Drinking roof runoffs can cause serious health problems in children and adults.
That is the conclusion of a study conducted by experts at Kwame Nkrumah University of Science and Technology's Department of Chemistry (KNUST).
Rainwater harvesting is an alternative source of water in Ghana, where many families do not have access to potable water.
The roofing materials, on the other hand, have been found as having an impact on the water quality.
The study, which was published in the journal Science of the Total Environment in 2022, looked for specific compounds and how they may affect people's health.
"We intended to examine heavy metal concentrations, physicochemical, and bacteriological characteristics in roof runoffs, as well as estimate the water quality index and health risk these metals offer to consumers," says the study's primary author.
Rainwater was collected in the Ejisu municipality from Aluzinc, Aluminum, Galvanized, and Asbestos roofing materials.
As a contrast, the scientists utilized rainfall gathered directly from the sky.
Heavy metals including Cadmium, iron, and chromium, as well as certain viruses, were discovered to be above the WHO threshold.
Cadmium in runoff from asbestos roofs, for example, was discovered to be the most dangerous.
"Cd, Fe, Cr, turbidity, pH, E.coli, total, and fecal coliform levels were all over the WHO guideline for drinking water in all runoffs from the four roofing materials."
"Of all the roof runoffs, cadmium recorded the highest non-cancer health risk to children and adults," he stated.
"Runoffs from the four roofing materials had an estimated water quality index of over 100, suggesting that they were unfit for consumption."
"Oral exposure to Cd in runoffs from Asbestos roofing material resulted in hazard quotients of 9.53 and 4.08 for a toddler and an adult, respectively," he stated.
The water taken directly from the sky, on the other hand, was far safer.
"There was a substantial difference between control samples and roof runoffs in pH, EC, Zn, Cd, Cr, Fe, E. coli, total and fecal coliform levels," he said.
As a result, the researchers advise against drinking rainwater.