The Alamosa River Corridor 15 Years After Remediation Began at Summitville Mine

A Master’s Thesis

Presented to the Faculty of the

College of Science and Mathematics

Colorado State University-Pueblo Pueblo, Colorado

In Partial Fulfillment Of the Requirements for the Degree of

Masters of Science in Applied Natural Science (Biology Emphasis)

By Jared Romero

Colorado State University – Pueblo August, 2010

CERTIFICATE OF ACCEPTANCE

This Thesis Presented in Partial Fulfillment of the Requirements for the Degree

Masters of Science in Applied Natural Science (Biology Emphasis)

By Jared J. Romero

Has Been Accepted By the Graduate Faculty of the

College of Science and Mathematics Colorado State University- Pueblo

APPROVAL OF THESIS COMMITTEE: ______Graduate Advisor (Dr. Moussa Diawara) Date ______Committee Member (Dr. Jack Seilheimer) Date ______Committee Member (Dr. Chad Kinney) Date ______Graduate Director (Dr. Jeffrey Smith) Date

ACKNOWLEDGEMENTS

A special thanks to Dr. Moussa Diawara, Dr. Jack Seilheimer, Dr. Chad Kinney, Dr. Annette Gabaldon, Dr. Jeff Smith, Jim Carsela and Dr. Richard Kreminski for assisting and guiding me through this process. I would also like to thank Dr. Marty Jones, Dr. Benita Brink, Theresa Jimenez, Martin and Ellen Romero, Jerome and Brenda Romero, Michelle Romero and Mackenzie Holdershaw for all of their assistance in this process.

TABLE OF CONTENTS

TITLE PAGE GRADUATE PROGRAM ACCEPTANCE ACKNOWLEDGMENTS i TABLE OF CONTENTS ii ABSTRACT iii-v LIST OF FIGURES vi-ix LIST OF TABLES x-xii LIST OF EQUATIONS xiii INTRODUCTION 1-15 STUDY OBJECTIVES AND HYPOTHESIS 15-17 MATERIALS AND METHODS 17-30 RESULTS 30-124 DISCUSSION 124-157 LITERTURE CITED 158-165 APPENDIX (THESIS DEFENSE PRESENTATION) 166

ABSTRACT:

THE ALAMOSA RIVER CORRIDOR 15 YEARS AFTER REMEDIATION

BEGAN AT SUMMITVILLE MINE Jared J. Romero

Summitville Mine lies in Rio Grande National Forest in southwestern Colorado.

Summitville Mine contributed to the contamination of the Alamosa River Ecosystem by

leaking acids and heavy metals into Wightman Fork an Alamosa River Tributary. The

poor conditions of the Alamosa River have been well documented since 1917. However, the damaging effects caused by operations at Summitville Mine during 1985-1992 were

much greater than the contamination that exists due to the volcanic geology of the area.

The Alamosa River and Terrace Reservoir, an irrigation reservoir that the Alamosa River

flows into, had a viable fish population, prior to Summitville Consolidated Mining Corp.,

Inc. beginning a cyanide heap leaching pad operation in 1985. By 1990 the Colorado

Division of Wildlife had reported that a fish population no longer existed in Terrace

Reservoir. In 1992 the EPA and other government agencies began studies of the affected

areas and in 1994 began remediation efforts. The last collected document that analyzed

sediment along the Alamosa River was in 2000 and the last study that analyzed Alamosa

River water samples was in 2003. Since 2003 there have been no studies performed to

our knowledge to determine the health of the Alamosa River Ecosystem and the impact

of the remediation. We hypothesized that the remediation effort has been successful and

that the majority of any potential heavy metal contamination was no longer coming from

Summitville Mine, but rather from the volcanic geology of the Mountains. Our main

objective was to evaluate the effectiveness of the remediation efforts initiated in 1992 to

reduce heavy metal concentrations in Terrace Reservoir and along the Alamosa River

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corridor. Specifically we 1) compared concentrations of heavy metals in water, sediment and tree core samples collected upstream, at and downstream from the mining site; and 2) compared the concentrations of all inorganic elements (heavy metals and others) upstream, at and downstream of the mining site to the concentrations recorded in 2000 and 2003.

This study determined the heavy metal concentrations in water, sediment, and tree core samples during the 2009 runoff season. This was done in order to determine if the ecosystems health has improved since remediation began in 1992. Previous reports looked at concentrations of aluminum, arsenic, cadmium, copper, iron, lead, nickel and zinc. Our 2009 study included these heavy metals, however we determined the concentration of 27 heavy metals in water, sediment and tree cores using an ICP-MS.

Statistical analysis was performed on heavy metals that were analyzed in previous studies as well as any heavy metal that was not in compliance with the Colorado Department of

Public Health and/ Environment (CDPHE) standards in water or the Ecological Soil

Screening Concentrations (ECSSL) for soil and tree cores. Concentrations of aluminum, arsenic, cadmium, copper, iron, lead, nickel and zinc all decreased in 2009 water samples when compared to previously reported concentrations. However, aluminum, cadmium, copper and manganese concentrations were still above the CDPHE standards in water.

Cadmium, copper, iron, nickel, and zinc concentrations all decreased in sediment samples when compared to previous year's results, but remained above ECSSL concentrations.

Concentrations of aluminum, arsenic, lead and manganese concentrations all increased in

2009 when compared to previously reported data in sediment. Arsenic, lead and manganese all were above the sediment ECSSLs. Heavy metal limits in both aspen (sc.

Populus tremuloides.) and cottonwood (sc. Populus deltoids) species were below

ECSSLs; however the results indicated that heavy metals could move in between rings of the entire tree. Our study found that the majority of the heavy metal contamination is not coming from the volcanic geology. Summitville Mine still remains as the major contamination source for most of the heavy metals contamination in the Alamosa River

Ecosystem, contrary to our hypothesis.

List of Figures

Figure 1: An Artists Representation of the Summitville-Platoro 2 Caldera

Figure 2: An Artists Rendition of the Volcanically Altered Geology 5 in the Alamosa Watershed

Figure 3: Dissolved Oxygen’s (DO) Reduction Results in Pyrite 10 Oxidation by Ferric Ions

Figure 4: Map of the Alamosa Watershed Marked with 2009 Field 23 Sampling Locations and GPS Coordinates

Figure 5: Mean Dissolved Oxygen (DO) Values from the 2009 33 Collections Season with Their Corresponding Standards set by the Colorado Department of Public Health and Environment (CDPHE)

Figure 6: The Number of Times the Dissolved Oxygen (DO) 34 Concentrations were Below Standards set by the Colorado Department of Public Health and Environment (CDPHE)

Figure 7: Aluminum Concentrations (ppb) in Water Samples Along 38 the Alamosa River

Figure 8: Arsenic Concentrations (ppb) in Water Samples Along the 41 Alamosa River

Figure 9: Copper Concentrations (ppb) in Water Samples Along the 43 Alamosa River

Figure 10: Iron Concentrations (ppb) in Water Samples Along the 46 Alamosa River

Figure 11: Lead Concentrations (ppb) in Water Samples Along the 49 Alamosa River

Figure 12: Selenium Concentrations (ppb) in Water Samples Along 51 the Alamosa River

Figure 13: Cadmium Concentrations (ppb) in Water Samples Along 54 the Alamosa River

Figure 14: Manganese Concentrations (ppb) in Water Samples 55 Along the Alamosa River

Figure 15: Nickel Concentrations (ppb) in Water Samples Along 56 the Alamosa River

