Assessment of combustion products of medical waste incinerators in Alexandria

ABSTRACT

The emissions and ashes from medical waste incinerators might perform a threat to the environment and the public health. The aim of the present work is to evaluate the emissions and ashes of six medical wastes incinerators in six hospitals in Alexandria. Five air pollutants were sampled and analyzed in the emissions comprising smoke, lead, carbon monoxide, sulphur dioxide and nitrogen dioxide.Ash samples were analyzed for bacterial count, volatile substances, lead and cadmium. Shape and color of ash were observed visually. The results of the present study have revealed that all the average values of gases in the six incinerators were within the limits stated in Egyptian environmental law, where as carbonaceous particulate [smoke] averages of the six incinerators have exceeded the maximum allowable limit in the law. On the other hand, lead concentration in emissions were far below the maximum allowable limit in the law. Incinerator No6 emissions have been significantly higher in CO, NO 2, SO 2 and smoke concentration than the other five incinerators P<0.001, P<0.0006, P<0.0001, and P<0.002 respectively. There was no significant variation in bacterial count of ash samples at 20°C and 37°C between the six studied incinerators. Volatile substance percentage of ash samples in the six incinerators were much higher than the recommended percentage. There was a highly significant variation between the six incinerators [p<0.005]. Lead and cadmium concentrations in ash samples were much higher than those in developed countries, meanwhile, more or less as those in developing countries. It is recommended to state specific realistic emissions limits for medical waste incinerators and to substitute sporadic incinerators in hospitals by two central incinerators in proper places outside the city