Chapter-02 Review of Literature A lot of analytical work has been carried out on natural water bodies, both fresh water and marine water, throughout the globe and as such a voluminous literature is available on the subject. In view of the above and to understand the topic of research in a better way, appropriate information in the world wide scientific area was collected through literature surveys by the detailed study of various books, internet websites, national and international journals. For the objective of the present research, a critical assess of literature was carried out to gather information on various relevant aspects and the considerable information was collected and reviewed the issues written by the scientist pertaining to the research topic. Finally literature review was done for collecting information related to river water pollution including water quality and physicochemical aspects of water. Some information was also collected about heavy metal pollution with their impact on aquatic biota and about mathematical modeling in water. The review of Literature shows the proof of work carried out pertaining to the research topic. It was found that various researchers have worked on different aspects related to river water pollution due to heavy metals. There are various institutes and organizations who are involved in the research and development in the field hydrobiology and different kind of aspects related to river water quality. The National and International institutes like WHO (World 34
Health Organization), CPCB (Central Pollution Control Board), MPCB (Maharashtra Pollution Control Board) and NEERI (National Environmental Engineering Research Institute), Central Water and Power Research Station are also involved in the research and development in the field of river water analysis and research. The understandable thought about literature review at national and international level is given below:Gautam, 1990 reported that India is a country having various land forms and rivers. There are 14 major rivers in India. Water, the universal solvent because of high dielectric constant has the property of dissolving most of the substances but the access of these substances leads to water pollution. Trivedy J.R. et. al., 1992 mentioned in their study that most of the cities and towns have developed along the banks of rivers because of the multipurpose-use of river water. But unfortunately some rivers are being polluted by indiscriminate disposal of sewage and industrial wastes. WHO, 1992 and 1997 report states that Europe and America confront enormous water pollution. Over 90% of Europe's rivers have high nitrate concentrations, mostly from agrochemicals, and 5% of them have concentrations at least 200 times greater than nitrate levels that occur in unpolluted rivers. In greater Sao Paulo, Brazil, 300 million tons of untreated effluents from 1,200 industries are dumped into the Tiete River every day as it flows through the city. As a result, the river flows with high concentrations of lead, cadmium, and other 35
heavy metals. The city also dumps some 1,000 metric tons of sewage into the river each day, of which only 12% is estimated as treated .water is essential for the survival of humans, animals and plants. Water is also home to a very wide range of microflora and microfauna, creating a fascinating environment of extreme biological importance, but which attracts too little attention. Fresh water is emerging as one of the most critical natural resource issues facing humanity. Water is, literally, the source of life on earth. The human body is 70% water. Human beings can survive for only a few days without fresh water. It is estimated that 31 countries, accounting for under 8% of the world population, face chronic fresh water shortages. By the year 2025, however, 48 countries are expected to face shortages, affecting more than 2.8 billion people -35% of world's projected population. Among countries likely to run short of water in the next 25 years are Ethiopia, India, Kenya, Nigeria, and Peru. Parts of other large countries, such as China, already face chronic water problems. Nix and Merry, 1990 and Miyabara et. al., 1994 studied that Urban rivers are also polluted with discharge from sewage treatment plants, overflowing sewage causes by rainfall causing fecal contamination which is a major concern in the river near the town area where the surface water are used by local residents. Crossette, 1995 study reveals that the supply of the freshwater that is available to humanity is shrinking, in effect, because many fresh water resources have become increasingly polluted or dried. In 36
some countries lakes and rivers have become receptacles for a vile assortment of wastes, including untreated or partially treated municipal sewage, toxic industrial effluents, and harmful chemicals that leached into surface and ground waters from agricultural activities. Caught between finite and increasingly polluted water supplies on one hand and rapidly rising demand from population growth and development on the other, many developing countries face uneasy choices. Serageldin, 1995 stated that the lack of freshwater is likely to be one of the major factors limiting economic development in the decades to come, warns the World. According to Saxena and Chauhan, 1993 there are fourteen major rivers in India and the CPCB 1996-97 report indicate that majority of them are polluted. The river Yamuna, once a river of mythical status, today breeds malaria, cholera and jaundice diseases which claim the lives of thousands of living beings. Anil Agarwal, 1997 mentioned in the study that India consumes around 86311 tonnes of technical grade insecticides each year to cover 182.5 million hectares of cultivated lands. Some of these compounds, such as DDT, have been banned from agricultural use, but are still used for vector control under public health programmes. The insecticide concentrations in the river water are, therefore, dependent on agricultural practices. According to the IARI study, residues of persistent organochlorines, which are still used in large quantities in India, are found in many rivers, including the Yarnuna . 37
