Studies on Some Physico-Chemical and Microbiological Characteristics of Potable Water Used in Some Rural Areas of Surat District ( Gujarat )

A physico chemical and microbiological study of the ground water of some villages of Surat district of Gujarat state (India) has been made. Physico chemical parameters such as colour, odour, taste, temperature, pH, electrical conductivity, TS, TDS, total hardness, total alkalinity, calcium, magnesium, iron, sodium, potassium, chloride, sulphate, nitrate, fluoride and silica were determined. In microbiological study, total coliforms, E. coli, sulfate reducing anaerobic bacteria, pseudomonas aeruginosa, yeast and mould were investigated. Samples were taken from ten sampling points in ten different villages viz. Parvat(S-1), Kharvasa(S-2), Bonand(S3), Vesu(S-4) Amroli(S-5), Kadodara(S-6), Chalthan(S-7), Variyav(S-8), Gaviyar(S9) and Bhairav(S-10). Samples were taken four times in year in the month of May, August, November and February to check the seasonal effects. In village Gaviyar, Gujarat Water Supply and Sewerage Board has set up a treatment plant to supply good quality potable water in few surrounding coastal villages. In all other cases samples were taken from bore-well. Here study reported is for samples taken in May-2004 and August-2004.For colour, iron, sulphate, nitrate, fluoride and silica, instrumental methods like spectrophotometry were used. “Hach-Odyssey spectrophotometer” which has facility to store calibration curves and which can display the value for that parameter directly was used. In present study programmes of “Hach” with their reagents were used while some programmes were prepared by us using our reagents. This is an excellent instrument and results of this instrument are validated by USEPA. Sodium and potassium was determined using flame photometer. It was found that some water samples have higher TDS, chlorides, total hardness and total alkalinity than the permissible limits. In all cases samples were not found to contain significant quantities of bacteria and water was palatable from this point of view.


Introduction
In continuation of earlier studies on ground water 1 , here we report the physico-chemical as well as microbiological studies of potable water used in some rural areas of Surat district, Gujarat.Because of the geographical isolation and remoteness, people residing in the rural area, mostly do not have access to safe drinking water.In the absence of fresh water supply, the people are forced to take water from any source that lies near their village.In most of the interior rural area, the borewell water is used for drinking and other domestic purposes.Borewell water is the under ground water that has come mainly from the seepage of surface water and is held in subsoil and pervious rocks.Borewell water is generally of good quality and is difficult to pollute.The use of fertilizers, pesticides and insecticides in rural area, manure, lime, septic tank, refuse dumps, etc. are the main sources of borewell water pollution 2 .The water used may be unsafe chemically as well as microbiologically.Chemically unsafe water shows long term and slow effect while microbiologically unsafe water creates short term problems such as dysentery, diarrhea, jaundice, gastrointestinal disorders, fever and amoeboisis which may assume epidemic proportions 3 .The work on microbiological pollution is still lacking.Kaushik and Prasad 4 , Thapliya et al. 5 , Shrivastav et al. 6 , Riccharia and Mishra 7 , Garoda et al. 8 and J.Hussain et al. 9 are among the few workers who have worked on microbiological quality of water.

Experimental
Water samples were collected in the first week of May-2004 and the first week of August-2004.The villages selected were Parvat(S-1), Kharvasa(S-2), Bonand(S-3), Vesu(S-4) Amroli(S-5), Kadodara(S-6), Chalthan(S-7), Variyav(S-8), Gaviyar(S-9) and Bhairav(S-10).For physico-chemical analysis water samples were collected in properly washed polyethylene bottles while for microbiological analysis sterile glass bottles were used.Standard procedures were adapted for the determination of both physico-chemical and microbiological analysis. 10or spectrophotometric determination of colour, fluoride, iron, nitrate, sulphate and silica, "Hach -Odyssey Spectrophotometer (USA)" was used.This instrument has facility to store calibration curves and which can display the value for that parameter directly was used.In present study, programmes of "Hach" with their reagents were used while some programmes were prepared by us using our reagents.This is an excellent instrument and results of this instrument are validated by USEPA.Sodium and potassium were determined with the help of microprocessor based flame photometer.Calcium, magnesium, total hardness, chloride, total alkalinity were estimated by titrimetric methods.
For microbiological study, the modern, Membrane Filter Technique (MFT) were used.All the culture media used were of "Hi-Media Products".

