Browsing by Author "Balakrishna, K."
Now showing 1 - 10 of 10
- Results Per Page
- Sort Options
Item Natural and anthropogenic factors controlling the dissolved organic carbon concentrations and fluxes in a large tropical river, India(2006) Balakrishna, K.; Kumar, I.A.; Srinikethan, G.; Mugeraya, G.Carbon studies in tropical rivers have gained significance since it was realized that a significant chunk of anthropogenic CO2 emitted into the atmosphere returns to the biosphere, that is eventually transported by the river and locked up in coastal sediments for a few thousand years. Carbon studies are also significant because dissolved organic carbon (DOC) is known to complex the toxic trace metals in the river and carry them in the dissolved form. For the first time, this work has made an attempt to study the variations in DOC concentrations in space and time for a period of 19 months, and estimate their fluxes in the largest peninsular Indian river, the Godavari at Rajahmundry. Anthropogenic influence on DOC concentrations possibly from the number of bathing ghats along the banks and domestic sewage discharge into the river are evident during the pre-monsoon of 2004 and 2005. The rise in DOC concentrations at the onset of monsoon could be due to the contributions from flood plains and soils from the river catchment. Spatial variations highlighted that the DOC concentrations in the river are affected more by the anthropogenic discharges in the downstream than in the upstream. The discharge weighted DOC concentrations in the Godavari river is 3-12 times lower than Ganga-Brahmaputra, Indus and major Chinese rivers. The total carbon fluxes from the Godavari into the Bay of Bengal is insignificant (0.5%) compared to the total carbon discharges by major rivers of the world into oceans. Springer Science+Business Media, Inc. 2006.Item Natural and anthropogenic factors controlling the dissolved organic carbon concentrations and fluxes in a large tropical river, India(2006) Balakrishna, K.; Kumar, I.A.; Srinikethan, G.; Mugeraya, G.Carbon studies in tropical rivers have gained significance since it was realized that a significant chunk of anthropogenic CO2 emitted into the atmosphere returns to the biosphere, that is eventually transported by the river and locked up in coastal sediments for a few thousand years. Carbon studies are also significant because dissolved organic carbon (DOC) is known to complex the toxic trace metals in the river and carry them in the dissolved form. For the first time, this work has made an attempt to study the variations in DOC concentrations in space and time for a period of 19 months, and estimate their fluxes in the largest peninsular Indian river, the Godavari at Rajahmundry. Anthropogenic influence on DOC concentrations possibly from the number of bathing ghats along the banks and domestic sewage discharge into the river are evident during the pre-monsoon of 2004 and 2005. The rise in DOC concentrations at the onset of monsoon could be due to the contributions from flood plains and soils from the river catchment. Spatial variations highlighted that the DOC concentrations in the river are affected more by the anthropogenic discharges in the downstream than in the upstream. The discharge weighted DOC concentrations in the Godavari river is 3-12 times lower than Ganga-Brahmaputra, Indus and major Chinese rivers. The total carbon fluxes from the Godavari into the Bay of Bengal is insignificant (0.5%) compared to the total carbon discharges by major rivers of the world into oceans. © Springer Science+Business Media, Inc. 2006.Item Organic carbon transport and C/N ratio variations in a large tropical river: Godavari as a case study, India(2005) Balakrishna, K.; Probst, J.L.This study gives an insight into the source of organic carbon and nitrogen in the Godavari river and its tributaries, the yield of organic carbon from the catchment, seasonal variability in their concentration and the ultimate flux of organic and inorganic carbon into the Bay of Bengal. Particulate organic carbon/particulate organic nitrogen (POC/PON or C/N) ratios revealed that the dominant source of organic matter in the high season is from the soil (C/N = 8-14), while in the rest of the seasons, the river-derived (in situ) phytoplankton is the major source (C/N = l-8). Amount of organic materials carried from the lower catchment and flood plains to the oceans during the high season are 3 to 91 times higher than in the moderate and low seasons. Large-scale erosion and deforestation in the catchment has led to higher net yield of organic carbon in the Godavari catchment when compared to other major world rivers. The total flux of POC, and dissolved inorganic carbon (DIC) from the Godavari river to the Bay of Bengal is estimated as 756 10 9 and 2520 109 g yr-1, respectively. About 22% of POC is lost in the main channel because of oxidation of labile organic matter, entrapment of organic material behind dams/sedimentation along flood plains and river channel; the DIC fluxes as a function of alkalinity are conservative throughout the river channel. Finally, the C/N ratios (?12) of the ultimate fluxes of particulate organic carbon suggest the dominance of refractory/stable soil organic matter that could eventually get buried in the coastal sediments on a geological time scale. Springer 2005.Item Oxygen and hydrogen isotopic composition of major Indian rivers: A first global assessment(2005) Lambs, L.; Balakrishna, K.; Brunet, F.; Probst, J.L.Nine major rivers have been sampled around the Indian subcontinent to give an overview of the surface water characteristics. Both 18O and deuterium have been measured to determine the origin of the water and the possible evapotranspiration process. The major ions have also been analysed to obtain complementary information. Although some basins have been studied previously (mainly in the north), this is the first attempt at a wider investigation of major Indian rivers. The results are discussed from the perspective of the hydroclimatological, geographical and geological specificity of the river basins. ? 