Alternative construction materials from industrial side streams: Are they safe?

The global population is continually generating vast amounts of waste materials across various sectors, leading to environmental challenges associated with landfill disposal. This study aims to examine the leachate and the antimicrobial properties of several waste materials to explore their potential applicability in the construction industry. Here, ICP-OES analysis and Kirby Bauer test were conducted on ready-mix concrete plant (powder residues), precast industries, recycled alkali-activated materials, municipal solid waste incinerated (MSWI) bottom ash, MSWI fly ash, High alumina tailing, and High magnesia tailing, to explore their potential applicability in the construction industry. Aluminium, calcium, silicon, potassium, and magnesium were the major ions leached from the waste materials, with MSWI fly ash and bottom ash showing higher levels of heavy metal leaching. The levels of leached aluminium, barium, chromium, lead, and zinc from MSWI fly ash and bottom ash were quantified, with values reaching up to 28.7 ppm, 4 ppm, 3.9 ppm, 11 ppm, and 25 ppm, respectively. Additionally, all samples demonstrated some level of antimicrobial activity against Escherichia coli and Staphylococcus aureus, which could be related to their alkaline pH and the release of certain ions. Improper disposal of waste materials in an open environment can potentially lead to contamination by heavy metals and harmful bacteria, which can pose a significant health risk during handling. This study results provided valuable information regarding the safety of using these wastes in the construction industry.