eChapters

Carbohydrates are widely prevalent in the plant kingdom, comprising the mono, di-, oligo-, and polysaccharides. The common monosaccharides are glucose, fructose, galactose, ribose etc. The disaccharides, i.e., the combination of two monosaccharides include sucrose, lactose and maltose. Starch and cellulose are polysaccharides consisting of many monosaccharide residues. Cellulose is the most abundant organic compound on this planet since it forms part of the cell wall in plants.

Aldehydes (–CHO) and ketones (= CO) are active groups in carbohydrates. Carbohydrates contain many hydroxyl groups as well. The number of hydroxyl groups varies with the number of carbon atoms. Monosaccharides contain the free aldehyde or ketone group. Some disaccharides have the free aldehyde group (maltose) and some do not have the free ones (sucrose). The polysaccharides, starch and cellulose, are polymers of monosaccharides linked through the active groups. The chemical properties of saccharides vary depending upon the number of hydroxyl groups and the presence or absence of –CHO/= CO groups. These variations are the basis in the development of colour reactions to identify the saccharides. Some simple tests used to identify the presence/absence of certain saccharides are listed below:

Nitrogen is a nutrient and occurs in many forms including ammonia, organic, nitrate and nitriteeach of which may be tested for in a variety of ways. Under normal circumstances, the nitrite form of nitrogen will not be present in large quantities due to its rapid oxidation orconversion to nitrate. The presence of large concentrationsof ammonia in a stream or lake can create a large oxygen demand. This demand is caused by the conversion of ammonia to nitrate. High concentrations of nitrate in waste water treatment plant effluent can cause algae to grow in large quantities.

Current status

For many years, the protein contentof foods has been determined on the basis of total nitrogen content, while the Kjeldahl (or similar) method has beenalmost universally applied to determine nitrogen content (AOAC, 2000).Nitrogen content is then multiplied by a factor to arrive at protein content. This approach is based on two assumptions: thatdietary carbohydratesand fats do not contain nitrogen, and thatnearly allof the nitrogen in the dietis present as amino acids in proteins. On the basis of early determinations, the average nitrogen (N) content of proteins was found to be about 16 per cent, which led to use of the calculation Nx6.25(1/0.16 = 6.25) to convertnitrogen contentinto protein content.

In chemistry, and especially in biochemistry, a fatty acid is a carboxylic acid with a long aliphatic tail (chain), which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms, from 4 to 28. Fatty acids are usually derived from triglycerides or phospholipids. When they are not attached to other molecules, they are known as “free” fatty acids. Fatty acids are important sources of fuel because, when metabolized, they yield large quantities of ATP. Many cell types can use either glucose or fatty acids for this purpose.

Equipment

1. Adjustable pipette.
2. 20-ml glass beaker.
3. Atomic Absorption Spectrophotometer.

Phytochemicals are chemical compounds that occur naturally in plants (phyto means “plant” in Greek). Some are responsible for color and other organoleptic properties, such as the deep purple of blueberries and the smell of garlic. The term is generally used to refer to those chemicals that may have biological significance, for example antioxidants, but are not established as essential nutrients. Scientists estimate that there may be as many as 10,000 different phytochemicals having the potential to affect diseases such as cancer, stroke or metabolic syndrome. The potential of the phytochemicals have large scale pharmacological and biological activities such as antioxidant constituents (hydrolysable tannins, phenolic acid and flavonoids) of the plant materials for the care of health and protection from coronary heart diseases, cancer, anti-carcinogenic and anti-mutagenic effects. Varieties of herbaceous vegetables are protective against various diseases, particularly cardiovascular diseases. These herbaceous plants and species are harmless sources for obtaining natural antioxidants. Antioxidant constituents can delay or inhibit the oxidation of lipids and other compounds by inhibiting the propagation of oxidation chain reaction (Hussain et al., 2011)

Primarily, antioxidant effect is due to phenolic compounds such as phenolic acid, flavonoids and phenolic diterpenes and their mode of action for antioxidant compounds is due to its redox reaction properties which can absorb and neutralize free radicals by quenching singlet and triplet oxygen. Vitamins are organic substances necessary for metabolism. Human diet does not always contain the required amount of vitamins for the normal growth and maintenance of the body function and as such cannot produce enough quantity for their body metabolism, so it can be obtained from fruits, vegetables and foods. Deficiency of vitamins can cause serious human health diseases and sometimes, very small concentrations are required for maintenance of good human health.

The effects of global warming and/or climate change are of concern both for the environment and human life. Evidence of observed climate change includes the instrumental temperature record, rising sea levels, and decreased snow cover in the Northern Hemisphere. According to the IntergovernmentalPanel for Climate Change (IPCC) Fourth Assessment Report, “most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in [human greenhousegas] concentrations. It is predicted that futureclimate changes will include further globalwarming (i.e., an upward trendin global mean temperature), sea level rise, and a probable increase in the frequency of some extreme weather events. Ecosystems are seen as being particularly vulnerable to climate change. Human systems are seen as being variable in their capacity toadapt to future climate change. To reduce the risk of large changes in future climate, many countries have implemented policies designed to reducetheir emissions of greenhouse gas.

ABSTRACT

Bioinformatics is a critical tool in designing the molecular biology experiments. The xeroxing of specific part of genome needs correct primer designing. Primer designing has central role in molecular biology right from cloning, sequencing, gene expression profiling by real time PCR, genotyping by RFLP, SNP analysis by real time PCR and auto sequencer. In this chapter we are describing how to proceed for experimental designing right from data mining from GENEBANK to designing of primers for various common molecular genetic analysis work. The write up also describes in silico evaluation of primers, various off line commercial and non-commercial software, on line free software and trouble shootings in primer designing, The different strategy described in context of primer designing would be of immense use of researchers.

ABSTRACT

A number of secondary metabolites are produced by cyanobacteria involving the non-ribosomal peptide biosynthetic pathway. Some of these compounds have potential biotechnological applications, whereas others (the cyanotoxins) are undesired due to their toxicity to animals. The occurrence of toxic cyanobacterial blooms in freshwater bodies that are used as source for human consumption, recreation and irrigation are frequent nowadays due to increasing artificial eutrophication of these environments. It is important to monitor toxin-producing strains in order to prevent the adverse effects caused by their toxins to human and animal health. Thus, the development of rapid and sensitive methods for the detection of cyanotoxins is important as they could be useful to monitor water supplies and contribute for watershed monitoring strategies. Current methods include cell counting, microscopic identification and toxin analysis by biochemical and analytical techniques. However, in recent years, molecular biology techniques, such as polymerase chain reaction (PCR), have been used to amplify specific regions within biosynthetic genes for rapid and sensitive identification of toxic cyanobacteria. The aim of this chapter is to provide an update of cyanotoxin biosynthesis and discuss the advances and limitations of molecular biology regarding its application as indicative of cyanotoxin production.

