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This paper discusses the ancient perennial water abstraction structures-Keni-developed by the tribal communities in Wayanad district, Kerala, southwest coast of India. Keni is shallow wooden abstraction structure built in the soil zone where the water table is near or above the ground level. These traditional water abstraction structures are perfect example of water harvesting and water purification. As a preliminary assessment, a detailed survey of the Keni in the district is conducted and the result of the chemical analysis of water from the Keni is presented in this paper. Water from Kenis meet the drinking water quality standards prescribed by the BIS. [ABSTRACT FROM AUTHOR]

Indian beach placer sand deposits are, in general, ilmenite-rich. However, some concentrations are dominated by pyriboles. The Chavakkad-Ponnani (CP) area along the northern Kerala coast is one such deposit. This paper deals with the general character of the heavy minerals of CP with special emphasis on the characters of ilmenite. Most Indian beach sand ilmenites are of good quality. However, our observations on the ilmenites of CP using Optical Microscope, SEM and EPMA reveals that these are mineralogically very complex. The CP ilmenite varies from pure ilmenite to highly impure variety having intergrowths and inclusions of other oxide and silicate minerals. Ilmenite occurs as mixcrystals and forms intergrowth structure with hematite and Ti-hematite/ulvöspinel; contains inclusions of hematite, quartz, and monazite. On the other hand ilmenite also occurs as inclusions within hematite and garnet. The pyriboles are dominantly amphiboles with hornblende-composition. Interestingly an inclusion of gold has been recorded within amphibole of hornblende composition. Garnets are mostly of almandine and pyrope type. Subordinate heavy minerals are sillimanite, zircon and rutile. Characteristic morphology, mineralogy and chemistry of amphibole, garnet and ilmenite together indicate that the placer sands of CP area are derived from the amphibolites, granite gneisses and basic igneous rocks lying in the hinterland towards the eastern border of Kerala. Though the overall quality of ilmenite is poor, highgrade ilmenite concentrate can be generated (of course with lower yield), by adopting precise mineral processing techniques. The CP deposit can be considered as a second-grade deposit but it has potential for future exploitation. [ABSTRACT FROM AUTHOR]

Parts of the coastal tracts of southern Kerala, India are among the well-known High Background Radiation Areas (HBRA) of the world, attributed to the presence of radionuclides in the monaziterich beach sand deposits. A comparative study of the radon concentrations in groundwater in the high and normal background radiation areas in the coastal tract has been taken up using analytical data of 24 ground water samples collected from tube wells of ranging in depth from 6.0 to 300.0 m. The radon concentration in the samples ranged from 0.88 to 25.80 Bq.L−1. The mean radon concentration in the study area, including those from the HBRA are within the maximum contamination levels of 300 pCi.L−1 (11.10 Bq.L−1) recommended by the United States Environmental Protection Agency except for a sample collected from Chavara. Groundwater from the high background radiation areas has significantly higher concentrations of radon ranging from 2.84 — 25.80 Bq.L−1 when compared to the normal background areas where the concentrations range from 0.86 — 7.46 Bq.L−1. Radon concentration does not show significant correlation with depth of sampled wells. The mean annual effective doses of ingestion and inhalation from water-borne radon, though comparatively higher in HBRA, are well below the average doses reported from all natural sources. [ABSTRACT FROM AUTHOR]

Data collected from bore wells drilled by Central Ground Water Board in Bharathapuzha river basin in Kerala have been analyzed to understand the spatial distribution of yields in Precambrian crystalline rock aquifers and their possible relation to lineaments in the area. Bore wells show wide variation in yields in both charnockites and migmatites. Bore wells in the depth range of 50 to 100 m are most productive in the area and drilling of wells below 150 m may not be economical due to the dying out of fractures at depth. Bore well yields showed a decrease with increasing distances from lineaments in the area. Analysis of the yield data of bore wells with respect to the lineament orientations indicated that bore wells drilled along N-S and SE-NW lineaments are the most productive, whereas those located along NNE-SSW and ESE-WNW lineaments are the least productive. Yields of bore wells, in general, are found to be influenced by the ruptural deformations in the geologic past, with the high yielding wells lying mostly on the lineaments along the directions of compression. [ABSTRACT FROM AUTHOR]

Mineral concentration and ilmenite characterization of the Thothapally - Kayamkulam Barrier Island of the southern Kerala has been studied. 96.86% concentrations of heavy minerals are recorded in the surficial and core samples (4 m) in the southern Kayamkulam and northern Thothapally areas. The total heavy mineral content decreases with depth. The primary heavy mineral suite of the surficial and core samples consists of ilmenite, sillimanite, zircon, garnets, rutile, monazite and magnetite. Longshore current and onshore-offshore movements of sediment during the southwest monsoon are primarily responsible in sorting of the heavy minerals. TiO content in ilmenite is significantly higher in the Kayamkulam core sediments than the surface samples. XRD analysis supports intensive weathering and alteration leading to the higher TiO concentration. Higher percentage of ferric iron than ferrous iron in the core samples reveals that considerable weathering occurred under burial condition. SEM examination of ilmenite grains reveal the presence of solution pit, chemical leaching, corrosion and replacement textures, supporting the intense epigenetic alteration and weathering under subaerial condition and post-depositional changes by water-table condition. [ABSTRACT FROM AUTHOR]

The groundwater in the study area generally shows an acidic trend as evidenced by the low pH values, particularly in lateritic aquifers. Spatial assessment indicates that the southern part of the coastal aquifers shows elevated pollution levels during post monsoon season. Most of the groundwater is of Na-Cl facies in post monsoon and which slightly changes to Na-Mg-Cl facies during pre monsoon. Inter relationship between chemical parameters were also studied to understand the groundwater facies. Salinity hazard, percentage of sodium, SAR, integrated SAR and EC and RSC, were considered for judging the usefulness of groundwater for irrigation. Landuse map was prepared and water sample locations were superimposed on it, in a GIS platform, to assess the variation in water quality in different landuse classes. The outcome of the present study indicates that the concentration of certain parameters exceeds the recommended limits and hence mitigation measures are needed to be adopted to ensure safe drinking water. [ABSTRACT FROM AUTHOR]