Figure 16: Zinc Concentrations (ppb) in Water Samples Along the 57 Alamosa River

Figure 17: Aluminum Concentrations (ppm) in Sediment Samples 63 Along the Alamosa River

Figure 18: Iron Concentrations (ppm) in Sediment Samples Along 64 the Alamosa River

Figure 19: Figure 19. Vanadium Concentrations (ppm) in Sediment 65 Samples Along the Alamosa River

Figure 20: Arsenic Concentrations (ppm) in Sediment Samples 69 Along the Alamosa River

Figure 21: Cadmium Concentrations (ppm) in Sediment Samples 72 Along the Alamosa River

Figure 22: Cobalt Concentrations (ppm) in Sediment Samples 74 Along the Alamosa River

Figure 23: Copper Concentrations (ppm) in Sediment Samples 77 Along the Alamosa River

Figure 24: Lead Concentrations (ppm) in Sediment Samples Along 79 the Alamosa River

Figure 25: Manganese Concentrations (ppm) in Sediment Samples 82 Along the Alamosa River

Figure 26: Nickel Concentrations (ppm) in Sediment Samples 84 Along the Alamosa River

Figure 27: Selenium Concentrations (ppm) in Sediment Samples 87 Along the Alamosa River

Figure 28: Zinc Concentrations (ppm) in Sediment Samples Along 89 the Alamosa River

Figure 29: Arsenic Concentrations (ppm) in Cottonwood Tree 92

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Cores Above and Below Terrace Reservoir

Figure 30: Cadmium Concentrations (ppm) in Cottonwood Tree 93 Cores Above and Below Terrace Reservoir

Figure 31: Cobalt Concentrations (ppm) in Cottonwood Tree Cores 94 Above and Below Terrace Reservoir

Figure 32: Copper Concentrations (ppm) in Cottonwood Tree Cores 95 Above and Below Terrace Reservoir

Figure 33: Lead Concentrations (ppm) in Cottonwood Tree Cores 96 Above and Below Terrace Reservoir

Figure 34: Manganese Concentrations (ppm) in Cottonwood Tree 97 Cores Above and Below Terrace Reservoir

Figure 35: Nickel Concentrations (ppm) in Cottonwood Tree Cores 98 Above and Below Terrace Reservoir

Figure 36: Selenium Concentrations (ppm) in Cottonwood Tree 99 Cores Above and Below Terrace Reservoir

Figure 37: Silver Concentrations (ppm) in Cottonwood Tree Cores 100 Above and Below Terrace Reservoir

Figure 38: Zinc Concentrations (ppm) in Cottonwood Tree Cores 101 Above and Below Terrace Reservoir

Figure 39: Arsenic Concentrations (ppm) in Aspen Tree Cores 103 Above and Below Wightman Forks junction with the Alamosa River

Figure 40: Cadmium Concentrations (ppm) in Aspen Tree Cores 104 Above and Below Wightman Forks Junction with the Alamosa River

Figure 41: Lead Concentrations (ppm) in Aspen Tree Cores Above 105 and Below Wightman Forks Junction with the Alamosa River

Figure 42: Zinc Concentrations (ppm) in Aspen Tree Cores Above 106 and Below Wightman Forks Junction with the Alamosa River

viii

Figure 43: Cobalt Concentrations (ppm) in Aspen Tree Cores 107 Above and Below Wightman Forks Junction with the Alamosa River

Figure 44: Copper Concentrations (ppm) in Aspen Tree Cores 108 Above and Below Wightman Forks Junction with the Alamosa River

Figure 45: Manganese Concentrations (ppm) in Aspen Tree Cores 109 Above and Below Wightman Forks Junction with the Alamosa River

Figure 46: Nickel Concentrations (ppm) in Aspen Tree Cores 110 Above and Below Wightman Forks Junction with the Alamosa River

Figure 47: Selenium Concentrations (ppm) in Aspen Tree Cores 111 Above and Below Wightman Forks Junction with the Alamosa River

Figure 48: Silver Concentrations (ppm) in Aspen Tree Cores 112 Above and Below Wightman Forks Junction with the Alamosa River

Figure 49: Mean pH Values from the 2009 Collections Season with 114 the Corresponding Standards set by the Colorado Department of Public Health and Environment.

Figure 50: The number of times the pH values were below 117 standards set by the Colorado Department of Public Health and Environment.

List of Tables

Table 1: A List of Remediation Efforts That Have Been Completed 11 or are Underway at Summitville Mine

Table 2: Definitions of Water Usage in the State of Colorado 18-19

Table 3: Alamosa River Water Standards Set by the Colorado 20-21 Department of Public Health and Environment

Table 4: Alamosa River Segment Descriptions and Water 24 Classifications

Table 5: May –August 2009 Dissolved Oxygen (DO), Mean 31-32 Temperature and pH Readings for the Alamosa River

Table 6: Aluminum Standards for Sections Sampled Along the 39 Alamosa River in 2009 compared to Median and Maximum Values from Previous Studies

Table 7: Arsenic Standards for Sections Sampled Along the 42 Alamosa River in 2009 Compared to Maximum Values from Previous Studies

Table 8: Copper Standards for Sections Sampled Along the 45 Alamosa River in 2009 compared to Median and Maximum Values from Previous Studies

Table 9: Iron Standards for Sections Sampled along the Alamosa 47 River in 2009 compared to Median and Maximum Values from Previous Studies

Table 10: Lead Standards for Sections Sampled along the Alamosa 50 River in 2009 compared to Maximum Values from Previous Studies

Table 11: Selenium Standards for Sections Sampled along the 52 Alamosa River in 2009 Compared to Maximum Values from Previous Studies

Table 12: Cadmium Standards for Sections Sampled Along the 58 Alamosa River in 2009 Compared to Maximum Values from Previous Studies

Table 13: Manganese Standards for Sections Sampled Along the 59 Alamosa River in 2009 Compared to Median and

Maximum Values from Previous Studies

Table 14: Nickel Standards for Sections Sampled Along the 60 Alamosa River in 2009 Compared to Maximum Values from Previous Studies

Table 15: Zinc Standards for Sections Sampled Along the Alamosa 61 River in 2009 Compared to Median and Maximum Values from Previous Studies

Table 16: Table 16. May–August 2009 Aluminum Concentrations 66 at 5cm and 15 cm Depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Aluminum Designated for each Segment of the Watershed

Table 17: May–August 2009 Iron Concentrations at 5cm and 15 cm 67 Depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Iron Designated for each Segment of the Watershed

Table 18: May–August 2009 Vanadium Concentrations at 5cm and 68 15 cm Depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Vanadium Designated for each Segment of the Watershed

Table 19: May-August 2009 Arsenic Concentrations at 5cm and 15 71 cm depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Arsenic designated for each segment of the watershed

Table 20: May–August 2009 Cadmium Concentrations at 5cm and 73 15 cm Depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Cadmium Designated for each Segment of the Watershed

Table 21: May–August 2009 Cobalt Concentrations at 5cm and 15 75 cm Depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Cobalt Designated for each Segment of the Watershed

Table 22: May–August 2009 Copper Concentrations at 5cm and 15 78 cm Depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Copper Designated for each Segment of the Watershed

Table 23: May–August 2009 Lead levels at 5cm and 15 cm depths 81 collected along the Alamosa River and the Ecological Soil Screening Levels for Lead designated for each segment of the watershed

