首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   88篇
  免费   0篇
废物处理   5篇
环保管理   1篇
综合类   3篇
基础理论   19篇
污染及防治   33篇
评价与监测   21篇
社会与环境   6篇
  2023年   1篇
  2022年   12篇
  2021年   9篇
  2020年   1篇
  2019年   2篇
  2018年   3篇
  2017年   6篇
  2016年   2篇
  2015年   1篇
  2014年   6篇
  2013年   11篇
  2012年   2篇
  2011年   6篇
  2010年   3篇
  2009年   1篇
  2008年   4篇
  2007年   3篇
  2006年   6篇
  2005年   2篇
  2004年   2篇
  2003年   1篇
  2002年   4篇
排序方式: 共有88条查询结果,搜索用时 15 毫秒
61.
An attempt has been made in this study to evaluate the groundwater quality in two industrial blocks of Ghaziabad district. Groundwater samples were collected from shallow wells, deep wells and hand pumps of two heavily industrialized blocks, namely Bulandshahar road industrial area and Meerut road industrial area in Ghaziabad district for assessing their suitability for various uses. Samples were collected from 30 sites in each block before and after monsoon. They were analyzed for a total of 23 elements, namely, Ag, Al, As, B, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, Se, U, V, and Zn. In addition to these elements, some other parameters were also studied viz: color, odor, turbidity, biological oxygen demand, chemical oxygen demand (COD), dissolved oxygen, total dissolved solids and total suspended solid. The water quality index was also calculated based on some of the parameters estimated. Out of the 23 elements, the mean values of 12 elements, namely, Al, As, Ca, Cd, Cr, Mg, Mn, Na, Ni, Pb, Se, and U, were higher than the prescribed standard limits. The concentrations (in milligram per liter) of highly toxic metals viz., Al, As, Cd, Cr, Ni, Pb, Se, and U, ranged from 1.33–6.30, 0.04–0.54, 0.005–0.013, 4.51–7.09, 0.14–0.27, 0.13–0.32, 0.16–2.11, and 0.10–1.21, respectively, in all groundwater samples, while the permissible limits of these elements as per WHO/BIS standards for drinking are 0.2, 0.01, 0.003, 0.05, 0.07, 0.01, 0.04, and 0.03 mg L?1, respectively. The EC, pH, and COD in all samples varied from 0.74–4.21, 6.05–7.72, and 4.5–20.0 while their permissible limits are 0.7 dS m?1, 6.5–8.5, and 10 mg L?1, respectively. On the basis of the above-mentioned parameters, the water quality index of all groundwater samples ranged from 101 to 491, and 871 to 2904 with mean value of 265 and 1,174 based on two criteria, i.e., physico-chemical and metal contaminations, respectively while the prescribed safe limit for drinking is below 50. The results revealed that the groundwater in the two blocks is unfit for drinking as per WHO/BIS guidelines. The presence of elements like As, Se, and U in toxic amounts is a matter of serious concern.  相似文献   
62.
Here, we develop a mathematical model which investigates the impact of growing population and rampant mining on forest resources, present in an urban region. In order to demonstrate the effect imposed by the overgrowing population on the environment, population pressure is incorporated in the model, which augments mining activities in the given region. The obtained model is studied qualitatively using stability theory of differential equations, while it is quantitatively analyzed through numerical simulation. The results of the model reveal that a whopping increase in unchecked mining activities, induced through excessive population growth, leads to declination of forest resources in a region. Therefore, sustainable mining is suggested through control measures imposed by the government on mining activities.  相似文献   
63.
