The current environmental impact of base-metal mining at the Tui Mine, Te Aroha, New Zealand

The current environmental impact of base metal mining at the Tui Mine, Te Aroha and gold mining near Waihi, was investigated by analysis of local waters, stream sediments, and aquatic vegetation X-ray diffraction analysis of heavy metal fractions in stream sediments showed the presence of pynte in the upper reaches of the Tunakohoia and Tui Streams that drain the mineralised reefs and Tui tailings dam Relatively immobile lead (galena) was retained close to the source, whereas copper and zinc minerals were more mobile and distributed further downstream from the areas of mineralisation Gold was determined in sediments from the Ohinemun and Waitekaun Rivers along with other heavy metals derived from sulphide mineralisation at Waihi and Waitekaun Analysis of waters from the Tui and Tunakohoia Streams showed concentrations of arsenic, cadmium, lead and zinc above recommended levels for potable water in the upper parts of these waterways The discharge of these streams into the Waihou River (sampled upstream from Te Aroha and downstream to past Paeroa) did not have any significant effect on heavy-metal concentrations in this river Aquatic macrophytes sampled in the Waihou, Ohinemun and Waitekaun Rivers had very high heavy-metal concentrations compared with the ambient water and should be considered as potentially useful for assessing the impact of low-metal fluxes into the waters Gold was detected in aquatic macrophytes from streams draining both the Martha Mine at Waihi and the Golden Cross Mine at Waitekaun and indicated the possibility of prospecting for gold by analysis of these plants.