Table 24: May–August 2009 Manganese Concentrations at 5cm and 83 15 cm Depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Manganese Designated for each Segment of the Watershed

Table 25: May–August 2009 Nickel Concentrations at 5cm and 15 85 cm depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Nickel Designated for each Segment of the Watershed

Table 26: May–August 2009 Selenium Concentrations at 5cm and 88 15 cm Depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Selenium Designated for each Segment of the Watershed

Table 27: May–August 2009 Zinc Concentrations at 5cm and 15 90 cm Depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Zinc Designated for each Segment of the Watershed

Table 28: Table 28. 2009 Median and Average pH Values 115 Compared to Previously Reported Values

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List of Equations

Equation 1: Pyrite Oxidation by Atmospheric Oxygen 4

Equation 2: Sulfur Oxidation by Ferric Ions 4

Equation 3: Generation of Ferrous Sulfates 9

Equation 4: Destruction of Cyanide Using Hydrogen Peroxide 14

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INTRODUCTION

Summitville Mine is located in the San Juan Mountain Range of the Rocky

Mountains, in southwestern Colorado at an approximate elevation of 11,500 ft (Plumlee

1995). It is located within the Rio Grande National Forest, approximately 2 miles east of

the continental divide (Ketellapper, 2000). The San Juan Mountain range was previously

a series of steep active volcanoes (USGS 1995A). Theses volcanoes formed over 30

million years ago; since that time natural erosion has helped to deteriorate the slopes of

these volcanoes. Summitville Mine is located in the north-northwest region of a unique

geological region known as the Summitville-Platoro caldera complex (Bethke et al.

2004). Calderas are formed when the central part of a volcano collapses or explodes,

resulting in a crater that has a diameter much greater than its previous vent. The

Summitville and Platoro calderas intersect along the Pass Creek-Elwood Creek Fault

zone that runs in a northwesterly trend. The Summitville-Platoro caldera complex was

formed by the collapse of the volcanoes summit on two separate occasions. First the

Platoro summit collapsed, and then the newer summit on the Summitville side collapsed forming the Summitville-Platoro caldera. The Summitville-Platoro caldera complex and its sheer size can be visualized in Figure 1.

After the formation of the caldera complex; the rocks inside the volcano that formed the Upper Alamosa River Corridor and the Summitville Mine location were exposed to hydrothermal alteration events. Hydrothermal alteration is a process where the rocks inside the volcano are being exposed to hot corrosive water that is produced by the volcanic system (USGS 1995A). For the formation of the water products the volcano was probably connected to the water table, and the mixing of the magmatic fluids and cooler

Figure 1. An Artist’s Representation of the Summitville-Platoro Caldera. This image was modified from the Alamosa River Watershed Restoration Master Plan and Environmental Assessment (CWCB 2005A). The Summitville-Platoro Caldera is a vast area that includes Summitville Mine, Wightman Fork and Platoro Reservoir.

ground water was inevitable. The magma below Summitville contained many dissolved gases, such as hydrogen sulfide (H2S), and sulfur dioxide (SO2). As the magma cooled

the gases were released. During the gases ascensions, the gases combined with water

(H2O) vapor to form sulfuric acid (H2SO4). The extremely corrosive sulfuric acid traveled through the faults and fractures of the volcano causing a type of disintegration in rocks known as acid sulfate alteration. Acid sulfate alteration results in the surrounding rock becoming porous and allowing the metals in the metal bearing water solutions to deposit as solid minerals into the rock (USGS 1995A; Gray and Coolbaugh 1994; and

Bethke et al. 2004). Rocks are typically able to withstand attacks by acid solutions due to

their natural buffering capacity; however, due to the sheer amount of acid alteration that

is found in the area, the quantity of the acid attacks must have been extremely severe and

numerous (USGS 1995A).

There were two main hydrothermal alteration events at the Summitville-Platoro

caldera complex, the first event occurred in the upper Alamosa River Corridor (USGS

1995A). This event affected an 11 square kilometer area of rock. These rocks are located

in the areas of the Iron, Alum and Bitter Creek basins. The metal bearing water solutions

that caused the acid leaching in the area of Iron, Alum, and Bitter Creeks did not carry

gold, silver or copper. Since there were no precious metal deposits in these areas they

were not extensively mined. The Summitville hydrothermal alteration, affected an area

around 3 square kilometers. The Summitville area did have metal bearing water solutions

that carried gold, silver and copper; which, formed precious metal deposits within the

altered porous rock. In addition to the precious metals, many other compounds were

deposited in the porous rocks such as, pyrite, enargite, chalcopyrite, covellite and

chalcocite.

When the aforementioned minerals encounter erosion and oxidation due to mining

activities or weather such as snow and rain, they have the capacity to generate large

amounts of acid. Formation of acid mine drainage (AMD) requires abiotic and biotic

processes for its generation. During mining activity large amounts of mining waste are

piled up outside of the mine, these piles are known as spoils (Eby 2004). When pyrite is

exposed to oxidizing conditions such as being piled up outside of mine shafts, it will

undergo an initial oxidation reaction with atmospheric oxygen as seen in equation 1

(Madigan et al. 1997).

2+ 2- + 1. FeS2(s) + 3.5O2(g) + H2O(aq) Fe (s) +2SO4 (s) +2H (g)

The abiotic reaction above results in sulfur being oxidized and the generation of acidic conditions. The ferrous ions that are liberated in reaction 1 are stable to further oxidation under pH conditions about 3 or lower. After the initial abiotic process, iron oxidizing bacteria (e.g., Thiobacillus ferrooxidans) can further oxidize ferrous ions to ferric ions.

The biotic oxidation of iron by bacteria is a major factor in the continued generation of

AMD under low pH conditions. The ferric ions will further oxidize sulfur continuing to generate AMD as seen below in equation 2.

3+ 2+ 2- + 2. FeS2(s) + 14Fe (s) + 8H2O(aq) 15Fe (s) + 2SO4 (s) +16H (g)

The minerals in the Summitville Mine area were exposed to large amounts of

sulfuric acid during their volcanic formation leaving them unable to buffer against new

acids generated by AMD and weather (USGS 1995A). These hydrothermally altered

areas that surround the Alamosa River can be seen in Figure 2. Acid drainage can also

Figure 2. An Artist’s Rendition of the Volcanically Altered Geology in the Alamosa Watershed. This image was modified from a United States Geological Survey gif. file (USGS 1995B). The red areas indicate the hydrothermally mineralized areas. The location of Alum, Iron, and Bitter Creek in the volcanically altered area (segment 3a) explains why water conditions in the Alamosa River were poor, prior to mining activity at Summitville Mine.

occur in highly mineralized areas and can naturally have adverse affects on the

environment as seen in the volcanically altered area (segment 3a). Therefore, the

Alamosa River is not only affected by AMD from the mine, but also acid drainage from

the volcanically altered area (segment 3a). During the runoff season and during rain

storms the acids and heavy metals from both areas enter an extensive series of small and

intermediate creeks that flow into the Alamosa River. The effects of the AMD and acid

drainage on the Alamosa River and its tributaries have been seen for many years.

Reports of poor conditions in Alum, Iron, and Bitter Creeks can be traced back to

1917 (Filas and Gormley 1993). The waters of these three creeks were said to have sulfuric and acidic qualities. All three tributaries are also located within an 11 square kilometer area identified by the United States Geological Survey (USGS) as the older of two hydrothermal alteration areas. The conditions present in these three tributaries can be attributed to the volcanic geology of the area since none of these tributaries were highly disturbed by mining activity or extensively explored (USGS 1995A). These three tributaries join the Alamosa River prior to its junction with the Wightman Fork the mine drainage. The water from the volcanically altered tributaries and the mine drainage all flow downstream into Terrace Reservoir.

