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Assessment of drinking water quality in the Al-Gassim region of Saudi Arabia
EnvironmentInternational,Vol. 23, No. 2, pp. 247-251.1997 Copyright 01997 ElsevierScienceLtd Printedin the USA. All rights resewed 0160-4120/97517.00+.00
PI1 SO160-4120(97)000011-1
ASSESSMENT OF DRINKING WATER QUALITY IN THE AL-GASSIM REGION OF SAUDI ARABIA Hago M. Abdel Magid Department of Soil and Water, College of Agriculture and Veterinary Medicine, King Saud University Branch, Al Gassim, Buraydah, Saudi Arabia
EI 9512-395 M (Received 4 December 1995; accepted 7 January 1997)
Thechemicalandmicrobiologicalqualityof potablewaterin the Al-GassimRegionof SaudiArabia was investigated.The analyticalresultsobtainedindicatedthat thereare considerablevariations amongthe examinedsampleswith respectto their chemicalconstituents,which only occasionally fell abovethe maximumpermissiblelevelsof the Saudidrinking water standards.Of all the water classesstudied,the locally storedmunicipalwater showedthe highestmeanconcentrationfor the chemicalconstituentsmeasured.Microbiological analysesindicatethat the only issue of true concernis the total coliform, which was too numerousto count and, therefore,warrantsmore &knf,iOn.
Copyright 01997 ElsevierScienceLtd
INTRODUCTION
During the past two decades,the regulation of water quality has undergone radical changes.Drinking water
standards have been developed to define a quality of water that is safe and acceptable to the consumer. Therefore, most of these standardsset limits for organisms or chemical constituents that are dangerous, potentially hazardous,or obnoxious to consumers.The U.S. Environmental Protection Agency (USEPA 1976) specified levels of organic and inorganic constituents for current drinking water standards.For example, the appendix to the U.S. drinking water standardsrecommends that the fluoride concentrations, depending on average ambient temperature, be within a range that slightly varies above and below 1 mg/L (USEPA 1976). At higher levels, fluoride can be harmful, and at moderately high concentrations- above 3 to 5 mg/L it may discolor or cause structural damage to some teeth (AWWA 1971; NRC 1977,1980,1982). At high dosages,it can be an active toxicant and causessevere 247
illness or death. There are other constituents of water that may affect human health. An important one encountered occasionally, and subject to a specific limit in drinking water standards, is nitrate. The World Health Organization (WHO 1971) recommended a drinking water standard of 45 mg/L of NO; (10 mg/L NO,’ - N). In the Kingdom of Saudi Arabia, the quality of drinking water is currently receiving some attention (SASO 1984; Hashim 1990; Garawi and Al-hendi 1993). SASO (1984) developed drinking water standards for both bottled and municipal (unbottled) water to define a quality of water that is safe and acceptable to the consumer. These standards set limits for the permissible and the maximum contaminant level of indicator organisms and chemical elements that endanger the health of consumers.A substantial number of these standardsare based on the WHO 1971 international standardsfor drinking water.
248
This study investigated some of the chemical and microbial aspectsof drinking water quality in the AlGassim Region of Saudi Arabia and compared these with the locally acceptablewater quality standards. MATERIALS AND METHODS
The water samplesused in this study were obtained from various sources.Thesesampleswere divided into two main classes,bottled water and municipal water. Bottled water Locally produced bottled drinking water (LBW) is bottled and distributed by registeredcompaniesall over the Kingdom. Imported bottled drinking water (IBW) is obtained from the foreign sourceslisted in Table 1. Municipal water 1) Commercial municipal water (CMW) is supplied to consumers by commercial drinking water service stations. These stations sell water to the public after treatment with chlorine (residual chlorine range: 0.20.5 mg/L) and maintain a fluoride concentrationwithin a range of 0.6- 1 mg/L. 2) Locally stored municipal water (LSMW) is pumped directly to individual homes through a piped network and stored in concrete underground reservoirs after treatment with chorine (residual chlorine range: 0.20.5 mg/L). 