REMOVAL OF DISSOLVED COPPER AND IRON AT THE FRESH-WATER-SALTWATER INTERFACE OF AN ACID-MINE STREAM

The King River, Tasmania, contains elevated levels of heavy metals, in particular copper, a result of the discharge of mine tailings and aci d mine water from the Me Lyell copper mine, which operated until late 1994, Samples were collected from the lower Ring River in July 1994, o ver a 48-h period, during which time the power station at the head of the river was off for the first 24 h, Saline water was observed in the delta region during this low flow period, and dissolved iron and copp er were found to exhibit nonconservative behaviour with salinity, Remo val of dissolved copper, as the river enters the harbour, was confirme d by laboratory experiments, The removal mechanism appears to be depen dent on rapid pH increases and the formation of amorphous iron flocs w hich occur in the estuary, and results in a significant proportion of dissolved copper being removed from solution. (C) 1997 Elsevier Scienc e Ltd.