INTRODUCTION:
Groundwater destruction of local water system, construction of dam etc. lead to the reduction of the groundwater recharge. Because of global warming groundwater reduction takes place as evapo-transpiration needs are higher when temperature goes up. In the mined areas groundwater recharge system gets disturbed. In India according to the report of the national commission on integrated water resources development (GOI September 1999), the total replenishable groundwater is estimated as 432 Billion Cubic Meter (BCM). Out of this i.e. 71 BCM (15%) is utilized for domestic, industrial and other uses and 325 BCM for irrigation.
Although ground water is not easily contaminated, once this occurs it is difficult to remediate, and in the developing world, such remediation may prove practically impossible. In Maharashtra, as per the government of India answer in parliament, groundwater of Aurangabad district is affected by excess nitrate (over 45mg/L) and excess fluorides (1.5gm/L)1.
It was reported that the fertility rate of male mice exposed to NaF for 10 weeks reduces significantly2. This impairment in male fertility was dose dependent and increased as the concentration of NaF increased. The large increase in medical waste volume from the growing trend of using plastics and disposable goods. The continued expansion and construction of new facilities, and the hazards of handling and disposing of infectious waste. When the medical waste contain heavy metals is disposed, it create some serious environmental problems.
The needles, syringes, aluminum cans or out-dated instrument of machines are incinerated and the residues are often dumped in landfills. This harms the environment in numerous ways, foremost by contaminating ground water3.
1. Indicators of water pollution:
Various water quality characteristics which can give us complete information regarding physical, chemical and biological quality of water as well as waste water are being discussed here.
Temperature: Biological activity is enhanced by higher temperature up to 60ºC. The growth and death of micro-organisms, kinetics of BOD is also regulated to some extent by water temperature. It may also affect dissolution of gases, pH, conductivity etc.
pH: pH is a numerical expression that indicates that the degree to which a water is acidic or alkaline and is an operational parameter. Corrosion effects may become significant at a pH below 6.5 and scaling may become a problem at a pH above 8.5. In natural waters, the pH is controlled by the carbon dioxide, carbonate-bicarbonate equilibrium.
Conductivity: It depends on the concentration of dissociated salt as well as on colloidal suspensions. It get affected by temperature, pressure and rate of flow, but it is not affected by dissolved silica or undissociated molecules which do not carry current4. The conductivity of water is due to ionic species present in it. There are several pathways by which different ions enter into water body. The groundwater contaminated with dissolved hydrocarbons shows reduction in specific conductance due to the higher resistivity of the hydrocarbon components. Also it is possible that there could be an enhancement of the specific conductance of groundwater from polar organic compounds such as organic acid and biosurfactants, produced during degradation5.
Total Solids: Matter suspended or dissolved in water or wastewater is considered as solids. A high amount of solids in water generally makes it not desirable for consumption. Solid analyses are important in the control of biological and physical wastewater treatment processes and for assessing compliance with regulatory agency wastewater effluent limitations.
Total Suspended Solids: As we know that there are two types of pollution sources, point and non-point sources pollutants. Total suspended solid is non-point source pollutant. Suspended solids in water mainly comprise of silt, sand and minerals eroded form the land. Due to siltation reservoirs and dams are filled with soil particles and other solid materials. This reduces the water storage capacity of the dams and reservoirs and thus shortens their life.
Total Dissolve Solid: The inorganic cations and anions such as Na+, Ca2+, Mg2+, Cl-, SO42-, PO-34, etc. are mostly responsible for groundwater is directly related to the TDS in water. Apart from this there are pieces of sand, salt, leaves, fine organic matter etc. Very high value of suspended solid indicates high particulate matter due to pollution or eutrophication and hence is not a sign of healthy ecosystem. The TDS imparts undesirable taste. It also causes gastro-intestinal irritation. TDS is the total amount of mobile charged ions, including minerals, salts or metals dissolved in a given volume of water. While TDS is not considered a primary pollutant, high TDS level typically indicate hard water and may lead to scale build up in pipes, reduced efficiency of water filters, hot water heaters etc and aesthetic problems such as bitter or salty, taste. High value of TDS in drinking water may laxative and can cause foaming. Excessive amounts may be unsuitable for irrigation low level of dissolved salts is not very potable. Increase in the TDS in groundwater is due to enhanced weathering of minerals from acids produced as byproducts during degradation process.