3) Well water (WW) is obtained from surface wells located in the Al-Ras area of the Al-Gassim Region, Central Saudi Arabia. It is not chlorinated and is conveyed to interested consumers in commercial tankers approved by municipal authorities. Water samplesfor chemical analysis were collected in plastic bottles. The water from commercial service stations and surface wells was taken through hoses normally used for the delivery of water whereas water from home reservoirswas drawn using plastic buckets. The water sampleswere taken to the laboratory (ambient temperature 25 “C) and analysis was carried out immediately. Physical and chemical methods Both physical and chemicalmethodsof determination were employed in this work. Analytical grade BDH products(BDH ChemicalsLtd., Poole, England),unless otherwise stated, were used to prepare reagents and calibration standards. Deionized distilled water was
H.M. Abdel Magid
Table1.Sources of importedbottled drinking water. Commercial name Countryof bottling Tasmanian Australia Perier France Evian France Ramlbsa Sweden Valvert Belgium used to prepareall reagentsand dilution standards,and as dilution water. Glassware was washed with dilute nitric acid (1: 15) followed by several portions of deionized distilled water (APHA 1971). The determinationswere carried out according to the Standard Methods for the Examination of Water and Wastewater (APHA 1985) and Richards (1954). In these determinations, pH was measured by a Meterohm pH-meter (Model 632) calibrated agamst two standardbuffer solutions of known pH values (pH 7 and pH 9) produced by Winlab Ltd., MaidenheadBerkshire, England. Electric conductivity (EC) (dS/m at 25 “C) was measuredby a Beckman Solu Bridge type equipment calibrated using anhydrous KCL solution (0.0 1N) adjustedat 25 “C.Na’ and K’ were determined by flame photometer (Corning Model M410 instrument). Ca” and Mg’+ were determinedby titration with etbylenediaminetetraaceticacid (EDTA) disodium salt solution (O.OlN). F was determined by the SPADNS [Sodium 2- (parasulfophenylazo) - 1,8 dihydroxy-3,6 naphthalene disulfonate] calorimetric method using NaF for preparation of the standard solution. Iron was determinedby the calorimetric phenanthroline method using the Bausch and Lomb Spectronic 2000 spectrophotometer. Ferrous ammonium sulfate was used to preparethe standard iron solution. Cl was determined by titration using standard silver nitrate solution and potassiumchromate(5% solution) as an indicator. SO,was determined turbidimetrically using Model ANA 14A turbidimeter (Tokyo Photo-electric Co. Ltd., Japan).NO; was determinedby the phenoldisulphonic acid method using Spectronic2000 spectrophotometer. KNO, was used to prepare the standardNO,‘solution. Total hardnesswas obtained by calculation from Ca” and Mg* determined concentrations. Total dissolved solids (IDS) were determined by thoroughly mixing a measuredvolume of eachwater sampleand allowing it to evaporate in a weighed porcelain dish on a steam bath. The residue was dried to constant weight in an electric oven set at 105°C.
249
Drinking water quality in Al-Gassim,SaudiArabia
Table 2. Saudi standards for unbottlcd and bottled drinking water (1984). Substanceor Characteristic
Municipal (unbottled) water Optimum limit
Maximum permissiblelimit
Bottled water Maximum permissiblelimit
(mH.4 TDS 500 1500 100 - 700 Total hardness(as Ca COr) 100 500 300 Electric conductivity 0.8 2.3 5-l (EC) (dS/m): pH range 7.0 - 8.5 9.2 * 6.5 - 8.5 Calcium (as Ca+*) 75 200 75 Magnesium (as Mg+*) 30 ** 150 30 Manganese(as Mn) 0.05 0.5 0.05 Chloride (as Cl-) 200 600 250 Sulfate (as SO,-) 200 400 250 Nitrate (as NO;) <45 45 45 Fluoride (as F) 0.6 - 1 1.0 0.6 - 1 Iron (Total, as Fe) 0.1 1.0 0.3 Copper (as Cu) 0.05 1.5 1.0 Zinc (as Zn) 5.0 15.0 5.0 Negative Total coliform (MEN/100 mL) Negative Negative * The lowest permissiblelevel is around pH 6.5. ** Not more than 30 mg/L if there are 250 mg!L of sulfate; if there is less sulfate, magnesium up to 150 mg/L may be allowed.