The Alamosa River enters Terrace Reservoir before continuing downstream to the

San Luis Valley floor where it is used for irrigation. Terrace Reservoir was originally constructed in 1911 for use as an irrigation reservoir; this is still its primary function today (CDPHE 2001). Water that is released from Terrace Reservoir is used for agricultural irrigation, livestock watering, and wildlife habitat. Crops that are grown using water from the Alamosa River include alfalfa, barley, wheat and potatoes. A 1994

study found significantly higher concentrations of copper, manganese and nickel in

alfalfa crops irrigated with water from Terrace Reservoir (Erdman and Smith 1995).

Concentrations of copper, manganese and nickel in alfalfa crops irrigated with water

from Terrace Reservoir were determined to be significantly higher when they were

compared with metal concentrations in alfalfa crops grown in fields irrigated with water

from a different source. The concentrations of these metals in the alfalfa crops irrigated

with water from Terrace Reservoir were below or close to nutritional needs for cattle.

However, copper concentrations were approaching non-tolerable concentrations for

sheep. This study also analyzed metal concentrations in water irrigation samples and

determined that the irrigation water from Terrace Reservoir had elevated metal

concentrations when compared to other irrigation sources. The study determined that the

elevated metal concentrations in the irrigation water from Terrace Reservoir had only

minor effects on the soil chemistry, and demonstrated that increased metal concentrations

caused by Summitville Mine were having effects in crops further downstream. The

Alamosa River also feeds wetlands that are habitat for aquatic life, and is a temporary

home for many species of migratory waterfowl that visit the San Luis Valley each year.

Dating as far back to 1889, the Alamosa River had been known as a trout stream

containing Rio Grande Cutthroat Trout. However, by 1985 the Cutthroat Trout

populations had disappeared (Rupert 2001). Reports of reproducing Brook Trout in the river still remained. From 1960 to 1990, Terrace reservoir was stocked with Rainbow

Trout for anglers, but by July of 1990, the Colorado Division of Wildlife had reported that fish no longer existed in the reservoir. On June 23rd, 1990 the copper concentration in

the Alamosa River, upstream of Terrace reservoir, was 1,270μg/L, which was

significantly higher than the concentration of 30μg/L measured in 1986 (Rupert 2001).

The 96-hour LC50 for copper (the concentration of copper that will kill 50 percent of the

test species in four days) for rainbow trout is 52 µg/L. Even though volcanic

contamination and some early lode and placer mining contamination were present in the

Alamosa River, the increased acid and metal loadings from Summitville are suspected in

the disappearance of stocked fish from both Terrace Reservoir and farm holding ponds

along the Alamosa River (Plumlee 1995).

The disappearance of fish from the Alamosa River Watershed could have also

been attributed to low dissolved oxygen (DO) content in the water. A low DO

concentration is a characteristic that is present in many polluted rivers (Lloyd 1961). Fish

species generally are unable to survive DO concentrations below 3 mg/L (Murphy 2007).

When fish are in low oxygen containing water they will increase the volume of water

passing through the gills in order to meet their oxygen demands (Lloyd 1961). By

increasing the rate of water passing through the gills they are also increasing the amount

of heavy metal toxins crossing the gill epithelium where most toxins are absorbed, thus

making toxicity and death more rapid. The optimal DO concentrations for adult trout is

anywhere between 9-12 mg/L. The general DO requirements for segments in the

Alamosa River, except for the Wightman Fork mine drainage (segment 6), which has no

general DO requirement, is 7 mg/L during spawning and 6 mg/L when spawning is not occurring (USFWS 2005).

DO concentrations have been shown to decrease when high concentrations of ferrous sulfate are present (Oba and Poulson 2008). The Alamosa River most likely has high concentrations of ferrous sulfate due to the large amounts of pyrite in the surround

geology (King, 1995; Bethke et al. 2004) Pyrite can be directly oxidized by atmospheric

oxygen resulting in the formation of ferrous sulfates as seen below in equation 3 (Hu et

al. 2006).

3. FeS2(s) + 3O2(g) FeSO4(s) + SO2(g)

DO does not interact directly with pyrite, but its reduction causes the oxidation of pyrite by generating reactive ferric ions on the pyrite surface (Moses and Herman 1991).

This process removes DO from the rivers by reducing DO to H2O. The reduction of DO

and the oxidation of pyrite can be seen in Figure 3.

Historically, mining of gold and silver began at Summitville around 1870

(CDPHE 2009B). Placer gold was first discovered in the Summitville area in 1870 and

by 1873 several gold lodes had been identified (Gray and Coolbaugh 1994). Prior to the

1960’s Summitville was mined using underground tunnels where the high grade ore

would be extracted from veins (USGS 1995A). Summitville was shut down due to these

techniques not being very economical and since the gold was scattered in small amounts

over large areas. From 1985-1992, Summitville Consolidated Mining Corp., Inc.

(SCMCI) used open-pit mining and cyanide heap-leaching techniques to extract gold from low grade ore. These operations resulted in a series of environmental problems.

There was a significant increase in the amount of acidic and metal-rich drainage from the site. There were several leaks of cyanide-bearing solutions from the heap-leach pad and several surface leaks that were entering into Wightman Fork of the Alamosa River.

Leakage from the mine caused the release of heavy metals (copper, cadmium, manganese, zinc, lead, nickel, aluminum and iron) into the water (CDPHE 2009A).

Figure 3. Dissolved Oxygen’s (DO) Reduction Results in Pyrite Oxidation by Ferric Ions. This figure was modified from Moses and Herman (1991). DO does not interact directly with pyrite, but its reduction causes the oxidation of pyrite by generating reactive ferric ions on the pyrite surface (the chemical reaction above is illustrative but not balanced in its details). This process removes DO from the rivers by reducing DO to H2O. TS indicates a transition state while P corresponds with the product of the reactions above. The product of the steps above is the starting point for the next step in the cycle.

SCMCI declared bankruptcy in December of 1992 and abandoned Summitville; the site

has since been under the control of the Environmental Protection Agency’s (EPA)

Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) or more commonly known as a Superfund site (USGS 1995A). Summitville was later

added to the EPA’s National Priorities List in May of 2004. The total cost for clean up

were first estimated at $100 to $120 million dollars. To date the cleanup costs at

Summitville have exceeded $180 million dollars and this was prior to the Valley Courier

News Paper reporting in the Fall of 2009 that President Barack Obama’s stimulus plan

would add another 10 to 25 million for the cleanup efforts at Summitville (Mullens

2009).

Remediation efforts to clean up Summitville Mine and the Alamosa River have

been underway since 1992. Beginning in 1992, the EPA and Colorado Department of

Public Health and Environment (CDPHE) began several interim projects that were

designed to slow down the amount of AMD coming for the Summitville Mine site

(CDPHE 2009A). The CDPHE was the lead agency on the largest interim project that

has been implemented at the site; they were in charge of site wide reclamation and

regevetation. Prior to any remediation being completed at Summitville Mine, a remedial

investigation and feasibility study for the Summitville Site was conducted by the

CDPHE. Their study began in 1998 and outlined final construction of long term projects

that must be completed to wrap up the cleanup efforts at Summitville Mine; as well as

smaller interim measures that were already completed. There have been several projects

to date that have been completed at the Summitville Mine site, a list of completed and

ongoing projects is provided in Table 1.

