Effect of Rainfall Variability on pH and Electrical Conductivity of Springs and Groundwater in Zanzibar Urban West Region

Authors

  • Abdul A. J. Mohamed
  • Ibrahim Abdul Rahman Faculty of Science (FOS) Universiti Brunei Darussalam Jalan Tungku, Brunei Darussalam
  • Lee H. Lim Faculty of Science (FOS) Universiti Brunei Darussalam Jalan Tungku, Brunei Darussalam

Keywords:

Zanzibar, rainfall, Electrical conductivity, pH

Abstract

This study reports on an analysis conducted to determine the effect of rainfall on pH and electrical conductivity (EC) of Zanzibar groundwater sources. In June 2012, thirty water samples were collected from spring and underground water sources for fecal coli (FC) and total coli (TC), alkalinity, phosphate (PO4-P) and ammoniacal nitrogen (NH4-N) analysis. The Palintest photometer procedures were used to determine the levels of alkalinity, PO4-P, and NH4-N, while FC and TC were analyzed following the standard methods for the examining water and wastewater, method 909A. In August and October 2012, Horiba multiparameter meter was used to measure EC and pH levels in water samples. The levels of PO4-P, NH4-N, and alkalinity in water samples were in the range of 0.08-5.15 mg L-1, 0.03-6.71 mg L-1 and 47- 430 (as mg L-1 CaCO3) respectively. During dry period, the lowest and the highest EC levels were 181.02 µS cm-1 and 6180 µS cm-1 respectively, while 167.36 µS cm-1 and 7985.03 µ /cm-1 were the respective lowest and highest EC levels measured during wet period. The variation of pH levels during dry and rainy period were in the range of 6.31- 8.30, and 7.13 - 8.44, respectively. During dry and wet period, 40% and 17% of the samples respectively had EC level beyond the guideline recommended by World Health Organization (WHO). 33% of the water samples were free from FC and TC contamination. FC and TC contaminated 43% and 67% of the water sources respectively. The presence of FC, TC and elevated levels of EC in some of water samples warns for the groundwater quality thus rendering them unsafe for human consumption.

 

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Published

2014-02-14

How to Cite

Mohamed, A. A. J., Rahman, I. A., & Lim, L. H. (2014). Effect of Rainfall Variability on pH and Electrical Conductivity of Springs and Groundwater in Zanzibar Urban West Region. Asian Journal of Applied Sciences, 2(1). Retrieved from https://ajouronline.com/index.php/AJAS/article/view/898