After 3, 6 and 12 months the samples were picked up from the soil, gently cleaned by soft sponge, rinsed with distilled water, then dried at temperature 30 ��C to a constant weight, photographed and weighted to determine the mass loss of the tested mate

After 3, 6 and 12 months the samples were picked up from the soil, gently cleaned by soft sponge, rinsed with distilled water, then dried at temperature 30 ��C to a constant weight, photographed and weighted to determine the mass loss of the tested materials.