Organic matter: There are various pathways by which organic matter enter into the groundwater these pose serious environment problems. David Dulin and et al6 showed that photolysis of chlorobenzene, 2 and 4-chlorobiphenyl and 2and4-chlorobiphenyl ethers in water with 250-300 nm light produce corresponding phenols or in the case of 2-chlorobiphenyl ether, dibenzofuran exclusively, Half lives for photolysis of these chloroaromatics in sunlight and water range from 460 years to 5 days. The toxic effect of DDT was observed during the investigations of robin mortalities on the Michigan state University campus in 1957. The near elimination of robin populations occurred over a period of about 10 years beginning with the application of DDT to control the Dutch Elm disease in 1954. Lethal concentrations of DDT found in the brain and muscle tissues were related to the accumulated of DDT found in the soil and in earthworms consumed by birds7. It was reported8 that municipal solid waste incinerator releases polychlofurans in the atmospheric air, which get accumulated on the nearby soil9 and enter into water bodies.
Organophosphorous pesticides have a short half life in the human body i.e. on the order of hours and their metabolites have half lives on the order of days10. Urinary metabolite may reflect not only individual’s contact with pesticide parent compounds, but also contact with metabolites present in the environment.
Organochlorine pesticides, polychlorinated biphenyls, and polybrominated diphenyl ethers are persistent organic pollutants. The bioaccumulation of persistent organic pollutants (POP) in maternal adipose tissue was found to depend on age, dietary pattern, ethnic groups, etc. The high POP was observed in the women11, suffering from gestation diabetes mellitus, which causes alteration in lipid metabolism. Adenosine triphosphate (ATPase) enzymes in vertebrates are vital for regulating oxidative phosphorylation, ionic transport, muscle function and several other membrane transport dependent phenomena. Na+-K+ ATPase has a central role in branchial transpithelial ion transport in fish. This enzyme is present in the cell membrane of all vertebrates and particularly abundant in tissues associated with ionic and osmotic regulation. It was reported12 that insecticides have toxic impact on Na+-K+ ATPase of economically important freshwater fish. Biological treatment has been commonly used in Western Europe to produce chemically and biologically safe as well as aesthetically pleasing water. In Japan, biological treatment is used to remove aquatic pollutants such as odour, NH4-N and BODs from raw water. Submerged biofilm processes have been installed in Northern China since early 1990s for pretreating polluted raw water13.
During disinfection of drinking water, waste water and recreational water using chloramines generally nitrosoamine is formed. Several nitrosamines are carcinogens. The dimethylamine and trimethyl amine are human waste constituents14. The waste material discharges form industries adversely affect the organic matter present in the soil, which ultimately affect the groundwater tables. The organic matter present in water determined from total carbon content of it. These OM produced on land are transferred from soil to hydrosphere, due to percolation or leaching. The main sources of OM are domestic waste or food and fertilizer or organic chemical industry effluents. The organic matter combines with metal, either through co-ordinate or covalent bond. These organometallic compounds are more toxic than original inorganic metal. For example, in water, micro-organisms are responsible for alkylation, for example organotin product species are more toxic to aquatic biota than tin itself. Toxicity increases with number of alkyl groups in RnSn($-n)+ series where n=1 to 3. Toxicity is inversely proportional to length of alkyl group. The second effect is that organic matter decomposes by utilizing dissolved oxygen and their by leaving the aquatic system in oxygen-deprived state.
The organic matter present in water also constitute of humic acid. The humic substances react with many specific anthropogenically derived organic compounds that are found in water. Hence the humic acid or materials influence greatly the interactions between other metals and organics. The colloidal OM is important mediator in partitioning of metals between truly dissolved and particulate phases e.g. by acting as colloidal pumps15.
