1	Metal Loading in Peru Creek By: Brendan Cusick
2	Peru Creek Info Summit County, Colorado. Near Keystone Ski Resort 8km in length and feeds into the Snake River. About 27-51% of total flow for the Snake River. Many mining catchments located within the watershed. Elevation about 10,500ft.
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4	Importance For remediation of Peru Creek it is imperative to locate the major sources of contamination. Money has already been spent to clean up around Pennsylvania Mine. Pennsylvania Mine found to be one of the smaller contributors of contamination.
5	Source of Metal Loading Caused by mines. Process called Acid Rock Drainage (ARD). Over 1900km of streams, rivers and lakes, in Colorado, are affected by ARD.
6	Causes of ARD Atmospheric oxidation of iron-sulfur minerals (FeS2). Minerals usually isolated from the atmosphere, come in contact with atmosphere. Runoff from tailings piles and drainage from adits are highly acidic and highly concentrated with metals.
7	Reactions in ARD 1) 2 FeS₂ + 7 O₂ + 2 H₂O = 2 Fe²⁺ + 4 SO₄^2- + 4 H⁺ Pyrite + Oxygen + Water = Ferrous Iron + Sulfate + Acidity 2) 4 Fe²⁺ + O₂ + 4 H⁺ = 4 Fe³⁺ + 2 H₂O Ferrous Iron + Oxygen + Acidity = Ferric Iron + Water 3) 4 Fe³⁺ + 12 H₂O = 4 Fe(OH)^{3 ¯} + 12 H⁺ Ferric Iron + Water = Ferric Hydroxide + Acidity 4) FeS₂ + 14 Fe³⁺ + 8 H₂O = 15 Fe ²⁺ + 2 SO₄^2- + 16 H⁺ Pyrite + Ferric Iron + Water = Ferrous Iron + Sulfate + Acidity
8	Effects of ARD Lowered pH in the tailings and adits leads to and increase in dissolved metals. Mixes with the receiving waters creating a lowered pH and higher metal concentrations. Low enough pH and high enough metal concentration kills aquatic life.
9	Basis for my project Sabre Duren’s Master thesis. Tracer coupled with synoptic sampling. Covered 7 km stretch of Peru Creek. Attempted to locate the major area of metal loading along Peru Creek. Took place August of 2002.
10	Basis for My Project
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12	My Project Tracer experiment coupled with synoptic sampling. 6 sampling sites from below the wetlands to just below Warden Gulch. From injection point to site #6, 1.3km. Injection lasted 3 hours, from 10:45-13:45.
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14	My Project Took place July 10, 2004. LiCl used as the conservative substance. Sampled for Fe, Zn, Li, Cl, DOC. Flow, pH, conductivity, and temperature were taken on site.
15	Field Methods Samples Li, taken directly from stream every 5 minutes during rising and falling limbs, and every 15 in-between. Fe, Zn, and Cl, taken every half hour and filtered. DOC, taken every hour.
16	Field Methods Readings Flow, taken at beginning and end of experiment with pygmy meter. pH, Conductivity, and Temperature, taken throughout the day with hand-held pH/Conductivity probe.
17	Analysis Li and Zn; Atomic Absorption Spectrometer. Fe; UV Vis. DOC; Total Organic Carbon Analyzer. Cl; Ion Chromatograph.
18	Calculations Li Flow Inj. Rate (L/s) * Inj. Li Conc. (mg/L) = Set Flux (mg/s) Set Flux (mg/s) / Site’s Avg. Plateau Li Conc. (mg/L) = Site’s Flow (L/s) Fe / Zn Flux Site’s Flow (L/s) * Site’s Fe or Zn Conc. (mg/L) = Site’s Fe or Zn Flux (mg/s)
19	Calculations % Loading From Sites 1-6 (Site’s Flux (mg/s) / Sum of Flux for Sites 1-6 (mg/s)) 100 = % Loading From Sites 1-6 If sites Flux <0, then it was not considered for loading calculations. % Loading For Entire Stream % Loading From Sites 1-6 August 2002 values of Loading for the Warden Gulch Reach = % Loading For Entire Stream
20	Results An inflow between sites 2 and 3 was found to be a major cause of the metal loading and pH drop associated with this stretch of Peru Creek.
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22	pH
23	Conductivity
24	DOC vs. Dist. Downstream
25	Flow vs. Dist. Downstream
26	Li Conc. vs. Dist. Downstream
27	Fe vs. Dist Downstream
28	Zn vs. Dist. Downstream
29	Sites 1 and 2 LiCl Variability
30	Sites 3 and 4 LiCl Variability
31	Sites 5 and 6 LiCl Variability
32	Results
33	Conclusions Inflow, major source of contamination. Better place for remediation to occur. Between Sites 2 and 3, there is also some unaccounted flux of Fe and Zn. Possibly due to ground water inflow. Between Sites 1 and 2, there is a high loading of Fe. Possibly due to ground water inflow. If Sites 1-4 cleaned up, about 70% of Fe and 40% of Zn loading could be dealt with.
34	Special Thanks Advisor: Diane McKnight Grad Students: Marcie Appel Chris Jaros Sabre Duren REU participants (plus Pete) Math/Bio program
35	References Interstate Mining Compact Commission (IMCC), 1992. Inactive and Abandoned Non-Coal Mines: a Scoping Study. Prepared for IMCC of Herndon, VA by Resource Management Associates, Clancy, MT. Cooperative Agreement, X-817900-01-0. Duren, S., 2002. Quantitative Hydrologic Evaluation of Dissolves Metal Loading and Transport in Peru Creek, an Acid Rock Drainage Stream; Summit County, Colorado. University of Colorado at Boulder, p130.
36	Questions ?