ABSTRACT

Biotransformation is an essential step in the elimination of drugs and reduction of their toxicity. The use of fungi in biotransformation reactions can provide information about the metabolism of new drugs and facilitate the attainment of necessary amount of metabolites for toxicological and pharmacological evaluation. Biotransformation studies require the right choice of the microorganisms and also of the culture conditions (pH, substrate, oxygen, salts, temperature, etc). The optimization of these procedures is essential to achieve good results. The fundamental aspects of drug biotransformation by fungi are discussed here as well as some applications showing that many fungi are used in biotransformation studies, mainly Cunninghamella species. Several species mimic the mammalian metabolism producing the same metabolites observed in humans.

ABSTRACT

Methylotrophy is a phenomenon by which microorganisms derive energy, and in many cases, cell carbon from reduced molecules that have no C–C bond (also called C1compounds). This gains significance because of its unique mode of nutrition, the ability to utilize more than one metabolic pathway and its vast distribution among various groups of bacteria and yeasts. It is one of the earliest modes of energy metabolism present in microorganisms, through which microorganisms are able to utilize a wide range of compounds, which are considered unsuitable for most forms of life. In the present chapter we focus on various aspects of methylotrophy, and the application of methylotrophic bacteria in a spectrum of biological activities and commercial possibilities.

ABSTRACT

Plant growth promoting (PGP) bacteria play an immense role in promoting crop growth mainly by direct mechanisms such as N_2-fixation, phosphate solubilization and phytohormone production and indirectly may help to suppress pathogens or contribute to enhance absorption of nutrients leading to increase yields. The N₂fixers are grouped based on their niche adaptation as endophytic nodular symbionts (Rhizobium spp.), free living (Azotobacter spp.), associative symbionts (Azospirillum spp.) and endophytic non-nodular symbionts (Azoarcus and Gluconacetobacter diazotrophicus). In the recent past, phosphate solubilizing and phytohormone synthesizing bacterial communities also gained momentum.

ABSTRACT

Soil borne fungal pathogen causing root diseases of vegetables are difficult to control by chemical methods. The existing biocontrol bacteria are not very effective in control of soil borne fungal pathogens. As such very less number of bacterial biopesticide is available commercially to control the fungal pathogens. Increasing concerns in recent years about human health and environmental problems due to chemical pesticides, couple with increasing pest resistant to chemical, have led to a reappraisal of our approach to control pest and disease in crops. The trends now are towards a management concept in which the best combination of tools is used to manage plant diseases below economic thresholds with minimal risk to human health and environment. The modern management concept includes extensive use of biocontrol agents which are harmless to non-target organisms. Development of effective technology for control of pest and disease by using microbial resources of a region to enhance the quality of ecosystem is a potential alternative approach to chemical control of plant diseases. In such strategy, search for microorganisms and biological system is an important prerequisite prior to development and practical exploitation of biocontrol. Rhizosphere microorganisms are shown to be perspective candidate for biocontrol agent as they provide the front line of defense for plant roots against the attack by various plant pathogens causing the most diseases of vegetables and crops. Chemical control of soil-borne fungal pathogen had been the subject of growing concern because of their adverse effect on the environment and emergence of chemical pesticide resistant to plant pathogen, moreover, soil borne pathogens are very difficult to control. Crop rotation, breeding for resistant plant varieties and application of pesticides are insufficient to control root diseases of important plants because they survive as sclerotia and has got wide host range.

ABSTRACT

Endophytes are microorganisms that live inside the host plant tissues without causing symptoms of disease. There has been a crescent interest in the prospecting of these microorganisms as sources of novel and bioactive natural products. In fact, a significant number of interesting natural products have been reported in the last years. In this chapter some aspects regarding the endophytes are detailed: the relationship with their host plants, isolation, preservation, taxonomy, cultivation, frequently isolated strains, tropical endophytes, novel structures isolated and also their biological activities.

Key words: natural product, endophytic fungi, plant fungus interaction, secondary metabolites.

ABSTRACT

The world ocean with a coastline of approximately 3,50,000 km is the largest ecosystem on earth. Marine organisms are the major, sustaining components of ecosystem processes and are responsible for biogeochemical reactions that drive our climate changes. Despite this, many marine organisms are poorly described and little is known of broad spatial and temporal scale trends in their abundance and distribution. With new molecular and analytical techniques we can advance our knowledge of marine biodiversity at the species level to understand how marine biodiversity supports ecosystem structure, dynamics and resilience. We can then interpret environmental, ecological and evolutionary processes controlling and structuring marine ecosystem biodiversity. In biotechnology applications marine microbes represent a potential source for numerous commercially important biomolecules and their bioremediation capabilities are also remarkable. They also play a crucial role in decomposition of organic matter and cycling of nutrients. Microbes also serve as food for some bottom-living organisms. Understanding and preserving biodiversity was one of the most important global challenges for the past 20 years and will continue to be an important scientific issue into the new millennium. Our knowledge of marine microbial diversity has, however, been severely limited by relying on microorganisms that have been cultured which are less than 1%.

ABSTRACT

Industrial and agricultural activities and the disposal of waste products have resulted in the contamination of many terrestrial environments. Industrial effluents often contain considerable amount of potentially toxic compounds such as Cd, As, Pb and Hg. Due to their small size, which provides a large contact area that can interact with the surrounding environment, microorganisms are the first biota showing the impact of toxic compounds. Microorganisms being in intimate contact with the soil environment are considered to be the best indicators of soil pollution. In general, they are very sensitive to low concentrations of contaminants and provide a rapid response to soil perturbation. Rhizobium spp. are ubiquitous gram-negative soil bacteria that have a profound scientific and agronomic significance due to their ability to establish nitrogen-fixing symbiosis with legumes, which is of major importance to the maintenance of soil fertility and to feed livestock and populations in many developing countries. Therefore, the present work aimed to evaluate the impact of heavy metals on Rhizobium populations isolated from different locations contaminated with heavy metals. In order to reach this goal some physicochemical parameters that influence metal bioavailability were determined, as well as their concentrations in soil. Cadmium tolerance of Rhizobium isolates was screened in artificial media and the highest cadmium concentration allowing growth was defined as the maximum resistance level (MRL). The heavy metal tolerance variability found among Rhizobium isolates, suggests that beyond basic metabolic machinery also exist variations that allow isolates to display distinct tolerance responses to Cd stress. To better understand Rhizobium cadmium tolerance, wall-bound and intracellular Cd was determined. Sensitive and moderately tolerant isolates showed low intracellular Cd amounts when compared to extremely tolerant isolates, which were able to withstand intracellular Cd concentrations 40 times higher. Lipopolysaccharides (LPS) bind cations unspecifically, so they constitute the initial defence mechanism to heavy metals since they sequestrate cations and therefore prevent their entry into the cell. LPS quantity varied significantly between isolates. LPS increases were observed in most sensitive, moderately tolerant and tolerant isolates, evidencing an attempt of cells to adjust to cadmium entry. These results may be of great importance for understanding how Rhizobium persists in contaminated soils. They also provide important data to the development of bioremediation processes and to the improvement of soil productivity.