Water pollution is a global problem. There are various water-related activities such as water shed management, irrigated agriculture, fisheries, navigation and transport, hydropower development tourism16. A large of water is used for irrigation purpose. Imbalances between water needs and resources are likely to induce conflicts between categories of users i.e. rural, urban, industrial17 etc. A wide variety of volatile and synthetic organic chemicals, pesticides, inorganic chemicals, radionuclide and disinfection byproducts are present in water supplies18.
Elevated trihalomethane, pesticide and heavy metal concentrations may also be associated with greater risk of still birth, spontaneous abortion, preterm delivery, birth defects and low birth weight. When organic pollutants enter aquatic systems, they tend to accumulate in aquatic organism due to their hydrophobicity and resistance to biodegradation19.
Perfluoroctane sulfonate is widely distributed in the environment. In mammals it gets accumulated in the liver and serum, as well as in the brain. It has toxic effect on liver, cardiovascular system, embryo, reproductive system immunological and nerve system.
Chemical Oxygen Demand: COD test determines the oxygen required of chemical oxidation of organic matter with the help of strong chemical oxidants. COD is expressed as ppm of oxygen taken from a solution of potassium dichromate in two hours. COD is important parameter in management and design of the treatment plants because of its rapid in determination values are taken as basis for calculations of efficiency of plants. COD depends on presence of organic matter, nitrates, sulphates, reduced metal ions etc. The presence of toxins and other unfavorable conditions such as pH, for the growth of micro-organisms do not affect COD values.
Total Phosphate: Phosphate is an important plant nutrient present in water. Its study helps to determine the state of primary production in water. Higher value of phosphate in reservoir water is due to agricultural wastes and use of fertilizers. Domestic waste contains approximately 1.6 Kg of phosphorous capita per year of which 64% is from p-builders used in synthetic detergants20.
Chloride: The anions are acidic and when taken in high concentration can alter the acid-base load of the body. This tends to produce low grade chronic metabolic acidosis and hence hypercalcuria, calcium is released from the bone and osteoclastic activity sets in dietary. Anions have important physiological effects in man such as electrolyte balance and constituents of gastric juice, maintenance of pH, cell signaling, potent vasodilator, platelet aggregation inhibitor, and bactericidal activity21.
The iodine ion present in ground water varies in the
range of 0.01 to 2.00
. Because of
chlorination of water, an iodinated trihalomethane may form nitrogen as ammonia
or organic amines, was found to enhance iodoform formation during chlorination
of iodides containing water22. When organic mater is present along
with chlorine in water, it leads to by products such as tirhalomethanes,
bromo-dichloromethane, chloromethane etc. Among these trihalomethane is
carcinogenic some of these are genotoxic. The chlorinated organic matter is
responsible for bladder cancer, colorectal cancer and adverse pregnancy
outcomes23. Chlorides coupled with sodium impart salty taste, when
its concentration is more than 250 mg/L. There is no identified authentication
that chlorides constitute any human health hazard. For this reason, chlorides
are generally limited to 250mg/L in supplies intended for public use. Magnesium
chlorides in water generate hydrochloric acid after heating which is highly
corrosive and create problems in the boiler24.
Sulphate: Sulphur is an essential element for ruminants. A diet deficient in sulphur results in decreased microbial protein synthesis, microbial number, and lactate utilization. High concentrations of sulphates in drinking water decreased feed and water consumption.
Water, during periods of high ambient temperatures, can provide substantial quantities of sulphur to finishing steers. Excessive sulphur consumption has deleterious effects on performance of feedlot steers. Adverse effects of high concentration of sulphate in water were more extreme for younger cattle and with high ambient temperature25. Sulphate is contributed to ground water from fertilizers.
