Analysis of the impact of weathering conditions on the leachability of selected heavy metals from municipal solid waste incineration residues

The management of municipal solid waste incineration (MSWI) residues may represent an environmental challenge, particularly in the case of fly ash, due to their hazardous properties. These residues can contain high concentrations of heavy metals, which may be released into the environment through leaching processes, particularly under the influence of climatic factors. Due to the toxicity of heavy metals, improper management of MSWI residues can lead to soil and water contamination. The aim of this study was to analyze the impact of temperature and humidity variations, as well as aging processes including UV irradiation, on the changes in release of barium (Ba), chromium (Cr), copper (Cu) and zinc (Zn) from bottom and fly ashes. To evaluate these changes, a batch leaching test was conducted. The analysis of changes in the forms of heavy metals was also considered in the speciation study. The simulation of environmental factors was carried out in specially designed climate and aging chambers. The results indicate a relationship between the analyzed atmospheric conditions and the leaching levels of Cr, Cu, and Zn. However, no clear trend in the leaching behavior of these heavy metals could be established. An increase in the release of Cr and Zn under temperature variations, including freezing and thawing, was observed in one type of sample (bottom ash). Under the influence of aging conditions, an increase in the leachability of Cr and Cu was noted for both bottom ash and fly ash. In contrast, a tenfold decrease in leachability was observed for Zn in fly ash. The results of this research could contribute to a better understanding of heavy metal mobility in MSWI residues under selected environmental exposure conditions and provide useful information for their environmental assessment and management. Weathering simulation of MSWI residues