Quality and Health Risk Assessment of Harvested Rainwater Collected from Corrugated Iron Rooftops in Gashaka Lamorde, Mubi, Adamawa State, Nigeria

Abstract

This study assessed the quality of rainwater harvested from corrugated iron rooftops in Gashaka Lamorde, Mubi Metropolis, Adamawa State, Nigeria, to determine its suitability for domestic use and evaluate associated health risks. Rainwater samples were collected from selected locations during the rainy season between May and September. Standard analytical procedures were used to determine physicochemical parameters, heavy metal concentrations, and microbiological quality, while health risk assessment models were applied to evaluate carcinogenic and non-carcinogenic risks in adults and children. The results showed variations in water quality across sampling locations and periods. Most physicochemical parameters were within recommended drinking water standards, while heavy metals detected were generally below permissible limits. However, total coliform bacteria were detected in several samples, indicating microbial contamination likely associated with rooftop debris and environmental pollutants. Non-carcinogenic health risks were generally within acceptable safety limits, although children showed relatively higher exposure risks than adults. Carcinogenic risk values were mostly within internationally acceptable limits. Overall, harvested rainwater from corrugated iron rooftops in the study area can serve as an alternative domestic water source, but routine monitoring, proper rooftop maintenance, and appropriate treatment before consumption are recommended to ensure public health safety.