Nitrate-Nitrogen: Highly N fertilizers coffee plantations in the tropics may leach nitrate-N (NO3-N) to groundwater, due to permeable soils and high rainfall intensity26. In the vertical very large concentrations and concentration gradients in NO3-N have been observed. Most have attributed these nitrogen “bulges” to idealized root water extraction and exclusion similar to that suggested for chloride accumulation. Rare infiltration events are postulated to move the excess chloride and nitrogen deep in the vadose zone27. Consumption of water containing nitrates at levels higher than 49 mg NO3-/L can lead to methaemoglobinemia in infants and, in the long term, may be potentially carcinogenic for human beings suggest a nitrate threshold between 50 and 90 mg NO3-/L and points out that no risk for human water containing less than 45 mg NO3-/L (~ 10 N/L)28.
Total Hardness: Calcium and magnesium dissolved in water are the two most common minerals that make water “hard”. The degree of hardness becomes higher as the calcium and magnesium content increases, and is related to the concentration of multivalent cations dissolved in the water. Hardness is most commonly expressed as milligrams of calcium carbonate equivalent per litre. Water containing less than 17.1 mg of calcium carbonate per litre is generally being considered as soft, slightly hard with less than 60 mg/L, moderately hard from 60 to 120 mg/L, hard from 120 to 180 mg/L and very hard with 180 or more mg/L of calcium carbonate. Hard water does not present a health risk, as long as the minerals are not heavy metal salts29. Therefore, why is hardness such a matter of concern? The answer is that extremely hard water may shorten the life of plumbing and less the effectiveness of certain cleaning agents. Calcium reacts with bicarbonate ions to form insoluble calcium carbonate (scale) Therefore, depending on pH, hard water may cause scale deposition in the distribution system, heat exchange equipment and boilers. Besides, soap is less effective in hard water because it reacts to form the calcium or magnesium salt of the organic acid of the soap30.
Calcium Hardness: The impact of water hardness on urinary stone formation remains unclear, despite a weak correlation between water hardness and urinary calcium, magnesium, and citrate excretion. Tap water, however, can change urinary electrolytes in patients who form calcium stones31. Mg2+ and Ca2+ at concentrations typically found in hardwaters (30–100mg/L) promote THM (Trihalomethane) formation in the disinfection process by hypochlorite32.
Magnesium Hardness: Ca2 + and Mg2 + are important for ionic regulation of freshwater fish because both ions influence the permeability of biological membranes, preventing diffusive flow and high ionic loss to water. The eggs incubated at water hardness of 150 mg/L CaCO3 presented the lowest hatch rates and post-hatch survival values at higher Ca2+ concentrations. These results suggest that the increase of water hardness to 70 mg/L CaCO3 using either Ca2 + or Mg2 + improved hatch rate, but the increase of waterborne Ca2 + above 20 mg/L, irrespective of water hardness, is not indicated for incubation of silver catfish eggs because it reduces post-hatch survival33.
Total Nitrogen: Application of inorganic fertilizers and manure to cropland can also result in significant sources of contamination to groundwater resources. Agriculture is the main cause of diffuse pollution, which is quite difficult to deal with and prevent, as pesticides and fertilizers are spread on very extrude area. Intensive cattle farming, wide variety of veterinary pharmaceuticals also as growth promotes. Manure is regarded as a very valuable fertilizer, as it contains essential nutrients for plant growth such as nitrogen, phosphorous, organic carbon potassium etc.34
Potassium: It is well known that the capacity of plants to oppose salinity stress strongly depends on the status of their K+ nutrition. Increasing K+ supply in the root environment may mitigate the reduction of plant biomass due to an increase in salinity35. A high K+/Na+ ratio might be more important for many species than simply maintaining a low concentration of Na+36. Potassium starvation is regularly accompanied by sodium toxicity.
Application of wastewaters with these high potassium levels has been found to increase the overall level of soil fertility, with the exception of alkaline effluents which can dissolve soil organic carbon. Long-term applications of such wastewater may cause the build-up of soil potassium and decrease the hydraulic conductivity of the receiving soils. These potential impacts are uncertain and have been inadequately researched. Regulatory limits for potassium in drinking water have been set only by the European Union with no toxicological or physiological justification37.
