RESULTS

The resultsrevealed that pH ranged from 8 to9. Minimum pH (8.0 ± 0.11) was observed from Ramsinghpura village and Maximum (9.0 ± 0.14) was observed from Sukhiya village (Table 1 and Fig. 1). pH is expressed as a number ranging from 0-14. The number is an expression of the concentration of H⁺ ion in the solution. All water samples were found to be within limit but alkaline in nature (Table 2). pH showed positive correlation with fluoride and negative correlation with other parameters (Table 3).

Trivedi (1988) also reported fluoride concentration associated with alkalinity. According to WHO (1996), the permissible limit for pH is 6.9 to 9.2. Fluoride (F^-) variedfrom 0.2 to5.4 ppm. Minimum (0.2 ± 0.08 ppm) and maximum (5.4 ± 0.11 ppm) concentration of Fwas observed from Ramsinghpura and Sukhiya villages respectively (Table 1, Fig. 2). Permissible limit for F^- concentration is 1-1.5 ppm according to WHO (1996). The data revealed that 10% villages of Sanganer Tehsil are affected with high concentration of F^-, whereas 42% villages had lower F^- content. However, 48% villages contained optimum limit of fluoride concentration (Table 2). A positive correlation (r=+0.893) was observed between F and pH (Fig. 3) as earlier reported by Teotia and Singh (1981) and Trivedi (1988).

EC is a numerical expression of ability of an aqueous solution to carry electric current. USPH recommended permissible limit for electrical conductivity (EC) is 300 µmhos/cm. The values of EC ranged from 483-9570 µmhos/cm. Minimum (483 ± 36.68 µmhos/cm) and maximum (9570 ± 161.65 µmhos/cm) EC was reported from Sukhiya and Ramsinghpura villages respectively (Table 1 and Fig. 4). By analyzing the results, all water samples showed EC higher than permissible limit (Table 2). EC signifies the amount of TDS in water. Findings of the present study were in agreement with the results of the survey conducted by Gupta et al. (1994). The total dissolved solids (TDS) in drinking water reveal the saline behaviour of water, which indicates the organic pollution level of water. TDS ranged from 242 to 4650 mg/l. Minimum (242 ± 39.26 mg/l) and maximum (4650 ± 254.03 mg/l) concentration of TDS was observed from Sukhiya and Ramsinghpura villages respectively (Table 1 and Fig. 5). According to WHO (1996), TDS should be between 500-1500 mg/l. TDS was found to be within limit in 72% villages, lower in 12% villages, whereas 16% villages showed TDS higher than limit (Table 2). In this study, significant positive correlation (r=+0.995) was observed between EC and TDS (Table 3, Fig. 6). Calcium hardness (Ca-H) ranged from 4 to 172 mg/l. Minimum Ca-H (4 ± 1.15 mg/l) was observed from Sukhiya village whereas maximum Ca-H (172± 6.92 mg/l) was reported from Ramsinghpura Village. Magnesium hardness (Mg-H) ranged from 2 to 132 mg/ l. Minimum (2 ± 1.15 mg/l) and maximum (132 ± 6.92 mg/l) values were reported from Sukhiya and Ramsinghpura villages respectively. Ca-H and Mg-H combined to form total hardness. TH varied from 90 to 700 mg/l. Minimum (90 ± 24.24 mg/l) and maximum (700± 57.74 mg/l) was reported from Sukhiya and Ramsinghpura villages respectively (Table 1 and Fig. 7). WHO recommended safe permissible limit for hardness i.e. 100-500 mg/l (Table 2). In groundwater, hardness is mainly due to carbonates, bicarbonates, sulphates and chlorides of Ca and Mg. Ca H was within permissible limit in 14% villages whereas 86% villages contained Ca H below than limit (Table 2). Mg-H was below than limit in 50% villages and 50% villages showed Mg-H within optimum limit. Total hardness was higher in 6% villages; below than limit in 6% villages whereas 88% samples contained TH within optimum limit (Table 2). In this study, hardness showed negative correlation with F- and pH (r= -0.544; r= -0.702) (Table 3 and Fig. 8). The results are in agreement with the findings of Trivedi (1988) and Sharma (2003). Chloride (Cl) varied from 42 to 2173 mg/l. Minimum (42 ± 6.92 mg/l) was reported from Sukhiya village and maximum (2173 ± 99.88 mg/l) was observed from Ramsinghpura village (Table 1 and Fig. 9). The chloride content was higher than permissible limit (200-600 mg/l) in 10% villages whereas lower in 82% villages. Only 8% villages were within optimum limit (Table 2). High content of chloride gives salty taste to water. Carbonate (CO₃ ^-2 ) ranged from 24 to 216 mg/l. At some villages CO₃ ^-2 concentration is negligible. Minimum (24 ± 6.92 mg/l) and maximum (216 ± 11.55 mg/l) content of CO₃ ^-2 was observed from Bhapura, Girdharipura Chak Nos. 1,2,3,4,5,8,14, Khatipura and Ramsinghpura respectively. Minimum bicarbonate (HCO3 -) (49 ± 6.35 mg/l) observed from Lalya ka bas village and maximum (1244 ± 87.18 mg/l) was reported from Ramsinghpura village. CO₃ ^-2 and HCO3 - together make total alkalinity.

