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《地球科学和环境保护期刊（英文）》
>The Effect of the Challawa Industrial Estate on the Physicochemical Properties and Heavy Metal Levels of Portable Water Supply in Kano Metropolis, Nigeria
The Effect of the Challawa Industrial Estate on the Physicochemical Properties and Heavy Metal Levels of Portable Water Supply in Kano Metropolis, Nigeria
It has been observed that the portable water quality obtained from various locations in Kano Metropolis has shown greater variations in the recent past. Attempts have been made to ascertain the reasons for the variations even though the supplies were from only two treatments plants that obtain their raw water from the same source. A total of 92 water samples comprising of raw (from plants) and treated (from the plants and taps) were collected during rainy and dry seasons between April 2010 and May, 2012 and analyzed using standard analytical techniques. The results of analysis gave the physiochemical properties with range as follows: pH (0.06 ± 6.7 - 6.04 ± 0.02) conductivity (7.23 ±0.04 - 13.33 ± 0.22 S/Cm), turbidity (5.00 ± 0.01 - 449.22 ±1.32 NTU), suspended solids (107.33±3.45 - 712.11 ±5.33 mg/dm3), total dissolved solids (18.50 ± 0.85 -186 .78 ± 2.48 mg/dm3 ), alkalinity (12.53± 0.32 - 80.75 ± 1.23 mg/dm3) and hardness (29.50 ± 1.22 - 58.67 ± 2.34 mg/dm3). The pH values were generally acidic while the turbidity and total solid especially in some locations were higher than the permissible levels set by the World Health Organization for portable water. The concentration of heavy metals (mg/dm3) were found in the following ranges Fe (0.10 ± 0.04 - 0.30 ± 0.02), Cu (0.01 ± 0.001 - 0.03 ± 0.002), Zn (0.13 ± 0.06 - 0.39 ±0.02), Pb (0.03 ± 0.01 - 0.17 ± 0.02), Mn (0.03 ± 0.004 - 0.13 ± 0.003), Cr (0.10 ± 0.04 - 0.31 ± 0.03). The highest values of Fe, Cu and Mn were recorded along the older distribution channel of Challawa. The levels of Pb and Cr were generally high in both routes which are also observed in the raw water used at the two treatments plants. The results obtained from heavy metal concentrations fell within the maximum allowable limit set by the World Health Organization for portable water except in the cases of Pb and Cr. The high Fe, Mn, Cu levels as obtained in the Challawa route were attributed to leaching from rusting in the old galvanized metal pipe-work in the distribution channel. The levels of chromium and lead were similar in the two networks showing that the raw water used in the both treatment plants were responsible for the high values obtained and were not effectively removed by the treatment processes.
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