Comparison of three procedures (single, sequential and kinetic extractions) for mobility assessment of Cu, Pb and Zn in harbour sediments

The mobility of Cu, Pb and Zn in harbour sediments was investigated using single, sequential and kinetic extraction techniques. Each type of extraction provides different information on the mobility of these elements in the environment. The single HCl extraction assesses general mobility, the sequential extraction assesses geochemical partitioning and kinetic extraction allows quickly and slowly mobilized elements to be identified. Kinetic extraction also allows the influence of extraction duration to be assessed. The results presented in this paper highlight the complementary information provided by different types of mobility studies. The lack of correlation between element mobility and total metal concentration emphasises the inadequacy of using total metal concentrations in risk assessment.