Microbiological methods The three-tube procedureusing lactose broth (Difco) was used for estimating the most probable number (MPN) of coliform organisms.Tubeswere incubatedat 37°C for 48 h and the MPN was obtained according to the Standard Methods for the Examination of Water and Wastewater (APHA 1985; Geldreich 1975). The confvmed coliforrn test was done by culturing positive tubes into brilliant green bile broth (Difco) and incubating at 37°C for 48 h. Statistical analyses were performed using an IBM compatible 486 computer. The meansobtained for the various water quality parametersmeasuredwere evaluated according to the current local (Saudi Arabian) drinking water quality standardssummarizedin Table 2 (SASO 1984). RESULTS AND DISCUSSION
Table 3 shows the data for the means of the water quality parameters measured for each of the water
classes used in this study. These data revealed that there are considerablevariations among the examined samples with respect to their constituents, which occasionallyfell above the maximum permissiblelevel of the Saudi standardsshown in Table 2. However, all the parameters studied lie within the permissible range of the current Saudi drinking water quality standards.Of all the water classesstudied, the LSMW showed the highest mean concentration for the chemical constituents measured. Except for a few instances (for example, F- and NO,- ions) the means for the concentrations of the cations Ca, Mg, and K, and pH value and TDS of the municipal drinking water samplesstudied (Table 3), fall either within the permissible or maximum permissible range of the 1984 Saudi standards (Table 2). The level of F, as shown in Table 3, is low in LSMW, adequate in CMW, and high in WW. The 1984 Saudi standard (Table 2) recommendsthat the level of F in unbottled water be less than 0.6 mg/L but not greater than 1 mg/L. On the other hand, NO,- concentration is
32 13.2 40 19.7 185.5 40.4 131.3 Nd 0.6 Nd Nd 6.6-7.6 7.2 0.22-0.40 0.36 48-172 118.8 Negative
8.3-68.5 3.9-29.6 10-100 1.2-54.7 50-477.9 12.4-95.7 24.0-336 Nd
Mea n 25.7 9.6 35.6 19 161.9 29.4 119.6 Nd -
SD
Nd 0.38 PB 0.12 EC (dS/m) 55 Tm @dU Total coliform: (MPN/l 00 mL) Nd = not detectable. - = not determined. * = too numerous to count in all samples of this source.
Na’ K’ Ca+z Mg+’ Total hardness (ma): Cl SO,-NO, FFe”
Range
Mea n
146.6 48.6 96.9 20.6 334.5 221.8 303 Nd < 0.4 Nd Nd 7.7-8.5 8.0 1.3-1.5 1.4 818-924 873.8 Negative
140-154 46-51.9 80-l 10 6-27 300-37s 114-356 240-384 Nd
Raw
LSMW
characteristic
CIVlW
MuniciDal water
Substance or
Nd 0.24 0.06 40.1
5.3 1.8 11 6.9 27.4 78.5 56.2 Nd
SD
S-103 0.7-3.1 0.0-0.8 7.6-8.1 0.2-1.3 95-700
O-150
3.7-84 1-3 16-176 1.9-21 64-488 8-184
Rm+= 30.3 1.9 56.8 8 169.5 44.3 52.7 28.8 1.8 0.01 7.9 0.47 262.7 Positive *
Mean
0.19 0.29 159.3
25.4 0.64 43.8 4.8 113.4 49.1 46.3 33.1 0.63
SD 36.2 1.8 18.7 3.9 62 37.5 22.3 6.6 0.63 Nd 7.3 176.8 Negative
1 lo-250
Mea n
12-191.5 0.2-4.42 2.4-6 1-9 10.2-153 9.5-70.9 8.5-50 0.03-18 0.5-0.7s Nd 6.9-7.6
Raw
LBW
49
31.2 1.3 14 2.5 37.6 19.3 14.4 6 0.08 Nd 0.23
SD
-
17 0.63 95 7.8 277.8 25.1 22.7 Nd Nd Nd 6.1
Mea n
IBW
Negative
s-35 0.2-l 67.9-148 0.3-24.0 178.1-385.5 4.5-70 10-36.6 Nd Nd Nd s-7.7 -
Range
Bottled water
Table 3. Chemical composition (mg/L) and total coliform count @LPN/LOOmL) of municipal and bottled water samples.
