首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
4.
Principles of the theory of the ecological mechanism of water self-purification based on multiple functions of the biota in freshwater and marine ecosystems are formulated. In developing this theory, the results of the author's experiments with filtering hydrobionts have been used. These results indicate that the water self-purification mechanism is vulnerable to the impact of some pollutants and, in particular, surfactants. Conclusions drawn on the basis of the theory have practical significance for biodiversity conservation and for the sustainable use of the biological resources of aquatic ecosystems.  相似文献   

5.
本文采用复杂网络分析方法,结合区域分析与相似性分析,比较了十大进口国(地区)原油贸易空间结构差异.复杂网络分析旨在以入度、权重及结构熵勾勒出十大原油进口国(地区)石油贸易的拓扑结构差异,并在拓扑结构分析中结合区域分析以揭示十大贸易国(地区)原油进口贸易空间格局构成之不同;相似性分析则是在拓扑结构和空间结构研究基础上,进一步量化了十大进口国(地区)的空间结构差异程度及区位在进口国(地区)原油贸易空间格局形成中的作用.研究表明,主要进口国与地区的原油进口贸易空间结构存在显著差异.而地理区位差异越大的国家与地区间,贸易空间结构差异越大.除中国外,各原油进口大国与地区更倾向于选择较经济的进口地域;显著的多元化与均质化则导致了中国贸易空间格局的不经济.研究结果提示我们,多元化不应以过多牺牲经济性为前提,中国应权衡所面临的客观环境选择适合区域合作伙伴,才能更好的落实多元化进口策略,切实解决可能面临的石油安全问题.  相似文献   

6.
Tolerance of Freshwater Invertebrates to Changes in Water Salinity   总被引:5,自引:0,他引:5  
Tolerance to an increase or decrease in water salinity was studied in experiments with some species of freshwater turbellarians, oligochaetes, leeches, mollusks, crustaceans, caddis flies, biting midges, and chironomids from water bodies of the Upper Volga basin. Insect larvae and crustaceans were most tolerant, whereas mollusks and leeches were sensitive to a decrease in water salinity. Specific responses of the studied species to changes in water salinity were revealed.  相似文献   

7.
The contents of 90Sr and 137Cs and the pattern of their redistribution in the soil and plant cover of floodplain ecosystems have been assessed. It is shown that the radionuclide distribution across the floodplain and along the river flow is determined by the formation of a barrier to their migration near the river channel, at which less mobile 137Cs accumulates. The soil and plant cover of the central floodplain are enriched with 90Sr. Differences in radionuclide migration in floodplain soils and their input into plants are determined by the relationship between the processes of their immobilization and migration with soil water.  相似文献   

8.
Cadmium (Cd) is considered as a potential toxin that is principally dispersed in natural and agricultural environments through anthropogenic sources. Untreated municipal sewage, often a potential source of Cd, is generally used to irrigate urban agricultural soils in many developing countries. A study was carried out to determine Cd concentration in untreated municipal sewage and sewage-irrigated soils and vegetables. The metal ion concentration in municipal sewage was found 3-fold (0.03mgL–1) its permissible concentration in irrigation water (0.01mgL–1). Ammonium bicarbonate–diethylene triamine pentaacetic acid NH4HCO3–DTPA) extractable Cd concentration in top 0.15m soil ranged between 0.25 and 0.34mgkg–1. Soil Cd concentration was significantly correlated with soil clay content, pH, electrical conductivity, and cation exchange capacity. Cadmium availability index (CDI) decreased with an increase in soil depth. The metal ion was found in leaf (0.17–0.24mgkg–1 fresh weight) and fruit (0.07–0.18mgkg–1 fresh weight) portions of all the sampled vegetables: bitter gourd (Momordica charantia L.), cauliflower (Brassica oleracea L.), eggplant (Solanum melongena L.), fenugreek (Trigonella foenumgraecum L.), okra [Abelmoschus esculentus (L.) Moench], onion (Allium cepa L.), pumpkin (Cucurbita pepo L.), and spinach (Spinacia oleracea L.). Leafy tissue accumulated Cd about twice that of the fruit portion. Our results suggest that prolonged ingestion of sewage-irrigated leafy vegetables can develop such Cd levels in human body that may cause a number of illnesses.  相似文献   

9.
The distribution of fine conducting roots of Siberian spruce, Siberian fir, and Scotch pine over the soil profile was studied in the taiga ecosystems polluted with heavy metals and SO2. Under conditions of heavy pollution, tree roots were not found in the forest litter. Regardless of the level of technogenic load, the largest amount of conducting roots concentrated in the upper layer of mineral soil.  相似文献   

10.
Changes in the properties and ecological functions of soils under the effect of farming are considered. Evidence is provided that optimization of the structure of land inventory with regard to environmental conditions in a concrete region is a promising approach to the conservation and restoration of disturbed and degraded soils. A classification of soils with respect to their arability is proposed as a theoretical basis for reorganizing agricultural land use.  相似文献   

