Abstract :
Treatment of healthcare waste either by incinerating or open burning in a pit produces bottom ashes which contains heavy metals and other chemicals which are toxic, persistent and accumulate in the food chain resulting in adverse health effects in human and the environment. The study investigated the level of heavy metals in the ashes of thermally treated medical waste from four health care facilities in Ghana. Two batch of the ash samples were collected from two hospital incinerators and the other two from medical waste burnt in an open-pit. The samples were collected on different days but within the same month, stored and transported to Water Research Institute laboratory
for heavy metals analysis. The concentrations of Pb, Cd, Cr and Hg were assessed using Atomic Absorption Spectrophotometry (AAS). The results proved that the concentrations of heavy metals were higher for the waste treated in the incinerator than those burnt in the open pit. The average
concentration of the metals in the ashes were in the following decreasing order Pb>Cr>Hg>Cd. The mean concentration of Pb from the incinerated bottom ash was 147.5mg/kg and Cd was 2.5mg/kg whilst the open pit was (69.67mg/kg) and (1.34mg/kg) respectively. All the metals investigated exceeded the Dutch and Danish limit values for maximum permissible levels of heavy metals in good
soil quality and therefore classified as harmful and toxic and therefore proper attention should be given to the ash disposal at the landfill sites.
Keyword :
Bottom ash; Ghana; Heavy metals; Healthcare waste; Incineration.