13.4 0.33 36.1 9.6 86.6 30.9 11.4 Nd Nd Nd 1.4
SD
Drinking water quality in Al-Gassim,SaudiArabia
relatively higher in W W than in any of the water samples studied. However, the general mean for NO, concentration in this class lies within the permissible range of the 1984 Saudi standards(Table 2). Generally, the meansfor the concentrationsobtained for the chemical constituents of bottled water are in good agreement with the 1984 Saudi standards(Table 2). Exemptions to this generalization are a few measurementsthat fall above (Ca” concentration of IBW) or below (pH value of IBW) the 1984 Saudi standards for bottled water. Microbiological examination of the well water samples showed a high coliform count (MPN/lOOmL). The 1984 Saudi standard requires a negative coliform test for every 100 mL of water examined after treatment with chlorine to kill bacteria. This high count of coliform may be attributed to contamination of the hoses used by humans, including farmers and livestock owners, and to the exposureof thesedelivery hosesto dust storms. Previous workers, elsewhere, indicated that dust storms and livestock activity in the vicinity of surface wells increasesmicrobial loads and bacterial inputs (Stephensonand Street 1978; Hamad and Dirar 1982). On the other hand, the bottled water samples used in this study showed negative coliform tests (Table 3), which confirms that they are devoid of any fecal contamination. According to the manufacturers’ labels,thesewaters are treated either with ozone, U.V. light, or by reverse osmosis. Acknowledgment-The author acknowledgesthe assistanceof the technical staff of the Department of Soil and Water, College of Agriculture and Veterinary Medicine, El-Gassim,Buraydah.Special thanksareto Dr. Abd Rub El Nabi M. Abdel Hadi and Mr. ChnarJumaa Abu Jayabfor their unlimited assistance.
251
REFERENCES API-IA (AmericanPublic Health Association).Standardmethodsfor the examination of water and wastewater. 13th ed. New York, USA: APHA; 1971. APHA (AmericanPublic Health Association).Standardmethodsfor the examination of water and wastewater. 16th ed. New York, U.S.A.: APHA; 1985. AWWA (American Water Works Association). Water quality and treatment.New York: McGraw-Hill; 1971. Garawi, M.S.; Al-hendi, H.A. Spectroscopicstudy of the metallic constituentsin someundergroundwater in Al&a&n area,Saudi Arabia. Arab Gulf J. Sci. Res. 11: 47-56; 1993, Geldreich, E.E. Handbook of evaluating water bacteriological laboratories. 2nd ed. Cincinnati, OH: U.S. Environmental ProtectionAgency; 1975. Hamad, Z.H.; Dirar, H.A. Microbiological examination of Sabeel water. Appl. Environ. Microbial. 43: 1238-1243; 1982. Hashim,A.R. Analysis of water and soils for Ashafa Toraba Wahat and Wehait. J. King SaudUniv. (Science)2: 87-94; 1990. NRC (National ResearchCouncil). Drinking water and health. Vol. 1. Washington, D.C.: National Academy Press; 1977. NRC (National ResearchCouncil). Drinking water and health. Vol. 3. Washington,D.C.: National Academy Press; 1980. NRC (National ResearchCouncil). Drinking water and health. Vol. 4. Washington,D.C.: National Academy Press; 1982. Richards, L.A. Diagnosis and improvement of saline and alkali soils.Handbook No. 60. Washington, D.C.: U.S. Department of Agriculture; 1954. SASO (Saudi Arabian Standards Organization). Bottled and unbottled drinking water. PP 1-8. SSA 4090984. 2nd edition. ISSN: 1319-2302: 1984. Available from: SASO Information Center, P.O. Box 3437, Riyadh, 11471, Saudi Arabia. Stephenson,G.R.; Street, L.V. Bacterial variations in streamsfor SouthwestIdaho rangelandwatershed.J. Environ. Qual. 7: 150157; 1978. U.S.EPA(U.S. EnviromnentalProtectionAgency). National interim primary drinking water regulations. Publication EPA/S 70/9-76003. Washington,D.C.: GovernmentPrinting Office; 1976. WHO (World Health Organization). International standards for drinking water. 3rd ed. Geneva:WHO; 1971
PI1 SO160-4120(97)000011-1
ASSESSMENT OF DRINKING WATER QUALITY IN THE AL-GASSIM REGION OF SAUDI ARABIA Hago M. Abdel Magid Department of Soil and Water, College of Agriculture and Veterinary Medicine, King Saud University Branch, Al Gassim, Buraydah, Saudi Arabia
EI 9512-395 M (Received 4 December 1995; accepted 7 January 1997)
Thechemicalandmicrobiologicalqualityof potablewaterin the Al-GassimRegionof SaudiArabia was investigated.The analyticalresultsobtainedindicatedthat thereare considerablevariations amongthe examinedsampleswith respectto their chemicalconstituents,which only occasionally fell abovethe maximumpermissiblelevelsof the Saudidrinking water standards.Of all the water classesstudied,the locally storedmunicipalwater showedthe highestmeanconcentrationfor the chemicalconstituentsmeasured.Microbiological analysesindicatethat the only issue of true concernis the total coliform, which was too numerousto count and, therefore,warrantsmore &knf,iOn.
