MICROBIAL ANALYSIS OF WATER OBTAINED FROM OVERHEAD TANKS IN KARU, NASARAWA STATE, NIGERIA

Abstract

Globally, at least 2 billion people use a drinking water source, which is contaminated, as reported in WHO guidelines for drinking water. It is even more critical for human beings as they depend upon it for food production, industrial and waste disposal, as well as a cultural requirement. Here in Nigeria it is a common practice to construct water storage tanks using plastic, metal or concrete. Water being the most important natural resources to plants and animals alike, Water storage is a necessity especially in developing nations or regions where there is lack of constant water supply. However, concern has risen over the safety of stored water over a long period of time as this could breed micro-organisms. This study was conducted to determine the quality of water stored externally in storage tanks. Water samples were obtained from 7 different storage tanks at homes in Karu local government area, Nasarawa state. The water samples were investigated for microbial presence, using series of biochemical tests. The viable bacterial, total coliform and faecal coliform counts were taken via the use of standard plate count method and differential media. A total of 7 bacteria were isolated from the stored water samples collected. The bacterial isolates were: Escherichia coli, Staphylococcus epidermis, Streptococcus spp., Micrococcus luteus, Enterobacter spp., Staphylococcus aureus and Enterococcus luteus. The total coliform and faecal coliform ranged from 4.3 to 62.0 and 6.0 to 24.7 cfu/ml respectively. A fungi count was also carried out ranging from 0.3 to 32.0 cfu/ml. A total of 5 fungi isolates were identified, which include Penicillium spp., Aspergillus niger, Aspergillus flavus, Trichoderma spp, and Mucor using microscopic and macroscopic evaluation. The study revealed that the quality of water in storage tanks depends on the source from which it was drawn and the handling of the tank by its users. Recommendations were made that good quality water from borehole should be stored and storage tank owners clean their tanks 3 or more times per year.