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11.
Babu SH Kumar KS Suvardhan K Kiran K Rekha D Krishnaiah L Janardhanam K Chiranjeevi P 《Environmental monitoring and assessment》2007,128(1-3):241-249
A procedure was developed for the determination of Cd, Cu, Zn, Co, Ni, Mn, Pb and Mo in water samples by inductively coupled
plasma atomic emission spectrometry (ICP-AES) after preconcentration on a morpholine dithiocarbamate (mor-DTC) supported by
bagasse (Saccharam aphisinaram). The sorbed elements were subsequently eluted with 4,M HNO3 and the acid eluates were analysed by ICP–AES. The influence of various parameters such as pH, flow rate of sample, eluent
concentration, volume of the sample and volume of eluent were investigated to enhance the sensitivity of the present method.
A 20,mL disposable syringe served as preconcentration column. Under the optimal conditions Cd, Cu, Zn, Co, Ni, Mn, Pb and
Mo in aqueous sample was concentrated about 100-fold. The sorption recoveries of elements were higher than 99.6%. The method
is also applied for the analysis of natural and spiked water samples. 相似文献
12.
Nila Rekha P Kanwar RS Nayak AK Hoang CK Pederson CH 《Journal of environmental monitoring : JEM》2011,13(9):2550-2558
Monitoring the concentration of NO(3)-N from agricultural fields to the subsurface and shallow ground water resources have received considerable interest worldwide, since agriculture has been identified as a major source of nitrate-nitrogen (NO(3)-N) pollution of groundwater systems in intensively farmed watersheds. A study was conducted to quantify the impact of two tillage practices viz. chisel plow (CP) and no till (NT) with liquid swine manure application on nitrate leaching to the shallow ground water system under corn-soybean production system. This study is part of the long-term field experiments conducted at Iowa State University using completely randomized block design. The NO(3)-N concentrations in the shallow ground water were monitored at three depths viz., a network of subsurface drains at a depth of 1.2 m and piezometers at depths of 1.8 m and 2.4 m. Results of this study showed that the average NO(3)-N concentration during the study period was 16.1 mg l(-1), 14.4 mg l(-1) and 11.8 mg l(-1) at 1.2 m, 1.8 m and 2.4 m depths, respectively implying significant amount of NO(3)-N leaching past the subsurface drain depth of 1.2 m into the shallow groundwater but the NO(3)-N concentration decreases with the depth. The NO(3)-N concentrations in shallow groundwater were significantly higher under the chisel plow system in comparison with the no till method of tillage. Fall application of liquid swine manure caused more leaching in comparison with the spring application. Higher NO(3)-N concentration was observed under corn in comparison with the soybean plots. An in-depth analysis of the data showed a definite relationship between the NO(3)-N concentration in subsurface drain water at a depth of 1.2 m and shallow groundwater at depths of 1.8 m and 2.4 m depths. 相似文献
13.
A survey of macro-invertebrates and their monthly variations occupying the Tons river in Doon Valley was conducted from August
2003–July 2004. Macro-invertebrate collections and water samples were taken from three sampling stations every month during
the period of study. All the hydrological attributes were measured monthly for 1 year. The present study showed that the water
velocity, hydromedian depth, turbidity and dissolved oxygen and nature and size of the bottom substrates do play a major role
in determining the macro-invertebrate diversity of Tons river. The ecological relevance of the measured hydrological attributes
was investigated by comparing their degree of correlation with invertebrate density and diversity. The Shannon–Wiener index
(H′) of macro-invertebrates was found to be highest (3.60) during spring season (February and March) and lowest (2.59) during
monsoon season (July and August). The high values of diversity index of macro-invertebrates at all the three sampling sites
indicate diverse macro-invertebrate communities in the Tons river in Doon Valley, India. 相似文献
14.
In a matched data set consisting of survey responses from both members of 39 dual earner couples, work and family involvement was used to predict job satisfaction, marital satisfaction, stress and work restructuring of both members of the couple. In general, the wives were found to be restructuring their work activities more than their husbands. Couples whose members had high levels of family involvement were experiencing high levels of marital satisfaction and low levels of stress. In addition, the coded responses to seven open ended questions provided qualitative data reflecting what specific types of work restructuring arrangements were most popular and the reasons for work restructuring. 相似文献
15.