Copyright 01997 ElsevierScienceLtd
INTRODUCTION
During the past two decades,the regulation of water quality has undergone radical changes.Drinking water
standards have been developed to define a quality of water that is safe and acceptable to the consumer. Therefore, most of these standardsset limits for organisms or chemical constituents that are dangerous, potentially hazardous,or obnoxious to consumers.The U.S. Environmental Protection Agency (USEPA 1976) specified levels of organic and inorganic constituents for current drinking water standards.For example, the appendix to the U.S. drinking water standardsrecommends that the fluoride concentrations, depending on average ambient temperature, be within a range that slightly varies above and below 1 mg/L (USEPA 1976). At higher levels, fluoride can be harmful, and at moderately high concentrations- above 3 to 5 mg/L it may discolor or cause structural damage to some teeth (AWWA 1971; NRC 1977,1980,1982). At high dosages,it can be an active toxicant and causessevere 247
illness or death. There are other constituents of water that may affect human health. An important one encountered occasionally, and subject to a specific limit in drinking water standards, is nitrate. The World Health Organization (WHO 1971) recommended a drinking water standard of 45 mg/L of NO; (10 mg/L NO,’ - N). In the Kingdom of Saudi Arabia, the quality of drinking water is currently receiving some attention (SASO 1984; Hashim 1990; Garawi and Al-hendi 1993). SASO (1984) developed drinking water standards for both bottled and municipal (unbottled) water to define a quality of water that is safe and acceptable to the consumer. These standards set limits for the permissible and the maximum contaminant level of indicator organisms and chemical elements that endanger the health of consumers.A substantial number of these standardsare based on the WHO 1971 international standardsfor drinking water.
248
This study investigated some of the chemical and microbial aspectsof drinking water quality in the AlGassim Region of Saudi Arabia and compared these with the locally acceptablewater quality standards. MATERIALS AND METHODS
The water samplesused in this study were obtained from various sources.Thesesampleswere divided into two main classes,bottled water and municipal water. Bottled water Locally produced bottled drinking water (LBW) is bottled and distributed by registeredcompaniesall over the Kingdom. Imported bottled drinking water (IBW) is obtained from the foreign sourceslisted in Table 1. Municipal water 1) Commercial municipal water (CMW) is supplied to consumers by commercial drinking water service stations. These stations sell water to the public after treatment with chlorine (residual chlorine range: 0.20.5 mg/L) and maintain a fluoride concentrationwithin a range of 0.6- 1 mg/L. 2) Locally stored municipal water (LSMW) is pumped directly to individual homes through a piped network and stored in concrete underground reservoirs after treatment with chorine (residual chlorine range: 0.20.5 mg/L). 3) Well water (WW) is obtained from surface wells located in the Al-Ras area of the Al-Gassim Region, Central Saudi Arabia. It is not chlorinated and is conveyed to interested consumers in commercial tankers approved by municipal authorities. Water samplesfor chemical analysis were collected in plastic bottles. The water from commercial service stations and surface wells was taken through hoses normally used for the delivery of water whereas water from home reservoirswas drawn using plastic buckets. The water sampleswere taken to the laboratory (ambient temperature 25 “C) and analysis was carried out immediately. Physical and chemical methods Both physical and chemicalmethodsof determination were employed in this work. Analytical grade BDH products(BDH ChemicalsLtd., Poole, England),unless otherwise stated, were used to prepare reagents and calibration standards. Deionized distilled water was
H.M. Abdel Magid
