分析表明,随着麻疯树种子产量的增加,财务净现值趋于下降,但是种子油的成本下降,减排温室气体的贡献和能量效率都增加。最后,基于麻疯树种子油的生命周期分析,提出了提高经济、环境和能量效率的途径。〖  相似文献   

6.
界牌河段航道整治工程于1994年动工,1998年基本结束。为了防止在施工过程中对白Ji豚和长江江豚造成意外伤害,并对整治河估的环境变化对白Ji豚和长江江豚的影响 作出了评价,作者在1995年至1999年在界牌河段对白Ji豚和江豚的活动和航道整治前后的情况进行了监测。调查结果表明,介牌般道在整 治过程中没有对白Ji豚和江豚造成伤害,原来百航严重的界牌航道得到了有效的整治,同时也有利于白Ji豚和江豚的活动  相似文献   

7.
中国政府已经核准《京都议定书》   总被引:1,自引:0,他引:1  
国务院总理朱基 2 0 0 2年 9月 3日在南非约翰内斯堡召开的可持续发展世界首脑会议上讲话时向世界宣布 ,中国政府已核准《〈联合国气候变化框架公约〉京都议定书》。朱基总理在讲话中说 :“中国政府认为 ,《联合国气候变化框架公约》及其《京都议定书》为国际合作应对气候变化确立了基本原则、提供了有效框架和规则 ,应当得到普遍遵守。”现在 ,欧盟各成员国及日本已批准了该议定书。朱基表示 ,中国希望其他发达国家尽快批准或核准议定书 ,争取使其在今年内生效。近年来 ,我国各级政府为应对气候变化付出了极大努力 ,特别是在提高能源…  相似文献   

8.
膜技术用于处理石油化工废水的案例研究表明该技术用于我国船舶油水分离从技术上也是可行的。基于对膜技术工艺参数选择的分析,设计了可投入实际应用的二级油水分离器方案,由一级处理装置和用于深度处理的二级膜分离装置组成。膜分离装置的孔径和膜材料的亲水/油性依据进水情况进行确定;操作温度为室温;跨膜压差应控制在0.1~0.2MPa;膜分离装置的进水油含量和进水流量应由一级处理装置进行调节,以使其适合膜分离装置的最佳运行状态。  相似文献   

9.
崇西湿地冬季潮滩鱼类种类组成及多样性分析   总被引:8,自引:0,他引:8  
根据2006年冬季在崇西湿地进行的光滩和草滩插网渔获调查,首次对冬季长江口潮滩鱼类种类组成、多样性及相关环境因子作了分析。结果表明:冬季崇西湿地潮滩鱼类主要由淡水小型鱼类组成,共23种,隶属7科,20属。光滩和草滩插网的最大优势种皆为油,两种网具的渔获种类组成具一定的相似性。在一个潮周期内,3种多样性指数D、H′ 和J值波动范围较大,小汛潮时多样性指数比其它潮汛低。白天和晚上潮水的鱼类种类数无显著变化(P>0.5),但在个体数和生物量上白天较晚上潮水高(P<0.5)。水温、潮汐大小对潮滩鱼类丰度影响较大,而与盐度相关较小。此外,天气状况也是影响潮滩鱼类的一个重要因子。总之,潮滩鱼类的种类组成和多样性受到各种环境因子的综合影响。  相似文献   

10.
人与自然的对抗主要表现为四个方面:人类征服、改造甚至掠夺自然;自然又加倍报复人类;人类与动物争夺生存环境;人类与动物相互伤害。要实现人与自然从对抗走向和谐。必须树立人与自然和谐相处的自然观。改变传统的经济发展观。以及树立科学文明的消费观等等。  相似文献   

11.
In this paper, we present the first measurement of radon concentrations in drinking groundwater from private and public deep-bored wells located in the south-eastern area of Korea. The measurements were carried out on 439 samples by using a liquid scintillation method. The results show that the radon concentrations of the samples range from 0 to about 300 Bq l(-1). We find that Sasang ward shows the highest median value of radon concentration among 13 different wards, while Jung ward has the lowest. We find that the radon concentrations are highly dependent on the type of geological rock aquifers.  相似文献   

12.
The radon activity concentration in ground water from drilled and dug wells on the horst S?der?sen in Southern Sweden has been determined with two different methods, gamma activity measurements with a germanium HPGe detector and alpha activity measurements with plastic track detectors. The results are consistent. High activity concentration is connected to granite bedrock. Dug wells have low concentrations and no trivial correlation between concentration and depth of the well is found. Large local variations exist. Activity concentrations > 700 Bq/l appear to be associated with leakage from layers of volcanic origin. The concentration from drilled wells is found to be quite constant over a 3 year period but short time variations appear to be significant. Evaporation from the open surface of a normal cooking vessel is slow with an activity gradient delta A/A of about 0.1-0.2 per hour at room temperature whereas even modest heating of water in e.g. a coffee machine is very efficient and reduces the radon activity concentration by > 90% in one process.  相似文献   

13.
Data from 1,122 brine injection wells, 24,515 dry holes, 20,877 plugged oil/gas wells, and 256 water wells were mapped with a geographic information system (GIS) and statistically analyzed. There were 9, 107, and 58 water wells within 750 m of a brine injection well, dry hole, or plugged oil/gas well, respectively. Computed median concentrations were 157 mg/l for chloride, 0.8 mg/l for bromide, and 169 microg/l for barium. The maximum chloride concentration was 2,384 mg/l, close to 10 times the secondary drinking water standard. Shallow water wells and water wells near plugged oil/gas wells had significantly higher chloride and bromide levels.  相似文献   

