Monotonous decreasing leaching behavior of geogenic contamination from marine sediments by up-flow column percolation tests

Abstract

Up-flow column percolation tests were conducted to discuss the rigor interpretations and the engineering applications, adequate descriptions of which have been limited. Two types of marine sediments were tested using the two different sizes of columns (Φ 5 cm×h 10 or 30 cm) with a flow rate of 12 or 36 mL/h. Trends in concentrations with pore volumes of flow (PVF) were examined. Since the concentration trends of selenium provided a monotonous decrease and showed the maximum value of approximately 0 PVF, and showed half of the maximum value less than 1 PVF, their leaching was considered to diminish immediately. On the other hand, arsenic and fluorine concentrations showed initial increases and consequent decreases, therefore their leaching continued after 10 PVF. Since monotonous decreasing leaching contaminants show the maximum concentration of approximately 0 PVF, a more realistic risk analysis can be conducted to obtain the maximum concentration from column tests. To investigate the trends in concentrations, column tests should be carried out at least 2 PVF.