Table 1. A List of Remediation Efforts That Have Been Completed or are Underway at Summitville Mine1

Year Descriptions of the remediation that are underway or have already been completed The EPA and CDPHE took over the site due to the potential harm that Summitville Mine could 1992-1994 have caused to the environment and the people in surrounding communities. Initial reports were published with decisions on how cooperating government agencies would mitigate concerns with the following areas/topics; the water treatment plant, the Cropsy Waste 1994 Pile, the Beaver Mud Dump, the Summitville Dam impoundment, Summitville Mine pits, the heap leach pad detoxification, and reclamation. 1994-1995 The heap leach pad was detoxification 1994 The Reynolds adit was sealed The Cropsy Waste Pile, Beaver Mud Dump, 1996 Summitville Dam Impoundment and mine pit were all closed. 1996-2000 Modifications were done to the existing water treatment plant 1994-1998 The restoration and re-vegetation of Cropsy Valley was completed 1998 A cap was added to the heap leach pad 1998 Reclamation of heap leach pad, and north west dump was completed 1998-2001 A site wide remedial investigation and feasibility study was completed 2001 A site wide report was published 2002 Site wide reclamation was completed 2004 The new water treatment plant design was completed 2004-2005 Construction of contaminant source collection structures was completed The CDPHE assumed the lead role for the wastewater treatment plant and site operation and 2005 maintenance 2006 There was a rule change before the Water Quality Control Commission for the Alamosa River Wightman Fork and the Summitville dam impoundment were improved upon with the installation 2008-2009 of micro-hydro-power 2010 Construction of the new water treatment plant is to begin

1 CDPHE 2009A

The reclamation work that has been done at Summitville mine has consisted of

permanent roads being identified and constructed for access to key areas at the mine

(Ketellaper 2000). The site was retrofitted with an extensive series of pipelines and

ditches to manage site drainage (Ketellaper 2000; CDPHE 2009A). The ditches were

engineered to withstand a 500-year storm event, therefore a large storm could not cause

great damage to the site and endanger the public and habitats further downstream

(CDPHE 2005). Slopes and depressions surrounding the mine that were greater than 3:1

were graded to reduce water infiltration at the mine site (CDPHE 2001).The subsoil’s in

disturbed areas around the mine had a mix of limestone and mushroom compost added to

them prior to the areas being re-vegetated (Ketellaper 2000). Approximately 250 acres were re-vegetated around the Mine (CDPHE 2009B).

Waste rock piles were removed from the Cropsy Waste Piles and Beaver Mud Dump to reduce the generation of AMD. The waste rock piles were backfilled into open mine pits to reduce water percolation into the ground (CDPHE 2009B). The open mine pits were lined with three feet of clay and then had five feet of lime kiln dust added to them to help with acid neutralization prior to any mine waste being backfilled into them (Ketellaper

2000). The mine adits (underground mine entrances) were plugged to reduce acid drainages that could come from the mine workings (CDPHE 2009A; CDPHE 2009B).

Additionally the Summitville Dam height was raised, as well as being further modified with the addition of a new spillway and stabilized with the installation of a gravel drain and sand filter (Ketellaper 2000).

Equally important to the structural components and the cleanup of mine waste at

Summitville Mine was the treatment of waste water in the heap leach pad prior to its

release downstream. The preexisting water treatment plant was retrofitted in order to treat 1.4 million gallons of contaminated water per day (CDPHE 2009B). The old water treatment plant is to be replaced by a new water treatment plant that is to undergo construction in 2009-2011. A precipitation process is used to treat the water and remove heavy metals prior to release in Wightman Fork (Ketellaper 2000). This study was unable to determine the exact chemical reagents that are used in the precipitation process at

Summitville Mine. After the precipitation process the clean water is then pumped back into a clean storage facility and the solids are removed. A 90 million gallon wastewater holding pond was also constructed to help with the removal of metals and acidity.

The heap leach pad also required extensive work, since this is where the low grade gold ore was isolated using a cyanide solution. The heap leach pad at Summitville

Mine has been detoxified, capped and revegetated in order to reduce the concentrations of cyanide in it, and also to reduce the infiltration of snowmelt and precipitation (CDPHE

2009B; Ketellaper 2000). The heap leach pad was detoxified using a chemical treatment method (Ketellaper 2000). This method consisted of rinsing the heap leach pad with clean water. After the rinse, a 70% hydrogen peroxide solution was injected into the water cyanide solution as it was treated in the onsite water treatment plant. The addition of the hydrogen peroxide allows the cyanide to be converted to cyanate as seen in equation 4

(Akcil 2003).

- 2+ - 4. H2O2 + CN Cu + catalyst OCN +H2O

After the cyanide was removed using the hydrogen peroxide, the water was further treated using a precipitation process for the removal of metals before water being

released into Wightman Fork. The removal of cyanide was discontinued after September,

1995 once water and sediment samples from the heap leach pad showed a reduction in

cyanide concentrations and no health hazards were present.

The heap leach pad has been further improved by regrading it into a dome shape

prior to the addition of a cap (Ketellaper 2000). The cap that was put in the heap leach

pad consisted of a geocomposite drain that was placed between two layers of

geosynthetic clay liner. A geosynthetic clay liner is a liner that has bentonite clay

between two layers of geosynthic fabric. The geosynthetic layer is to help reduce water

infiltration. The cap was then covered by a 1.2129 meters (m) thermal layer that consists

of two different layers itself. The first layer that made up the thermal layer was 1.0668 m

deep; it consisted of heap leach pad material that had been mixed with crushed limestone.

The second layer was 15.2 centimeters (cm) deep and consisted of sediment that had

limestone and mushroom compost added to it. Limestone was added to both layers to

help neutralize the soil, and mushroom compost was also added to help facilitate plant

growth and sustainability.

STUDY HYPOTHESIS AND OBJECTIVES

The cleanup efforts are still underway at Summitville Mine; however, to the best

of our knowledge data of recently conducted evaluations of the heavy metal contaminates

in the water and sediment from the Alamosa River are missing or not available. The last

publication that contained water quality data for the Alamosa River was printed in 2005

by cooperating government agencies (CWCB, 2005A). The data presented in this publication were collected from 1986 to 2003. Sediment analysis along the Alamosa

River was last done in the year 2000, by the Rocky Mountain Consultants and the

Environmental Protection Agency (EPA). The EPA samples were collected in 2001, and

the Rocky Mountain Consultants data was collected in 2000. Consequently, it was critical

to provide updated information on water and sediment from the Alamosa River by

determining the effectiveness of the remediation efforts in reducing contamination. We

hypothesize that the water quality of the Alamosa River and the surrounding ecosystem is

now cleaner 15 years after EPA’s remediation efforts began. We further hypothesize that the majority of the water contamination is no longer coming from Summitville Mine, but from the volcanic geology of the mountains. We aimed to evaluate the effectiveness of the remediation efforts initiated in 1994 to reduce heavy metal concentrations in Terrace

Reservoir and along the Alamosa River corridor following environmental degradations caused by mining operations from 1985-1992. Specifically, we 1) compared concentrations of heavy metals in water, sediment and tree core samples collected at and downstream from the mining site to concentrations in samples collected upstream from the mining site; and 2) compared the concentrations of a selected few inorganic elements

(heavy metals and others) at the mining site to the concentrations recorded in 2000, 2003, and to current metal standards.

