Gregory,VL; Reinhard,M (1999): Hydrodehalogenation of 1 to 3 carbon halogenated organic compounds in water using a palladium catalyst and hydrogen gas. Environmental Sciences & Technology, 33(11): 1905-1910.
Supported palladium (Pd) metal catalysts along with H2 gas show significant potential as a technology which can provide rapid, on-site destruction of halogenated ground-water contaminants. Pd cataly2es the rapid hydrodehalogenation of nine 1- to 3-carbon HOCs, resulting in little or no production of halogenated intermediates. Initial transtormation rates were compared for 12 HOCs using 1 w/w% Pd-on-Al2O3 (Pd/AI) and metallic Pd catalysts in clean, aqueous batch systems at ambient pressure and temperature. Half-lives of 4-6 min were observed for 5-100,uM (1-10 mg/L) aqueous concentrations of PCE, TCE, cis-, trans-, 1,1-OCE, carbon tetrachloride, and 1,2-dibromo-3-chloropropane at ambient temperature and pressure with 0.22 9/1> of catalyst. Using Pd/AI, TCE transformed quantitatively 197%) to ethane without formation of any detectable chlorinated intermediate compounds. This implies 8 direct conversion of TCE to ethane at the Pd surface. Carbon tetrachloride transformed primarily to methane and ethane and minor amounts of ethylene, propanel and propylene. Chloroform is a reactive intermediate (20%}. Formation of C2 and C3 products implies a free radical mechanism. Methylene chloride, 1,1-dichloroethane, and 1,2-dichloroethane were non-reactive. Reaction mechanisms and kinetic models are postulated for TCE, carbon tetrachloride, and chloroform transformation.
He,C (1999): Use of hydrologica budget and chemical data for ground-water assessment. Journal of Planning Management, 125(4): 234-238.
This paper uses a hydrologic budget method and partial chemical data to evaluate the availability of ground water for irrigation supply in a humid region through a case study of the Saginaw Bay basin, Mich. Concentrations of chloride are used to evaluate the quality of ground water for irrigation. The results indicate that ground water does not appear to be a reliable source for regional irrigation supply in the study area. The case study demonstrates that the integration of a hydrologic budget and water quality data is an effective approach in the analysis of the limit of ground water for irrigation development in humid regions when intensive hydro-geologic monitoring and modeling are unaffordable.
Hosmani,SP; VAsanth Kumar,L; Partha,S; (1999): Ecological significance of biochemical parameters in certain fresh water lakes of Mysore. Journal of Environmental Biology, 20(2): 121-124.
Studies on biochemical aspects of water pollution based on analysis of glycolic acid, chlorophylls, phycobiliproteins and total dissolved solids were made in twenty lakes in around Mysore city. Four categories of water have been recognized based on the range of glycolic acid present. The high values of glycolic acid may be due to high contents of organic pollutants coupled with high intensities of light during summer that inhibit algal photosynthesis and increase the percentage of extracellular release. The glycollate excrete may directly reflect the growth and photosynthetic activity of phytoplankton. High amounts of pollutants enhance the growth of bluegreen algae and in tum increase phycobiliproteins. Phytoplankton members of Euglenaceae also occur as mixed organisms to be of lesser relevance. Total dissolved solid content is high in Melkote lake, possibly due to the regular disturbance by devotees visiting the temple tank.