W. K. Kadongola, 1997 study reveals that most of the rivers in the urban areas of the developing countries are the ends of effluents discharged from the industries. African countries and Asian countries experiencing
rapid
industrial
growth
and
this
are
making
environmental conservation a difficult task. Dhembare et. al., 1997 reported that Water of good quality is required for living organisms. The quality of water is described by its physical, chemical and microbial characteristics. But if, some correlations were possible among these parameters, then significant ones would be fairly useful to indicate the quality of water. Klohn and Wolter, 1998 study reflects that agriculture forms the biggest contributor for water pollution even more so than industries and municipalities. Virtually in every country, where agricultural fertilizers and pesticides are used, there are reports of contaminations of groundwater aquifers as well as surface waters. Animal wastes from another source of persistent pollution in some areas. The water that goes back into rivers and streams after being used for irrigation is often of degraded quality with excess nutrients, salinity, pathogens and sediments that often render it unfit for any use, unless cleaned-typically at great expense-by water purification plants. Carty, 1991 and Allaoui, 1998 reported that pollution is a vexing problem in developing countries where the population is growing
rapidly,
development
demands
are
increasing,
and
governments have different investment priorities. In developing countries, on an average, 90% to 95% of all domestic sewage and 38
75% of all industrial waste are discharged into surface waters without any treatment. Javed and Hayat, 1999 report showed that in an aquatic ecosystem plankton showed a great tendency to accumulate metals in their bodies from water and sediments. Some of these elements are toxic to living organisms even at quite low concentration, whereas others are biologically essential and natural constitutes of the aquatic ecosystems and only become toxic at very high concentration. Studies have demonstrated that the determination of metal concentration in suspended matters and planktons are more sensitive than the dissolved concentration when used as indicators of contamination in hydraulic systems. According to Stevenson and Pan, 1999 study shows that High cost of complex chemical analysis, complicated and time consuming procedures of sample preparation, analysts search for quicker and more specific methods. Biological assessment or Bio- monitoring is a valuable assessment tool that is receiving increased use in water quality monitoring programs of all types and is a useful alternative for assessing the ecological quality of aquatic ecosystems since biological communities integrate the environmental effects of water chemistry, in addition to the physical and geomorphological characteristics of Rivers and lakes. Reuters, 1999 highlighted that more than half of the World’s major rivers are being seriously depleted and polluted, degrading the surrounding ecosystem, thus threatening the health and livelihood of 39
the people who depend upon them for irrigation, drinking and industry. As per the World Commission on water for the 21'' century, 25 million people fled their homes in 1998 because of the depletion, pollution, degradation and poisoning of rivers, out numbering the war related rehgees for the first time in history. Koshy and Nayer, 1999 mentioned that river, though most important water resources of the world are being polluted by indiscriminate disposal of sewage, industrial wastes and a plethora of human activities. Pollution of rivers first affecting its physicochemical quality systematically destroys the biotic community disrupting 32 the delicate food web. However pollution has several dimensions and the effective monitoring and the control of river pollution requires the expertise from various disciplines. Reuters,1999, Koshy M. and Nayar T.V., 1999 study reveals that Environmentalists bewail the degradation of the 1367 km of Yamuna- the largest tributary of Indias holy river, the Ganges that originates from 6387 meters high glacier in the Himalayas. The environmental
degradation
gained
momentum
due
to
rapid
industrialization, poor sanitation and unscientific waste disposal procedures which have absolutely no concern for the environment. A. J. Horowitz, 1995 and G. F. Riedel et. al., 2000 report states that people along the river use water for many purposes. However, the surface water quality is deteriorating due to anthropogenic activities, industrialization, farming activities, transportation, urbanization, animal and human excretions and domestic wastes. Variation in the 40
quality and quantity of river water due to natural and anthropogenic activities is widely studied in the case of several world rivers. Olajire and Impekperia, 2000 study reveals that pollution is a serious problem as almost 70% of India’s surface water resources and a growing number of its groundwater reserves have been contaminated by biological, organic and inorganic pollutants. In South Asian countries such as Nepal, India and Bangladesh, pollution of rivers is more severe and critical near urban stretches due to huge amounts of pollution load discharged by urban activities. S. B. Jonnaladda et. al., 2001 reported that availability of good quality water for drinking purpose is very essential for healthy human society, the greatest danger to human health from water pollution. Many rivers, stream in developing countries are heavily polluted due to industrial and sewage discharge. Hassan et. al., 1998a and 1998b, Shrestha, 2001, Ogbeibu and Oribhabor, 2002 showed in their study that the construction of dam in the riverine system changes the biological and ecological conditions of rivers. Alteration occurs in the floral and faunal characteristics near the dammed site. The developments like construction of dams and barrages along the river results in low water flow. Dams causes physical alteration of tail waters or downstream areas, changes in water temperature, channel morphology or stream substrates and loss of spawning and rearing habitat due to upstream flooding, thus impacting indigenous fishes.
