The potential leachability from natural road construction materials

Leaching characteristics are used for the evaluation of waste materials in road construction. Few leaching tests have been performed on natural rock m aterials which implies that there is a lack of data to be used in compariso n with waste materials. In order to form a basis for comparison of the leac hability, nine natural road construction materials in Sweden were investiga ted using the availability test NT ENVIR 003. The results show that the lea chable amounts of heavy metals and sulphur generally are very small, but un der oxidising conditions the solubility of sulphide bound elements increase s notably. Vanadium and chromium are probably present as ionic substitutes for other elements in mineral lattices and show very low leachability. The leachable amounts of some heavy elements, e.g. zinc, nickel and copper are higher in the rock materials and gravels than in the blast furnace slags. ( C) 1999 Elsevier Science B.V. All rights reserved.