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531.
Unless the change in emissions is substantial, the resulting improvement in ozone air quality can be easily masked by the meteorological variability. Therefore, the meteorological and chemical signals must be separated in examining ozone trends. In this paper, we discuss the use of the Kolmogorov-Zurbenko filter in evaluating the temporal and spatial variations in ozone air quality utilizing ozone concentration data from several monitoring locations in the northeastern United States. The results indicate a downward trend in the ozone concentrations during the period 1983-1992 at most locations in the northeastern United States. The results also reveal that ozone is a regional-scale problem in the Northeast.  相似文献   
532.
533.
Organochlorine pesticide residues in sediment and fish samples collected from the east and west coasts of India are presented. HCH isomers and DDT and its metabolites are the predominantly identified compounds in most of the samples. Despite the higher quantity of consumption, HCH and DDT levels in fish in India were lower than those in temperate countries suggesting a lower accumulation in tropical fish, which could be due to rapid volatilization and degradation of these insecticides in the tropical environment. The predominance of alpha- and beta-HCH reflect the use of technical grade HCH in India. The high temperature in the tropics also enhances the elimination rate of chemicals in fish, as the biological half-lives of semivolatile compounds such as DDT are short at high temperature.  相似文献   
534.
535.
Effluents from wastewater treatment plant (WWTP) have been reported to have a broad spectrum of endocrine disrupting compounds (EDCs). The majority of studies have focused on the occurrence of estrogenic activity, while ignoring nuclear hormone receptors (NRs) pathways. In the present study, a battery of in vitro yeast bioassays and a cell bioassay, including antagonistic and agonistic effects on estrogen receptor (ER), androgen receptor (AR), progesterone receptor (PR), estrogen- related receptor (ERR) and aryl hydrocarbon receptor (AHR), were conducted to evaluate the removal efficien- cies of EDCs by different treatment processes of a WWTP located in Beijing. Estrogenic, anti-estrogenic, anti- androgenic, anti-progesteronic, anti-ERR and the activa- tion of AHR activities were detected in samples from all treatment processes and the receiving water. The concen- tration of estrogenic contaminants with estradiol (E2) equivalent concentrations ranged from 0.82 x 10-9 to 3.54 x 10 9g Ee_EQ.L-1. The concentration of anti-estrogenic contaminants with 4-hydroxytamoxifen (4-OHT) equiva- lent concentrations ranged from 1.24 × 10-6 to 2.36 x 10-6 g 4-OHT-EQ.L-1. The concentration of anti-androgenic contaminants ranged from 2.21 x 10-s to 3.52 × 10-6g flutamide-EQ. L-1. The concentration of anti-progesteronic contaminants ranged from 3.15 x 10^-5 to 2.71 x 10^-4g RU486-EQ. L-1. The concentration of anti-ERR contami- nants ranged from 7.09 x 10-5 to 6.50 x 104 g 4-OHT-EQ × L^-10. The concentration of AHR activators ranged from 1.7 × 10-10 to 3.4 × 10^-10g TCDD-EQ-L-1. These processes including secondary clarifier, coagulation, as well as coal and sand filtration could eliminated 67.2% of estrogenic contaminants, 47.0% of anti-estrogenic contaminants, 98.3% of anti-androgenic contaminants, 88.4% of anti- progesteronic contaminants, 65.4% of anti-ERR contami- nants and 46.9% of AHR activators. WWTP effluents contain multiple receptor disruptors may have very complex adverse effects on exposed organisms.  相似文献   
536.
Centralized sewage treatment plants may not be a sustainable solution for a developing country such as India. Therefore, we conducted for the first time an integrated assessment of the different technologies currently used for sewage treatment in the state of West Bengal, India. Five decentralized sewage treatment plants and one centralized sewage treatment plant located in different parts of Kolkata were evaluated. We compared influent and effluent water quality, energy consumed, capital and operating costs, and treated wastewater reuse potential. F test was used to validate results on the effect of working days and holidays and seasons on treated water quality. Wastewater management strategy was assessed by performance indicators. Our results show that treatment efficiency was lowest in anaerobic plants not because of faulty technology but due to unskilled operation. Therefore, performance improvement of plants is expected if factors such as monitoring, training of staff, regular and scrupulous desludging, reuse aspects, and rational water tariff are implemented earnestly.  相似文献   
537.