41
Pennington et. al., 2001 and Kistemann et. al., 2002 discussed about river water pollution and stated that Water resources of highly industrialized cities in India have been chronically polluted. Major Indian rivers, such as Ganga, Yamuna, Tapti, Narmada, Sone, Chambal Damodar, Krishna, Cauvery, Brahmaputra, Mahi and other rivers are severely polluted. According to CPCB report, 90% of the water supplied in India to the towns and cities is polluted, out of which only 1.6% get treated. According to the Ministry of Environment and Forest (MoEF), most of rivers in India are polluted, mainly because of district inflow of untreated sewage resulting in unacceptable levels in them of BOD, SS. Even high microbial growths are noted with the aquatic systems that gradually increases eutrophication of water bodies. Dwivedi and Pandey, 2002 focused on algae which are frequently found in polluted and unpolluted water and due to their behavior they are generally considered useful to determine the quality of water. These are very suitable organisms for the determination of the impact of toxic substances on the aquatic environment because any effect on the lower level of the food chain will also have consequence on the higher level. Algae are used for assessing the degree of pollution or as indicator of water pollution of different water bodies. According to Tong and Chen, 2002 view land use types fecal contamination which is a major concern in the river correlate with most water quality characteristic. Runoff from land surface carries the 42
residues from the land into river system which known as non-point sources pollution. Expansion of urban areas in any river basin effect the environment in terms of the increase of pollution load into river system and changes to surface water quality. Nevertheless, substantial modification on flood runoff and water quality found to be contributed by urban development. Sinha, 2002 Mentioned that a similar situation appears to exist at Dalmianagar and this has caused great damage to the riverine biota, particularly fish fauna as a result of alteration in the physico-chemical parameters. Costa et. al., 2003 found that the conversion of vegetation will disrupt the hydrological cycle of a drainage basin by altering the balance between rainfall and evaporation of the area. Alemaw and Chaoka, 2003 reported that water, the unique substance, occupies the three forth of world’s area for which earth is indeed a watery planet. Its omnipresence divides the world into two major environments viz; aquatic and terrestrial. The aquatic environment, which according to the present know ledge, constitutes about 26.6 trillion tons of water. Man’s lives is directly or indirectly sustain by water and are intimately associated with it. The man and biosphere program (MAB) of UNESCO has laid emphasis on the studies on impact of various human activities in water and other resources. Unnisa and Khalilullah, 2004 work reveals that water is constantly misused and abused by human kind. Definition of 43
freshwater is water containing less than 1,000 milligrams per liter of dissolved solids often salt. Needless to mention here that growth in human population in the last century has severely damaged the aquatic resources as it has done to all other renewable resources. The longing for more production has thus impelled the inputs of sophisticated technologies leading to changes in their ecology. The change in water course together with multiple uses far beyond their assimilation capacities has severely affected their quality and availability. Natural surface water bodies like rivers and streams are subjected to pollution comprising of organic and inorganic constituent. Tiwari, 2004 study highlight that the pollution potential of river Pandu contaminated heavily by the discharge of various industries. Elizabeth Ngoye and John F. Machiwa, 2004, work reflects that river water pollution in India are serious issues like Bagmati River in the Kathmandu valley, Yamuna River at Dehli, Buriganga River of Dhaka, Tamiraparani River and Ruva River suffer from severe pollution. Water of River Hindon was also found to be more polluted than river Narmada. A. C. Chindah et. al., 2004, V. Emongor et. al., 2005, A. A. L. Furtado et. al., 1998, C. N. C. Ugochukwu, 2004 reported that water is the commonest fluid in nature. Water is also a vital resource for agriculture, manufacturing and other human activities. In urban areas, the careless disposal of industrial effluents and other wastes in rivers & lacks may contribute greatly to the poor quality of river water.
