Practical assessment techniques for the impact of acid mine drainage on riverine systems

New technical procedures and protocols have been developed to assess the environmental impact of acid mine drainage (AMD) on riverine (lotic) systems. The impact of AMD is characterised at community level to identify and prioritise key mechanisms. Conductivity is used as a rapid field method to assess the strength of AMD and the degree of contamination of both surface and ground waters. Toxicity is assessed using both the Activated sludge Inhibition Test and the Microtox Bioassay procedure. Evaluation and calibration of test methods should be done using artificial AMD. Fish toxicity testing is also examined, and in-situ toxicity assessment using macro-invertebrates is also evaluated for riverine conditions. Biological surveillance and sediment contamination assessment procedures are reported. A substrate-classification index provides a rapid visual assessment of AMD impact on rivers; while an objective water quality index allows sensitive classification of both (AMD) and contaminated waters, regardless of relative variation of key parameters. To be effective, these new techniques should be used within the framework of a remediation or management strategy. An example of such a strategy is given for Avoca mines in Ireland.