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Toxicity Approaches to Assessing Mining Impacts and Mine Waste Treatment Effectiveness
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| Abstract: | The USEPA Office of Research and Development's National Exposure Research Laboratory and National Risk Management Research Laboratory have been evaluating the impact of mining sites on receiving streams and the effectiveness of waste treatment technologies in removing toxicity for the past six years. The effectiveness of site assessments and minewaste treatment technologies in reducing toxicity was assessed using toxicity tests on the Summitville mine site, Clear Creek and North Fork of Clear Creek, Burleigh Tunnel and Big Five Tunnel in Colorado and Calliope Mine, Crystal Mine, Lily Orphan Boy Mine, Peerless Mine and Sure Thing Mine in Montana. Water samples were collected from the stream sites or mining sites and shipped to the USEPA Aquatic Research Facility in Cincinnati, Ohio. A series of acute aquatic toxicity tests with Pimephales promelas, the fathead minnow, and Ceriodaphnia dubia, a freshwater invertebrate, were conducted on these samples. In addition to these tests, a 7-day growth test using rainbow trout, Oncorhynchus mykiss, was conducted on Summittville minewaste samples. The purpose of these tests was to establish the level of toxicity for the discharge from the different mine sites and to evaluate the effectiveness of different treatment processes used at these sites. The results from the tests on the effluents from treatment technologies used at the Sure Thing and Lily Orphan Boy mine sites indicate that there is a significant reduction in toxicity. For the Sure Thing Mine treated effluent, C. dubia survival LC50 value was increased by 670 fold and the No Observable Acute Effect Level (NOAEL) by 640 fold. The P. promelas LC50 value was increased by 24 fold and the NOAEL value by 20 fold. For the Lily Orphan Boy treated effluent the C. dubia LC50 value increased by 160 fold and the NOAEL by 320 fold. The P. promelas LC50 value increased by 21 fold and the NOAEL by 40 fold. For the Summittville Mine Treatment System, treated mine discharge samples displayed reduced toxicity of approximately 7-8 fold for C. dubia, 10 fold for rainbow trout, and about 5 fold for the fathead minnow as compared to untreated mine waste. However, in order to remove all the acute toxicity from the mine discharge, the concentration of metals from both treatments have to be reduced by a 1000 fold for C. dubia survival, or a 100 or 50 fold for rainbow trout, and fathead minnow survival, respectively. |
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| Citation: | Lazorchak, J. M., M. E. Smith, E. R. Bates, and R. C. Wilmoth. Toxicity Approaches to Assessing Mining Impacts and Mine Waste Treatment Effectiveness. Presented at Hardrock Mining Conference, Westminster, CO, May 7-9, 2002. |
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| Contact: |
Linda Ransick - (513) 569-7395 or ransick.linda@epa.gov
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| Division: |
Ecological Exposure Research Division |
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| Branch: |
Molecular Ecology Research Branch |
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| Product Type: |
Abstrct/Oral |
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| Presented: |
05/07/2002 |
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