44
Eletta and Adekola, 2005 stated that the pollution of rivers and streams with chemical contaminants has become one of the most critical environmental problems of the century. It is estimated that each year 10 million people die from drinking contaminated water. Water is one of the most common and precious resources on the earth without there would be no life on earth. Mustapha and Omotosho, 2005 stated that the interactions of both the physical and chemical properties of water play a significant role in composition, distribution and abundance of aquatic organisms. Sundaray et. al., 2006 studied on water quality of the Narmada river basin, river Bagmati and the Mahanadi basin. Sivakumar et. al., 2000, Sachidanandamurthy and Yajurvedi, 2006, Krishnan et. al., 2007, Duran and Suicmez, 2007, Smitha et. al., 2007 stated that during the last several decades, the water quality of the Indian rivers has been deteriorating due to continuous discharge of industrial wastes and domestic sewage. Jain et. al., 2004 highlight on evidence from the studies on the rivers like Mahanadi, Narmada, Uppanar, Gola and the Gangas supports the view. They also mentioned that Rapid urbanization and industrialization, intensive agriculture and growing demand for energy during the last few decades has affected the physico-chemical parameter and biological attributes of ground and surface water. Saxena et. al., 2001, Singh et. al., 2007, V. K. Gaur et. al., 2005, Singh et. al., 2005, according to their evidences tributaries of the Ganges, including the rivers Yamuna and they have been documented 45
different physico-chemical aspects. Among Indian rivers, those flowing through the Indo- Gangetic Plains. Singh and Singh, 2007, and D. Mukherjee et. al., 1993 documented the physical, chemical and biological aspects of the Ganga River. Purushothaman and Chakrapani, 2007 and Singh et. al., 2002 have studied and analysed heavy metals such as Cr, Mn, Fe, Co, Ni, Cu, Zn, and Pb in the sediments of the Ganga river basin. Singh et. al., 2004, Y. Ouyang et. al., 2006,Cidu and Biddau, 2007 have stated that seasonal variations in agricultural activity, storm water runoff, interflow and atmospheric deposition
have strong
effects on river water quality Thus, characterization of seasonal variability in surface water quality is imperative for evaluating temporal variations of river pollution from natural or anthropogenic contributions. According to Tiwary and Dhar, 1994 & Chang, 2008 opinion anthropogenic activities in the river basin affect the physico-chemical properties of river which have indirect effect on the biological resources interacting with each other, apart from degrading the environment. Pollution of a river first affects its chemical quality and then systematically destroys the community disrupting the delicate food web. Evidence related to impact caused due to industrialization and increased populations on the aquatic environmental conditions have been noted from different rivers around the globe.
