Geochemical study of groundwater from 58 selected fluoride-rich areas in different parts of India that includes eight states indicates that:1. These groundwaters are alkaline in pH (7.4-8.8) andtheir electrical conductivity varies from 530-2,680 lS/ cm and fluoride concentration from 1.7-6.1 mg/l. Presence of fluoride-bearing minerals in the host rocks and their interaction with water is considered to be the main cause for fluoride in groundwater. 2. The decomposition, dissociation and dissolution are the main chemical processes for the occurrence of fluoride in groundwater. During rock-water interaction, concentration of fluoride in rock, aqueous ionic species and residence time of interaction, etc. are also important parameters. 3. This study indicates that 85% groundwater samples have EC: 1,000-2,000 lS/cm, pH: 7.5-8.5, and HCO 3 /Ca (epm ratio): 0.8-2.3. 4. The Ca and HCO 3 contents of groundwater samples have shown good correlation with fluoride.

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Design and analysis of a single-feed arrangement of stacked rectangular patches is proposed, which is capable of providing circular polarization along with broadband performance. An antenna is designed on a glass epoxy FR-4 substrate with overall thickness of the structure less than 8 mm or 0.11 0 . The patch area of the corner truncated driven patch is marginally smaller than that of a parasitic patch to achieve improved performance. Both driven and stacked patches have narrow slots of unequal size in a way that their centers lie one over the other. The locations of the feed point, the amount of corner truncation of the driven patch, and the size of slots on both the driven and the stacked patches are optimized. Axial ratio bandwidth better than 11% and impedance bandwidth better than 27% may be achieved with the proposed geometry. Measured gain and axial ratio variations of the proposed antenna with frequency are compared to simulated results for better understanding. The measured E-and H-plane radiation patterns in the entire impedance bandwidth are identical in shape, and the direction of maximum radiations is normal to the patch geometry. In the entire axial ratio bandwidth range of the proposed antenna, the E-plane left circularly polarized patterns are nearly 15 dB higher than the corresponding right circularly polarized patterns.Index Terms-Axial ratio bandwidth, broadband, circularly polarized, radiation patterns, stacked microstrip antenna.

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Fluoride (F) contamination study had been carried out to see its allocation in Kurmapalli watershed, Nalgonda district, Andhra Pradesh, India. The study area is located about 60 km SE of Hyderabad city. The groundwater is the main source of water for their living. The groundwater in villages and its surrounding are affected by fluoride contamination and consequently the majority of the people living in these villages has health hazards and is facing fluorosis. The purpose of this study is to identify the wells with high F, raise awareness in people, study the water chemistry, and also find out the source of F in groundwater.