ABSTRACT

An understanding of the metabolism of heavy metals facilitates biotechnological use of these functions just recently, although heavy metals comprise the major part of the elements in the periodic table. Due to their ability to form complex compounds, some heavy metals are essential trace elements. In any case, essential or not, most heavy metals are toxic at higher concentration. Heavy metal pollution from last few decades has led to an increased environmental concern. Heavy metal like cadmium is a non-essential toxic heavy metal and is also being increased in soil during last few years posing a serious threat to environment and human health worldwide. Therefore, remediation strategies of the contaminated sites are great concerns and can be achieved by a number of different physico-chemical and biological means.

ABSTRACT

Plasmids are circular, double-stranded DNA molecules which replicate autonomously from the chromosome of the host organism. Plasmids are found in many bacterial species and often confer upon the host cell phenotypic characteristics such as resistance to antibiotics, resistance to heavy metals, ability to produce particular protiens, conjugative (mating) ability and ability to degrade xenobiotc compounds. One of these degradative plasmids may encode a complete catabolic pathway (such as toluene to pyruvate, formate and acetaldehyde) or partial degradative steps, such as octane to octanol. In this later case, the remainder of the pathway may be encoded by chromosomal genes, by genes of other plasmid present in the host, or by other microorganisms. Many degradative plasmids possess a broad host range, especially among the gram-negative bacterial species.

There are different mechanisms which may be involved in the evolution of aromatic pathways in general and in the process of adaptation of microorganisms to xenobiotic substrates in particular. Gene transfer, the occurrence of plasmids in bacteria in the natural environment is an important pool of genetic information residing on plasmid vehicles may flow among indigenous microorganisms. Since many examples of self-transmissible plasmids that carry genes for degradation of aromatic or other xenobiotic compounds are known, and their role in spreading these genes to other microorganisms is well characterized. Early, studies of TOL, NAH, and SAL plasmids revealed strong homologies among these plasmids in regions both inside and outside the catabolic gene clusters. Plasmids, pJP4, pAC25, and PSS50, catabolic plasmids carrying genes for chloroaromatic degradation, have strongly homologous plasmid backbone that determine replication and transfer function. Furthermore, the chlorobenzoate plasmid p51 was also shown to be homologous to pJP4 outside regions of the catabolic genes. These observations suggest that a few common self-transmissible ancestor replicons (includes origin of replication and replication gene) may have been involved in acquisition and spread of different catabolic genes. DNA

ABSTRACT

Heavy metal contaminated soils are biologically inactive and extremely poor in soil fertility status. These metals are highly resistant and cannot be easily degraded by either chemical reactions or amendments. Microorganisms are biological softwares capable of degrading the metals efficiently. Among microorganisms, mycorrhizas are known to circumvent metal toxicities through a series of processes that assist in immobilization in biological systems which converts toxic metals into less or nontoxic forms. There are five mechanisms such as biosorption, solubilization, hyphal transport, detoxification and dilution are involved in promoting tolerance of host plants to heavy metal toxicities. These processes are strategies that can be exploited to phytoremediate the contaminated soils. The phytoremediation strategies encompass tolerance of mycorrhizal fungi, phytostabilization (preventing entry of heavy metals into plants), phytoextraction (luxuriant uptake and transport to shoots) and intercropping or crop rotation with mycorrhizal dependent hyperaccumulators or non-hyperaccumulators. Despite mycorrhizas are natural, the indigenous population is not sufficient enough to induce tolerance of host plants to abiotic and biotic stress conditions. This necessitates adopting recommended agronomic practices to promote mycorrhizal colonization in natural agro-ecosystem or to derive full benefits from phytoremediation strategies. Thus mycorrhizas are important naturally occurring microorganisms capable of withstanding highly contaminated metal sites and offer protection against phytotoxicities caused by heavy metals.

ABSTRACT

The continuing depletion of the stratospheric ozone layer mainly due to release of man-made atmospheric pollutants such as chlorofluorocarbons (CFCs) have resulted in the increase of solar ultraviolet-B radiation (UV-B; 280-315 nm) reaching to the Earth’s surface. UV-B is a small (less than 1% of total energy) but highly active component of the solar spectrum that can penetrate to biologically significant depths in lakes, ponds, rivers and oceans. It has been demonstrated that UV-B can cause wide ranging effects including mutagenesis, destruction of proteins/enzymes, inhibition of a number of vital metabolic processes and formation of thymine dimers in DNA leading to death of a number of organisms. A number of microbes including strict photoautotrophs always grow in lighted habitats and thereby always sense and face the stress of solar UV-B radiation. Similarly, humans are also exposed to varying levels of UV-B radiation depending upon the altitudes and latitudes of the location. A wide ranging effect of UV-B such as cataracts, skin cancer, immunosupression etc. has been reported in human. Damaging effects of increased UV-B radiation has also been shown in a number of microbes. These effects include inhibition of growth and survival, decrease in photosynthetic pigments, loss of PS II and RuBISCO activity, inactivation of nitrogenase enzyme and inhibitory effects on several other metabolic processes. Among photosynthetic pigments, phycobiliproteins seem to be the primary target of action since phycobilisomes are completely disintegrated after UV-B exposure. In this contribution an attempt has been made to put in perspective the main effects of UV-B radiation on microbes and human health.

