Paintcrete leachability in fresh water and marine environments

Waste latex paint is considered the largest (by volume) household liquid hazardous waste collected in Canada and the USA. A technology for recycling latex paint in Portland cement concrete with added value was developed at The University of Western Ontario. The present study investigates the leaching of hazardous species from concrete incorporating recycled paint, known as ‘paintcrete’ as a partial replacement for mixing water. Specimens from concrete mixtures with various proportions of paint were subjected to simulated field environments including freezing–thawing and wetting–drying cycles, both in fresh and simulated seawater. The leachates from these specimens were analysed for heavy metals and glycols. It was found that the leaching of heavy metals from concrete specimens incorporating 15–25% paint and subjected to wetting–drying and freezing–thawing cycles, either in fresh water or artificial seawater, was not significant compared with values measured for a reference concrete mixture with no paint. The leaching concentrations of heavy metals were well below the contaminant levels according to the hazardous waste regulatory limits. In addition, glycol concentrations in the leachates at the end of a total of 100 cycles of freezing–thawing were much lower than the concentration of glycols in the original paint. Glycol leachates were also found to be acceptable based on environmental guidelines for glycols in surface water.