14.
This study employed geographic information systems (GIS) technology to evaluate the vulnerability of groundwater to pesticide pollution in Thailand. The study area included three provinces, Kanchana Buri, Ratcha Buri, and Suphan Buri, located in west-central Thailand. Factors used for the vulnerability assessment included soil texture, slope, land use, well depth, and rainfall. These vulnerability factors were reclassified to a common scale, and a weighted average was computed to yield a vulnerability score. Vulnerability factors and weights were assigned considering pesticide concentrations in 90 wells throughout the study area. Well depth was the most significant vulnerability factor. Groundwater vulnerability maps were generated for several pesticides. The eastern, agricultural part of the study area has relatively deep wells and fine soils. Shallow wells are present in the mountainous west; however, fewer pesticides are applied in that region. Consequently, much of the study area had a medium groundwater vulnerability rating, although there were pockets of high vulnerability, for example, in agricultural areas with shallow wells. The groundwater vulnerability maps are effective for identifying locations warranting more detailed groundwater pollution and vulnerability investigations.  相似文献   

15.
The dynamics of wolf attacks on domestic ungulates at the levels of population group (the region of Central Forest Nature Reserve) and population (Tver oblast) have been analyzed over the period of 1971 to 2015. It has been found that the frequency of attacks increases during the phase of predator population growth under the effect of qualitative changes within the population. An increase in the frequency of attacks and the number of sheep and calves killed per attack also takes place in the summer–autumn period, as a consequence of training wolf cubs in methods of killing prey. Therefore, domestic animals are not only a source of food for the wolf but also an object for training the young.  相似文献   

16.
拟除虫菊酯杀虫剂对水生态系统的毒性作用   总被引:21,自引:0,他引:21  
拟除虫菊酯杀虫剂主要用于防治棉田、菜地、果树和茶叶上的农业害虫以及卫生害虫,也用于渔业生产上杀灭寄生虫。近几年来其使用量越来越大,是传统有机磷农药的替代品。它具有高效广谱、低残留的特点,对光稳定,在哺乳动物体内代谢、排泄迅速,但是对水生态系统危害较大。报道了拟除虫菊酯杀虫剂对水生生物的急、慢性毒性和中毒机理的研究进展,阐述了有待研究的方向。  相似文献   

17.
Contaminated wells, located in six south/western and western states of Nigeria, were sampled and analysed for pollution characteristics. Results of analysis indicated migration of contaminants into the wells from places where there was a potential source. There was a significant microbiological population in the wells placed near domestic waste sites. Also, there were excessive levels of trace heavy metals in those placed near metal dumping sites. On the other hand, the contaminants were minimal in wells that were not close to polluting sources. The studies revealed that groundwater contamination occurred primarily by dumping of wastes, wrong placement of waste disposal facilities, and improper construction of wells. The groundwater sources (wells, etc.) are used when pipe-borne water facilities are inadequate.  相似文献   

18.
Water quality for 13 wells in El-Salaam, in a new city near Cairo, has been investigated. Those wells were dug specifically to provide water for a company specializing in broiler poultry production. The water was analyzed for the following bacteriological parameters: total bacterial counts (102–104), total coliforms (<1?102), fecal coliforms (<1?102) fecal streptococci (<1?103), aerobic spore formers (102–104) and total counts for Clostridia (<1?103) per 100 mL. Chemical parameters such as pH, sulphate, alkalinity, hardness, and pesticides indicate that the water is unacceptable for poultry production. This study illustrates the need for monitoring and maintaining the integrity of groundwater sources at El-Salaam.  相似文献   

19.
Total organic halogen (TOX) was evaluated as a means to detect contamination of groundwater by halogenated organics. Groundwater samples from monitoring wells at 10 Canadian landfill sites were analyzed for carbon adsorbable TOX, total organic carbon and volatile organics. Low concentrations of TOX (range, ND-44; median 8 μg Cl L?1) were found at nine sites, and elevated TOX levels (?2072 μg Cl L?1) at the tenth site. This latter site was studied in greater detail, and TOX and GC-MS analyses were carried out for volatile, base neutral, and acid extractable fractions of the water in six monitoring wells at this site. The TOX and GC-MS techniques were found to provide complementary information. GC-MS analysis detected high concentrations of 1,2-dichloroethylene, trichloroethylene, toluene, and ethylbenzene in some of the wells. TOX measurements, however, indicated the presence of halogenated contaminants in the base-neutral and acid extractable fractions, which had not been detected by GC-MS.  相似文献   

20.
This paper presents the results of radon concentration measurements in the drinking water from the municipal water supply system and private wells located in the north-eastern part of Poland. The measurements were carried out on 643 samples using a liquid scintillation method. The mean value was found to be 5262 Bq m-3 with a maximum of 38347 Bq m-3. The samples were obtained from different water-bearing levels, i.e. surface water, deep borehole water and well water and have respective mean values of 3398, 5178 and 6155 Bq m-3. In 57 water samples, a guideline maximum level of 11,000 Bq m-3 was found to be exceeded. The observed radon concentration in water can contribute to a 2% increase in indoor radon concentration.  相似文献   

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