Status of insecticide contamination of soil and water in Haryana, India   总被引:2,自引:0,他引:2  
Twelve samples each of soil and ground water were collected from paddy-wheat, paddy-cotton, sugarcane fields and tube wells from same or near by fields around Hisar, Haryana, India during 2002–2003 to monitor pesticide residues. Residues were estimated by GC-ECD and GC-NPD systems equipped with capillary columns for organochlorine, synthetic pyrethroid and organophosphate insecticides. In soil, HCH (0.002–0.051 μg g−1), DDT (0.001–0.066 μg g−1), endosulfan (0.002–0.039 μg g−1) and chlordane (0.0002–0.019 μg g−1) among organochlorines, cypermethrin (0.001–0.035 μg g−1) and fenvalerate (0.001–0.022 μg g−1) among synthetic pyrethroids and chlorpyriphos (0.002–0.172 μg g−1), malathion (0.002–0.008 μg g−1), quinalphos (0.001–0.010 μg g−1) among organophosphates were detected. Dominant contaminants were DDT, cypermethrin and chlorpyriphos from the respective groups. In water samples, HCH, DDT, endosulfan and cypermethrin residues were observed frequently. Only chlorpyriphos among organophosphates was detected in 10 samples. On consideration of tube well water for drinking purpose, about 80% samples were found to contain residues above the regulatory limits.  相似文献   
64.
Abstract

This study reports degradation of azoxystrobin (AZOXY) and imidacloprid (IMIDA) in the rice straw (RS)/corn cob (CC) and peat (P)/compost (C)-based biomixtures. The effect of biomixture preconditioning (10?days incubation prior to pesticide application), pesticide concentration and moisture content was evaluated. Results suggested that conditioning of biomixture greatly affected IMIDA degradation where half-life (t1/2) was reduced by 5–9 times. This was attributed to higher microbial biomass carbon content and dehydrogenase activity in the conditioned biomixtures. Pesticide application in the conditioned biomixture did not show any negative impact on soil microbial parameters. Both pesticides degraded at faster rate in the rice straw-based biomixtures than in the corn cob-based biomixtures. Degradation slowed down with increase in initial concentration of pesticides in biomixture and 1.6–3.0 (AZOXY) and 2.4–3.6 (IMIDA) times increase in t1/2 values was observed. The moisture content of biomixture showed positive effect on degradation which increased when moisture content was increased from 60 to 80% water holding capacity. The effect was significant for IMIDA degradation in the corn cob-based biomixtures and AZOXY degradation in the peat biomixtures. The rice straw-based biomixtures were better in degrading AZOXY and IMIDA and can be used in biopurification systems.  相似文献   
65.
Environmental Science and Pollution Research - Nanoparticles (NPs) are one of the major class of emerging contaminants identified in aquatic environment. There is a probability that they can...  相似文献   
66.
Atmospheric dry deposition to leaf surfaces at a rural site of India   总被引:1,自引:0,他引:1  
Dry deposition flux of major ions (Na+, K+, Ca2+, Mg2+, NH4+, F-, Cl-, NO3- and SO4(2-) to natural surfaces [guava (Psidium guyava) and peepal (Ficus religiosa) leaves] are determined at Rampur, a rural site of semi-arid region of India. Dry deposition flux is the highest for Ca2+ on guava leaves and for NH4+ on peepal leaves. Overall dry deposition flux is higher on guava leaves than of peepal leaves. The variation in deposition flux may be due to surface characteristics (surface roughness) and arrangement of leaves. Peepal leaves are arranged along the axis of the stem, whereas guava leaves are at right angles to the stem. The deposition flux of cations contributes 66% and 76% of dry deposition of all major ions on guava and peepal leaves, respectively as soil is major contributor towards dry deposition flux in tropical regions. ANOVA revealed no significant seasonal difference in deposition, although there is a trend for higher in winter. Deposition velocities of NH4+, NO3- and SO4(2-) are greater on guava leaves than peepal leaves, which can be attributed to the rougher surface of the guava leaf.  相似文献   
67.