46
B. Padmanabha and S. L. Belagali, 2007, Karthi A. Geetha and Geeta Divvakar, 2008 according to their point of view
Indian
agriculture receives most of its water from surface sources like river, reservoir, dam etc. However, now a day the river water is largely influenced by discharge of industrial as well as domestic waste while flowing through big towns and increases the water pollution in rivers. This changes the physical and chemical characteristics of river water and hence the quality of river water for different use. Saksena et. al., 2008 study shows that the wastes discharge from sewage, industry, agriculture and anthropogenic activities are seriously polluting the water which promotes the growth of pathogenic microorganisms. Pollution is as old as man himself. Water the most vital source for all kinds of life on this planet, is also the resource adversely affected both qualitatively and quantitatively by all kinds of human activities on land, in air or in water. Pollution of river in India has now reached to a point of crisis due to unplanned urbanization and rapid growth of industrialization. Many workers studied on various aspects of rivers based on physico-chemical and bacteriological parameters of Chambal River at Madhya Pradesh by Saksena et. al., 2008, Kor River at Fars, Iran by Shayestehfar et. al., 2008, Atharabanki River at Paradip by Barik and patel, 2004, Ganaga River from Narora to Kannauj by Gaur et. al., 1997 and underground water along river Vaigai in Madurai city by Rajasekaran et. al., 2004.These research is carried out on water quality of river in different places and in each places it has received greater 47
attention. For good and long life the good quality of water is very important. Rita N. Kumar et. al., (2009), Tiwari T. N. and Mishra M., 1985, Ashwani Kumar and Anish Dua, 2009 have assessed the water quality variation to evaluate the water quality index of Rivers. According to A. Begum et. al., 2009 view in India the riverine systems are getting polluted day by day. Their study reveals that today acute pollution prevails in many rivers such as Krishna, Tapti, Bramhaputra, Ganga, Hoogly and Brahmani etc. As the water flows downstream, it picks up silt, minerals and mineral salts from the soil and rock in the river bed. Many other pollutants enter river water as it flows
downstream,
including animal waste,
human
sewage,
agricultural runoff, urban runoff, industrial effluents, and mining effluents, due to which unfortunately, most of the rivers are facing pollution problem or under threat of pollution. A. Begum et. al., 2009 reported that life cannot exist without water because it is the major component of all living things. It is important both physiologically and ecologically as it plays an essential role in temperature control and also is the medium in which many organisms live. Now a day due to rapid growing urbanization, the quality of land water is being deteriorated by mixing up of industrial wastes and domestic sewage in our rivers. There are several studies related to the assessment of water quality of Rivers. Nikhil Raj and P. A. Azeez 2009, Muhamed Ashraf P. and M. K. Mukundan, 2007, A. G. Murugesan, 2007, Najafpour 48
Sh., 2008, Priyanka Trivedi, 2009, N. Singkran, 2010 and many others have conducted studies related to water quality in India. Rivers and streams are highly heterogeneous in spatial as well as temporal scales and several investigators have studied the physico-chemical dynamics of rivers. Singh 2010 studied that the impact of the industrial effluents and domestic sewage on river Ganga at Allahabad and reported that all the pollution parameters are beyond the permissible limits and unfit for human consumption. Islam et. al., 2010 reported that especially in urban areas, the careless disposal of industrial effluents and other wastes contributes greatly to the contamination of the water. Yadav and Kumar, 2011 have studied on the impact of industrial effluents on water quality of Kosi River in Rampur district (India) which showed physico-chemical parameters are above the permissible limits. Increased pollution load in fresh water bodies increases the nutrient level of water and causes a violent alteration in pH, reduction in oxygen content and high osmotic pressure. Moscow et. al., 2011 are of opinion that most of the rivers flowing in urban areas are at the end point of effluents discharge and if not treated and properly controlled can also pollute the ground water. Broman et. al., 1991 findings reflect the heavy metal toxicity in Mytilus and algae respectively. The magnitude of the danger of environmental pollution by heavy metals was realized from the 49
Minamata disaster caused by Hg and ltai-ltai incidence by Cd. For any organism to grow and reproduce normally, micronutrients or trace elemenrs are necessary in at least very low concentrations and these elements cannot be replaced by any other mineral factors. The micronutrients needed by various algal species are iron, manganese, zinc, copper, molybdium, cobalt, vanadium, boron etc. Many of the trace elements are normal constituents of aquatic organisms and are essential for their metabolism by having definite functional roles. Each of the trace metals either singly or in combination, along with the major environmental parameters can affect the biota as a whole and the food chain in particular. Apart from the existence of these elements in natural conditions, there is considerable input from land run-off especially if there is a discharge point from manmade sources. These trace metals which form essential nutrients enhancing the growth at threshold levels can pose problems of toxicity when there is a subtle increase in concentrations resu ting in impairment of growth kinetics, physiological activity as well as intracellular changes. Schnoor et. al., 1997 showed that metals in natural waters can exist in many different chemical forms, including the free ion (e.g. Cu2+), dissolved inorganic forms (e.g. hydroxides, carbonates, sulfates), organic complexes (metal bound to dissolved organic matter), and variety of particulate forms bound to clays or incorporated into the matrix of soil particles. The relative distribution of these forms is a function of environmental conditions including pH,
