Bacterial characterization and quantification of rainwater harvested in a rural community in Nigeria

Abstract

This study investigated the bacteriological quality of rainwater (RW) harvested from storage facilities located in Ekpoma, a rural community in South-South Nigeria, and the possible health implications resulting from its intermittent or incessant consumption. In this study, 162 samples were collected from different storage devices located in Idumegbo, Ihumudumu, Ujoelen, Emaudo, and Ukpenu Extension areas. In total, ten (10) bacteria species namely: Escherichia coli (E. coli), Salmonella typhimurium, Bacillus subtilis, Micrococcus luteum, Klebsiella pneumoniae, Pseudomonas aeruginosa, Clostridium perfringens, Enterococcus faecalis, Proteus vulgaris, Yersinia pestis were predominant in the samples. Specifically, 30.2 % of the samples contained E. coli, 16.6 % contained Micrococcus luteum, 14.8 % contained Bacillus subtilis, 12.96 % contained Klebsiella pneumoniae, 11.1 % contained Salmonella typhimurium, 7.41 % contained Clostridium perfringens, 3.7 % contained Proteus vulgaris and Yersinia pestis, and 1.85 % contained Pseudomonas aeruginosa and Enterococcus faecalis. The bacterial load (Heterotrophic Plate Count) measured in the water samples varies widely between 292 x 104 CFU/mL to 2455 x 104 CFU/mL, while E.coli count were in the range of 40 x 104CFU/mL to 884 x 104CFU/mL for all districts in both open and closed tanks. The ANOVA and Welch two sample t-test conducted for open and closed tanks also showed no statistical difference in E. coli counts across all locations (p < 0.05). These results suggest that both the open and closed tanks are affected by multiple sources of pollution, and that airborne pollutants are not a major contributor to E. coli contamination. This further indicates that legacy bacterial contamination plays a significant role in the contamination process. The findings of this study demonstrate that the water is unfit for drinking and constitutes a serious threat to public health. Therefore, chlorination, boiling before use, following best management practices (BMPs) and non-structural management measures (nSMMs) developed at a rural, location-specific scale are progressive and proactive measures can be introduced to prevent or reduce contamination.