Development of biological monitoring programs to detect mining-waste impacts upon aquatic ecosystems of the Alligator Rivers Region, Northern Territory, Australia

Abstract

The Alligator Rivers Region (ARR) lies in the wet-dry tropics of northern Australia where highly seasonal, summer rains fall between November and April. The Region encloses Kakadu National Park, renowned for its rich and diverse, cultural and natural heritage and also as the location of significant mineral deposits including uranium, gold, platinum and palladium. Research programs considered necessary for the protection of the environment from the effects of mining in the Region have been underway since 1978 and have included extensive studies of physicochemical limnology and of the biota of aquatic and terrestrial ecosystems. These early baseline and ongoing studies are reviewed in relation to the development and refinement of techniques and procedures to monitor and assess effects of mining activities on aquatic ecosystems of the Region.

Benthic macroinvertebrate and fish communities (or representative populations or assemblages within these communities) have been selected as the most practical and useful groups of organisms for use in the current programs of biological monitoring in the ARR. Adequate monitoring of macroinvertebrate community structure requires identification to species level; deficiencies in taxonomic information have been redressed in recent studies.

Present studies are confined to a seasonal tributary (Magela Creek) of the East Alligator River near the Ranger Uranium Mine and, until recently, in the upper South Alligator River near the Coronation Hill gold, platinum and palladium prospect. A variety of monitoring methods is presently under development. These range from the detection of short-term effects of releases of waste-water from mine sites during the wet season to the detection of longer-term effects of mining generally. Included in the program are experimental field manipulations aimed at improving the design and sensitivity of community-based techniques for biological monitoring.