Researchers from the Department of Chemistry, Kwame Nkrumah University of Science and Technology (KNUST) have warned children and adults about the dangerous health effects of drinking rainwater from roofs.
Rainwater have been a source of water for a very long time. When water running through taps are no longer accessible, this becomes an alternative source.
However, scientist have said that drinking rainwater is unsafe due to the roofing materials.
The findings, published in the 2022 edition of the journal, Science of the Total Environment, addressed substances found in rainwater and how it can impact consumers’ health.
“We wanted to assess heavy metals concentration, physicochemical and bacteriological parameters in roof runoffs and estimate the water quality index and health risk these metals pose to consumers,” lead scientist, Prof. Osei Akoto said.
For the study, rainwater was harvested from Aluzinc, Aluminum, Galvanized, and Asbestos roofing materials within the Ejisu municipality. They also collected samples directly from the sky for comparison.
In conclusion, the scientist found heavy metals such as Cadmium, iron, chromium and some germs in the water which was above WHO standard. The Cadmium was found to pose the biggest risk.
“All runoffs from the four roofing materials recorded Cd, Fe, Cr, turbidity, pH, E.coli, total and fecal coliform levels above WHO limit for drinking water.
“Cadmium recorded the highest non-cancer health risk to children and adults in all the roof runoffs,” he explained.
“The estimated water quality index for runoffs from the four roofing materials exceeded 100 indicating their unsuitability for drinking.
“Hazard quotients of 9.53 and 4.08 were estimated for a child and an adult respectively via oral exposure to Cd in runoffs from Asbestos roofing material,” he said.
Meanwhile, the water collected directly from the sky was much safer.
“There was a significant variation in pH, EC, Zn, Cd, Cr, Fe, E. coli, total and fecal coliform levels between control samples and roof runoffs,” he noted.
The researchers therefore advised against drinking rainwater.