The results of the current study were compared to maximum, mean, median and range concentrations recorded between 1986-2003 and reported in 2001 and 2005. This approach was used because metal concentrations in the water and sediment vary

depending on the volume of water in the Alamosa River. Comparing the mean metal

concentrations with the metal standards allows us to determine if metal concentrations

that are regularly found are exceeding these standards. Comparisons of the maximum

metal concentrations with the standards allow us to determine if the standards are being

exceeded by extreme conditions. Comparing both the mean and maximum metal concentrations to the standards allows us to better visualize what is truly happening in the

Alamosa River Ecosystem. Median concentrations in water samples were used for comparison purposes because previous reports did not provide mean metal concentrations in water. Comparison of range data allows for the visualization of metal concentrations for the whole collection season, since it contains the minimum and maximum concentration for each segment. Due to the complexity of water laws and regulations the

Alamosa River was evaluated by segments. Each segment of the Alamosa River has its own usage and metal standards set by the Colorado Department of Public Health and

Environment (CDPHE) that we will be comparing our water results with. In the State of

Colorado water quality determines how the water can be used; the definitions of water classifications that are used to describe the waters of the Alamosa River can be seen in

Table 2. The Alamosa River has specific guidelines that must be met in respect to heavy metal concentrations. The metal standards that are specific for each segment that we sampled in the Alamosa River can be seen in Table 3.

MATERIALS AND METHODS

Area of Study

The sampling areas for the water, sediment and tree core collections were identified from the 1995 United States Geological Survey (USGS) publication,

Environmental Considerations of Active and Abandoned Mine Lands, Lessons from

Summitville, Colorado (USGS 1995A). We used the tree core map that was provided in the previous report to identify our collection sites. All of the sample sites in this map were re-sampled, with the exception of site E due to its rough access, and also sites

Table 2. Definitions of Water Usage in the State of Colorado1

Classifications Definitions Primary Contact Recreational activities were the ingestion of small quantities of water is likely to occur. Such activities include but are not Recreation limited to swimming, rafting, kayaking, tubing, windsurfing, water-skiing, and frequent play by children. Class E - Existing Primary Contact Use Recreation Class E These surface waters are used for primary contact recreation or have been used for such activities since November 28, 1975 Class P - Potential Primary Contact Use

These surface waters have the potential to be used for primary contact recreation. This classification shall be assigned to Recreation Class water segments for which no use attainability analysis has been performed demonstrating that a recreation class N P classification is appropriate, if a reasonable level of inquiry has failed to identify any existing primary contact uses of the water segment, or where the conclusion of a UAA is that primary contact uses may potentially occur in the segment, but there are no existing primary contact uses.

Class N - Not Primary Contact Use Recreation Class These surface waters are not suitable or intended to become suitable for primary contact recreation uses. This N classification shall be applied only where a use attainability analysis demonstrates that there is not a reasonable likelihood that primary contact uses will occur in the water segment(s) in question with in the next 20-year period. Class U - Undetermined Use

Recreation Class These are surface waters whose quality is to be protected at the same level as existing primary contact use waters, but for U which there has not been a reasonable level of inquiry about existing recreational uses and no recreation use attainability analysis has been completed. This shall be the default classification until inquiry or analysis demonstrates that another classification is appropriate.

1 CDPHE 2007B

Table 2. (cont.) Definitions of Water Usage in the State of Colorado1

Classifications Definitions These surface waters are suitable or intended to become suitable for irrigation of crops usually grown in Colorado and which Agriculture are not hazardous as drinking water for livestock. These surface waters presently support aquatic life uses as described below, or such uses may reasonably be expected in Aquatic Life the future due to the sustainability of present conditions, or the waters are intended to become suitable for such uses as a goal:

These are waters that (1) currently are capable of sustaining a wide variety of cold water biota, including sensitive species, or Class 1 - Cold (2) could sustain such biota but for correctable water quality conditions. Waters shall be considered capable of sustaining water Aquatic such biota where physical habitat, water flows or levels, and water quality conditions result in no substantial impairment of the Life abundance and diversity of species.

These are waters that (1) currently are capable of sustaining a wide variety of warm water biota, including sensitive species, Class 1 - Warm or (2) could sustain such biota but for correctable water quality conditions. Waters shall be considered capable of sustaining Water Aquatic such biota where physical habitat, water flows or levels, and water quality conditions result in no substantial impairment of the Life abundance and diversity of specifies.

Class 2 - Cold These are waters that are not capable of sustaining a wide variety of cold or warm water biota, including sensitive species, and Warm due to physical habitat, water flows or levels, or uncorrectable water quality conditions that result in substantial impairment of Water Aquatic the abundance and diversity of species. Life

1 CDPHE 2007B

Table 3. Alamosa River Water Standards Set by the Colorado Department of Public Health and Environment1

River Section Numerical Standards Physical and Biological Metals Standards μg/L (Metals are shown by Element Symbol) Segment 3a DO=6.0 mg/L Al(ac2)=750 Cu(ac)=TVS Ni(ac/ch)=TVS DO=7.0mg/L (during spawning) As(ch3)= 100(TR4) Fe(ch)12000(TR) Se(ac/ch)=TVS Seasonal Stds. Cd(ac/ch)=TVS5 Pb(ac/ch)=TVS Ag(ac/ch)=TVS 12/1-2/28: pH=3.52-9.0 Cu(ac/ch)=TVS Mn(ac/ch)=TVS Zn(ac/ch)=TVS 3/1-5/31: pH=4.0-9.0 6/1-8/31: pH=4.73-9.0 9/1-11/31: pH=3.94-9.0 Segment 3b DO=6.0 mg/L Al(ac)=750 Cu(ch)=30 Se(ac/ch)=TVS DO=7.0 mg/L (during spawning) As(ch)= 100(TR) Fe(ch)12000(TR) Ag(ac/ch)=TVS pH=6.5-9.0 Cd(as/ch)=TVS Pb(ach/ch)=TVS Zn(ac/ch)=TVS Cu(ac)=TVS Mn(ac/ch)=TVS Seasonal Stds: Ni(ac/ch)=TVS 5/1-9/30 Al(ch)=87

Segment 3c DO=6.0 mg/L Al(ac)=750 Cu(ac/ch)=TVS Se(ac/ch)=TVS DO=7.0 mg/L (during spawning) Al(ch)=87 Fe(ch)12000(TR) Ag(ac/ch)=TVS pH=6.5-9.0 As(ch)= 100(TR) Pb(ac/ch)=TVS Zn(ac/ch)=TVS Cd(as/ch)=TVS Mn(ac/ch)=TVS Cu(ac/ch)=TVS Ni(ac/ch)=TVS

1 USFWS 2005 2 ac: Acute standard 3 ch: Chronic standard 4 TR: Total recoverable concentrations 5 TVS: Table value standard

Table 3. (cont.) Alamosa River Water Standards Set by the Colorado Department of Public Health and Environment1

River Section Numerical Standards Physical and Biological Metals Standards μg/L (Metals are shown by Element Symbol) Segment 3d DO=6.0 mg/L Al(ac2)=750 Fe(ch)12000(TR) Se(ac/ch)=TVS DO(during spawning)=7.0 mg/L Al(ch 3)=87 Pb(ach/ch)=TVS Ag(ac/ch)=TVS pH=6.5-9.0 As(ch)= 100(TR4) Mn(ac/ch)=TVS Zn(ac/ch)=TVS Cd(as/ch)=TVS5 Ni(ac/ch)=TVS Cu(ac/ch)=TVS