11.
本文从城市土壤中重金属元素的污染来源、污染危害、污染空间特征、污染评价方法和治理方法等方面来对我国城市土壤重金属污染问题的研究进展进行综述,并提出了相关的治理对策建议。  相似文献   

12.
The amount of several air pollutants emitted in some cities including Hangzhou, Ningbo, Huzhou, Shaoxing and Jiaxing of Zhejiang Province is based on pollution source census data of Zhejiang Province in 2010. This paper focused on the release of air pollutants such as NOx, SO2, CO, PM2.5, PM10 and VOC, and calculated the total amount of those air pollutants. It analyzed air pollutant emission factors and found that the electricity and heat production industry released the largest amount of pollutants.  相似文献   

13.
The amount of several air pollutants emitted in some cities including Hangzhou,Ningbo,Huzhou,Shaoxing and Jiaxing of Zhejiang Province is based on pollution source census data of Zhejiang Province in 2010.This paper focused on the release of air pollutants such as NO_(x2),SO_2,CO,PM2.5,PM10 and VOC,and calculated the total amount of those air pollutants.It analyzed air pollutant emission factors and found that the electricity and heat production industry released the largest amount of pollutants.  相似文献   

14.
The influence of the Kosogorsky Metallurgical Plant (KMP; Tula region, Russia) on the abundance and biodiversity of carabid beetles and soil macrofauna and on the trophic activity of soil biota was studied. Metal concentrations in the impact plot were many times higher than those in the control plot located on the same transect. As the transect approached KMP, both the abundance of soil invertebrates (geobionts) and trophic activity of the soil biota remained unchanged, whereas the abundance and diversity of carabids (herpetobionts) decreased drastically. It is suggested that the impact of the KMP on herpetobionts is accounted for by modification of the structure of ecosystems and that herpetobiontic and geobiontic groups of the macrofauna respond differently to this impact because of differences in the ecological mechanisms of population response.  相似文献   

15.
The main causes of non-point source pollution in Taihu Lake are the improper ways of crop production, animal husbandry, and daily runoff. The paper discusses the relationship between countrywomen and non-point source pollution control by 731 questionnaires in Weidu village and 466 questionnaires in Dapu Town. The roles of countrywomen have changed in families and they have close relationship with non-point source pollution. Furthermore, we discuss the possibility and methods of organizing countrywomen in non-point source pollution control.  相似文献   

16.
战争造成的环境创伤是巨大的,本文以详实的背景资料,通过海湾战争、越南战争等实例,分类描述了现代战争中爆炸物、生化武器、泄漏物等对大气环境、水环境、土壤环境、气候以及地质结构的影响,并由此剖析战争原因,通过处理好本国利益与全人类利益、增强综合国力与人类长远利益、反对霸权主义与打击恐怖主义三对关系,在法律的框架下让人类远离战争,提出了促进世界和平和可持续发展的行动建议。  相似文献   

17.
农田非点源污染带给我国水环境的污染负荷越来越大,现行的水资源保护标准体系尚不完善,且明显缺位,难以对农田水环境污染进行定量化管理和控制。本文分析了建立农田水污染物排放标准的必要性,阐述了建立该标准应遵循的原则,构建了将农田管理与污染物排放相协调的农田水污染控制标准框架与体系,探索该标准在实践过程中的推行机制,为该标准制定和实施进行了前瞻性研究。  相似文献   

18.
中国环境污染密集型产业脱钩的异质性及产业转型   总被引:1,自引:0,他引:1  
根据现有文献,研究中国的经济增长与环境污染的脱钩,需要将不同环境密集型产业与经济增长的关系分别测算,然后进行比较。本文选取了工业污染的三大来源——废水、废气和固体废物,每种污染源对应着一类环境密集型产业。这三种产业密集排放的污染物的量与经济增长之间的脱钩关系及其内在机制,这是本文研究的重点。本文借鉴Tapio弹性分析模型构建了我国经济增长与不同环境密集型产业之间的脱钩状态的分析模型,并对脱钩状态和程度的判定标准做了规定。随后,对2001-2009年四个时期的经济增长与不同环境密集型产业集中排放的污染物的量之间的脱钩指数进行了测算,同时测算了各产业污染的工业产值弹性及其工业产值的GDP弹性,并对脱钩状态和程度做了判定。结果表明:三类产业的脱钩程度各不相同,其动力机制与发展前景也有所不同,因而需要有针对性地采取规制和治理措施。  相似文献   

19.
20.
The taxonomic composition, concentration, and distribution of meroplankton have been studied in Gaidamak Bight, Peter the Great Bay, chronically exposed to anthropogenic impact. It has been demonstrated that, in addition to larvae of benthic invertebrates resistant to pollution, the larvae of other species are always abundant in the bight. They drift with currents from neighboring clean water areas, thus maintaining the high reproductive potential of meroplankton in the bight. Therefore, if this water area was cleared of pollutants, it could be populated again by species that have disappeared from it.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号