Leachability of metal (Cd, Ni, Zn, Cu, and Pb)-spikedsediments using sequential extractions

摘要

ABSTRACT Measurements of availability and mobility are required in order to prevent potential toxic hazards. Column leaching experiments were conducted to determine the degree of mobility and the distribution of zinc (Zn), cadmium (Cd), nickel (Ni), copper (Cu) and lead (Pb) following spiking of the sediments. Metal distribution and release from sediments were related to pH, clay and sand. This study revealed that after periods of drying and leaching for several weeks, Cu and Pb will be more strongly bound and Cd, Zn and Ni less strongly bound to sediment particles. Although the average residual fraction (RES) was lower for Cd (23), this fraction still accommodated > 50 of the added Zn (54), Ni (62), Cu (59) and Pb (42) in most of the sediments. The order of solubility for the added metals in fours studied sediments were Cd (6.1) > Ni (1.8) > Zn (1.1) > Cu (0.7). Strongly adsorbing metals such as Cu and Pb were least affected by pH and buffering capacity. Metals like Cd, Ni and Zn in the acidic environment they would have high mobility. Therefore, unlike Pb and Cu, the release of Cd, Ni and Zn from different sediments was affected by sediment type.