Invitro effects of fly ash on alveolar macrophages

The cytotoxicity of fly ash particles on alveolar macrophages were studied using an in vitro culture system. Rat alveolar macrophates were harvested from pulmonary lavage and incubated with fly ash particles for 24 h. The fly ash particles used for investigation were from two sources: coal-fired power plant (FA I) and municipal incinerator (FA II). The particle size distribution and the metallic contents (Cr, Cd, Cu, Fe, K, Mg, Mn, Ni, Pb and Zn) of the fly ash were measured. The levels of several metallic elements (Fe, Mg and Cr) were very high in both samples. FA II particles, however, have considerably higher concentrations (ten to hundred-fold) of Cd, Mn, Pb, Cu, K and Zn than FA I. FA II was found to be more toxic than FA I on cultured alveolar macrophages as indicated by the cell viability (trypan blue exclusion) and the amount of lactate dehydrogenase released into the culture medium. The difference in cytotoxicity of the two fly ash samples was confirmed under scanning electron microscope.