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Ground water ecosystem surrounding the uranium processing facility at Jaduguda, India has been studied for natural uranium distribution. Annual intake of uranium through drinking water for members of public residing around the uranium complex is found to be in the range of 41.8 Bquy^–1 - 44.4 Bquy^–1. The intake and ingestion dose is appreciably low (<2 Sv.y^–1) which is far below the WHO recommended level of 100 uSv.y^–1. The excess life time radiological risk due to uranium natural in drinking water is insignificant and found to be of the order of 10^–6. Even the highest concentration of uranium was found to be 28 ug.l^–1 is away (at 1.5 to 5 km distance) from mining industry and well below the acceptable limit. The ground water in the area around the uranium facility is not affected by the mining activity. The ground water in three zones is safe and reflects the natural distribution of uranium

Radium, thorium, and radioactive lead isotopes in groundwaters: application to the in situ determination of adsorptiondesorption rate constants and retardation factors. Water Resour. Res., 1982Res., , 18, 1663Res., -1675. Kozowska, B., Walencik, A., Dorda, J. and Zipper, W., Radon in groundwater and dose estimation for inhabitants in spas of the Sudety Mountain area, Poland. Appl. Radiat. Isot., 2010, 68, 854-857. 19. Zouridakis, N., Ochsenkühn, K. M. and Savidou, A., Determination of uranium and radon in potable water samples. CATALYSED exchange of deuterium (D) between hydrogen (H) gas and liquid water (liquid phase catalytic exchange (LPCE) reaction) using bi-thermal hydrogen water (BHW) process is receiving considerable attention for heavy water production 1 . This is because it is more energy-efficient and environment-friendly compared to the existing 'girder sulphide' and 'ammonia-hydrogen' processes. The catalysed exchange involves two stepsfirst, deuterium exchange between hydrogen gas and water vapour at the catalytic site and subsequently equilibration of deuterated water vapour with liquid water at gas-liquid interface, which results in the transfer of deuterium from gas to liquid phase. Success of the process requires simultaneous presence of H 2 gas and water vapour at the catalytic site and easy accessibility of liquid water to water vapour involved in isotopic exchange reaction. However, because the solubility of H 2 gas in water is poor, if the catalytic site is covered with liquid water, the exchange of deuterium between hydrogen gas and water vapour is highly impeded 2 . Therefore, a primary requirement for the LPCE process is that the catalyst should allow access of gaseous reactants to the catalytic RESEARCH COMMUNICATIONS CURRENT SCIENCE, VOL. 109, NO. 10, 25 NOVEMBER 2015 1861 However, these show good activity only up to atmospheric pressure and rapidly lose activity as the pressure is increased above atmospheric pressure. This has limited the use of the LPCE process for relatively low-throughput applications like removal of tritium from heavy water of the moderator used in pressurized heavy water reactor operation 10 . The reduction in catalyst activity at higher pressure is believed to arise due to ingression of water at such pressure through pores in the fibrous network or mesh structure of the commonly used hydrophobic binders like PTFE and SDBC. Indeed, the studies carried out by Malhotra et al. 11 showed how the size and distribution of pore in binder contribute to the loss of activity at higher pressure. To address this issue, we have explored different approaches like high-pressure melting of PTFE film, PTFE overcoat, coating of other binders like polyvinylidenedifluoride (PVDF), perfluoroalkoxyalkanes (PFA), etc. to control the porosity of the film. These studies have led us to the successful development of hydrophobic platinumdoped carbon aerogel (PtCA) catalyst that shows good catalytic activity even up to 20 bar.In our earlier studies we had mixed PtCA powder synthesized...

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