Leaching of per- and polyfluoroalkyl substances (PFAS) from municipal solid waste incineration bottom ash intended for utilization as secondary aggregates in road subbase

Ten samples of mineral fraction derived from waste incineration bottom ash (MIBA) from Denmark (N = 7), Sweden (N = 1), and the Czech Republic (N = 2) underwent targeted analysis of 59 per- and polyfluoroalkyl substances (PFAS) in the solid phase and eluates from a batch leaching test at a liquid-to-solid ratio of 2 L/kg. The solid content, expressed as Sigma 59PFAS(S), ranged from 0.21 f 0.03 mu g/kg DM to 21.6 f 1.47 mu g/kg DM. The leached amounts, expressed as Sigma 59PFAS(L), ranged from 204 f 63 ng/kg DM to 3250 f 77 ng/kg DM. The results of the leaching tests were normalized to "PFOA-equivalents" (PFOA-eq) and used to estimate the bulk leaching emissions from the utilization of MIBA in typical road construction scenario. The calculated bulk leaching emissions associated with the utilization of 100 thousand tons of MIBA in road subbase were 6-30 g PFOA-eq per 10-21 years (Danish MIBA), 30 g PFOA-eq per 10-22 years (Swedish MIBA), and 271 g PFOA-eq per 14-30 years (Czech MIBA) depending on the effective infiltration and annual precipitation rates. This first approximation of the source term provides invaluable information for assessment of the environmental impact of MIBA utilization beyond landfill applications, pending further validation by subsequent research.