Batch and column experiments are used to study the effects of ground mussel shell amendment on the retention of heavy metals in acidic mine soil. The soil pH increases proportionally with the mussel shell concentration employed. Mussel shell amendment increases Cu, Cd, Ni and Zn retention in mine soil when compared with unamended soil. In fact, Cu retention was 6480 mu mol kg(-1) (43% of the total added) when the maximum metal concentration (1570 mu M) was added to the unamended soil, whereas retention reached 15,039 mu mol kg(-1) (99.9% of the total Cu added) when soil was amended with 24g kg(-1) mussel shell; in the case of Cd, adsorption increases from 3257 mu mol kg(-1) (15% of the total added) for the unamended soil, to 13,200 mu mol kg(-1) (87% of the total added) for the shell-amended soil; Ni retention increased from 3767 mu mol kg(-1) (25% of the total added) corresponding to unamended soil, to 11,854 mu mol kg(-1) (77% of the total added) for the shell-amended soil; and finally, Zn retention increased from 4684 mu mol kg(-1) (31% of the total added), for unamended soil, to 14,952 mu mol kg(-1) (98% of the total added) for shell-amended soil. The results of the constant flow transport experiments show that the addition of the 24 g kg(-1) mussel shells can retain Cu, Cd, Ni and Zn within the first few centimetres of the column length, indicating the usefulness of ground mussel shells to drastically decrease the mobility and availability of these pollutants and to facilitate soil remediation. (C) 2013 Elsevier B.V. All rights reserved.