Three years of leachate emissions from munici
pal solid waste incineration bottom ash and crushed rock in a full-scale test road were evaluated. The im
pact of time, construction design, and climate on the emissions was studied, and the
predicted release from standard leaching tests was com
pared with the measured release from the road. The main
pollutants and their res
pective concentrations in leachate from the roadside slo
pe were Al (12.8–85.3 mg l
p>−1p>), Cr (2–125 μg l
p>−1p>), and Cu (0.15–1.9 mg l
p>−1p>) in ash leachate and Zn (1–780 μg l
p>−1p>) in crushed rock leachate. From the ash, the initial Cl
p>−p> release was high (
p://www.sciencedirect.com/scidirimg/entities/223c.gif" alt="not, vert, similar" border=0>20 g l
p>−1p>). After three years, the amount of Cu and Cl
p>−p> was in the same range in both leachates, while that of Al and Cr still was more than one order of magnitude higher in ash leachate. Generally, the release was faster from material in the uncovered slo
pes than below the
pavement. Whether the road was as
phalted or not, however, had minor im
pacts on the leachate quality. During rain events, diluted leachates with res
pect to, e.g., salts were observed. The leaching tests failed to simulate field leaching from the crushed rock, whereas better agreement was observed for the ash. Com
parisons of constituent release from bottom ash and conventional materials solely based on such tests should be avoided.