Simulation of Metals Transport and Toxicity at a Mine-Impacted Watershed: California Gulch, Colorado

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• 作者：Mark L. Velleux ; Pierre Y. Julien ; Rosalia Rojas-Sanchez ; William H. Clements ; John F. England ; Jr.
• 刊名：Environmental Science & Technology
• 出版年：2006
• 出版时间：November 15, 2006
• 年：2006
• 卷：40
• 期：22
• 页码：6996 - 7004
• 全文大小：678K
• 年卷期：v.40,no.22(November 15, 2006)
• ISSN：1520-5851

文摘

The transport and toxicity of metals at the CaliforniaGulch, Colorado mine-impacted watershed were simulatedwith a spatially distributed watershed model. Using adatabase of observations for the period 1984-2004, hydrology,sediment transport, and metals transport were simulatedfor a June 2003 calibration event and a September2003 validation event. Simulated flow volumes were withinapproximately 10% of observed conditions. Observedranges of total suspended solids, cadmium, copper, andzinc concentrations were also successfully simulated. Themodel was then used to simulate the potential impactsof a 1-in-100-year rainfall event. Driven by large flows andcorresponding soil and sediment erosion for the 1-in-100-year event, estimated solids and metals export from thewatershed is 10 000 metric tons for solids, 215 kg for Cu, 520kg for Cu, and 15 300 kg for Zn. As expressed by thecumulative criterion unit (CCU) index, metals concentrationsfar exceed toxic effects thresholds, suggesting a highprobability of toxic effects downstream of the gulch. Moredetailed Zn source analyses suggest that much of theZn exported from the gulch originates from slag piles adjacentto the lower gulch floodplain and an old mining sitelocated near the head of the lower gulch.