Assessment of Heavy Metals in the Bottom Ash from Incineration of Medical (Sharp) Waste

Abstract

The bottom ash produced during incineration contains toxic heavy metals that can persist for a long time in the environment and accumulate in the food chain; when indiscriminately disposed of, it can adversely affect public health. The study aimed at assessing the level of heavy metals in the bottom ashes produced during the incineration of sharp medical waste. Bottom ash samples were collected from the ash pit of the incinerator twice a month for four months (two months in the rainy and two months in the dry season) in triplicates. Five grams of the sieved samples were analyzed for cadmium (Cd), chromium (Cr), Nickel (Ni), iron (Fe), lead (Pb), Copper (Cu), and zinc (Zn) using atomic absorption spectrophotometer. The mean concentrations of these heavy metals during the study period in decreasing order were Fe (18,504.66) > Zn (16,292.11) > Cr (374.47) > Pb (179.78) > Cu (128.91) > Cd (1.28) > Ni (0.50) mg/kg. The concentrations of the assessed heavy metals in the bottom ash samples obtained were compared with notable international guidelines, and it was deduced that the concentrations of all the heavy metals were above the acceptable limits except for Nickel, whose concentration was below the limit set for it.