Risk for increased metal leakage due to ageing of landfills?

As landfill ages, oxygen will start to penetrate, We investigated whether aeration of a landfillaffected metal leaching, We found that aeration increased cation exchange capacity, butdecreased the buffering capacity and the metal-binding capacity. Leachates from an aeratedlandfill contained less than half the amount of aluminium and iron and more than double theamount 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 theoriginal landfill when recirculated. Leachate from the original landfill treated with leachatefrom the aerated landfill contained more than twice as much cadmium, copper, iron, sulphurand zinc than leachate from the identical anerobic landfill. We conclude that precautionsshould be taken considering the fate of deposited metals when extrapolating results derivedfrom studies on landfills at earlier degradation stages to landfills in more progressed phases.