Incineration of different types of medical wastes: emission factors for particulate matter and heavy metals.

Previously published results for emission factors of medical waste incineration do not include enough information about the incinerated waste composition. This paper reports the first emission factors estimated for particulate matter, As, Cd, Cr, Pb, Mn, Hg, and Ni, considering that medical waste is segregated in different types according to Portuguese legislation. The main purpose was to evaluate the influence of incinerated waste composition and segregation practice on emission factors. One "controlled-air" incinerator without air pollution control devices was used for the incineration either of mixtures with a defined composition or of a specific waste type. Previously published emission factors are not associated with the composition of the incinerated mixture, and the results showed that the usefulness of those emission factors is very doubtful. The existence of different waste classifications also reduces the usefulness of previously published results. To protect human health, appropriate equipment to control atmospheric pollutants must be used, since the legal limits for pollutant concentrations were strongly surpassed (226 times higher than the limit for Hg), with risks for patients and workers of the hospital and exposed population. It was concluded that rigorous segregation practices and adequate management methodologies allow reducing 80% of the amount of wastes that must be incinerated, practically eliminating Hg and Pb emissions and reducing those of PM, As, Cd, Cr, Mn, and Ni, respectively, 98, 90, 92, 84, 77, and 92%.