Leaching morphology characteristics and environmental risk assessment of 13 hazardous trace elements from municipal solid waste incineration fly ash

Fly ash from municipal waste incineration contains large amounts of hazardous trace elements. In this study, the total contents and chemical forms of 13 hazardous trace elements (Hg, As, Se, Pb, Cd, Cr, Mn, Ni, Cu, Zn, Ba, Co and Sb) in MSWI fly ash during one week were analyzed in order to reveal their environmental leaching risk and migration capacity. The contents of the different trace elements varied greatly, with the lowest amount, only 3.75 mu g/g, recorded for Se and the highest amount of up to 2009.43 mu g/g for Zn. The effective fractions of all elements exceeded 20%, and the effective fraction of Cd was as high as 97.16%. The risk of each trace element in MSWI fly ash was evaluated using the RAC method and Nemerow Pollution Index method. The RAC evaluation showed that all trace elements pose at least a low risk to the environment. The Nemerow Pollution Index analysis indicated that the risk of Cd and Sb is extremely high and results in a "Seriously polluted" risk level for the combined fly ash contamination. Therefore, suitable measures should be taken to avoid harm to the surrounding environment before MSWI fly ash is discharged.