PRACTICAL ASSESSMENT TECHNIQUES FOR THE IMPACT OF ACID-MINE DRAINAGE ON RIVERINE SYSTEMS

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