Table1.Sources of importedbottled drinking water. Commercial name Countryof bottling Tasmanian Australia Perier France Evian France Ramlbsa Sweden Valvert Belgium used to prepareall reagentsand dilution standards,and as dilution water. Glassware was washed with dilute nitric acid (1: 15) followed by several portions of deionized distilled water (APHA 1971). The determinationswere carried out according to the Standard Methods for the Examination of Water and Wastewater (APHA 1985) and Richards (1954). In these determinations, pH was measured by a Meterohm pH-meter (Model 632) calibrated agamst two standardbuffer solutions of known pH values (pH 7 and pH 9) produced by Winlab Ltd., MaidenheadBerkshire, England. Electric conductivity (EC) (dS/m at 25 “C) was measuredby a Beckman Solu Bridge type equipment calibrated using anhydrous KCL solution (0.0 1N) adjustedat 25 “C.Na’ and K’ were determined by flame photometer (Corning Model M410 instrument). Ca” and Mg’+ were determinedby titration with etbylenediaminetetraaceticacid (EDTA) disodium salt solution (O.OlN). F was determined by the SPADNS [Sodium 2- (parasulfophenylazo) - 1,8 dihydroxy-3,6 naphthalene disulfonate] calorimetric method using NaF for preparation of the standard solution. Iron was determinedby the calorimetric phenanthroline method using the Bausch and Lomb Spectronic 2000 spectrophotometer. Ferrous ammonium sulfate was used to preparethe standard iron solution. Cl was determined by titration using standard silver nitrate solution and potassiumchromate(5% solution) as an indicator. SO,was determined turbidimetrically using Model ANA 14A turbidimeter (Tokyo Photo-electric Co. Ltd., Japan).NO; was determinedby the phenoldisulphonic acid method using Spectronic2000 spectrophotometer. KNO, was used to prepare the standardNO,‘solution. Total hardnesswas obtained by calculation from Ca” and Mg* determined concentrations. Total dissolved solids (IDS) were determined by thoroughly mixing a measuredvolume of eachwater sampleand allowing it to evaporate in a weighed porcelain dish on a steam bath. The residue was dried to constant weight in an electric oven set at 105°C.
249
Drinking water quality in Al-Gassim,SaudiArabia
Table 2. Saudi standards for unbottlcd and bottled drinking water (1984). Substanceor Characteristic
Municipal (unbottled) water Optimum limit
Maximum permissiblelimit
Bottled water Maximum permissiblelimit
(mH.4 TDS 500 1500 100 - 700 Total hardness(as Ca COr) 100 500 300 Electric conductivity 0.8 2.3 5-l (EC) (dS/m): pH range 7.0 - 8.5 9.2 * 6.5 - 8.5 Calcium (as Ca+*) 75 200 75 Magnesium (as Mg+*) 30 ** 150 30 Manganese(as Mn) 0.05 0.5 0.05 Chloride (as Cl-) 200 600 250 Sulfate (as SO,-) 200 400 250 Nitrate (as NO;) <45 45 45 Fluoride (as F) 0.6 - 1 1.0 0.6 - 1 Iron (Total, as Fe) 0.1 1.0 0.3 Copper (as Cu) 0.05 1.5 1.0 Zinc (as Zn) 5.0 15.0 5.0 Negative Total coliform (MEN/100 mL) Negative Negative * The lowest permissiblelevel is around pH 6.5. ** Not more than 30 mg/L if there are 250 mg!L of sulfate; if there is less sulfate, magnesium up to 150 mg/L may be allowed.
Microbiological methods The three-tube procedureusing lactose broth (Difco) was used for estimating the most probable number (MPN) of coliform organisms.Tubeswere incubatedat 37°C for 48 h and the MPN was obtained according to the Standard Methods for the Examination of Water and Wastewater (APHA 1985; Geldreich 1975). The confvmed coliforrn test was done by culturing positive tubes into brilliant green bile broth (Difco) and incubating at 37°C for 48 h. Statistical analyses were performed using an IBM compatible 486 computer. The meansobtained for the various water quality parametersmeasuredwere evaluated according to the current local (Saudi Arabian) drinking water quality standardssummarizedin Table 2 (SASO 1984). RESULTS AND DISCUSSION
Table 3 shows the data for the means of the water quality parameters measured for each of the water
classes used in this study. These data revealed that there are considerablevariations among the examined samples with respect to their constituents, which occasionallyfell above the maximum permissiblelevel of the Saudi standardsshown in Table 2. However, all the parameters studied lie within the permissible range of the current Saudi drinking water quality standards.Of all the water classesstudied, the LSMW showed the highest mean concentration for the chemical constituents measured. Except for a few instances (for example, F- and NO,- ions) the means for the concentrations of the cations Ca, Mg, and K, and pH value and TDS of the municipal drinking water samplesstudied (Table 3), fall either within the permissible or maximum permissible range of the 1984 Saudi standards (Table 2). The level of F, as shown in Table 3, is low in LSMW, adequate in CMW, and high in WW. The 1984 Saudi standard (Table 2) recommendsthat the level of F in unbottled water be less than 0.6 mg/L but not greater than 1 mg/L. On the other hand, NO,- concentration is
32 13.2 40 19.7 185.5 40.4 131.3 Nd 0.6 Nd Nd 6.6-7.6 7.2 0.22-0.40 0.36 48-172 118.8 Negative
8.3-68.5 3.9-29.6 10-100 1.2-54.7 50-477.9 12.4-95.7 24.0-336 Nd
Mea n 25.7 9.6 35.6 19 161.9 29.4 119.6 Nd -
SD
Nd 0.38 PB 0.12 EC (dS/m) 55 Tm @dU Total coliform: (MPN/l 00 mL) Nd = not detectable. - = not determined. * = too numerous to count in all samples of this source.