50
hardness, and the presence of organic matter and/or inorganic particulates. According to Singh, 1994 and Fazeli, 1998 views heavy metal pollution mainly arises from the effluents of industrial units. There are various common industrial units releasing toxic heavy metals into environment. Irrigation by effluents released from paper mills and fertilizer factories are adding various alkalies, ammonia, cyanides and heavy metals into the water resources. Among all the pollutants, heavy metals are most dangerous one as these are non –biodegradable and persist in environment. These enter into the water resources through both natural and anthropogenic sources. Javed and Hayat, 1999 mentioned that many trace elements such as arsenic, cadmium, copper, lead and selenium can be toxic to aquatic biota because plankton has the ability to concentrate heavy metals from their aquatic environment. Investigators like Angadi, 1996, Graham, 1996, Knauer, 1996 and Bhattacharyya, 2000 found out that the tolerance limit of various phytoplankton to different trace metals like Cu, Zn, Pb, Ni, Mn and Cd. Phytoplankton species vary in their tolerance to trace metals. They furnish little information regarding the significance of trace elements in algal nutrition. G. B. MacFarlane et. al., 2000 stated that the pollution of the aquatic environment with heavy metals has become a worldwide problem during recent years, because they are indestructible and most of them have toxic effects on organisms. 51
Augusthy et. al., 2000 highlight on heavy metals in the sewage water and reported that the water contains large quantities of zinc, iron and copper. It appears that indiscriminative discharge of industrial effluent into sewerage system has led to high concentration of heavy metals. Nogami et. al., 2000 reported that food in the form of plankton is also an important source for heavy metal enrichment in fish body potentially leading to bio-magnification, the increase of pollutants up the food chain. According to Chow et. al., 1998 and Katiyar and Katiyar, 2000 observation in spite of the importance of these trace elements in algal growth and metabolism, a little attention has been paid on them on the nutritional point of view. Most of the reports available focus on the toxicological impacts of trace elements especially those belonging to the class heavy metals. Volesky, 1990 and Bishop, 2002 observations shows that more attention is being given to the potential health hazards posed due to heavy metals. The term heavy metal refers to any metallic chemical element that has a relatively high density. The density of heavy metals is usually more than 5.0 g/cm3. Rainbow, 1997 and Rainbow, 2002 study reveals that
all
aquatic organisms take up trace metals either from the surrounding aquatic medium or from food, whether or not these metals are essential to metabolism, Thus, metal bioaccumulation is a good
52
integrative indicator of the chemical exposures of organisms in ecosystems. Hodson and Spargue, 1998, Phillip, 2002 study focused on that the toxic effects of metal on aquatic ecosystems ranged from a complete loss of biota to subtle effects on rates of reproduction, growth
and
mortality
of
organisms.
However,
total
metal
concentrations in sediments do not necessarily reflect concentrations that are available to biota. Aquatic organisms have been used in comparative monitoring of pollution effects in different systems and to locate source of toxicants. Kaushik A., 2002 finding reflects on heavy metal pollution of river Yamuna in the industrially developing state of Hariyan. Metal like that Fe, Ni & Co concentration exceeded the maximum permissible limits prescribes for drinking all along the river. In India C.G.W.B., 1999 report states that water demand is increasing year by year. In the year 1997 – 1998, water demand was 629 Km3/year which is projected to be 1180 Km3/year in 2050. Sponza D. and Karaoglue N., 2002 reported that environmental geochemistry and pollution studies of Aliga metal industry district. Rawat M. et. al., 2003 assessment report states that inventory compilation and distribution of heavy metals in waste water from small scale industrial areas of Delhi, India and also detected heavy metals such as Fe, Mn, Cu, Zn, Ni, Cr, Cd, Co & Pb using a GBC 902 atomic absorption spectrometer. The result indicates that SSI could be one of the point sources of metal pollution in the river system. 53
Singh and Mosley, 2003 report shows that Contaminants such as bacteria, viruses, heavy metals, nitrates and salt have found their way into water supplies as a result of inadequate treatment and disposal of waste (human and livestock), industrial discharges, and over-use of limited water resources. Vijver et. al., 2004 reported that all metals have the potential to cause toxic effects. As a result, metal accumulation is closely linked with toxicity. Kabala and Singh, 2001, Pueyo et. al., 2003 study reveals that the overall behavior of heavy metals in an aquatic environment is strongly influenced by the associations of metals with various geochemical phases in sediments. Geochemical distribution results have also been used as an aid in predicting potential contaminant mobility and bioavailability. Rainbow, 1997, Luoma and Rainbow, 2005 study reveals that although in a complex manner, because metal accumulation is influenced by a variety of factors, such as multiple routes of exposure i.e. diet and solution, chemical composition of the surrounding medium and physiological or biochemical effects on bioavailability. The metal accumulation levels vary widely among metals, organisms, and have different distributions between tissues and organs in the body. Aquatic organisms living in the same habitat may have very different body concentrations of trace metals, even within closely related species.
