TITLE:
The Effect of the Challawa Industrial Estate on the Physicochemical Properties and Heavy Metal Levels of Portable Water Supply in Kano Metropolis, Nigeria
AUTHORS:
Abdulrahman Audu, Abdulhakeem Idowu
KEYWORDS:
Heavy Metals, Industrial Estate, Kano Metropolis, Water
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.3 No.2,
April
1,
2015
ABSTRACT: 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.