ABSTRACT

Serious infections caused by bacteria that have become resistant to commonly used antibiotics have become a major global healthcare problem in the 21^st century. Antibiotic resistance, initially a problem of the hospital setting associated with an increased number of hospitals acquired infections usually in critically ill and immuno-suppressed patients, has now extended into the community causing severe infections difficult to diagnose and treat. In hospitals, most common resistant bacteria include methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci and gram-negative rods including Enterobacteriaceae and Pseudomonas aeruginosa. Vancomycin intermediate and resistant S. aureus, represent a new treatment challenge. In the community, penicillin and macrolide-resistant pneumococci developed several decades ago and are now present all over the world. More recently, communityacquired methicillin-resistant S. aureus has become a problem in several countries causing skin infections but also severe diseases. The molecular mechanisms by which bacteria have become resistant to antibiotics are diverse and complex. Bacteria have developed resistance to all different classes of antibiotics discovered to date. The most frequent type of resistance is acquired and transmitted horizontally via the conjugation of a plasmid. In recent times new mechanisms of resistance have resulted in the simultaneous development of resistance to several antibiotic classes creating very dangerous multidrug-resistant (MDR) bacterial strains, some also known as ‘‘superbugs’’. In many cases the use of antibiotics is unnecessary or questionable. The indiscriminate and inappropriate use of antibiotics in outpatient clinics, hospitalized patients and in the food industry is the single largest factor leading to

ABSTRACT

Frankia is a gram-positive, microaerophilic, actinomycete that enters into symbiotic associations with a number of woody dicotyledonous plants called actinorhizal plants. Frankia can fix atmospheric nitrogen through such associations. The actinorhizal-Frankia association is beneficial for the environment, since it increases the fertility of soils. Extensive studies on the biochemical and molecular aspects helped in the classification of Frankia. PCR-RFLP studies of the 16S rRNA and the nif regions of Frankia revealed considerable information regarding the diversity of Frankia strains, isolated from different parts of the world. The completion of three whole genomes of Frankia has bolstered the study of the molecular organization of the genome. Comparative genomics study of the three complete genomes revealed that, the strains reflected the biogeographical history of the host plants they infected. Striking similarity in the codon usage patterns highlights the fact that they may have evolved as a unit. In the present review we highlighted the taxonomy of Frankia and the host plants, the Frankia-actinorhizal association, regulation of infectivity, biochemical and molecular characterization, phylogeny and genomics of Frankia and stressed the need for metabolomic study of the Frankia-actinorhizal association.

ABSTRACT

The multi-sensor airborne geophysical survey was carried out over Nalgonda district, Andhra Pradesh, during the field season 2002-03, with an objective to locate potential areas for mineral exploration. The area comprises older metamorphic rocks of Peninsular Gneissic Complex of Archaeanage represented by gneisses, granite, amphibolite and banded magnetite quartzite. Leucocratic intrusive granite, extending over a length of about 40 km around Suryapet in NNW-SSE direction exhibits intense fracturing. Two sets of vertical to sub-vertical fractures have been noted in granite. Yellow stains observed in granite near fracture planes reveal the presence of secondary radioactive mineral encrustation. The ground magnetic and spectrometric observations indicated that the uranium mineralization is confined to these fractures in granite. Petrographic, ore-microscopic and scanning electron microscopic studies revealed evidences of metamict alteration surrounding monazite/apatite inclusions within biotite, and magnetite grains in granite. These studies also indicated evidences of discrete grains of uraninite / coffenite / pitchblende (containing Thand Ce). Chemical analysis of the rock samples (by NAA) collected from anomalous zone reveal high uranium concentration of the order of 1200 ppm, marked by high values of total Rare Earth Element concentration (800 ppm).

The leucogranites are characterized by high LREE and a negative Eu anomaly suggesting plagioclase fractionation. An ultramafic enclave near village Kutubsahipur shows highest concentration of both uranium (1240 ppm) and REE (890 ppm) analyzed by BARC and NAA Lab, GSI.

ABSTRACT

The carbonatites are genetically and geochemically distinct and contain several rare earth minerals that are unknown or are very rare in other types of rocks. A useful review of the REE’s in carbonatites is given by Cullers and Graf (1984), who point out that carbonatite contains the highest concentration of REE’s and highest LREE: HREE (La:Lu) ratio of any igneous rock. High REE abundances are considered as the diagnostic character of carbonatites to discriminate them against recrystallized limestone. Rare earth mineralization in carbonatities can be classified into three categories. The first is primary magmatic crystallization (bastnaesite). The second is hydrothermal mineralization and the third is supergene mineralization produced by weathering of carbonatitie bodies. The only economic Nb mineral in carbonatite is pyrochlore. Apatite deposits constitute the largest bulk mining in carbonatites and have higher phosphate content than marine phosphorites. Pyrochlore, cubic fergusonite, eschynite, Fe-Nb rutile, monazite apatite, bastnaesite and allanite are the rare earth minerals that are enriched in Tamil Nadu carbonatites. Such enrichment of above rare earths is typical of undersaturated alkaline complexes. The lanthanides are seen associated with these minerals, mainly the light lanthanides are predominant than heavier ones. Thus the carbonatite complexes provide the locus for several metal deposits that are presently of strategic importance, containing elements, which are otherwise largely dispersed in earth crust.

ABSTRACT

Worldwide reinterpretation of evolutionary history of sedimentary basins had commenced with the introduction of sequence stratigraphic concepts by geoscientists of Exxon. The eustatic sea level controlled deposition in sedimentary basins together with synchronous excursions of many trace elemental and stable isotopic compositions of sedimentary strata have led to a proposition that geographically widely separated sedimentary strata could be classified and correlated with ease by application of sequence stratigraphy and chemostratigraphy, relatively younger branches. This paper reviews the key definitions of these stratigraphic methods, presents an overview on their applicability in petroleum exploration, reservoir characterization and stratigraphic correlation. Considering the man-hours required for interpretation of sequences and chemozones from large quantum of core samples being generated from exploration activities and the possibility of human-error and biased nature of interpretations, an automation scheme involving statistical discrimination is suggested. The statistical discrimination method has been tested to have 76-100 % distinction of depositional units of Recent – Cretaceous in age in terms of sequences, chemozones, lithostratigraphic units, petrographic types and sedimentary microenvironments with 100% reproducibility of predictions. Hence, creation of a large database with well constrained subpopulations and putting it to use for recognition of depositional units and correlation of strata and reservoir characterization is suggested which may reduce operational inconsistencies and improve exploration strategies.