54
Lark et. al., 2006 examined the spatio-temporal variation in trace elements in Patuxent River, Maryland and reported the variations in nutrient level in the Nemunas river of Russia. Various researchers viz; K. De, 1989, Dara, 1995, V. P. Kudesia, 2000, Obodo, 2001and Waheed et. al., 2007 were studied on heavy metals. According to their opinion disposal of solid waste into open dumps is the normal practices by municipalities of our country. During the rainy season leachate formation takes place from the wastes which enter nearby water resources and penetrate deep down in to ground water. Leachates are composed
of
high
concentration of organic substances, soluble salts and other constituents including toxic heavy metals etc . According to Jain, 1978, Shrivastav, 2001 and Duruibe et. al., 2007 reported some finding that some metals like Cu, Fe, Mn, Ni, Zn are essential for life, many other metals like Cd, Cr, Pb have very detrimental effects if present beyond a certain limit. Woitke et. al., 2003, S. Oliveres-Rieumont et. al., 2005, Farkas et. al., 2007, S. Li. et. al., 2009 were highlighted on trace metal pollution. According to their opinion trace metals pollution in aqueous system can hardly be eliminated and are often recycled via physiochemical and biological processes, which continue to pose a risk of adverse effects on human health and aqueous ecosystem. Therefore, reaches worldwide focus their attention on quantitative investigation of the trace metals in aquatic ecosystem.
55
Kar et. al., 2008 has studied on Ganga River pollution and the contamination of inorganic and heavy metals in Ganga River. Jain, 2004 and Nwuche and Ugoji, 2008 highlighted on heavy metal pollution and their impact on environment. Their study reveals that heavy metals are sensitive indicators for monitoring changes in the water environment. However, to assess the environmental impact of contaminated sediments, information on total concentrations is not sufficient and particular interest is the fraction of the total heavy metal content that may take part in further biological processes. Begam et . al., 2009 were analyzed heavy metal concentration in soil and lichens from various localities of Hosur road of Banglore and shown the presence of significant amount of heavy metal. Dassenakis et. al., 1998, Miller et. al., 2003, Harikumar et. al., 2009 researchers commented on heavy metal pollution. According their opinion heavy metals like chromium, lead, cadmium, arsenic, etc. exhibit extreme toxicity even at trace levels. Rivers are a dominant pathway for metals transport and heavy metals become significant pollutants of many river systems. J. O. Nriagu, 1996, Sekhar et. al., 2005, K. Bengraine and T. F. Marhaba, 2009, Pertsemli and Voutsa, 2007, S. Li et. al., 2008, S. Li et. al., 2009, H. Feng et. al., 2004, Krishna et. al., 2009 have focused on quantifying the trace metals and their assessments on the aqueous environment. Pollutions of surface water with toxic heavy metals and elevated nutrients due to natural processes such as atmospheric deposition, erosion and mineral weathering as well as anthropogenic 56
activities such as urban, industry and agriculture are of great concern worldwide. The accumulation of heavy metals in aquatic ecosystems can lead to hazards on human and wildlife. Cataldo et. al., 2001, Hobbelen et. al., 2004, Koukal et. al., 2004, Okafor and Opuene, 2007, Mohiuddin et. al., 2010 have stated that heavy metals are among the most common environmental pollutants, and their occurrence in waters and biota indicate the presence of natural or anthropogenic sources. Their accumulation and distribution in soil, water and environment are increasing at an alarming rate causing deposition and sedimentation in water reservoirs and affecting aquatic organisms as well. According to report of Dassenakis et. al., 1998, Akcay et. al., 2003, Abdel- Ghani and Elchaghby, 2007, Nicolau et. al., 2006, Nouri et. al., 2009 the behavior of metals in natural waters is a function of the substrate sediment composition, the suspended sediment composition and the water chemistry. During their transport, the heavy metals undergo numerous changes in their speciation due to dissolution, precipitation, sorption and complexation phenomena which affect their behavior and bioavailability. The review on mathematical model in the water chemistry had been done by number of scientists and engineers have worked on the mathematical model related to water and waste water treatment technology (Horton, 1965, Brown, 1970, Orlob, 1983, Halfon, 1983, Tchobanoglous and Schroeder, 1985).
