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571.
Tibetan forests are located in the southeastern Tibetan Plateau, where the climate is dominated by the Indian monsoon. Due to the affinity to pollution sources and high organic carbon stocks, the fate of persistent organic pollutants in the Tibetan forests should be given more attention. In this study, seven soil profiles were investigated to obtain the vertical distribution of the organochlorine pesticides and polychlorinated biphenyls (PCBs) in the Tibetan forest soil. The results indicate that the DDTs are highly stable in the soil, with limited volatilization and leaching, while the more volatile PCBs were found in the deeper mineral layer, which means that they can translocate through the organic layer and move farther downward into the deep soil. The air-to-ground fluxes (estimated by the age of the organic layer) of the DDTs are one magnitude higher than those reported in a study on the Alps, suggesting the higher accumulation of DDTs by the Tibetan forest.  相似文献   
572.
Main physicochemical and microbiological parameters of collected petroleum-contaminated soils with different degrees of contamination from DaGang oil field (southeast of Tianjin, northeast China) were comparatively analyzed in order to assess the influence of petroleum contaminants on the physicochemical and microbiological properties of soil. An integration of microcalorimetric technique with urease enzyme analysis was used with the aim to assess a general status of soil metabolism and the potential availability of nitrogen nutrient in soils stressed by petroleum-derived contaminants. The total petroleum hydrocarbon (TPH) content of contaminated soils varied from 752.3 to 29,114 mg kg?1. Although the studied physicochemical and biological parameters showed variations dependent on TPH content, the correlation matrix showed also highly significant correlation coefficients among parameters, suggesting their utility in describing a complex matrix such as soil even in the presence of a high level of contaminants. The microcalorimetric measures gave evidence of microbial adaptation under highest TPH concentration; this would help in assessing the potential of a polluted soil to promote self-degradation of oil-derived hydrocarbon under natural or assisted remediation. The results highlighted the importance of the application of combined approach in the study of those parameters driving the soil amelioration and bioremediation.  相似文献   
573.
In recent years, Dechloranes have been widely detected in the environment around the world.However, understanding and knowledge of Dechloranes in remote regions, such as the Arctic,remain lacking. Therefore, the concentrations of 5 Dechloranes in surface seawater, sediment,soil, moss, and dung collected from Ny-lesund in the Arctic were measured with the concentrations 93 pg/L, 342, 325, 1.4, and 258 pg/g, respectively, which were much lower than those in Asian and European regions. The mean ratios of anti-Dechlorane Plus(DP) to total DP(fanti) in seawater, sediment, soil, moss, dung, and atmospheric samples were 0.36, 0.21, 0.18,0.27, 0.66, and 0.43, respectively. Results suggested that the main source of DP in seawater,sediment, soil, and moss was long-range atmospheric transport. However, the ratio identified in dung was different, for which the migration behavior of the organism is probably the main source of DP.  相似文献   
574.
The difference between fishermen's fishing catch and the optimal fishing catch is the basic reason for the transaction of marine fishing rights (TMFR). The effects of productive cost, non-productive cost, use-cost, transaction cost, productive revenue and non-productive revenue on the TMFR and the optimal fishing catch are analyzed. This paper draws following conclu- sions: the non-productive revenue has a positive effect on the TMFR, and other factors, such as non-productive cost, usecost and transaction cost, have a negative effect; the TMFR will promote the resource allocation; the high transaction cost may affect the implementation of TMFR.  相似文献   
575.
长江流域城市生态环境问题与跨世纪持续发展战略   总被引:12,自引:2,他引:10  
综合分析评价了长江流域城市的生态环境态势与问题,城市水环境依然恶化,特别是城市内河道,湖泊水质多污染严重。城市大气污染仍是加重趋向,一些特大城市汽车尾气污染上升,城市酸雨依然严重。城市生态问题沉重,绿地不足,热岛加重,地面沉降,水土流失等。沉重的生态环境赤字已深刻影响到城市经济社会的发展。面对二十一世纪,论证了长江流域城市发展战略,走城市可持续发展之路是唯一战略选择,而建设现代化的山水园林生态城市  相似文献   
576.
Present analyses of random amplified polymorphic DNA (RAPD) and Biolog GN substrate utilization pattern are combined to further study the diversity of microbial communities in four soils affected by agricultural chemicals. The results showed that the four soil microbial communities were apparently distinguishable in the diversity at RAPD level in terms of the richness and modified richness in the summer, which supports our previous report using the same soils in winter. A significant difference for the average well color development (AWCD) at 72 h incubation was found among the soils in winter using Biolog GN substrate utilization pattern, but this difference was not found among the soils in summer. However, Shannon-Weaver indices for microbial communities in the summer soils polluted by agricultural chemicals were significantly higher than those in winter at metabolic level; in contrast, no significant difference existed between the two seasons for microbial communities in the soil without chemical pollution. Present results suggest that the combined approach using RAPD and substrate utilization pattern could be used to effectively quantify microbial community diversity and its changes among the seasons in the soils affected by agricultural chemicals, simultaneously at molecular and physiological levels.  相似文献   
577.
广东省香蕉寒害风险分析   总被引:10,自引:2,他引:8  
根据各地寒害及香蕉的产量资料,从寒害对香蕉产量的影响出发,对广东省各地香蕉的灾损率、易灾性进行了分析,以寒害风险指数作为区划指标,对广东省的香蕉寒害风险进行了区划,并作了分区评述。  相似文献   
578.
改性氢氧化钙粉体的研制及其特性   总被引:1,自引:0,他引:1  
介绍了作为氯气清除剂的粉体应具有的特性,并对粉体的研制方法进行了简单叙述。同时,对改性氢氧化钙粉体特性作了详细介绍。不难看出,研制的改性氢氧化钙粉体具有高度活性,与氯气捕消器配合使用,将成为氯气泄漏时的抢险措施  相似文献   
579.
烧麦秆与大气污染   总被引:2,自引:0,他引:2  
王正心  高红 《四川环境》1997,16(4):35-38
本文就近3年来成都市周围烧麦杆,油菜秆所引起的大气环境污染的原因,危害加以分析,并提出对策及建议,由于成都市经济的高速发展,周围农村中不再用麦秆和油菜秆作为燃料而全部焚烧作肥料还田,同时由于3月多发生不利于大气污染物扩散的逆温现象及城市热岛效应,造成我市环境空气的严重污染,建议从立法、宣传及爱护资源等方面来改善人们的刑法陋习和加强对成都市大气环境的保护。  相似文献   
580.
THEPRELIMINARYTHEORYOFCOMMANDPREPARATIONSONURBANSEISMICDISASTERRESCUEANDRELIEFYaoQinglin(姚清林)(TheInstituteofGeology,StateSeis...  相似文献   
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