ABSTRACT

India is blessed with large reserves of strategic and economically important heavy minerals such as ilmenite, rutile, leucoxene, zircon, monazite, garnet and sillimanite. These deposits are mostly located in the coastal stretches of Peninsular India especially between the high tide line and 200-250m inland, with the exception of few inland deposits. Ilmenite is the largest constituent of the Indian beach sand deposits, followed by sillimanite and garnet. These minerals are one of the largest and higher grades in the World. The Indian Ilmenite resource base totals 348 million tones (Mt), along with 18 Mt of rutile, 21 Mt of zircon, 8 Mt of Monazite, 107 Mt of garnet and 107 Mt of sillimanite. Although Indian heavy mineral resources are one of the largest in the world, it is observed that the Production to Reserve Ratio (PRR) is a meager 0.0013; that is insignificant compared to other countries with similar resources.

ABSTRACT

Mineral exploration is not only highly imaginative and creative but a very costly activity as well. The fast emerging Geomatics technology is a real boon in mineral exploration as it encompasses a whole spectrum of solutions and services which are of great help for exploration geologists. Geological maps which generally form the basic requirement for any kind of natural resources inventory operations currently witness tremendous changes and the same is mainly attributed to the integration of Geomatics technology. Usage of Geomatics has revolutionized the art of mineral exploration as geological maps can be easily integrated with other important details like geomorphology, structure and tectonic pattern, geophysical data etc. This kind of data integration facilitates for the better identification of mineralized zones. In addition, GIS with its powerful analyzing capability provides tools at several stages in the process of mapping for building up a database containing various types of data for quantifying and extracting features related to mineralization. The present paper narrates an overview of mineral exploration using Geomatics technology.

ABSTRACT

We report here the occurrence of chrysoberyl bearing gem pegmatitesof Southern India. The Pan-African Chrysoberyl mineralization is associated with intrusive event of grey pegmatites within granulite facies parametamorphic aluminous khondalites. Lithological and structural controls of chrysoberyl mineralization are discussed. The chrysoberyl occurrences in southern India, southern Madagascar and Sri Lanka provide strong evidence for India-Sri Lanka-Madagascar juxtaposition in the East Gondwana assembly with the Achankovil Shear Zone of Southern India one side extending into Ranotsara Shear Zone in Southern Madagascar and other side into southern tip of Sri Lanka.

ABSTRACT

Sedimentological studies such as textural, heavy mineral and clay mineralogy have been carried out for Warkalli Formations at Varkala, situated in the southern part of Kerala, India. The X-ray diffraction study reveals that kaolinite is the only clay mineral present in all the samples with trace amounts of gibbsite and goethite. The higher amount of kaolinite and gibbsite indicates warm and humid paleoclimatic conditions. The textural analysis shows that the sediments are moderate to poorly sorted, nearly symmetrical to fine skewed and lepto to mesokurtic in nature. A plot of skewness against sorting shows fluvial trend. The major heavy minerals present in the samples are magnetite, ilmenite, rutile, sillimanite, anatase and zircon. It can be inferred from these studies that these sediments would have been deposited in a lagoon by fluvial action. During that time, the source region has experienced tropical humid climate with mean annual precipitation (MAP) above 200 cm and intensive chemical weathering. Heavy mineral assemblage indicates medium to high grade metamorphic source rocks.

ABSTRACT

The Cretaceous formation of Ariyalur area is well known for its lithological and faunal variation. It contains rich assemblages of fossils as well as the occurrence of economic deposits of limestone, gypsum, phosphatic nodules and clays. Representative Uttatur clay samples have been collected and analysed for physical and chemical properties. The physical properties such as fired colour, plasticity, fusing temperature, slaging nature, shrinkage test, bulk density, liquid limit, and plastic limit and Atterberg number etc. of uttatur clays have been determined. The chemical properties of the clays show low in silica and alumina and high iron and lime which make them suitable for low duty refractories and stoneware works.

ABSTRACT

54 foraminiferal species belonging to 29 genera, 23 families, 17 superfamilies and 5 suborders have been identified from Nagaland. Of the total species 16 are planktic and 38 are benthic forms. The age for the Upper Disang Group of Nagaland is assigned as Late Eocene, based on the presence of Late Eocene markers i.e. Globigerinatheka semiinvoluta, Cribrohantkenina inflata, Hantkenina alabamensis and Turborotalia cerroazulensis. As per the present study the Disang succession in Nagaland can be grouped into five biofacies. The Uvigerina dominated biofacies consisting Uvigerina cocoaensis, U. continuosa, U. eocaena, U. glabrans, U. jacksonensis and U. cf. steyeri. In some samples even up to 100 % Uvigerina were present. The localized occurrence of thick “Uvigerinids” in high percentage with pyritized test in this section indicates anoxic conditions, suggestive of possible source rock for oil.

ABSTRACT

Using a hand auger of 2 m length, upper, middle and lower core sediment samples of seventy nine in number have been collected from the Vaippar river, its tributaries and Vaippar beach in order to understand the role of Vaippar river and its tributaries in making up the Vaippar beach placer deposits. The heavies are found to be concentrated abundantly in fine and very fine size grades of all the samples collected from both the environments. The average heavy mineral concentration varies from 3.13 to 17.40 % in river bed while it is 6.19 – 64.82 % in the beach. In river bed, the pattern of concentration of heavies in upper, middle and lower core samples does not show any characteristic uniform pattern and inferred that it is controlled by the grain size of the parent rock, supply of sediments from the source, geomorphological features of the river and hydrological characters of running water. In the beach, the concentration of heavies are effected mainly due to the winnowing action of waves. However, a phenomenal increase in the heavy mineral concentration of beach samples might be due to the supply of sediments from other source besides the Vaippar river.

ABSTRACT

Lineaments are the surficial expression of sub-surface phenomena which are well discerned from low-orbital data, satellite data with its synoptic view and repetitive coverage and help to bring out more information on structural features hither to unknown by conventional geological surveys. Their study paved way to many new concepts on tectonism, mineralization, structural deformity etc. of an area both in regional and local perspective. In the present study, a small area was selected after careful observation, for their importance in mineral deposits. The lineaments are mostly structurally controlled and analysed for their relationship with the base metal deposits of the area. Moreover satellite parameters like spatial resolution, scale etc., and are observed for their changes in their orientation and relationship with the deposit of the study area, Jambughoda of Panchmahal District, Gujarat Satellite data of Landsat MSS and TM are used for the analysis. The results proved that the satellite parameters are important criteria and play a vital role in lineament analysis for mineral investigation.