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Thompson et. al., 2001 and Juahir et. al., 2004 studied on MLR. According to their opinion generally, multiple linear regression (MLR), may lead to incorrect identification of most the predictor due to collinearity between the input variables. MLR also allows the reduction of the dimensionality of non-linear data set by correction amongst a large number of variables in terms of underlying factors without neglecting any information from the original data set. Aertsen et. al., 2010 mentioned that although linear regression was one of the oldest statistical modeling techniques, their applications were still widely used in many linear relationships works. Despite the fact that many studies performed concluded that there is no general best modeling techniques, it still depends on the scope and objectives of the studies. The Central Pollution Control Board in monitoring water quality at 340 locations on various rivers has conducted detailed river basin studies and has identified 18 grossly polluted stretches, 14 less polluted stretches along 22 rivers based on the designated best use of primary water quality criteria. It is seen that grossly polluted stretches fall in 'D' and 'E' categories where water is not suitable for drinking even after conventional treatment and is almost not suitable for bathing, 6 stretches of less grossly polluted are of category 'D' which is only fit for propagation of wild life and fisheries. Industrial production globally has grown more than 50 fold over the past century. This rapid industrialization has a profound impact on the environment especially on water resources. Severe water pollution 58
coupled with depletion of ground water reserves is a serious and immediate environmental challenge in India. For example, in India industries relating to Tanning, Paper and Pulp, Fertilizer, Oil refineries, steel and Fermentation generate about 850 to 1300 million cubic meters of effluents per year. The total pollutant load levels from these sectors are estimated at 24594 tons per day BOD, 34759.22 ton per day COD excluding fertilizer Industry. Though the country has made appreciable progress in conventional wastewater treatment technologies, the access to advanced/sophisticated technologies pertaining to specialized physico-chemical and biological treatment of wastewater, floatation technologies, absorption and adsorption technologies etc. are limited. India has initiated wastewater treatment of highly organic wastewaters from distilleries, food processing units, diary, pulp and paper units and the like. In the small scale industry, the need is more of state-of-the-art, technologies that are practical i.e. with less operational problems and also treat most obvious pollutants cost effectively coupled with energy generation. It is a common sight to see large number of people easing themselves along the banks of rivers, streams and nallas which finally flow in the rivers. Dumping dead bodies and half burnt bodies is another cause of river contamination No data of these pollutants is available. However, there IS no doubt that these pollutants contribute to substantial organic as well as bacterial pollution. But there is a need to address these issues, wherever any river cleaning programme is under taken.
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Water quality monitoring of all the natural water bodies in the State is carried out by the MPCB primarily under the national and international schemes, Monitoring of Indian National Aquatic Resources (MINAR) and the Global Environmental Monitoring Scheme (GEMS), respectively. Samples are taken regularly each month from marked water sampling stations long the rivers and lakes for studies (Ignatius Pereira, 2002). Providing clean supplies of water and ensuring proper sanitation facilities would save millions of lives by reducing the prevalence of water related diseases. Thus, finding solutions to these problems should become a high priority for developing countries and assistance agencies.
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