Assessment of Physicochemical and Microbiological Characteristics of Rainwater Harvested from Different Rooftops in Owerri, Imo State, Nigeria

Abstract

Assessment of physicochemical and microbiological characteristics of rainwater harvested from different rooftops in Owerri, Imo State was carried out using standard methods. Rainwater samples collected from different rooftops were analyzed for quality and compared to the standard for World Health Organization (WHO) and the National Standard for Drinking Water Quality (NSDWQ). Rainwater was also collected directly from the rainfall and analyzed. The result of the physicochemical parameters showed that only the rainwater harvested from asbestos rooftop had the pH value that falls within WHO standard and NSDWQ. The turbidity value of rainwater harvested from the thatched rooftop was higher than the WHO standard and NSDWQ. Organisms isolated from the rainwater samples harvested from the rooftops include Pseudomonas aeruginosa, Escherichia coli, Klebsilla pneumonia, Entrobacter sp., Proteus mirabilis, Aspergillus sp., Penicillum sp., and Vibro sp. However, after molecular studies, K. pneumoniae, P. aeroginosa, E. coli, and P. mirabilis were the four bacterial species identified. The rainwater samples had high levels of microbial loads against WHO standard and NSDWQ. Rainwater sample from thatched rooftop had the highest total heterotrophic count (THC) but all the studied rainwater samples had THC higher than WHO standard and NSDWQ. The rainwater harvested directly from rainfall had low values for the physicochemical parameters and microbial loads considered in this study, when compared to the rainwater samples harvested from the rooftops. The bacterial and fungal isolates of rainwater samples from the rooftops have been associated with different diseases. There is a need to treat harvested rainwater properly before domestic or potable use. This study has assessed the physicochemical and microbiological characteristics of rainwater harvested from different rooftops in Owerri, Imo State, Nigeria.