ABSTRACT

Coastal zones are credited for the important role they play in the economic, industrial and commercial activities of many countries. Starting from the early fifties of the last century, coastal zones have attracted greater attention from the earth scientists owing to the discovery of huge hydrocarbon deposits in the Persian Gulf, Africa and South America. In addition, coastal zones especially those bordering Precambrian Cratons house significant quantities of economically important placer minerals which are being explored and exploited vigorously. In the present paper, sedimentary basins located along the continental margins of Tamil Nadu state, their geology and hydrocarbon potential are discussed. In addition, an attempt has also been made to demonstrate the usefulness of remote sensing techniques in the exploration of this strategic mineral.

ABSTRACT

Mapping and exploration of iron ore deposits in parts of Salem District is carried out based on the detailed field work and the interpretations of IRS-1C PAN data in the scale of 1:12,500 and aerial photographs (NRSA, Scale 1:4,000). The study results that the major rock types of the study area are banded magnetite quartzite, garnetiferous pyroxene granulite, amphibolite, garnetiferous pyroxenite, charnokite, talc tremolite, actionalite and dunite rocks. The Banded Magnetite Quartzite’s (BMQ) occur as enclaves within the hornblende gneisses at several parts of the study area. Topographically, the rocks constitute small low-lying linear ridges at some places it is found to be closely associated with garnet pyroxene granulites. A remarkable feature about the mode of occurrence of magnetite quartzite is its linear nature and the physical form, which could be described as a “Band”. All the bands possess an ENE-WSW strike and the dip is found to be steep (above 70 degrees) towards north. The rock in the hills of Godumalai, Vellalagundam, and Singipuram are highly deformed and contact with garnetiferous pyroxene granulite and hornblende gneisses. In hand specimen, the magnetite quartzite rock exhibits fine banding. In general no variation in grain size or thickness of banding could be seen megascopically. However, occasional increase in size of magnetite might be possible as seen from the coarser magnetite pebbles strewn in the channels of the area. There are two types of folds observed namely F1 and F2. The axial plane trace of the F1 varies in trend from WNW-ESE to WSW – ENE. The joints are traced in the directions of NNW-SSE to NNE – SSW and WNW – ESE to ENE-WSW. The interpretation of lineaments shows their trend directions of NNE-SSW, NE-SWand NNW-SSE. The above said work has carried out through detailed field work and interpretations using by IRS-1C PAN data in the scale of 1:12,500 and aerial photographs of NRSA, in the scale of 1:4,000 for the study area.

ABSTRACT

In Tamilnadu majority of the people are engaged in agricultural work and they mainly depend upon the water resources. But at present both surface and subsurface water has become deficient because of over exploitation. Since last few years, conventional methods were employed to improve the surface and subsurface water conditions. But these methods provide less accurate result and consume more time. So to improve the conditions modern tools, such as remote sensing and GIS are being used to identify the ground water potential zones in Tamilnadu. It provides accurate resulst and consumes less time.

A project was carried out in Gadilam lower sub basin which falls in the part of Cuddalore District, Tamilnadu. The IRS 1D imagery was collected and interpreted using image processing software and Geo media GIS Software in conjunction with collateral data to prepare Hydro geomorphology, land use, geology and lineament maps Field checks were made and transferred the field data on the base map. By application of overlay analysis of the above thematic maps, using GIS techniques, the recharge zones were identified.

The satellite image mosaic map of Gadilam lower sub basin was generated to identify ground water potential zones. Average monthly rainfall data for the past 50 years were collected. Using Remote sensing and GIS techniques, the thematic maps such as Geology, Geomorphology, Soil, Drainage, Land use, Lineament zones have been generated for this study. Geophysical survey was also conducted in various locations and the aquifer parameters were measured. Details related to land and water resources, cropping pattern, water levels and water qualities from PWD ground water division, land use and well censes data of villages from village Administrative Officer, tank details from PWD were collected and analyzed

After analyzing the various thematic maps, they were finally overlaid. Thus the groundwater potential zones of Gadilam lower sub basin was identified.

ABSTRACT

The geological and geomorphological features could be clearly demarcated in and around Salem area using IRS -IB LISS II satellite data. Geologically,the study area is classified into four major rock types fissile hornblende biotite gneiss, banded magnetite quartzites, peninsular gneiss, charnockites and quartzites. The geomorphological study reveals the buried pediments medium, buried pediments deep, bazada zone, along with lineaments. Intersections of the lineaments are the most prospective zones for further groundwater targeting. Shallow pediments and pediments are the less groundwater prospective zones. But detailed geophysical survey as required to sink new bore well, dug well, dug cum bore wells.

ABSTRACT

The present paper discusses about the Geoelectrical response over Charnockite rocks and Biotite Gneiss rock types of Sankaran kovil and Tenkasi Taluks of Tirunelveli District, Tamilnadu. The study area is adjoined to the Western Ghats which geologically comprises Archean crystalline hard rocks. In this attempt, about 7 Vertical Electrical Soundings (3 in Gneiss and 4 in Charnockite) have been carried out in both terrains. The VES values were interpreted with Schlumberger Sounding Dada Processing and Interpretation Program .The resistivity values varied from 68 m to 808 m with the layer thickness of 10m, 20 m and 29m in the biotite gneiss terrain. Similarly, the resistivity values varied from 48 m to 444 m with the layer thickness of 4m, 6m, 9m,18m & 29m in the charnockite terrain. But the depth to massive rock for both the rock types has been observed below 29m. In this study, a difference in resistivity with high resistivity values in gneissic terrain and lower values in charnockite terrain have been observed. The observed resistivity differences are mainly due to the presence of resisting minerals such as biotite and hornblende. Besides, other factors like weathering and water table also influence the resistivity values. Hence, it is summerised that the geoelectric methods are the best methods to understand the subsurface lithostudies.

ABSTRACT

The exponential growth of population and rapid industrialization, urbanization, deforestation and improper landuse practices have led to depletion and pollution of surface and ground water resources in Tamilnadu, India. In addition, a recurrent monsoonal failure further aggravates the problem of water even for drinking water. Water plays vital role in our day to day life and other developmental activities in the area. Thus, the availability of surface and sub surface water potential governs the processes of planning and development. The surface water resources are inadequate to fill the water demand and productivity through ground water is quite high as compared to surface water. Keeping this in view, the present study is aimed to identify the potential location of potable groundwater exploration in hard rock terrain. Thematic information on geomorphic landforms, Landuse/landcover and lineament details are extracted from remotely sensed data. Geology, Soil class, Drainage network and Slope map of the terrain were prepared using existing maps and collateral data by conventional method. GIS based model was developed and appropriate rank and weightage had been assigned to all categories based on local conditions/variations in each layer according to relative contribution towards the desired output. Since the present study built with logical condition and reasoning rule based approach for groundwater targeting, it has been successfully used and clearly demonstrated the capability of Remote Sensing and GIS techniques in identification of potable ground water potential zones.