Sodium: Sodium salts are generally highly soluble in water and are leached from the terrestrial environment to groundwater. The sodium present in water and food is rapidly absorbed from the gastrointestinal tract. Sodium is the principal cation found in the extra cellular body fluid and only small amounts are found within the cell. The LD50 values for rats and mice for sodium ion as the chloride salts are 1180 mg/Kg of body weight and 1572 mg/Kg of body weight respectively. Generally sodium is considered as essential to human life. It is not toxic but acute effects like nausea, vomiting, convulsions, muscular twitching and rigidity, and cerebral and pulmonary edema may cause due to its overdose. Till today, no concrete relation can be developed between sodium in drinking water and hypertension. No health base guideline for upper permissible limit has been proposed.
The higher level of NaCl either in drinking water or in the feed to the laying hens decreases shell thickness and shell calcium, and increases the number of damaged eggs but elevated level of NaCl in the drinking water was more deleterious to the eggs shells38. At present, there are no health standards for Na+ or Cl- in drinking water. EPA has identified a concentration of over 250 mg/L of either Na+ or Cl- as a concentration that can import a salt taste to drinking water.
Dissolved oxygen: The concentration of the dissolved oxygen indicates the pollution level of the water. The D.O. in waste water of kocabas stream in the Biga, Turkey39, was measured as higher than expected from polluted water. Due to the high flow rate of the stream, dissolved oxygen concentrations were high.
Colour: Colour occurs due to dissolved substances and their micro-biota. This is an indicator of decomposition of organic material40. It is necessary to treat the wastewater and remove the various contaminants presents in it, before releasing it, in environment. The organic chemicals get degraded by micro-organism, it deplete the dissolved oxygen of water bodies. Acidity and alkalinity are disruptive to life and hence has to be neutralized. Nitrogen containing materials cause blooms in lakes and ponds by micro-organisms.
2. Hydrochemistry: Water productivity usually refers to the amount of measurable output per unit of water that is used. Many factors determine water-use levels around the world: the extent and form of socioeconomic development, population size, climatic conditions, and the physical nature of a region41. Groundwater tables are falling at phenomenal rates, often more than one meter per year, in many parts of the world. Formerly perennial rivers and streams whose base flow was supplied by groundwater are becoming seasonal or disappearing altogether. Salt water is intruding inland in many coastal areas, and land is subsiding under cities. Groundwater is generally thought of as that water present below the land surface. More specifically, it is the underground water that fully saturates all fissure and pores below the earth’s surface. The definition of groundwater thus does not generally include water stored more temporarily between soil particles near the land surface. Groundwater is created by infiltration of precipitation, surface runoff, or water stored in surface bodies, including rivers and lakes, to an aquifer. Groundwater leaves aquifer and reenters the surface system through natural discharges to springs, seepage areas, surface-water courses, or the sea. Pumping of groundwater for agricultural and urban use has formed new sources of discharge, removing groundwater at a faster rate than local recharge and resulting in declining water tables. Aquifer recharge by filtration through the soil tends to remove and block impurities and creates a source for high-quality drinking water for domestic use. Fluoride is more of a problem in hard-rock aquifers and is directly linked to overexploitation of groundwater resources. Consumption of excessive fluoride in drinking water can lead to the debilitating disease of flourosis. It is estimated that 62 million people in India are affected with dental, skeletal, and nonskeletal flourosis. Chemical pollutants come mostly from industry or agricultural runoff. Biological pollutants are primarily derived from human or animal waste and agricultural runoff. Chemical pollutants tend to persist for long periods of time and may therefore contaminate even deep aquifers. Overabundance of groundwater is a problem in some parts of India, and large areas in the east (e.g., West Bengal) do not yet take full advantage of their groundwater.
Connate water is water entrapped in the interstices of sedimentary rock at the time it was deposited. It may have been derived from the ocean or fresh water sources and, typically, is highly mineralized. Water occurring in the zone of saturation is commonly referred to simply as groundwater. The rate of groundwater movement is governed by the permeability of the aquifer and the hydraulic gradient. To obtain an idea of the order of magnitude of natural flow rates, assume a slope of 10 ft/mile and a flow permeability of Ks = 10. This results in a rate of 0.0025 ft/day, where as a slope of 100 ft/mile and a high permeability of Ks = 5000 yields a velocity of 12.7 ft/day. Field tests have reported velocities of more than 100 ft/day; however a normal range is from 5 ft/year to 5 ft/day. Secular variations of ground water levels are those extending over periods of several years or more. Recharge is the governing factor, which depends upon rainfall intensity and distribution and amount of surface run off.
