Pulp mill sourced organic compounds and sodium levels in water and sediments from the Tarawera River, New Zealand

Two pulp mills downstream of Kawerau in New Zealand have discharged effluent into the Tarawera river for more than 30 years. Concentrations of sodium, fatty acids, resin acids, degraded resin hydrocarbons and chlorophenolic substances were determined at sites above and below the 2 pulp mills between November 1991 and February 1992 using GC with flame ionization detection and GC-MS. There was a rapid removal of resin acids in the 5.8 km section of river between the 2 mill discharge points. This might be due to interactions between geothermal discharges and mill effluents. Abietan-18-oic acid and dehydroabietic acid were the dominant resin acids in the second mill effluents. There was little removal of these resin acids and other pulp mill effluent compounds in the 21 km region of the river below the second mill discharge point. Levels of fatty acids, resin acids and degraded resin neutrals in sediment samples generally paralleled the levels found in water.