ABSTRACT

Assessment of groundwater potential has wide importance in the exploration, management and development of groundwater resource. The fact that geologic and topographic factors, such as, geomorphology, lithology, structure, soil and slope control the occurrence and movement of groundwater in a region has been made use of in satellite remote sensing to aid groundwater exploration. In hard rock terrains, due to lack of primary porosity, lineaments have greater importance as those can be zones of secondary porosity trapping groundwater in its pore spaces.

In the present study, an attempt has been made to delineate groundwater potential zones in the hard rock terrain in the Gayatri River basin in Kerala, India, using satellite data. The study area which lies between 10o 26’N and 10o 45’N latitudes and 76o 21’E and 76o 54’E longitudes covering an area of about 1000 square kilometers is a drought-prone area. Landsat 7 ETM image of Gayatri River basin has been interpreted visually in a digital environment using ERDAS Imagine software to create geomorphology and lineament maps. Further, with the help of ancillary data, various thematic layers like, lithology, soil, drainage density, etc. have been created and subsequently updated using information obtained from the satellite data. Slope map of the basin has been created using Shuttle Radar Topographic Mission (SRTM) data. Integration of the thematic layers has been done in Arc/Info GRID GIS environment by giving weights to various thematic layers according to their importance in terms of groundwater occurrence. Finally, groundwater potential map of the basin has been prepared by classifying groundwater potential zones as good, moderate and poor.

ABSTRACT

The upper Agniar and Vellar river basins principally consist of three major rock typesnamely pink granite, gneiss and charnockite. The major geochemical pattern of these igneous rocks when studied indicate that charnockites have a trend of low Mg2+ and high Ca2+ + Na O to high K+ end, whereas the same is vice – versa for hornblende biotite gneiss and also for granite gneiss. The pink granite has an intermediate trend between the charnockite and hornblende biotite gneiss. The value of SiO2 in all the rock types was found to increase with the increase of K2O, Na2O and Al2O3. Further, a decrease in the values of MgO, Fe2O3, TiO2 and CaO was noticed with an increase in SiO2. On the basis of the distribution pattern of these elements, the origin of the igneous suites in the above two basins was inferred.

ABSTRACT

Due to complex hydrogeological conditions it becomes very difficult to prospect the ground water resources especially in drought prone areas where the water table is very deep. The interpretation of geoelectrical sounding curves also becomes ambiguous. A semi empirical method namely theinverse slope method [Shankar Narayan and Ramanujachari, NGRI] is widely used since it is simple to operate without standard curves etc and it gives fairly good results. In some Government organizations like PWD [Ground Water Department] and TWAD Board of Tamilnadu, this inverse slope method is widely used for ground water exploration. Based on this methodology, ample of bore well points have been recommended in complicated hard rock terrains and the success rate is found to be encouraging. The study area, Kavalpatti, of Palani taluk in Dindigul district is a crystalline rock terrain, where geological, hydrogeological and geoelectrical investigations have been carried out to explore the ground water potential zone for agricultural purpose. The bore well drilled to a depth of 32 m has yielded 370 lpm. The interpreted geoelectrical section has been correlated with the litholog of bore well. Some bore well statistics [bore well points recommended based on this method] has been furnished, which reveals that this methodology is encouraging.

ABSTRACT

Over the past four decades groundwater has become a topic of discussion and investigation and as a result the knowledge of understanding groundwater conditions has radically improved. For the past quarter century, remote sensing has played a vital role to target the groundwater resources for the essential survival of horticulture and agriculture crops in drought-prone areas. GIS technology has made a rapid stride for the past one decade to amalgamate the data generated from various space-born platforms and the ground based surveys to facilitate the generation and use of various thematic information for groundwater resources assessment. The present study aims for the demarcation of various groundwater prospective zones in the West Doon Valley and its environs, falling in the SOI toposheet 53 F/15. The role of various parameters namely, Geomorphology, Geology, Lineaments, Drainage, Land Use, Water table and Slope has been integrated for delineating groundwater prospective zones. IRS IC LISS-III geocoded satellite image on 1:50,000 scale was used. Index overlay model has been applied for GIS analysis. The resultant map indicates five prospective zones, such as poor, low, moderate, high and very high groundwater prospective zones in the study area.

ABSTRACT

Airborne geophysical methods are presently used all over the world to support mineral exploration by providing basic geological information to supplement existing geological maps. The popularity of airborne geophysics is due to its lower cost for unit of area surveyed, as compared to all other methods of exploration. South India has been extensively covered by high altitude regional aeromagnetic surveys jointly by GSI and NRSA, low altitude multi-sensor surveys by foreign agencies, viz. M/s. Parsons, U.S.A. (Operation Hard rock Project) and BRGM/CGG, France, on contractual basis for GSI and by GSI (Twin Otter surveys) in selected belts and low altitude aeromagnetic surveys by NGRI in the SW part of the Cuddapah basin and the adjoining crystallines. Integrated studies of geophysical (airborne and ground), geological and remote sensing data have greatly helped not only in augmenting the geological knowledge of the region, but also in identifying several metallic prospects/ deposits. The present paper illustrates several case studies in demonstrating the utility of aerogeophysical data in geological mapping (identifying lithologies, structures and basement characteristics) and locating metallic prospects/ deposits.

ABSTRACT

With the increasing use of ground water for various activities, the fast decline in groundwater takes place. In order to prevent the aquifers from fast depletion, the ground water recharge is necessary. This study attempts to identify the favourable areas for groundwater recharge and suggest suitable recharge structures toaugment the aquifer system of the study area using Remote Sensing and GIS. The various thematic maps such as Geomorphology, Geology and lineaments, Soil, Slope, Land use, Drainage, Runoff, Depth to weathered zone, Groundwater level fluctuation and Water quality are used in the analysis. The favourable areas for groundwater recharge have been categorized into highly favourable, moderately favourable, less favourable and poor. To delineate areas favourable for recharge zone various themes are interpreted. The identification of ground water recharge zones for the study area is useful for improvement of water quality, quantity and better augmentation & management of Groundwater recharge.