Many ground water levels show a seasonal pattern of fluctuation. These result from influences such as recharge from rainfall and irrigation and discharge from pumping which follow well-defined seasonal cycles. Unconfined aquifers with water tables near ground surface frequently exhibit diurnal fluctuations which can be ascribed to evaporation and / or transpiration. Both processes cause a discharge of ground water into the atmosphere and have nearly the same diurnal variation because of their high correlation with temperature. Magnitude of transpiration fluctuation depends upon the type of vegetation, season and weather. Hot windy days produce maximum drawdowns, whereas cool cloudy days show only small variations. Fluctuation begins with the appearance of foliage and case after killing forests. Cutting of plants eliminates or materially reduces amplitudes. Transpiration discharge does not occur in nonvegetated areas, such as plowed fields, nor in areas where the ground water table is far below ground surface.
Studies have shown that the annual range of the earth’s temperature at a depth of 30 ft may be expected to be less than 1ºF. Analysis of thousands of records of groundwater temperature in the United State revealed that the temperature of groundwater occurring at a depth of 30 to 60 ft will exceed the mean annual air temp by 2 to 3ºF. Below this the temperature increases approximately 1ºF for each 100 ft in accordance with the geothermal gradient of earth’s crust42. Water recharge transports C, N, solutes, and microorganisms from shallow soils and surface environments to groundwater system. NO-3 and DOC concentrations increase in groundwater in periods of rapid recharge because of climate change, urbanization, and irrigation practices. The timing of recharge and land use critically influences C and N transport to groundwater. Groundwater in catchments typically has residence time on the order of tens to thousands of years. Water recharge before fertilizer use can contain intrinsically low NO-3 concentrations derived from soil organic N. Researchers have observed decreasing NO-3 concentrations with depth and groundwater are in multiple aquifer systems.DOC is converted to dissolved inorganic carbon (DIC) as microbes metabolize DOC and generate CO2 and alkalinity. At the same time, DON is converted to DIN, in the absence of O2, by microbial metabolism. Organic acids generated by respiration of organic matter are also consumed through mineral weathering along groundwater flow paths, producing DIC. Groundwater is usually high in DIC and DIN and low in DOC and DON, in contrast to soil and surface waters. The depth and length of groundwater flow paths strongly control the conversion of DOC to DIC and N cycling as well as the coupling back to surface systems. In regional flow systems, low recharge rate and long paths limit DOC transport into deep aquifers, making the total organic carbon (TOC) of the aquifer matrix the most important C source for N cycling. As groundwater containing high NO-3 concentrations comes in contact with organic-rich horizons along discrete flow paths, these localities can become zones of intense denitrification. Potential for denitrification in groundwater directly correlates to the amount of organic matter in the aquifer system, which is related to the regional geology.
In organic-rich groundwater systems, the quality of the TOC appears to be the primary control on microbial processes. Complex molecules in TOC are not easily degradable by N-reducing bacteria without the aid of fermenting microorganisms, which break down the long substrates that serve as electron donors for N reduction, such as acetate, formate, and hydrogen gas. The mixing of waters form various depths with different large screened intervals-can also affects samples collected from groundwater wells43. People need only basic amounts of water for drinking, cooling, cleaning, and hygiene to maintain human well-being. Rather, people seek water for goods and services, such as the production of food and industrial items, transportation communications, and the elimination of wastes.
