U.S. Geological Survey

Source, Transport, and Partitioning of
Metals between Water, Colloids, and Bed Sediments
of the Animas River, Colorado

By S.E. Church1, B.A. Kimball2, D.L. Fey1,
D.A. Ferderer1,T.J. Yager3, and R.B. Vaughn1

U.S. Geological Survey Open-File Report 97-0151



1U.S. Geological Survey, P.O. Box 25046, MS 973, Federal Center, Denver, CO 80225
2U.S. Geological Survey, 1745 West 1700 South, Salt Lake City, UT 84104
3U.S. Geological Survey, P.O. Box 25046, MS 415, Federal Center, Denver, CO 80225

This report is preliminary and has not been reviewed for conformity with
U.S. Geological Survey editorial standards.

Any use of trade, product, or firm names is for descriptive purposes only
and does not imply endorsement by the U.S. Government.




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Table of Contents

Executive Summary
Introduction
          Summary of Acid-Mine Drainage Studies in Other Areas
          Study Objectives
The Animas River Watershed
Previous Geochemical Work
Field Sampling
          Water and Colloids
          Stream Sediments
Results from Water and Colloid Data
          Synoptic Sampling of Water and Colloids, October 1995
                    Aluminum
                    Cadmium
                    Copper
                    Iron
                    Manganese
                    Strontium
                    Zinc
                    Arsenic, Mercury, and Selenium
          High-flow Sampling of Water and Colloids, Spring, 1996
          Dissolved Versus Colloidal Transport
                    Manganese
                    Iron and Aluminum
                    Copper
                    Zinc
          Comparison of Metal Loads During Low Flow and Snowmelt Runoff
Results from the Stream-Sediment Data
          Mineral Creek Drainage Basin
                    Arsenic
                    Cobalt
                    Copper
                    Lead
                    Strontium
                    Zinc
                    Vanadium
                    Lead-isotopic Data
          Cement Creek Drainage Basin
                    Arsenic
                    Cobalt
                    Copper
                    Lead
                    Strontium
                    Zinc
                    Vanadium
                    Lead-isotopic data
          Animas River Drainage Basin Upstream from Silverton
                    Arsenic
                    Cobalt
                    Copper
                    Lead
                    Strontium
                    Zinc
                    Vanadium
                    Lead-isotopic data
          Animas River Drainage Basin: Silverton, Colorado to Aztec, New Mexico
                    Arsenic
                    Cobalt
                    Copper
                    Lead
                    Strontium
                    Zinc
                    Vanadium
                    Lead-isotopic data
                    Metal transport from the La Plata Mining District
                    Metals from the smelter sites south of Durango
                    Urban metal signatures
                    Selenium and mercury in bed sediments of the Animas River
          Undiscovered Mineral Resources in the Silverton Area
          Geochemical Signature of Colloidal Component in Water and Bed Sediments
          Comparison of the 1995 and 1996 Bed-Sediment Data
          Calculation of the Contribution to the Total Amount of Metal in Bed Sediments from Various Sources
          Differential Sorbtion of Copper and Zinc by Colloids
Summary and Conclusions
References Cited
Appendix I. Methods used to prepare regional sediment geochemical maps
Appendix II. Analytical Methods
Appendix III. Site Identifications, Field Data, and Major Ion Chemistry from Samples from the Animas River Basin, 1995-96
Appendix IV. Metals in Water and Colloids from the Animas River Basin, 1995-96
Appendix V. HCl-H2O2 Data from Stream-Sediment Samples
Appendix VI. Total Digestion Data from Stream-Sediment Samples
Appendix VII. Lead-isotopic Data from Selected Samples

