Preliminary assessment of three new European leaching tests

Leaching tests are used for characterization purposes and are indispensable for characterization of waste- and building materials. In several countries the use of leaching tests is settled by legislation. Since Europe is becoming a more united community, legislation becomes more and more harmonized as a logical next step in a more European approach towards environmental issues. In this study a comparison is made between three leaching tests, which are being developed in CEN technical committee 292. The percolation test is basically a column filled with granulated material, which is percolated with simulated rainwater for 3 weeks. The amount of water corresponds to 10 times the amount of solid; the eluate is sampled in several fractions. The second test is the pH-stat test in which pulverized material is leached for 24 h at eight different pH-values with the same liquid/solid ratio of 10. The third test reported is the shake test, in which the maximum leachable amount is being investigated at the materials own pH-value. For this purpose pulverized material was used and the total amount, of water had again the same liquid/solid ratio of 10. A comparison was made in exchangeability of produced data. The results of the leaching experiments were comparable within limits of +20 to -43%. Other matters such as running time, information generated about leaching behavior and cost are also discussed. The pH-stat test gives the most information, but is expensive. The percolation test generates detailed information, whereas the shake test is a relatively inexpensive alternative for the percolation test.