Abstract
This study evaluated the water soluble lead and the transportable lead of artificial lead-contaminated soil amended with phosphate material using water extraction test and unsaturated leaching model test. After the tests, an insoluble lead mineral formed was determined using X-ray diffraction. The application of amendment could suppress the level of water soluble lead and transportable lead in the neutral and acidic contaminated soil containing lead carbonate or chloride. Formation of insoluble lead mineral such as pyromorphite was identified or detected in both of amended soils after the tests. In water extraction test, the suppression level of water soluble lead corresponded to 72.6% of total lead content in soil while the formation level of pyromorphite-lead was lower at 51.6% of total lead content, suggesting that the other mechanism explained the suppression mechanisms of water soluble lead in addition to the formation of pyromorphite. Suppression level of transportable lead was compatible with the formation level of pyromorphite-lead, indicating that dissolved lead was transformed to the pyromorphite through the transporting process in unsaturated soil, which resulted in the lead immobilization.
