Evaluation of bacteriological quality and essential elements in commercially bottled/packaged water produced and marketed in Southeastern Nigeria

The bacteriological quality and levels of essential mineral elements and organic acids were evaluated in 33 randomly selected bottled/packaged water samples produced and marketed in Southeastern Nigeria. The microbiological assay, essential mineral elements and organic acids were determined using American Public Health Association (APHA) standard methods. The distinguishing characteristics of the microorganisms identified were their psychotropic growth capabilities, motility at 37°C, growth in air, negative phenylalanine, deaminase, positive urease, catalase, oxidase and coagulase activities. Data obtained were compared with the accepted standards for safe drinking water as recommended by WHO/UNICEF. Some of the bacteria species recovered from the water samples included Escherichia coli, Bacillus subtilis and Staphylococcus aureus. The results show that only 9% of the samples investigated met the WHO/UNICEF standard of zero microbial load, 73% of the samples fell within 103 - 104 colony forming units (CFU)/100 ml, while 18% had the poorest with 106 CFU/100 ml. Major essential minerals found were calcium, sulphate, chloride, nitrate, bicarbonate and phosphate. Furthermore, the levels of these essential minerals were within the acceptable range in 76% of the samples while in others (24%) they were below the standard range recommended by WHO/UNICEF/APHA. There is need to maintain the approved standard level of chlorination in bottled /packaged water produced and sold in Southeastern Nigeria. Moreover, routine bacteriological quality assay by companies producing bottled/packaged drinking water should be enforced in Nigeria in particular and other developing countries in view of the findings in our study.