Segment 5 pH=6.5-9.0 As(ch)= 50(TR) Fe(ch)1000(TR) Se(ac/ch)=TVS Cd(as/ch)=TVS Pb(ac/ch)=TVS Ag(ac/ch)=TVS Cu(ac/ch)=TVS Mn(ac/ch)=TVS Zn(ac/ch)=TVS Ni(ac/ch)=TVS

Segment 6 No limits No limits No limits No limits Segment 9 D.O=6.0 mg/L Al(ac)=750 Fe(ch)1000(TR) Ni(ac/ch)=TVS DO(during spawning)=7.0 mg/L Al(ch)=87 Pb(ach/ch)=TVS Se(ac/ch)=TVS pH=6.5-9.0 As(ch)= 100(TR) Mn(ac/ch)=TVS Ag(ac/ch)=TVS Cd(as/ch)=TVS Mn(ch)=200 Zn(ac/ch)=TVS Cu(ac/ch)=TVS

1 USFWS 2005 2 ac: Acute standard 3 ch: Chronic standard 4 TR: Total recoverable concentrations 5 TVS: Table value standard

I, J, and K, due to them being located on private land. We chose an additional site above

Summitville Mine along Wightman Fork. This was done to provide a pristine control site for our study. The control site allows us to compare metal concentrations in the river above and below the mine to determine the effects that the mine has on the downstream portion of the Alamosa River. The Alamosa watershed is broken up into different segments. Each segment of the Alamosa watershed has different water standards.

Because of this we made sure that each of our sampling locations was located within the sections of interest. The sampling locations that were used in this study can be seen in

Figure 4. Descriptions of the sampling sites location can be seen in Table 4 as well as the segments specific water classification.

Sampling Method for Water

Water samples were collected in accordance with United States Geological

Survey (USGS) water sampling protocol (USDI 2009). Since our time period for sample collections was during the run off season, a Polyvinyl Chloride (PVC) pipe with a diameter of 3.1centimeters (cm) and 1.8288 meters (m) in length was designed with an extendable arm that allowed for the collection of samples from the middle of the river, from the safety of the bank. The extendable arm was a PVC pipe that had a diameter of

2.5 cm and was approximately 3.048 m in length. The arm slid in and out of the first PVC pipe. The second PVC pipe had a 90° angle with an additional 30.5 cm piece of PVC pipe at one end, which was notched to hold the nalgene container for water collection with plastic zip ties. The water samples were collected in sterile nalgene bottles upstream of any man made structure. The bottles were submerged to a depth of approximately 10 cm with the mouth of the bottle facing downstream so no organic matter was captured. The

Figure 4. Map of the Alamosa Watershed Marked with 2009 Field Sampling Locations and GPS Coordinates. This is a modified image is from the Alamosa River Watershed Restoration Master Plan and Environmental Assessment (River Watershed, 2005). It has been modified to show the 2009 field collection sites that were used for the completion of this study. The collection sites are indicated by the Xs. The collection sites were accessed by the use Forest Service Roads 255, 250 and 380.

Table 4. Alamosa River Segment Descriptions and Water Classifications1

Sampling River Description Classifications Location Section

Cold 1 Aq Life Mainsterm of Wightman Fork from source to west line of S30, T37N, 7 Segment 5 Recreation E R4E, including all tributaries and wetlands. Agriculture Manistem of Wightman Fork from the west life of S30, T37N, R4E to Recreation E 5 Segment 6 the confluence with the Alamosa River. Agriculture Mainsterm of the Alamosa River from immediately above the Cold 2 Aq Life 6 Segment 3a confluence with Alum Creek to immediately above the confluence of Recreation E Wightman Fork. Agriculture Mainsterm of the Alamosa River from immediately above the Cold 1 Aq Life 4 Segment 3b confluence with Wightman Fork to immediately above the confluence Recreation E with Fern Creek. Agriculture Cold 1 Aq Life Mainsterm of the Alamosa River from immediately below the 3 Segment 3c Recreation E confluence with Fern Creek to the Confluence with Ranger Creek. Agriculture

Cold 1 Aq Life Mainsterm of the Alamosa River from immediately below the 2 Segment 3d Recreation E confluence with Ranger Creek to the inlet of Terrace Reservoir. Agriculture

Cold 1 Aq Life Mainstem of the Alamosa River from the outlet Terrace Reservoir to 1 Segment 9 Recreation E Colorado Hwy 15. Agriculture

1 CWCB 2005A

bottles were always handled with sterile gloves. After collection the samples were labeled

and placed in Ziplock bags to be stored on ice until reaching the laboratory. Within 24

hours from collection, half of the water in each of the water samples was filtered through

a Corning 25mm sterile non-pyrogenic syringe filter and placed into its own sterile

nalgene container. The non-filtered halves were used to measure the total amount of

metals in the water. The filtered samples were used to measure the dissolved heavy

metals that were present in the water. After the samples were separated into a total

recoverable sample and a dissolved sample, trace grade nitric acid was titrated in to the

samples until they reached a pH of 2.0 (Creed et al. 1994). The addition of the trace grade

nitric acid was done for preservation and for the analysis of the samples while using the

Inductively Coupled Plasma-Mass Spectrometry (ICP-MS).

Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)

The water samples were processed in the Environmental Laboratories of the

Chemistry Department at Colorado State University- Pueblo and analyzed using an

Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) as described in the

Environmental Protection Agency (EPA) Method 200.8, Determination of Trace

Elements in Waters and Wastes by Inductively Coupled Plasma. Samples were

transferred into ≥20mL polypropylene centrifuge tube once in the tube the pH was double

checked to ensure it was at a pH of 2 and was then run in the ICP-MS. The ICP-MS analyzed the samples for 27 different heavy metals including: 23Na, 24Mg, 27Al, 31P, 39K,

40Ca, 44Ca, 51V, 52Cr, 55Mn, 56Fe, 59Co, 60Ni, 63Cu, 66Zn, 75As, 78Se, 98Mo, 107Ag, 111Cd,

121Sb, 133Cs, 137Ba, 202Hg, 205Tl, 208Pb, 232Th, and 238U. The heavy metals in the subset

were chosen based on one of the following requirements: the heavy metals concentrations

in water samples were previously recorded and reported upon in previous reports specifically dealing with the Alamosa River and/or the heavy metal concentrations must be below a specific standard set by the Colorado Department of Public Health (CDPHE).

Onsite Water Tests

In addition to analyzing the water for heavy metals, the dissolved oxygen (DO), pH and temperature for each site was recorded during each sampling. The DO was tested using a LaMotte DO Test Kit (Model EDO, Code 7414). Since the EPA would like to reintroduce fish into this watershed and Terrace Reservoir, we felt that it was important to determine if DO concentrations would be supportive at this state in the remediation for the reintroduction of fish (USGS 1995A; CWCB 2005A). The pH of the water was tested using an automated pH indicator from Oakton Instruments (Model 35624-03). The temperature of the water was recorded using two thermometers from Fisher brand. The thermometers were placed in the river for approximately 5 minutes and collected after all of the sampling was done at that site.

Sampling Method for Sediment

The sediment was collected using a Polyvinyl Chloride (PVC) sediment corer.