List of Figures

Figure 1. Index map of southwest Colorado showing Animas River watershed
Figure 2. Map of Animas River watershed showing topography and mines and prospects
Figure 3. Geologic map of the Animas River watershed
Figure 4. Structural map of the Silverton caldera
Figure 5. Geochemical map of Animas River watershed showing distribution of calcium
Figure 6. Geochemical map of Animas River watershed showing distribution of copper
Figure 7. Geochemical map of Animas River watershed showing distribution of lead
Figure 8. Geochemical map of Animas River watershed showing distribution of zinc
Figure 9. Hydrograph of the Animas River below Silverton Oct. 1, 1994 to Oct. 1, 1996
Figure 10. Map of Animas River watershed showing localities of water samples collected in Oct., 1995
Figure 11. Map of Animas River watershed showing localities of sediment samples collected in Oct., 1995
Figure 12. Dissolved and colloidal manganese concentrations from water samples, Oct., 1995
Figure 13. Dissolved and colloidal zinc concentrations from water samples, Oct., 1995
Figure 14. Dissolved and colloidal iron concentrations from water samples, Oct., 1995
Figure 15. Dissolved and colloidal aluminum concentrations from water samples, Oct., 1995
Figure 16. Summary diagram of mass transfer of aluminum in mixing zones downstream from Mineral and Cement Creeks
Figure 17. Summary diagram of mass transfer of iron in mixing zones downstream from Mineral and Cement Creeks
Figure 18. Comparison of metal loads for aluminum, iron, zinc, cadmium, copper and lead at low flow (Oct., 1995) and high flow (May-June, 1996)
Figure 19. Ribbon map showing copper dispersion in Animas River, Cement Creek, and Mineral Creek
Figure 20. Ribbon map showing lead dispersion in Animas River, Cement Creek, and Mineral Creek
Figure 21. Ribbon map showing zinc dispersion in Animas River, Cement Creek, and Mineral Creek
Figure 22. Metal distribution profiles for Mineral Creek
Figure 23. Lead-isotope distribution profile for Mineral Creek
Figure 24. Metal distribution profiles for Cement Creek
Figure 25. Lead-isotope distribution profile for Cement Creek
Figure 26. Metal distribution profiles for Animas River upstream from Silverton
Figure 27. Lead-isotope distribution profile for Animas River upstream from Silverton
Figure 28. Metal distribution profiles for Animas River: Silverton, Colo. to Aztec, New Mexico
Figure 29. Lead-isotope distribution profile for Animas River: Silverton to Aztec
Figure 30. Distribution profiles for selenium and mercury, Animas River
Figure 31. Downstream variation of the iron, aluminum, and copper to zinc ratios in colloids and bed sediments in the Animas River: Silverton to Aztec
Figure 32. Predicted sorbtion curves for metals by iron-hydroxides as a function of pH
Figure 33. Lead-isotopic model for dilution of metals derived from Animas River watershed
Figure 34. Normalized labile copper, lead, and zinc concentrations in bed sediments, Animas River
Figure A-II. Diagram showing process procedures for water and colloid samples

List of Tables

Table 1. Water quality standards for metals, Colorado
Table 2. Lead-isotopic data from mineral deposits and mill sites, Silverton area
Table 3. Semi-quantitative emission spectrographic data from heavy-mineral separates,Cunningham Creek and Animas River upstream from Howardsville
Table 4. Lead-isotope parameters for calculation of dilution of the metals in the Animas River from Silverton

List of Tables in Appendixes

Table A-II. Replicate analytical results from NIST standard reference materials
Table A-III. Site identifications, field data, and major ion chemistry for water from the Animas River and major tributaries, 1995-1996
Table A-IV. Metals in water and colloids in the Animas River and tributaries, 1995-1996
Table A-V.1. Partial digestion (2M HCl-1%H2O2) data from sediments and other samples, Animas River watershed, Oct., 1995
Table A-V.2. Partial digestion (2M HCl-1%H2O2) data from sediments and other samples, Animas River watershed, Aug. and Oct., 1996 watershed, Oct., 1995
Table A-VI.2. Total digestion data from sediments and other samples, Animas River watershed, Aug. and Oct., 1996
Table A-VII. Lead-isotopic data from sediments and other samples, Animas River watershed, Oct., 1995