Results and Discussion
All metabolic and physiological activities and life processes of aquatic organisms are generally influences by water temperature.In the present study temperature ranged from 27-31ºC.
The pH of the water body indicates the degree of deterioration of water quality.In the present study pH ranged from 7.07-8.10which lies within the range prescribed by ISI 11 , which is 6.5-8.5.The specific conductivity (SC), which is a measure of the dissolved ion concentration, was much higher than the permissible limits.In the present study it ranged from 271-3130 µS/cm.maximum SC was observed at vesu(S-4) during the study period.According to WHO 12 and ISI, total dissolved solids (TDS) value should be less than 500 mg/L for drinking water.In the present study it ranged from 110-1524 mg/L.Most of the samples have higher values of TDS than the prescribed value.
Total hardness in water is mainly due to the salts of calcium and magnesium.In the present study it ranged from 90-480 mg/L.Some samples have higher values than the prescribed by ISI, which is 300 mg/L.The limits of calcium and magnesium have been prescribed in the range 75-200 mg/L and 50-100 mg/L respectively.In the present study calcium and magnesium ranged from 14-100 mg/L and 7.29-97.2mg/L respectively.Total alkalinity of all samples ranged from 90-470 mg/L.All the samples have higher values than the prescribed limits, 200 mg/L, except the value of S-9.The chloride content in the samples ranged from 33.75-795.50mg/L.The highest chloride observed in the sample of Vesu (S-4).This may be due to its location, near Sea.The concentration of sulphate in all samples observed within the limits prescribed for sulphate content, 200 mg/L and it varies from 4.2-104.2mg/L during the study period.
Nitrate is one of the major constituents of organisms along with carbon and hydrogen as amino acids, proteins and organic compounds in ground water.In the present study nitrate ranged from 1.99-68.66mg/L which lies under the prescribed limits.Fluoride limits in drinking water from 1.0-1.5 mg/L. in the present study it ranged from 0.21-1.20 mg/L, which lies within the range.Iron is one of the most abundant elements in the earth's crust.Iron deficiency in the human body causes anaemia.In the present study it ranged from 1.0-1.24mg/L, which lies under the limits prescribed by WHO and ISI.
Sodium and potassium ranged from 31.6-295 mg/L and 0.3-174.4mg/L respectively.Sodium content more than 50 mg/L makes the water unsuitable for drinking purposes.The ground water of Vesu was found to have higher concentration of sodium and potassium.Sodium is the most important element, which influences the soil quality and plant growth either by affecting the permeability of soil by clogging or replacing other cations.The extent of replacement of other cation by sodium is denoted by sodium adsorption ratio (SAR) calculated by the following equation as described by Richards 13 .SAR = Na + / (Ca 2+ + Mg 2+ /2) 0.5 Where, Na + , Ca 2+ and Mg 2+ are in meq/L.SAR in present study ranged from1.154-7.294meq/L.Salinity Laboratory of Agriculture recommended the water classification according to the value of SAR.In present study SAR was found below the prescribed limit.
The concentration of bicarbonate and carbonate also influence the suitability of water for irrigation purpose 13,14 .One of these empirical approaches is based on the assumption that all Ca +2 and Mg 2+ precipitate as carbonate.Considering this hypothesis, Ealtron 14 proposed the concept of residual sodium carbonate (RSC) for the assessment of high carbonate waters.RSC is calculated by the following formula.RSC = (CO 3 2-+ HCO 3 -) -(Ca 2+ + Mg 2+ ) The water with high RSC will have high pH and makes soil infertile by depositing black alkali on the surface.According to a classification made by United States Salinity Laboratory water samples are safe for irrigation purpose with RSC value below 1.25 meq/L while water samples with RSC value above 2.5meq/L are unsuitable for irrigation purpose.In our study area RSC ranged from -1.977 to 5.807 meq/L.
Percentage sodium (PS) is another important factor to study sodium hazard.It is calculated as the percentage of sodium and potassium against all cationic concentrations.It is also used for adjudging the quality of ground water for the use of agricultural purpose.The use of high PS waters for irrigation purpose stunts the plant growth.It is calculated by the following formula.
PS = [(Na + + K + ) / (Ca 2+ + Mg 2+ + Na + + K + )] x 100 In the present study PS ranged from 23.469-74.338meq/L.All the samples were found good to permissible limit except S-4.Coliforms generally occur in drinking water due to contamination of sewage water or unhygienic practices.Coliforms in drinking water can cause amoebic dysentery and various other pathogenic complexities.In our present study it was not observed.
E. coli occurs in drinking water due to contamination of sewage water or unhygienic practices.Three types of diseases may be produced (i) they can produced abscesses in internal organs, septicemia, endocarditic, and meningitis (ii) produce a severe and often fatal type of epidemic diarrhea in infants and (iii) they are the cause of sporadic, nonepidemic summer diarrhea which occurs in children during their second and third summer of life.As coliforms was not observed, E.Coli was also absent in the present study.
Fungi are present, and have been recovered from, diverse, remote, and extreme aquatic habits including lakes, ponds, rivers, streams, estuaries, marine environments, wastewaters, sludge, rural and urban strormwater runoff, well waters, acid mine drainage, asphalt refineries, jet fuel systems, and aquatic sediments.The association between fungal densities and organic loading suggests that fungi may be useful indicators of pollution.This organism often occurs in faeces of humans, but in lower numbers than coliforms.It indicates faecal contamination.It helps in detecting the reconstitution of rehydration mixtures, baby foods and pharmaceutical preparations as well as surveillance of bottled water.In the present study it was absent.
Aearobic Microbial Counts are used to assess the general bacterial content of water.Sudden increase in colony count from a groundwater source may be an early sign of pollution of the aquifer, useful in evaluating the efficiency of water treatment processes -coagulation, filtration, and disinfection.In the present study it was determined at two temperatures, 20ºC and 37ºC.They were found within the limits.

Table - 6
Microbiological analysis report of Potable waters inAUGUST-2004 Studies on Some Characteristics of Potable Water