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藻垫对湖泊水体水华发生是否有影响及影响机制是目前水体富营养化研究的一个前沿课题。本文以北京南海子湖为例,研究湖底藻垫对水体水华爆发的影响。通过对干燥藻垫和水华过程新产生的藻垫进行培养对比实验,揭示不同时期形成的藻垫对水体藻生物量的影响即水华的影响。结果表明,不同干燥时间的藻垫均对水体藻生物量有影响,进入藻生长平台期,水体叶绿素a浓度范围为15~20 μg/L,而灭菌后的藻垫培养水体中叶绿素a浓度低于10 μg/L;水华爆发后新生成的藻垫对水体藻生物量也有贡献,培养水体叶绿素a范围也达到15-20 μg/L;干燥时间对藻垫培养后水体浮游植物生物量的影响较弱。 相似文献
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不同土壤重金属复合污染的有效态离子冲量表征 总被引:4,自引:0,他引:4
选择红壤、黄棕壤和潮土为对象,依据中国土壤环境质量二级和三级标准确定土壤重金属铜、锌、镉的污染浓度,通过生物盆裁试验研究在重金属Cu、Zn、Cd复合污染条件下牧草(黑麦草、紫花苜蓿)体内重金属含量和土壤中重金属有效态含量的相关性,结果表明,在3种不同性质的污染土壤上,牧草体内重金属的离子冲量与其对应土壤中重金属有效态的离子冲量之间均存在明显的相关性。校正土壤pH、牧草品种等因素后,土壤有效态离子冲量可以有效表征不同土壤-牧草系统的重金属复合污染。 相似文献
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The ethnic communities of Lugu Lake have experienced the rapid development of tourism because of the attractions of their culture and traditional customs as well as their beautiful environment. Tourism and other economic activities have a variety of socio-cultural effects on host communities. Based on a survey of 105 Mosuo families, statistic correlation analysis was used to examine the local people's viewpoints regarding marriage, language, traditional dress, diet, and factors which could lead to changes in people's opinions. The results show that although Mosuo people are more open to the outside world, Axia relationships and matrilineal families still dominate their life. More than 50% of interviewees have Axia relationships and live in matrilinear families. Tourism income, education and age are three important factors that impact on local people's viewpoints regarding their culture and life. People who are more educated and earn more money from tourism prefer traditional culture and customs. The younger generation is more likely to be affected by tourism because they have contact with the outside world more often in their everyday life. Further research is needed on how to protect the local culture from the boom in tourism, as well as how to minimise its influence on local residents. 相似文献
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Qin QZ Chen Y Fu TT Ding L Han LL Li JC 《Environmental monitoring and assessment》2012,184(3):1533-1540
To understand electromagnetic radiation field strength and its influencing factors of certain 110-kV high-voltage lines in
one urban area of Chongqing by measuring 110-kV high-voltage line’s electromagnetic radiation level. According to the methodology
as determined by the National Hygienic Standards, we selected certain adjacent residential buildings, high-voltage lines along
a specific street and selected different distances around its vertical projection point as monitoring points. The levels of
electromagnetic radiations were measured respectively. In this investigation within the frequency of 5–1,000 Hz both the electric
field strength and magnetic field strength of each monitoring sites were lower than the public exposure standards as determined
by the International Commission on Non-Ionizing Radiation Protection. However, the electrical field strength on the roof adjacent
to the high-voltage lines was significantly higher than that as measured on the other floors in the same buildings (p < 0.05). The electromagnetic radiation measurements of different monitoring points, under the same high-voltage lines, showed
the location which is nearer the high-voltage line maintain a consistently higher level of radiation than the more distant
locations (p < 0.05). Electromagnetic radiation generated by high-voltage lines decreases proportionally to the distance from the lines.
The buildings can to some extent shield (or absorb) the electric fields generated by high-voltage lines nearby. The electromagnetic
radiation intensity near high-voltage lines may be mitigated or intensified by the manner in which the high-voltage lines
are set up, and it merits attention for the potential impact on human health. 相似文献
340.
Yan Wang Xiaowen Ding Longxia Qian Hongrui Wang 《Frontiers of Environmental Science & Engineering》2007,1(3):320-324
Urban green land compensation plays an important role in county development, ecological environment management and many other fields. The concept, methods and principles of urban green land are introduced in this paper. According to the pay fee method, the value and ecological function of various types of urban green land were analyzed. The cost-benefit analysis method (CBAM) was used to estimate different external diseconomy benefits caused by green land loss. The authors applied CBAM to estimate such benefits in the case of Shanghai, China, and calculated the actual compensation value for green land. Results indicated that in 2002, the compensation value for the green land of Shanghai was RMB 8.58 × 105 Yuan/hm2. 相似文献