Contamination of groundwater in the Te Aroha area by heavy metals from an abandoned mine : Liping Pang, Journal of Hydrology (New Zealand), 33(1), 1995, pp 17–34

Abstract

Groundwater contamination from the copper/lead Tui mine was investigated by modelling the groundwater flow regime, monitoring groundwater quality, and studying the retention of heavy metal contaminants by the lithologic units of the receiving environments. Metal (Cu, Pb, Zn, Cd, Fe, Mn) concentrations in the groundwater define a leachate plume extending approximately 1 km downgradient of the tailings pond. The contaminated groundwater discharges to surface mountain streams which in turn recharge and contaminate groundwater in downgradient alluvial fans. The contamination front of iron was close to the tailings source because of its high retardation by the andesite aquifer, while the contamination front of cadmium was the furthest from the source indicating that it is the least retarded of the heavy metals. The volume and timing of contaminant desorption from the tailings for each of the heavy metals indicates the tailings will be a pollution source for hundreds to thousands of years. A number of measures to prevent contamination, including minimising groundwater contact with the tailings, are suggested