It is a common practice of municipal corporation of Aurangabad and other cities, to discharge domestic waste in the nearby nullah, river etc. This discharge of sewage results into depletion of oxygen content of water. It also stimulate algal growth the contamination due to sewage is also a measure cause of water borne diseases like cholera, typhoid, amoebiosis, hook warms, etc. The second most important source of pollution is industrial effluents. The effluents consist of organic and inorganic pollutants such as soil, greases, plastics, plasticizers, suspended solids, phenols, toxics etc. Most of these are non biodegradable and long time sustainable compounds. Pesticides are biologically active substances which are used to kill plants or animal pest. Pesticide is a general term, it include insecticides, herbicides, fungicides, nematocides etc. It is a common practice, in order to increase the productivity, in agriculture to use chemical fertilizers, pesticides and soil additives. These chemical are washed off with irrigation water, rainfall, drainage or leaching into the aquifers. The fertilizer leads to change in mobility status of nutrients in soils. Some nitrate containing fertilizers cause eutrophication.
The important cause of groundwater pollution is haphazard urban development, without adequate attention to sewage and waste disposal. The rapid industrialization without provision for proper treatment and disposal of waste and effluent also contribute to the groundwater pollution. It is very difficult to control groundwater pollution. It requires accurate information about the depth level of aquifer, the volume of the groundwater body, structure of the underlying stratum, and also on the physico-chemical and biological characteristics of the pollutants.
REFERENCE:
1. Krithika Ramalingam; Some Critical issues on Groundwater in India, Centre for water policy, 2005.
2. Ahmad Elbetieha, Homa Darmani, Ahmad S Al-Hiyasat; Fluoride, 33(3), 2000, 128-134.
3. T E E Abbas, E A El-Zubeir and O H Arabbi; World’s Poul Sci J, 65, 2009, 511-516.
4. David Dulin, Howard Drossman and Theodore Mill; Environ Sci Technol, 20(1), 1986, 72-77.
5. Howard E Johnson and Robert C Ball; Fate of organic pesticides in the Aquatic Environment doi 10.1021/ba-1972-0111.ch001.
6. Jing Ma, Kurunthachalam Kannan, Jinping cheng, Yuichi Horii, Quian Wu, and Wenhua Wang; Environ Sci Technol, 42(22), 2008, 8252-8259.
7. Thomas Mckone, Rosemary Castorina, Martha E. Harnly, Yu Kuwabara, Brenda Eskenazi and Asa Bradman; Environ Sci Technol, (41), 2007, 3233-3240.
8. Jing Tan, Qing Qing Li, Annamalai Loganath, Yap Seng Chong, Man Xiao, and Jeffrey Philip Obbard; Environ Sci Tecnol, 42, 2008, 2681-2687.
9. M S Prashanth and M David; Bull Environ Contam Toxicol, 84, 2010, 80-84.
10. J Y Hu, S L Ong, W J Ng, B P He, W J Liu, Z D Feng, X H Zhang, Z S Wang; Bull Environ Contam Toxicl, 71, 2003, 204-2011.
11. Nothalie Karpel Vel Leitner, Johane Vessella, Marcel Dore and Bernard Legube; Environ Sci Technol, 32, 1998, 1680-1685.
12. Jerome M Kemper, Spencer S Walse, and William A Mitch; Environ Sci Technol, 44(4), 2010, 1224-1231.
13. C O Edeogu; J Bio sci, 7(5), 2007, 745-751.
14. GH Loneragan, J J Wagner, D H Gould, F B Garry and M.A.Thoren; J Anim Sci, 79, 2001, 2941-2948.
15. Peter J Goebell, Cristina M Villanueva, Albert W Rettenmei, Herbert Rubben, Manolis Kogevinas; World J Urol, 21, 2004, 424-432.
16. G Venktesan, G Swaminathan; J Env Eng Landscape Management, 17(1), 2009, 1a-1g.
17. Eliot A Atekwana, Esteklla A Atekwana, Rebecca S Rowe, D Dale Werkema Jr, Franklyn O Legeall; J Appl Geophysics, 56, 2004, 281-194.
18. H C Kataria, Arun Singh, S C Pandy-Poll Res, 25(3), 2006, 553-556.
19. Enrica Alsaonati; Vera Slaveykova, Derve Gallard, Jean Philippe Croue, Marc F Bendetti; Water Research, 44, 2010, 223-231.
