Risk for increased metal leakage due to ageing of landfills?

Abstract

As landfill ages, oxygen will start to penetrate, We investigated whether aeration of a landfill
affected metal leaching, We found that aeration increased cation exchange capacity, but
decreased the buffering capacity and the metal-binding capacity. Leachates from an aerated
landfill contained less than half the amount of aluminium and iron and more than double the
amount of calcium, sulphur and zinc than leachates derived from an identical, but anaerobic,
landfill. The leachate from the aerated landfill was capable of extracting metals from the
original landfill when recirculated. Leachate from the original landfill treated with leachate
from the aerated landfill contained more than twice as much cadmium, copper, iron, sulphur
and zinc than leachate from the identical anerobic landfill. We conclude that precautions
should be taken considering the fate of deposited metals when extrapolating results derived
from studies on landfills at earlier degradation stages to landfills in more progressed phases.