Factors affecting heavy metal leaching from excavated rocks with natural contamination

When excavation works are executed at stratums that naturally contain heavy metals due to their geologic histories, time-saving and reliable assessment of contamination potential by the metals and metalloids in excavated soil/rock is required. Leaching of heavy metals from excavated rocks is induced as the results both from physical factors (crushing, exposure to water, temperature) and chemical factors ( oxidation, soil-water interaction, pH change, etc.). This paper addresses long term leaching behavior of arsenic and lead affected by these factors, which were determined by outdoor exposure tests conducted on the excavated rock samples weathered outdoors for more than two years. In addition, several time-saving laboratory tests for characterizing the contamination potential of arsenic and lead were validated by comparatively assessing the results of the outdoor exposure tests, to develop some simple evaluation methods of contamination potential by metals from natural resources.