Kumar KS Suvardhan K Rekha D Kiran K Jayaraj B Janardhanam K Chiranjeevi P 《Environmental monitoring and assessment》2007,127(1-3):67-72
Facile, selective and sensitive spectrophotometric method has been developed for the determination of bendiocarb in its insecticidal
formulations, fortified water, food grains, agriculture wastewater and agriculture soil samples with prepared reagents. The
method was based on alkaline hydrolysis of the bendiocarb pesticide, and the resultant hydrolysis product of bendiocarb was
coupled with 2,6-dibromo-4-methylaniline to give a yellow color product with λmaxof457 nmorcouplingwith2, 6−dibromo−4−nitroanilinetoproducearedcoloredproductwithλmax
of474~nmorcouplingwith2, 4, 6−tribromoanilinetoformorangeredcoloredproducthasaλmax
of465 nm.Underoptimalconditions, Beer'slawrangefor2, 6−dibromo−4−methylaniline(DBMA)wasfoundtobe0.6−−14.0~μgmL
-1, 0.8−−10.0 μgmL
-1
for2, 6−dibromo−4−nitroaniline(DBNA)and0.4−−10.0 μgmL
-1
for2, 4, 6−tribromoaniline(TBA).Themolarabsorptivityofthecolorsystemswerefoundtobe4.126~×~104
lmol
-1 cm
-1
forDBMA, 3.254×104
l~mol
-1 cm
-1
forDBNAand2.812×104
lmol
-1 cm
-1
forTBA.Sandell'softhecolorreactionsare0.018 μgcm
-2(DBMA), 0.052 μgcm
-2(DBNA)and0.065 μgcm
-2$ (TBA) respectively. The effect of the non-target species on the determination of bendiocarb was studied. The formation of
colored derivatives with the coupling agents is instantaneous and stable for 18 h, 30 h, and 12 h. Performance of the proposed
methods were compared statistically in terms Student's F and t-tests with the reported methods. 相似文献
16.
Pranav Chanchani Barry R. Noon Larissa L. Bailey Rekha A. Warrier 《Conservation biology》2016,30(3):649-660
Tiger (Panthera tigris) conservation efforts in Asia are focused on protected areas embedded in human‐dominated landscapes. A system of protected areas is an effective conservation strategy for many endangered species if the network is large enough to support stable metapopulations. The long‐term conservation of tigers requires that the species be able to meet some of its life‐history needs beyond the boundaries of small protected areas and within the working landscape, including multiple‐use forests with logging and high human use. However, understanding of factors that promote or limit the occurrence of tigers in working landscapes is incomplete. We assessed the relative influence of protection status, prey occurrence, extent of grasslands, intensity of human use, and patch connectivity on tiger occurrence in the 5400 km2 Central Terai Landscape of India, adjacent to Nepal. Two observer teams independently surveyed 1009 km of forest trails and water courses distributed across 60 166‐km2 cells. In each cell, the teams recorded detection of tiger signs along evenly spaced trail segments. We used occupancy models that permitted multiscale analysis of spatially correlated data to estimate cell‐scale occupancy and segment‐scale habitat use by tigers as a function of management and environmental covariates. Prey availability and habitat quality, rather than protected‐area designation, influenced tiger occupancy. Tiger occupancy was low in some protected areas in India that were connected to extensive areas of tiger habitat in Nepal, which brings into question the efficacy of current protection and management strategies in both India and Nepal. At a finer spatial scale, tiger habitat use was high in trail segments associated with abundant prey and large grasslands, but it declined as human and livestock use increased. We speculate that riparian grasslands may provide tigers with critical refugia from human activity in the daytime and thereby promote tiger occurrence in some multiple‐use forests. Restrictions on human‐use in high‐quality tiger habitat in multiple‐use forests may complement existing protected areas and collectively promote the persistence of tiger populations in working landscapes. 相似文献
17.
