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911.
城市污泥毒性有机物对草履虫综合毒性研究 总被引:1,自引:0,他引:1
本文以好氧发酵处理前、后城市污泥中毒性有机物提取液为实验液,以草履虫为实验动物进行了综合毒性研究。结果表明:好氧发酵前的实验液对草履虫的半致死浓度为5593mg/l,发酵后的实验液对草履虫的半致死浓度为56053mg/l。 相似文献
912.
Ximing Cai 《Journal of the American Water Resources Association》2005,41(3):679-692
ABSTRACT: This paper examines irrigation water supply deficit and associated risk indicators due to random climate events and potential effects on irrigated food production during the period 1996 to 2025 for seven river basins in the USA, China, and India. An integrated water and food model with global scope is applied for the analysis. The global climate regime during 1961 to 1990 is used to generate 30 climatic scenarios for the time period 1996 to 2025, and these scenarios are applied to the model in order to characterize the randomness of precipitation, runoff, and evapotranspiration, which affects both irrigation water supply and demand. The risk with random climate events is represented by reliability, variability, and vulnerability from different perspectives. Regarding irrigation water supply, Colorado will bear an increasingly unstable situation although the average water supply relative to the demand will maintain at a relatively high level; selected basins in China and India indicate that significantly lower levels of reliability and more deleterious affects from drought can be expected, but under a less variable condition due to assumed water storage increase. From 1996 to 2025, the effects of water deficits on irrigated food production are characterized with a nonlinear phenomenon and food production loss will be more sensitive to irrigation water supply deficit in the future. Future work following this paper needs to consider the impact of global climate change and the water quality of the irrigation return flow and result verification by local studies. 相似文献
913.
Only 1-2 percent of discarded dry batteries are recovered in China. It is necessary to find an economic and environmentally friendly process to recycle dry batteries in this developing country. Bioleaching is one of the few techniques applicable for the recovery of the toxic metals from hazardous spent batteries. Its principle is the microbial production of sulphuric acid and simultaneous leaching of metals. In this study, a system consisting of a bioreactor, settling tank and leaching reactor was developed to leach metals from nickel-cadmium batteries. Indigenous thiobacilli, proliferated by using nutritive elements in sewage sludge and elemental sulphur as substrates, was employed in the bioreactor to produce sulphuric acid. The overflow from the bioreactor was conducted into the settling tank. The supernatant in the settling tank was conducted into the leaching reactor, which contained the anode and cathodic electrodes obtained from nickel-cadmium batteries. The results showed that this system was valid to leach metals from nickel-cadmium batteries, and that the sludge drained from the bottom of the settling tank could satisfy the requirements of environmental protection agencies regarding agricultural use. 相似文献
914.
915.
在分析图书馆文化和图书馆能力的基础上,说明了图书馆文化和图书馆能力的辩证关系,进而探讨了图书馆文化在图书馆能力建设中是原动力,是一种心理和思想协调,强调的是人的发展,因而,体现了图书馆文化在图书馆能力建设中的价值. 相似文献
916.
本文报道了1979年天山巴半布鲁克区外贸站从博斯腾湖引进麝鼠1000余只,放养 于巴音布鲁克大小尤勒都期治泽地后10年内的资源消长,本报记者麝鼠不同栖息地的环境状况,外形特征,引进麝射种的利弊及其保护利用等问题。 相似文献
917.
Nitrous oxide and dinitrogen emissions from soil under different water regimes and straw amendment 总被引:13,自引:0,他引:13
In a laboratory study, soil amended with and without wheat straw (2.8 g kg(-1) soil) was incubated under 70% water holding capacity (WHC), continuously flooded and flooded/drained cycle conditions at 30 degrees C for 51 days. Dinitrogen and N2O evolution and ammonia volatilisation were measured during the incubation. Extractable NH4+-N and NO3--N were determined at the end of the incubation. Entrapped N2, N2O, and dissolved NH4+-N and NO3--N in drainage water were measured in the flooded/drained cycle treatment when the floodwater was drained. The results indicated that N loss through ammonia volatilisation was undetected in all treatments due to the low soil pH value (pHH2O= 5.87) and no air movement. The recovery of urea-15N as N2 was lowest in the continuously flooded treatments (0.75% and 0.96% with and without straw amendment, respectively), highest in the 70% WHC treatments (5.65% and 4.41%, respectively), and intermediate in the flooded/drained cycle treatments (1.79% and 2.65%, respectively). The recovery of urea-15N as N2O was in the same order as that of N2, negligible in the continuously flooded treatments, 0.01% and 0.07% in the flooded/drained cycle treatments, and 1.29% and 2.23% in the 70% WHC treatments, respectively. Peak N2O evolution rates were observed after the floodwater was drained but no substantial evolution was found after the soil was reflooded following drained periods. However, peak N2 evolution rates were observed after the onset of both drainage and re-flooding. Considerable quantities of N2 but no detectable N2O were entrapped in the flooded soil. 相似文献
918.
城市生活垃圾问题研究的系统动力学方法 总被引:5,自引:0,他引:5
蔡林 《环境污染治理技术与设备》2006,7(5):65-69
利用被称为战略与策略实验室的系统动力学方法,建立了城市生活垃圾问题的系统动力学研究模型;以北京市为实例,探讨了垃圾排放及污染随人口和经济发展的变化,以及污染和占地损失、绿色GDP核算、居民家庭、企事业单位生活垃圾与建筑垃圾组合收费方案等问题. 相似文献
919.
蔡立 《生态与农村环境学报》1995,(1)
用生物测定方法测定了土壤中绿磺隆残留量,建立了绿磺隆浓度(Y)与玉米根长(X)之间的相关模式:Y=30.562-36.38InX+14.828(InX) ̄2+2.043(InX) ̄3.此模式适用于土壤中0.1~4.0μg/kg浓度范围的绿磺隆残留量测定,最低检出量为0.1μg/kg。 相似文献
920.