ABSTRACT

The disposal of industrial effluents in rivers causes groundwater contamination. It is necessary to assess how these contaminants are likely to migrate in the groundwater system. In the present study, an attempt is made to study the migration of contaminants in the groundwater of Palar River basin in Tamil Nadu. Simulation of the contaminants was carried out by using numerical methods. The finite difference computer code MODFLOW (Modular 3-d finite difference flow) and MT3D (Mass transport 3-d) with Groundwater Modelling System (GMS) as pre and post processor was used to simulate the groundwater flow and transport in this study. The simulation was done in transient state for a time period of one year. It predicted the migration of plume of chlorides in groundwater. The changes in the distance and concentration rate of chlorides are identified for a particular period. Modelling provides a useful basis for contaminant transport studies, as well as in the evaluation of the hydrogeologic parameters relevant in the context of the transport problem.

ABSTRACT

Kadayampatty Panchayat Union is situated in the northern part of Salem district, adjoining the Dharmapuri district of Tamil nadu. It lies between the latitudes 11°45’ -12°N and longitudes 78° -78°15’E in the Toposheet No.58I/1. The study area mainly consists of the rocks of late Precambrian age that are characterised by migmatitic gneisses, Ultramafic rocks and Pyroxenite. In this study an attempt has been made for demarcating groundwater techniques. Resistivity of rock formation varies over a wide range, depending on the material density, porosity, pore size and shape, water content, quality and temperature. In relatively porous, highly jointed and fractured formation the resistivity is controlled more by water content and quality with in the formation then by the rock resistivity. For demarcating groundwater potential zones in the Kadayampatty Panchayat Union water table analysis and ten Vertical Electrical Sounding (VES) followed by Schlumberger electrode configuration were carried out. The maximum depth of investigation was 150mts. The electrode spreads were generally in steps of five meters interval up to 50 mts and 10 mts interval up to 150 mts. VES location were selected with in the study area with respect to their topographic features. Inverslope method proposed by Sankaranarayan (1974) et.al has been used to evaluate the geoelectrical parameters in order to demarcate to potential groundwater zones for new dug well and bore well locations. The lithological interpretation reveals that the presence of a maximum of five geoelectrical formations in the study area viz. Topsoil, weathered zone, fissure and fractured zone, fracture basement and fresh basement. Howevers all five formations do not occur throughout the study area, as the maximum and minimum of geoelectric layers are four and three respectively. Similarly a thin geoelectric layer was observed in some places also. The comparatively high resistivity values with corresponding high values of thickness are indicative of a wide stretch of unweathered and unfractured fresh rock layers. A highly weathered (saturated) basement is indicated by the extremely low resistivity value. The depth to the fresh basement varies.

ABSTRACT

Identification and mapping of fractures/lineaments and hydrogeomorphic units is prerequisite for undertaking ground water exploration and development in any terrain. Remote sensing and GIS techniques have been used for ground water potential mapping in Theni District. The study area has been divided into various geomorphic units based on visual interpretation of LISS III and PAN merged data in false colour composite on 1:50,000 scale. Ground water potential of each of the geomorphic units was assessed and correlated with geology, structure and recharge factors prevailing in the Theni District.

ABSTRACT

Trace Elements were analysed from water samples collected from bore wells from block 2, 5, 14, 26 and 29 at Neyveli Township. Lead Concentration has crossed the limit of ISI standard prescribed for drinking which is 0.100 ppm. Lead concentration in the order of 0.082 ppm at block 5 and 0.11 ppm in block 29 were observed. Cadmium concentration has also crossed the limit of ISI (0.010 ppm) for drinking purpose, which is 0.02 ppm in block 26. Chromium concentration has also crossed the permissible limit of ISI standards (0.05 ppm) for drinking, which is 0.098 ppm in Block 14.

The above elements when compared with ISI standards for drinking water have shown a slight increase in concentration of lead, cadmium & chromium. Concentration of lead in Neyveli basin may be attributed to basement geochemical sources influenced by physical and chemical weathering. High concentration of chromium and cadmium in the aquifer may be due to anthropogenic activity probably from effluents of closed briqueting & carbonization plant, which is due south of block 14.

ABSTRACT

Mecheri Panchayat union lies in the northwestern part of Salem district and adjascent to Dharmapuri district of Tamil Nadu. It lies between the latitudes 11°43’ -12° and longitudes 77° 48’ -78° 03’ of Toposheet No. 58 E/13 of scale 1:50,000 published by survey of India in 1973. Mecheri Panchayat union covers a total area of about 177.6 Sq.Km with a population nearly 1 lakh, live in 150 hamlets. Groundwater is the only replenshable nature resources available to man. The use of groundwater has been growing steadily over the years for domestic, agricultural and industrial purposes. Hydrogeochemical study is a dynamic process undergoing constant change in space and time. In unconfined aquifers, the change likely to be quite rapid and cyclic in nature with respect to the mode of recharge and discharge and related to the nature of host aquifer. In this study an attempt has been made for understanding the chemical quality of groundwater in theunconfined aquifer of Mecheri union. Groundwater samples have been collected from 10 representative dug wells lying in the Mecheri union during December 2004 and analysed by the standard procedures of water analyses. It is essential in determining its usefulness for domestic, industrial and agricultural purposes. Presentation of Geochemical data in the form of graphical charts such as Collin’s bar, Stiff’s polygon diagram, Pie diagram, Piper tri linear diagram, USSL classification and thematical maps were prepared for recognizing various hydrogeochemical types in the Mecheri union. Deleterious effects of fluoride on the human beings are well known. Fluoride are known to be beneficial, when present in concentration ranging from 0.5 ppm to 1.2 ppm. But when it exceeds the limit 1.2 ppm it is found to cause fluorosis. Dental, skeletal and non-skeletal fluorosis may be caused depending upon the concentration of fluorides in drinking water. The main source of drinking water for the majority of people of Mecheri union is groundwater obtained through dug and bore wells. The analysis of groundwater samples showing high (> 1.5 ppm) fluorite content observed in the following villages, viz Mallikundam, Kuttapatti Aranganur, Banapuram, Sathappadi, Mecheri town, Virudasampatti and Amaram.

ABSTRACT

The study narrates the importance of occurrence of groundwater in the crystalline terrain and its yield in different lithologies. In general, yield of well in the crystalline terrain of the study area is low. Average or mean yields for groups of wells in various regions are most commonly between 7 to 20 gpm: The smallest yields are encountered in granulitic terrain and this may be due to fracture closing rapidly with depth. The jointed and weathered geneses yield small but steady supply of water at shallow depth. Chemical quality of the groundwater from this terrain is generally satisfactory for most purposes.