Na’ K’ Ca+z Mg+’ Total hardness (ma): Cl SO,-NO, FFe”
Range
Mea n
146.6 48.6 96.9 20.6 334.5 221.8 303 Nd < 0.4 Nd Nd 7.7-8.5 8.0 1.3-1.5 1.4 818-924 873.8 Negative
140-154 46-51.9 80-l 10 6-27 300-37s 114-356 240-384 Nd
Raw
LSMW
characteristic
CIVlW
MuniciDal water
Substance or
Nd 0.24 0.06 40.1
5.3 1.8 11 6.9 27.4 78.5 56.2 Nd
SD
S-103 0.7-3.1 0.0-0.8 7.6-8.1 0.2-1.3 95-700
O-150
3.7-84 1-3 16-176 1.9-21 64-488 8-184
Rm+= 30.3 1.9 56.8 8 169.5 44.3 52.7 28.8 1.8 0.01 7.9 0.47 262.7 Positive *
Mean
0.19 0.29 159.3
25.4 0.64 43.8 4.8 113.4 49.1 46.3 33.1 0.63
SD 36.2 1.8 18.7 3.9 62 37.5 22.3 6.6 0.63 Nd 7.3 176.8 Negative
1 lo-250
Mea n
12-191.5 0.2-4.42 2.4-6 1-9 10.2-153 9.5-70.9 8.5-50 0.03-18 0.5-0.7s Nd 6.9-7.6
Raw
LBW
49
31.2 1.3 14 2.5 37.6 19.3 14.4 6 0.08 Nd 0.23
SD
-
17 0.63 95 7.8 277.8 25.1 22.7 Nd Nd Nd 6.1
Mea n
IBW
Negative
s-35 0.2-l 67.9-148 0.3-24.0 178.1-385.5 4.5-70 10-36.6 Nd Nd Nd s-7.7 -
Range
Bottled water
Table 3. Chemical composition (mg/L) and total coliform count @LPN/LOOmL) of municipal and bottled water samples.
13.4 0.33 36.1 9.6 86.6 30.9 11.4 Nd Nd Nd 1.4
SD
Drinking water quality in Al-Gassim,SaudiArabia
relatively higher in W W than in any of the water samples studied. However, the general mean for NO, concentration in this class lies within the permissible range of the 1984 Saudi standards(Table 2). Generally, the meansfor the concentrationsobtained for the chemical constituents of bottled water are in good agreement with the 1984 Saudi standards(Table 2). Exemptions to this generalization are a few measurementsthat fall above (Ca” concentration of IBW) or below (pH value of IBW) the 1984 Saudi standards for bottled water. Microbiological examination of the well water samples showed a high coliform count (MPN/lOOmL). The 1984 Saudi standard requires a negative coliform test for every 100 mL of water examined after treatment with chlorine to kill bacteria. This high count of coliform may be attributed to contamination of the hoses used by humans, including farmers and livestock owners, and to the exposureof thesedelivery hosesto dust storms. Previous workers, elsewhere, indicated that dust storms and livestock activity in the vicinity of surface wells increasesmicrobial loads and bacterial inputs (Stephensonand Street 1978; Hamad and Dirar 1982). On the other hand, the bottled water samples used in this study showed negative coliform tests (Table 3), which confirms that they are devoid of any fecal contamination. According to the manufacturers’ labels,thesewaters are treated either with ozone, U.V. light, or by reverse osmosis. Acknowledgment-The author acknowledgesthe assistanceof the technical staff of the Department of Soil and Water, College of Agriculture and Veterinary Medicine, El-Gassim,Buraydah.Special thanksareto Dr. Abd Rub El Nabi M. Abdel Hadi and Mr. ChnarJumaa Abu Jayabfor their unlimited assistance.
251
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