It ranged from minimum (49 ± 6.35 mg/l) Lalya ka bas to maximum (1460 ± 98.72 mg/l) from Ramsinghpura villages (Table 1 and Figure 10).Alkalinity washigherthan permissible limiti.e. (200 mg/l)in 98% villages,only 2% villages contained alkalinity belowthan limit (Table2). Alkalinity showedpositive correlation with EC, TDS, Cl, TH, NO₃^- , Na⁺ and K⁺ (Table 3). The results are in agreement with the results of Devi et al. (2003). High values of alkalinity give undesirable taste to water.

Minimum (39 ± 2.88 mg/l) and maximum (1000 ± 58.31 mg/l) Sodium (Na⁺) content was observed from Sukhiya and Ramsinghpura villages respectively (Table 1 and Fig. 11). Almost all the villages (98%) contained higher concentration of Na⁺ except in Sukhiya village wherein it was below limit. The acceptable limit for Na⁺ is 50 mg/l according to WHO (Table 2). Potassium (K⁺) content of water samples varied from 0.782 to 10.557 mg/l. Minimum (0.782 ± 0.22 mg/l) and maximum (10.557 ± 1.62 mg/l) K⁺ content were observed from Mandau and Ramsinghpura villages respectively (Table 1, Figure 12). All the water samples (100%) contained K⁺ content lower than permissible limit i.e. 20 mg/l (Table 2). Minimum (6 ± 1.15 mg/l) and maximum (202 ± 1.15 mg/ l) nitrate (NO₃^- ) content was observed from Narottampura and Ramsinghpura villages respectively. At two villages (Sukhiya and Mandau) NO₃ was in trace amount (Table 1 and Fig. 13). NO₃ content was lower than permissible limit (40-50 mg/l) in 64% villages; 10% were within limit whereas 26% villages had NO₃ concentration higher than limit. Higher concentration of NO₃ in water causes a disease called “Methaemoglobinaemia” or known as “Blue-baby Syndrome”. It is particularly infant disease upto 6 months of child (Agrawal, 1999).

DISCUSSION AND CONCLUSION

The data indicate that the groundwater of Sanganer Tehsil is highly deteriorated as it is polluted with high amount of fluoride, nitrate and alkalinity. Most of the parameters were either more than permissible limit or below limit. Therefore, the drinking water of villages of Sanganer Tehsil is not potable. To maintain quality of groundwater, the continuous monitoring of physicochemical parameters should be done and can be used for cooking and drinking only after prior treatment.

ACKNOWLEDGEMENT

Authors are thankful to State Ground Water Department, Government of Rajasthan and Head, Department of Zoology, University of Rajasthan, Jaipur for providing necessary facilities.

REFERENCES