Groundwater pollution risk from incinerated health-care waste bottom-ash at a national teaching and referral hospital in Kenya

Abstract

The bottom-ash left after incinerating health-care waste may contain heavy metals which may leach and pollute the environment if not properly disposed of. Bottom ash samples were taken from Moi Teaching and Referral Hospital incinerator, and disposal pit ashes from an excavation of an adjacent abandoned pit. Concentrations of total chromium, cadmium, lead, silver and mercury were analyzed with Atomic absorption spectrophotometer. Concentration of the heavy metals in the bottom ash and soils were found to exceed the maximum levels specified by National Environmental Management and Co-ordination Act and European Union Standards. There was evidence of heavy metals leaching from pit-ashes and permeating along the ground profile. These were traced at intervals of 250mm along the 2m excavated profile. The disposal pit was not lined making it possible for the leaching heavy metals to permeate and pollute the groundnut whose phreatic surface was at 2m depth.