EVALUATION OF THE REHABILITATION PROCEDURE OF A PYRITIC MINE TAILINGSPOND IN AVOCA, SOUTHEAST IRELAND

A 32 ha tailings pond used for the disposal of pyritic mine waste was examined after a period of eight years to determine the success of the rehabilitation plan used to revegetate the site. This was achieved by examining both the vegetation cover and the quality of the topsoil in order to determine the effect of the tailings. A number of floristic habitats were identified within the site indicating that succession ha d occurred since revegetation of the area with metal-tolerant grass sp ecies. Four main habitats were investigated: leguminous, grass, gorse and low canopy. The soil layer in Shelton Abbey was 25-30 cm deep and contained levels of nutrients and metals comparable to those found in unpolluted soils. It was followed by a 20-25 cm layer of mixed soil an d tailings, followed by the tailings only. The tailings retained eleva ted concentrations of metals indicating their unsuitability for growth of unadapted plant species. Vegetation from all habitats, analysed bo th in the summer and winter, contained higher levels of iron only comp ared with vegetation grown on unpolluted soils. Metals do not appear t o be significantly leached from the tailings either into the soil or i nto surface and ground waters, and have not been accumulated to above normal levels by plant uptake. The rehabilitation protocol used at the site appears to have been successful. However, the site needs to be m anaged on an on-going basis to ensure the integrity of the bund and re vegetated area, (C) 1998 John Wiley & Sons, Ltd.