Rani R Trivedi SP Singh P Singh RK 《Journal of environmental biology / Academy of Environmental Biology, India》2002,23(1):101-103
It was observed that clotting time decreased with the increased concentrations of LAS. However, the decrease was more pronounced at LC50 for 24 h and at the end of 96 h LC50, it was very close to control values. 相似文献
18.
Kumar KS Suvardhan K Rekha D Kiran K Rao GC Jayaraj B Janardhanam K Chiranjeevi P 《Environmental monitoring and assessment》2007,129(1-3):271-276
Facile, selective and sensitive spectrophotometric method has been developed for the determination of carbosulfan in insecticidal
formulations, fortified water, food grains, agriculture wastewater and soil samples with newly synthesized reagents. The method
was based on acid and alkaline hydrolysis of the carbosulfan pesticide, and the resultant hydrolysis product of carbosulfan
was coupled with 2,6-dibromo-4-methylaniline to give a yellow color product with λ
max of 464 nm or interaction with 2,6-dibromo-4-nitroaniline to produce yellow colored product with λ
max of 408 nm or coupling with 2,4,6-tribromoaniline to form red colored product has a λ
max of 471 nm. Under optimal conditions, Beer’s law range for 2,6-dibromo-4-methylaniline (DBMA) was found to be 0.2–12.0 μg
ml−1, 0.6–16.0 μg ml−1 for 2,6-dibromo-4-nitroaniline (DBNA) and 0.4–15.0 μg ml−1 for 2,4,6-tribromoaniline (TBA). The molar absorptivity of the color systems were found to be 3.112 × 104 l mol−1 cm−1 for DBMA, 3.214 × 104 l mol−1 cm−1 for DBNA and 3.881 × 104 l mol−1 cm−1 for TBA. Sandell’s of the color reactions are 0.013 μg cm−2 (DBMA), 0.012 μg cm−2 (DBNA) and 0.011 μg cm−2 (TBA) respectively. The effect of the non-target species on the determination of carbosulfan was studied to enhance the selectivity
of the proposed methods. The formation of colored derivatives with the coupling agents is instantaneous and stable for 28,
30, and 26 h. Performance of the proposed methods were compared statistically in terms Student’s F and t-tests with the reported methods.
An erratum to this article can be found at 相似文献
19.
Teresa MV Rekha K Bindu A 《Journal of environmental biology / Academy of Environmental Biology, India》2003,24(4):449-452
In the present study, the impact of sodium metabisulphite (Na2S2O5), a food preservative, on seed germination, growth and yield of Vigna sinensis, Savi has been evaluated. Observations clearly reveal the deleterious effect of Na2S2O5 on germination, stomatal development, stomatal index, chlorophyll content and yield. The shoot length exhibited a steady rise in length, while the biomass showed a gradual decrease with the increasing doses of Na2S2O5. 相似文献
20.
Suvardhan K Krishnaiah L Suresh Kumar K Rekha D Jayaraj B Ramanaiah S Chiranjeevi P 《Chemosphere》2006,62(6):899-904
A rapid, highly sensitive and selective spectrophotometric method for the determination of traces of selenium(IV) is described. The method is based on oxidation of p-nitroaniline by selenium(IV) followed by coupling reaction with N-(1-naphthalene-1-yl)ethane-1,2-diamine dihydrochloride (NEDA) in neutral medium to give red colored derivative with lambda(max) 515 nm and is stable for more than 10 days at 35 degrees C. Beer's law is obeyed for selenium(IV) in the concentration range of 0.02-3.2 microg ml(-1) at the wavelength of maximum absorption. The optimum reaction conditions and other analytical parameters were investigated to enhance the sensitivity of the present method. The detailed study of various interferences made the method more selective. The proposed method was successfully applied to the analysis of selenium in polluted water, natural water samples, plant material, soil samples, and synthetic mixtures. The results obtained were agreed with the reported methods at the 95% confidence level. The performance of proposed method was evaluated in terms of Student's t-test and Variance ratio f-test which indicates the significance of proposed method over reported method. 相似文献