20. Hsien-Wen Kuo, Shu-Lung Shu. Chin-Chung Wu and Jim-Shoung Lai ; Water, Air and Soil Poll, 114, 1999, 413-421.
21. Rongxing Cuo, Kaizhong Yong; Environ. Mang, 32(4), 2003, 433-44.
22. Christophe Bontemps and stephane Couture; Environ Devel Econ, 7, 2002, 643-657.
23. Eunyoung Kim, John C Little and Nancy Chiu; Environ Sci Technol, 38, 2004, 1799-1806.
24. Yawei Wang, Xuemei Li, An Li, Thanh Wang, Qinghua Zhang, Pu Wang, Jianjie Fu, and Guibin Jiang; Environ Sci Technol, 41, 2007, 6026-6032.
25. Faqi Wang, Wei Liu, Yihe Jin, Jiayin Dai, Wenguang Yu, Xiaohui Liu and Li Liu; Environ Sci Technol, 44, 2010, 1847-1853.
26. Jean-Michel Harmand, Hector Avila, Robert Oliver, Laurent Saint-Andre, Etienne Dambrine: doi;10.1016/j.geoderma 2010.04.032.
27. Manoj Menon, Ronald T Parratt Christian A Kropt, Scott W Tyler; J Arid Environ 74, 2010, 1033-1040.
28. Alexandre Bonton, Alain Rowleau, Christian Bouchard, Manuel J Rodriguez; Agri water Mgmt, 97, 2010, 824-834.
29. WHO/SDE/WSH/03.04/06, WHO, Geneva, 1996.
30. Marta I S Ver issimo, Jo ao A B P Oliveira, M Teresa S Gomes; Sensors and Actuators, B 127, 2007, 102–106.
31. Bradley F Schwartz, Noah S Schenkman, Jeremye E Bruce, Stephen W Leslie, and Marshall L Stoller; Urology, 60, 2002, 23-27.
32. Sergio Navalon, Mercedes Alvaro, Hermenegildo Garcia; J Haz Mat, 169, 2009, 901–906.
33. L V F Silva, J I Golombieski, B Baldisserotto; Aquaculture, 228, 2003, 279–287.
34. Jesus Garcia-Galan, Teresa Garrido, Josep Fraile, Antoni Ginerbreda, M Siliva, Diaz-Cruz, Damia Barcelo; J Hydro, 303, 2010, 93-101.
35. Delgado I C, Sa nchez-Raya A J; Comm Soil Sci and Plant Ana, 30(6), 1999, 773–84.
36. Cuin A, Miller A J, Laurie S A et al.; J Exp Bot, 54(383), 2003, 657–61.
37. M Arienzoa, E W Christena , B W Quaylea, A Kumarc; J Haz Mat, 164, 2009, 415–422.
38. Kathleen A Lohse, Paul D Brooks, Jennoifer C McIntosh, Thomas Meixner, and Travis E. Huxman; Annu Rev Environ Resour, 34, 2009, 65-96.
39. Meng-Xia Xu, Jian-Hua Yan, Sheng-Yong Lu, Xiao-Dong Li, Tong Chen, Ming-Jing Li, Hui-Fen Dai, Fei Wang, and Ke-Fa Cen; Environ Sci Technol, 43(4), 2009, 1023-1029.
40. Ozlem Tonguc Yayintas, Selahattin Yilmaz, Muhammet Turkoglu, Yusuf Dilgin; Environ Monit Assess, 127, 2007, 389-397.
41. V H McNeil and M E Cox; Environ Geo, 39(12), 2000, 13251.
42. Mark Giordano; Annu Rev Environ Resour, 34, 2009, 153-178.
43. David K Todd; Ground water hydrology, Wiley International Edition, 1959.
Received on 28.09.2011 Modified on 18.10.2011
Accepted on 27.10.2011 © AJRC All right reserved
Asian J. Research Chem. 4(12): Dec., 2011; Page 1812-1817