The present work includes a process for encapsulation by combining substantially simultaneously dry nonmetallic printed circuit boards (PCBs) powder and recycled high-density polyethylene (rHDPE) in an extruder to form a homogenous matrix. The extruded materials were then molded into standard tensile, flexural, and impact properties testing specimens. Nonmetallic PCB mainly consists of large amount of glass fiber–reinforced epoxy resin materials. Incorporation of 50 wt% nonmetallic PCB in rHDPE matrix had increased the flexural strength and modulus by 35% and 130%, respectively. Tensile strength reported to be constant without much improvement. However, the Young’s modulus has increased by 180%, with incorporation of 50 wt% nonmetallic PCB. The addition of 6 phr (parts per hundred) maleated polyethylene (MAPE) resulted in 2-fold increase in tensile and flexural strength. Regarding the leaching properties, Cu was identified as the metal that leached at the highest level from the raw nonmetallic PCB, at 59.09 mg/L. However, after the nonmetallic PCB was filled in rHDPE/PCB composites, the concentration of Cu was reduced far below the regulatory limit, to only 3 mg/L. Thermal properties of composites were studied, and it was found out that incorporation of nonmetallic PCB fillers in rHDPE resulted in low thermal conductivity, whereas mechanical strength of the composites showed maximum improvements at 220 °C. Overall, the encapsulation technique using nonmetallic PCB waste has formed a monolithic waste form that provides a barrier to the dispersion of wastes into the environment.
ImplicationsNonmetallic materials reclaimed from waste PCBs were used to analyze the chemical composition, and it was found that nonmetalllic PCBs mainly consist of glass fiber–reinforced epoxy resin materials. With such millions of glass fibers in nonmetallic PCBs, there are mass-excellent supporting bodies that enhance the mechanical properties of composites. In fact, utilization of nonmetallic PCB waste as filler in composites can dramatically restrain the solubility of heavy metals in leachate solution, thus making it safe to be used in practical products.  相似文献   
68.
A significant proportion of xenobiotic recalcitrant azo dyes are being released in environment during carpet dyeing. The bacterial strain Stenotrophomonas sp. BHUSSp X2 was isolated from dye contaminated soil of carpet industry, Bhadohi, India. The isolated bacterial strain was identified morphologically, biochemically, and on the basis of 16S rRNA gene sequence. The isolate decolorized 97 % of C.I. Acid Red 1 (Acid RED G) at the concentration of 200 mg/l within 6 h under optimum static conditions (temperature ?35 °C, pH 8, and initial cell concentration 7?×?107 cell/ml). Drastic reduction in dye degradation rate was observed beyond initial dye concentration from 500 mg/l (90 %), and it reaches to 25 % at 1000 mg/l under same set of conditions. The analysis related to decolorization and degradation was done using UV-Vis spectrophotometer, HPLC, and FTIR, whereas the GC-MS technique was utilized for the identification of degradation products. Phytotoxicity analysis revealed that degradation products are less toxic as compared to the original dye.  相似文献   
69.
In view of the stringent environmental regulations, availability of limited natural resources and ever increasing need of alternative energy critical elements, an environmental eco-friendly leaching process is reported for the recovery of lithium and cobalt from the cathode active materials of spent lithium-ion batteries of mobile phones. The experiments were carried out to optimize the process parameters for the recovery of lithium and cobalt by varying the concentration of leachant, pulp density, reductant volume and temperature. Leaching with 2 M sulfuric acid with the addition of 5% H2O2 (v/v) at a pulp density of 100 g/L and 75 °C resulted in the recovery of 99.1% lithium and 70.0% cobalt in 60 min. H2O2 in sulfuric acid solution acts as an effective reducing agent, which enhance the percentage leaching of metals. Leaching kinetics of lithium in sulfuric acid fitted well to the chemical controlled reaction model i.e. 1 ? (1 ? X)1/3 = kct. Leaching kinetics of cobalt fitted well to the model ‘ash diffusion control dense constant sizes spherical particles’ i.e. 1 ? 3(1 ? X)2/3 + 2(1 ? X) = kct. Metals could subsequently be separated selectively from the leach liquor by solvent extraction process to produce their salts by crystallization process from the purified solution.  相似文献   
70.
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