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231.
232.
Rain water was collected and analysed from a reference site, Dayalbagh and Taj Ganj, near the Taj Mahal in Agra. The ionic components Ca, Mg, Na, K, NH(4), Pb, Fe, Zn, SO(4), HCO(3), Cl and F were analysed along with pH, alkalinity and conductance. The average pH of rain water at both sites is 7.05. There is a dominance of alkaline components, particularly Ca. The rain water chemistry shows the importance of calcareous soil-derived materials in controlling the pH of rain water.  相似文献   
233.
The dominant use of coal in power sectors has been associated with adverse environmental impacts. Ambient air monitoring for the two size fractions of particulate matter, respirable suspended particulate matter (RSPM) and non-respirable suspended particulate matter (NRSPM) in the downwind and upwind directions of a large coal-fired power station in central India, was carried out. Collected samples of ambient particulate matter were analysed atomic absorption spectrophotometrically for 15 elements. Spatial variability in elemental composition of RSPM and NRSPM and the degree of enrichment of these toxic metals in RSPM were investigated. A significant spatial variability for the elements in RSPM and NRSPM and higher degrees of enrichment of the elements were observed.  相似文献   
234.
Different dilution levels of tannery treated effluent and their corresponding concentration of chromium (Cr6+) were studied in a petridish culture experiment on seed germination and seedling growth in radish (Raphanus sativus L). The different concentrations of Cr6+ (2, 5 and 10 ppm) and treated tannery effluent (10, 25 and 50%) showed reduction in seedling growth and related enzymatic activities with increase in concentration of Cr6+ in treatments and effluent both. The low concentration of chromium (2 ppm) and effluent dilution (10%) showed significant growth reduction separately. At this concentration of chromium and effluent dilution chlorophyll content, amylase, catalase and protein contents remained unchanged while with increase in Cr6+ concentration (>2ppm) and effluent dilution (> 10%) in treatments showed growth inhibitory effects.  相似文献   
235.
This article reviews critical linkages between land-use transition and human health in the Himalayan region by applying ecosystem approaches to human health (or EcoHealth). Land-use transition in the Himalayan and similar regions includes sedentarization, agricultural intensification, habitat modification, migration, change of livelihoods and lifestyles, biodiversity loss, and increasing flash floods. These transitions, which can have impacts on human health, are driven by state policies, a market economy, and climate change. Human health is dependent on access to ecosystem services for food, nutrition, medicine, fiber and shelter, fresh water, and clear air. Ecosystem management has been a key means of controlling disease vectors and creating suitable habitats for human well-being. The paper identifies the web of environmental factors that influence human health. Institutional and policy issues for land-use and health transitions are also discussed.  相似文献   
236.
Vulnerability indices are commonly used for characterizing the impacts on a region or comparing relative vulnerability across regions. Such indices are usually computed as a composite/aggregate across different components of vulnerability. Though such a single numerical value can be useful in many situations, a major disadvantage is that it leads to loss of information about how the different factors that went into making the composite index interact with each other, and contribute to making a place vulnerable. In this paper we develop an alternative approach for identifying hotspots, based on cluster analysis that seeks to address this problem by considering the different components of vulnerability separately. We compute different indices for each of the components of vulnerability. Cluster analysis helps in identifying the most vulnerable districts based on different combinations of the components of vulnerability. In addition to being methodologically more robust than the index approach, the clustering approach may have greater policy-relevance as it provides information about which aspects of vulnerability, policy needs to address in the most vulnerable districts. An erratum to this article can be found at  相似文献   
237.
The uptake of naturally occurring uranium, thorium, radium and potassium by wheat plant from two morphologically different soils of India was studied under natural field conditions. The soil to wheat grain transfer factors (TF) were calculated and observed to be in the range of 4.0 x 10(-4) to 2.1 x 10(-3) for 238U, 6.0 x 10(-3) to 2.4 x 10(-2) for 232Th, 9.0 x 10(-3) to 1.6 x 10(-2) for 226Ra and 0.14-3.1 for 40K. Observed ratios (OR) of radionuclides with respect to calcium have been calculated to explain nearly comparable TF values in spite of differences in soil concentration of the different fields. They also give an idea about the discrimination exhibited by the plant in uptake of essential and nonessential elements. The availability of calcium and potassium in soil for uptake affects the uranium, thorium and radium content of the plant. The other soil factors such as illite clays of alluvial soil which trap potassium in its crystal lattice and phosphates which form insoluble compounds with thorium are seen to reduce their availability to plants. A major percentage (54-75%) of total 238U, 232Th and 226Ra activity in the plant is concentrated in the roots and only about 1-2% was distributed in the grains, whereas about 57% of 40K activity accumulated in the shoots and 16% in the grains. The intake of radionuclides by consumption of wheat grains from the fields studied contributes a small fraction to the total annual ingestion dose received by man due to naturally existing radioactivity in the environment.  相似文献   
238.
The effluent limit guidelines are usually based on loading estimates of chemicals discharged into the environment. The loading estimates, calculated as the product of flow times concentration, have underlying mathematical relationships in terms of variances and covariances. These relationships are presented by using the moment generating function technique. Estimators of loading means are compared. Cramer-Rao bounds for the variances of unbiased estimators of the loading means are presented. Mathematical details underlying several part-whole and ratio estimators are also presented. An understanding of these relationships should provide unbiased estimates of loading means, variances and covariances.  相似文献   
239.
During a radiation emergency subsequent to a nuclear accident orweapon fallout, quick assessment of the ground contamination andthe resulting exposure is of prime importance in planning and execution of effective counter measures. For an online assessmentof ground contamination, it is essential to calibrate the detector system for several parameters viz. the source energy,source deployment matrix, the flight altitude and position abovethe contaminated surface. This article discusses the methodology to predict all the necessary parameters like photon fluence atvarious altitudes, the photo-peak counts in different energy windows, Air to Ground Correlation Factors (AGCF) and the doserate at any height due to air scattered gamma ray photons. Themethodology includes generation of theoretically simulated gammaspectra at a required detector position for a given source distribution on the ground using Monte-Carlo method provided by general purpose coupled neutron/photon transport code (MCNP CCC-200). Thus generated gamma spectra are analyzed to arrive at the required parameters mentioned above.  相似文献   
240.
Chemical mass balance model for source apportionment of aerosols in Bombay   总被引:1,自引:0,他引:1  
Aerosol samples collected within an industrial region of Bombay were analyzed for elemental concentrations using inductively coupled plasma emission spectroscopy, ultraviolet/visible spectrophotometry and X-ray fluorescence spectroscopy. Nineteen elements were selected as tracers of identified sources of aerosol in the region. The U.S. EPA chemical mass balance model was employed for source apportionment. Seven major source types were identified and the performance of the model was evaluated at different sampling locations. Model results were unsatisfactory at highly polluted sites in the study regions. It was found that U.S. EPA source profiles are not suitable for such regions in India and site-specific source profiles should be used in the application of chemical mass balance for source apportionment.  相似文献   
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