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Reactive Transport Modeling Of Remedial Scenarios To Predict Cadmium, Copper, And Zinc In North Fork of Clear Creek, Colorado
Citation:
BUTLER, B. A., B. S. CARUSO, AND J. F. Ranville. Reactive Transport Modeling Of Remedial Scenarios To Predict Cadmium, Copper, And Zinc In North Fork of Clear Creek, Colorado. J. A. Simon (ed.), Submitted to: Remediation Journal. John Wiley & Sons, Ltd., Indianapolis, IN, 19(4):101-119, (2009).
Impact/Purpose:
To use the WASP4/META4 model to predict dissolved metal concentrations, specifically cadmium (Cd), copper (Cu), and zinc (Zn) in the NFCC, following several potential remedial scenarios under both high- and low-flow conditions. The predicted concentrations then were compared to the site-specific water-quality standards (WQSs) to evaluate possible exceedances following remedial activities. Total metal concentrations also were simulated in modeling; however, only the dissolved concentrations are presented in this article due to their importance related to aquatic toxicity and the WQSs. To evaluate the ability and usefulness of WASP4/META4 to simulate metal concentrations in NFCC and other mining-impacted streams and make recommendations for potential improvements to the model.
Description:
The North Fork of Clear Creek (NFCC), Colorado is an acid-mine-drainage-impacted stream typical of many mountain surface waters affected by historic metal mining in the western United States. The stream is devoid of fish primarily because of high metal concentrations in the water (e.g., copper and zinc) and has large amounts of settled iron oxhydroxide solids that coat the streambed. The NFCC is part of the Central City/Clear Creek Superfund site, and remediation plans are being implemented that include treatment of three of the main point- source inputs and cleanup of some tailings and waste rock piles. This article examines dissolved (0.45-µm filterable) concentrations of cadmium, copper, and zinc following several potential remediation scenarios, simulated using a reactive transport model (WASP4/META4). Results from modeling indicate that for cadmium, remediation of the primary point-source adit discharges should be sufficient to achieve acute and chronic water-quality standards under both high- and low-flow conditions. To achieve standards for copper and zinc, however, the modeling scenarios suggest that it may be necessary to treat or remove contaminated streambed sediments in downstream reaches, as well as identify and treat nonpoint sources of metals. Recommendations for improvements to the model for metal transport in acid-mine drainage impacted streams are made. These recommendations are being implemented by the U.S. Environmental Protection Agency.
URLs/Downloads:
REACTIVE TRANSPORT MODELING OF REMEDIAL SCENARIOS TO PREDICT CADMIUM, COPPER, AND ZINC IN NORTH FORK OF CLEAR CREEK, COLORADO