环境雌激素(Environmental Estrogens, EEs)种类繁多、来源多样且分布广泛,大量工业添加剂、食品添加剂和农药类物质已被证实具有雌激素活性。EEs对人体生殖、神经、免疫等系统生物毒性,已经引起了公众的普遍关注。近年来的研究表明,EEs不仅可以结合雌激素核受体(nuclear Estrogen Receptor, nER)干扰正常的雌激素基因组信号通路,还能活化雌激素膜受体(membrane Estrogen Receptor, mER)引发快速的雌激素非基因组信号转导途径。本文总结了EEs通过nER、mER介导的多种雌激素基因组和非基因组信号途径及其产生的生物学效应,综述了在其毒理学作用机理基础上发展的环境样品的雌激素活性评估和EEs混合物的联合作用研究,以期为该类污染物的筛查、风险评估和进一步的机制研究提供参考。  相似文献   
538.
Traditional Central Himalaya societies face a range of socio-economic and environmental problems. The potential of science and technology has not yet been adequately and appropriately harnessed to overcome the development constraints posed by the fragile Himalayan environment. Thus there is a need for large-scale establishment of technology resource centers. The Garhwal Unit of GB Pant Institute of Himalayan Environment and Development established rural technology demonstration and training centers in three different agroecological zones between 550 and 2200 m asl and in 13–15 locations, with suitable technologies based on appropriate use and management of locally available bio-resources that ensure people participation. About 35 on-site training courses were organised for about 2329 participants. The participants were given on-site demonstrations, training and technical know-how on various technologies, to enable farmers to better understand problems faced during implementation of new technologies for sustainable management of natural resources. An action research framework and training manuals were also developed in consideration of local socio-economic condition. The documentation and analysis of research (quantitative and qualitative) and data related to cost–benefit analysis of the technologies adopted by farmers generated through this study has created wider sharing of farmer training outputs, at farm level, amongst the scientific communities and with policy planners.  相似文献   
539.
SUMMARY

A rich diversity of traditional crops occurs generally in the Himalaya and more particularly in Central Himalaya. Over forty species of food grains are grown in traditional agroecosystems of Central Himalaya, which have been managed by the local farming communities since time immemorial. These traditional crop varieties have evolved over centuries and are well adapted to the particular area. A number of edaphic, topographic and climatic factors associated with different selection pressures over centuries of cultivation resulted in immense variations in the crop species.

The grain and by-product yield of the majority of the traditional crops cultivated across an altitudinal gradient were worked out and compared with common food crops (paddy, wheat, mustard) at two points in time (1970-74, 1990–94) and it was found that almost all the traditional crops had slightly higher yields during 1970–74 than between 1990–94. However, common food crops grown during the Kharif season had higher yields during 1990–94 whereas, Rabi season crops exhibited higher yield during 1970–74. The yield of rainfed paddy remained static over the years across the altitudinal gradient. Among the traditional crops cultivated during the Kharif and Rabi seasons in mixed and pure forms at different altitudes were Macrotyloma uniforum (at higher altitude), Parilla frutescens and Vigna mungo (at middle altitude) and Panicum miliaceum (at lower altitude) which were found to be eco-energetically efficient. Avena sativa (oat) and mixed cropping of Fagopyrum esculentum and potato had higher energy efficiency ratios whereas the latter also exhibited a higher monetary output/input ratio. Crops like paddy and wheat with mustard, grown in irrigated land were found to be more eco-energetically efficient than the same crops grown in the rainfed land. In general, traditional crops possess higher nutritive value than the common food crops. The contribution of traditional crops to the local diet (kg/capita/year) and their energy and protein equivalents were higher during both time periods. It was observed that while exporting these traditional crops, the locals of the region are highly exploited by middlemen. Despite having huge potential, traditional crop diversity of this region has been reduced to a great extent during the last two decades. Besides, the area under cultivation with these crops has been declining rapidly. However, many of these crops possess immense potential to meet the growing food demand and ensure food security of an increasing population. Therefore, a comprehensive programme of conservation through various means and improvement of agronomic yield in their natural habitats is urgently needed.  相似文献   
540.
2,4,6-trichlorophenol (2,4,6-TCP) is a widespread probable human carcinogen and has been proven to have genotoxicity in in vitro assays. However, little genotoxicity information and no micronuclei induction data for 2,4,6-TCP is available from in vivo tests, especially for sex-specific differences. Following a preliminary test, a piscine peripheral erythrocyte micronucleus assay was conducted on medaka (Oryzias latipes) after a 28-day exposure to 2,4,6-TCP. In the present study, the mean micronuclei (MNC) frequencies of all of the groups increased in a dose-dependent manner, which indicated the potential genotoxicity of 2,4,6-TCP. Moreover, males were found to be more susceptible compared with females after a 28-day exposure to 2,4,6-TCP in all of the dosed groups above 10 μg·L?1. This is the first report on the potential of micronuclei induction and a sex-susceptible effect in the peripheral erythrocytes of mature fish after 2,4,6-TCP in vivo exposure.  相似文献   
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