18O values vary from light-isotope-enriched Himalayan rivers to heavy-isotope-enriched peninsular Indian rivers in a northwest-southeast gradient across the subcontinent. There is more evapotranspiration, leading to heavy isotope enrichment, in the peninsular (southern Deccan) rivers compared with the light-isotope-enriched snow- and glacier-melt-derived waters of the Himalayan rivers. The ?18O values of Indian rivers correspond roughly to the ?18O values of the rains falling over the subcontinent. However, the influence of tributaries is dominant over rainfall in rivers like the Narmada and Tapti. The Cauvery and Krishna rivers show maximum evapotranspiration and sodium pollution, as indicated by the ?18O values, deuterium excess and major ion data. Copyright 2005 John Wiley & Sons, Ltd.Item Selection criteria for decorative dimension stones(2014) Manjunatha, B.R.; Venkat, Reddy, D.; Krishnakumar, K.N.; Balakrishna, K.; Manjunatha, H.V.; Gurumurthy, G.P.Selection of decorative dimension stones suitable for exterior and interior decorations is one of the challenging tasks for geologists, architectural, structural and civil engineers. Therefore, understanding the knowledge of general properties of commercial grade rocks and their quality assessment are at most important before selecting stones for construction. In many instances, decorative dimension stones are usually preferred on the basis proximity. In such cases, the colour and textural characteristics may not only be suitable, but also weather out faster. In some instances, specific design may not suits the structure due to masking colour and other inherent defects. One of the secrets behind the success of commercial stone industry is the production of defect-free decorative dimension stone blocks. Generally, not all rocks available in the earth s crust are suitable for architectural and civil engineering construction purposes. In this study, the main criteria for the selection of commercial grade decorative dimension rocks will be discussed along with their trade names. Sometimes, trade names of rocks confuse with generic names. Here, therefore, both names of rocks, particularly marketed in India are given to avoid confusion among geologists, engineers and business persons. In addition, non-destructive methods of testing the mechanical properties of rocks - such as ultrasonic pulse velocity and uniaxial compressive strength are discussed. These methods seem to substitute the conventional, hazardous and destructive method of testing of decorative dimension stones. 2014 Cafet-Innova Technical Society. All rights reserved.Item Selection criteria for decorative dimension stones(CAFET INNOVA Technical Society cafetinnova@gmail.com 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2014) Manjunatha, B.R.; Venkat Reddy, D.V.; Krishnakumar, K.N.; Balakrishna, K.; Manjunatha, H.V.; Gurumurthy, G.P.Selection of decorative dimension stones suitable for exterior and interior decorations is one of the challenging tasks for geologists, architectural, structural and civil engineers. Therefore, understanding the knowledge of general properties of commercial grade rocks and their quality assessment are at most important before selecting stones for construction. In many instances, decorative dimension stones are usually preferred on the basis proximity. In such cases, the colour and textural characteristics may not only be suitable, but also weather out faster. In some instances, specific design may not suits the structure due to masking colour and other inherent defects. One of the secrets behind the success of commercial stone industry is the production of defect-free decorative dimension stone blocks. Generally, not all rocks available in the earth’s crust are suitable for architectural and civil engineering construction purposes. In this study, the main criteria for the selection of commercial grade decorative dimension rocks will be discussed along with their trade names. Sometimes, trade names of rocks confuse with generic names. Here, therefore, both names of rocks, particularly marketed in India are given to avoid confusion among geologists, engineers and business persons. In addition, non-destructive methods of testing the mechanical properties of rocks - such as ultrasonic pulse velocity and uniaxial compressive strength are discussed. These methods seem to substitute the conventional, hazardous and destructive method of testing of decorative dimension stones. ©2014 Cafet-Innova Technical Society. All rights reserved.Item Spatial and temporal variations in water quality, major ions and trace metals(2007) Deepa, V.J.; Balakrishna, K.; Mugeraya, G.; Srinkethan, G.; Krishnakumar, P.K.Godavari river at Rajahmundry is monitored for a period of seven months at five stations along its course for the physicochemical parameters, major ions and trace metals. This study is made to obtain a baseline data of the existing pollutants in this 'hotspot', which is set to become the industrial hub of Andhra Pradesh. Results indicate that A P Paper Mills may not be polluting the river at this period, contrary to what was expected. Clear picture will emerge, once the data for the rainy season is available. Local pollution from detergents and soap in the river is seen in the downstream (station VIP) as lot of bathing and washing activity is done on the banks. There is no pollution of Cu, Ni, Pb, As and Co in the Godavari river at Rajahmundry. In general the pollutant levels in all the stations analysed is within the prescribed limits set by BIS and WHO standards. Copyright Enviromedia.Item Spatial and temporal variations in water quality, major ions and trace metals(2007) Deepa, V.J.; Balakrishna, K.; Mugeraya, G.; Srinkethan, G.; Krishnakumar, P.K.Godavari river at Rajahmundry is monitored for a period of seven months at five stations along its course for the physicochemical parameters, major ions and trace metals. This study is made to obtain a baseline data of the existing pollutants in this 'hotspot', which is set to become the industrial hub of Andhra Pradesh. Results indicate that A P Paper Mills may not be polluting the river at this period, contrary to what was expected. Clear picture will emerge, once the data for the rainy season is available. Local pollution from detergents and soap in the river is seen in the downstream (station VIP) as lot of bathing and washing activity is done on the banks. There is no pollution of Cu, Ni, Pb, As and Co in the Godavari river at Rajahmundry. In general the pollutant levels in all the stations analysed is within the prescribed limits set by BIS and WHO standards. Copyright © Enviromedia.