Microbial and Heavy Metal Evaluation of Sachet Drinking Water in the Hohoe Municipality, Ghana

Aim: To study microbial and heavy metal composition in sachet drinking water in the Hohoe municipality in the Volta Region of Ghana.

Place and Duration of Study: The study was conducted in the Hohoe Municipality in the Volta region of Ghana and laboratory analyses were carried out at the Microbiology laboratory of the Department of Biochemistry and Biotechnology, Kwame Nkrumah University of Science and Technology between June 2018 and May 2019.

Study Design: Cross-sectional study.

Methodology: The study was conducted on three samples each of eight different brands of sachet water randomly selected across various towns from street vendors in the Hohoe Municipality for microbial and chemical analyses. 10ml of each sample was aliquoted under sterile conditions and cultured overnight in nutrient media. Enumeration and qualitative analyses of bacteria were performed using the pour plate method. For heavy metal analysis, 5 ml of concentrated HNO3 was added to 40 ml of each sample and heated at 100 °C for 20–30 minutes to reduce the volume to 20 ml. 30ml of distilled water was subsequently added and the mixture was analyzed using flame atomic absorption Spectroscopy.

Results: Out of total twenty-four samples analyzed, 50% of the sachet water was contaminated with total and fecal coliforms with the highest average coliform forming unit (cfu/ml) being 16.2 x 105 cfu/ml and the least 0.01 x 105 cfu/ml. There were Klebsiella spp, and Pseudomonas aeruginosa contamination in 50% of the sachet drinking water but Salmonella spp and E. coli were absent in all brands. Chromium was detected to be within the range of 0.40mg/L - 0.56mg/L in the sachet water while zinc was in the range of 0.03mg/L– 0.94mg/L. Chromium concentration in all sachet brands were above the WHO standard while zinc was within the acceptable range. Cadmium and lead were below detectable limits (BDL).

Conclusion: This study indicated that some of the sachet drinking water sold in the Hohoe Municipality is impure for human consumption. Inappropriate water purification procedures and improper handling of sachet water play a significant role in determining the overall quality of sachet drinking water.