The corer was hand-made from a piece of PVC pipe with a diameter of 3.1centimeters

(cm) and it was cut to a length of 35cm. The outer edge of the pipe was beveled towards the center so it would slide into the sediment. The sediment cores were collected on the bank of the river, analogous with the same location of the water sampling. Two sediment samples were collected; the first sample consisted of the first 5 cm of sediment, the second sample was the next 10 cm of sediment, for a total depth of 15 cm. The corer was pushed into the bank until it had reached the proper depth and then with a gloved hand,

suction was created on the free end of the corer, which was pulled out with the sediment

core inside of it. The two samples were stored in separate Ziplock bags, on ice until

returning to the lab. The sediment samples were collected at the two depths in order to

examine movement of heavy metals through the sediment. Upon returning to the lab the

sediment samples were oven-dried at approximately 30° C ±4°C for 24 hours (USEPA

1996). Samples were then sieved to particles with a diameter less than 2 millimeters

(mm) and stored in plastic containers until time of chemical analysis.

Chemical Digestion for Sediment Samples

The sediment samples were processed in the Environmental Laboratories of the

Chemistry Department at Colorado State University- Pueblo. The sediment samples were chemically digested in a microwave system using the Environmental Protection Agency

(EPA) Method 3052 (USEPA 1996). Samples were digested in Teflon tubes that contained a 100 milliliters (mL) quartz reaction vessel with 0.2 grams (g) of sediment,

4.5 mL of Trace grade Nitric acid and 1.5 mL of Trace grade HCl. After the quartz reaction vessel was prepared 10ml of H2O and 2 mL of H2O2 were placed on the outside

of the quartz vessel inside of the Teflon tube. The digestion was then run for a total of 15

minutes once the microwave reached 180°C. After the samples had been chemically

digested they were then run in the Inductively Coupled Plasma-Mass Spectrometry (ICP-

MS) for analysis of their heavy metal content. The sediment samples were analyzed with

the ICP-MS using EPA Method 6020A, Inductively Coupled Plasma-Mass Spectrometry

(USEPA 2007A). EPA Method 6020A is very similar to 200.8 however; it is for sediment and solid samples. The ICP-MS analyzed the sediment samples for the same 27 heavy

metals as water samples. The heavy metals in the subset were chosen based on one of the

following requirements: the heavy metals concentrations in sediment samples were

previously recorded and reported upon in previous reports specifically dealing with the

Alamosa River and/or the heavy metal concentrations must be below specific standards

known as the Ecological Soil Screening Levels (ECSSL) set by the Environmental

Protection Agency (EPA).

Sampling Method for Tree Cores

Two trees along the river were selected at random at each site, based on water and

sediment sampling sites. Two different species of trees had to be sampled due to tree

species changing as the sites increased in elevation. Cottonwoods (sc. Populus deltoids)

were sampled below and above Terrace Reservoir (segments 9 and 3d) and Quaking

Aspens (sc. Populus tremuloides.) were sampled at the rest of the sites (segments 3a, 3b,

3c and 6). The pristine site (segment 5) did not have any deciduous trees surrounding its

location, so no samples were collected there. The cores were taken from the tree at breast

height (1.5 meters) using a steel borer. After harvesting an individual core they were

placed in a Ziplock bag and placed in the cooler for transport to the laboratory where the

tree cores were oven-dried in glass containers at 70° C for 48 hours (Watmough and

Hutchinson 1995). The cores were then separated into ten year periods from 1980 to

2009. This was done that way the metal contamination could be evaluated for each of the decade time periods. The decade time periods were then homogenized using a mortar and pestle, prior to the samples chemical digestion.

Chemical Digestion for Tree Core Samples

Tree core samples were processed in the Environmental Laboratories of the

Chemistry Department at Colorado State University- Pueblo. Samples were chemically

digested in a microwave system using the Environmental Protection Agency (EPA)

Method 3052 (USEPA 1996). Samples were digested in Teflon tubes that contained a 6 milliliters (mL) quartz reaction vessel with 0.2 grams (g) of tree core, 1 mL of Trace grade Nitric acid and 0.5 mL of Trace grade HCl. After the quartz reaction vessel was prepared 10 ml of H2O and 2 mL of H2O2 were placed on the outside of the quartz vessel inside of the Teflon tube. The digestion was then run for a total of 15 minutes once the microwave reached 180°C. After the samples had been chemically digested they were then run in the Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) for analysis of their heavy metal content. The tree core samples were analyzed with the ICP-MS using

EPA Method 6020A, Inductively Coupled Plasma-Mass Spectrometry (USEPA 2007A).

EPA Method 6020A is very similar to 200.8 however; it is for sediment and solid samples. The ICP-MS analyzed the tree core samples for the same 27 heavy metals as water samples. The heavy metals in the subset were chosen based on one of the following requirements: the heavy metals concentrations in tree core samples were previously recorded and reported upon in previous reports specifically dealing with the Alamosa

River and/or the heavy metal concentrations must be below the specific plant standards in the Ecological Soil Screening Levels (ECSSL) set by the Environmental Protection

Agency (EPA).

Statistical Analysis

The water samples were statistically analyzed using a Mann Whitney test and a

Kruskal Wallis test in order to determine if the sample locations were significantly different than the pristine site (segment 5; Crocket 2006). These tests were used instead of an Analysis of Variance Test (ANOVA) due to the raw water data being skewed. The

sediment samples were not skewed; therefore they were analyzed using an ANOVA test.

The ANOVA test also tested to see if the sample locations were significantly different than the pristine sample site. The tree cores were statistically analyzed using an ANOVA test to determine if concentrations were significantly different among segments within a single decade. Paired T-Tests were used to determine if decades among individual sites were significantly different.

RESULTS

Onsite Testing Results

Dissolved oxygen (DO) concentrations in the 2009 sampling season ranged from

2.0-6.4 milligrams/liter (mg/L) in the Alamosa River. The DO concentrations of water samples that were collected at each segment for the entire season are provided in Table 5.

The majority of our samples did not meet the Colorado Department of Public Health and

Environment (CDPHE) minimum standard of 6 mg/L (Murphy 2007). Samples in the volcanically altered area (segment 3a), below the Wightman Fork mine drainage

(segments 3b and 3c) and below Terrace Reservoir (segment 9) were all below the

CDPHE standard of 6 mg/L (Figure 5). The 2009 mean DO concentrations and DO standards can be seen in Figure 5. Samples below the mine drainage (segment 3d) had 5 out of 6 concentrations below the CDPHE standard (Table 5; Figure 6). The number of times that the DO concentrations were not in compliance with the DO standards can be seen in Figure 6. The pristine site (segment 5) and the mine drainage (segment 6) have no dissolved oxygen (DO) CDPHE standards (USFWS 2005; Table 5). However; the pristine site (segment 5) is classified by the CDPHE as suitable for Class 1 Cold Water

Aquatic Life, Recreation 1a, and Agriculture uses. Both the Class 1 Cold Water Aquatic

Table 5. May –August 2009 Dissolved Oxygen (DO), Mean Temperature and pH Readings for the Alamosa River

River Segment Trip Date DO)Regulation (mg/L)1 DO (mg/L) Temperature (°C) pH Seasonal Requirement1 2009 pH Segment 3a 1 5/3/2009 DO= 6.0 3.8 3 3/1-5/31: pH=4.0-9.0 7.8 Segment 3a 2 5/27/2009 DO= 6.0 4.4 8 3/1-5/31: pH=4.0-9.0 8 Segment 3a 3 6/13/2009 DO= 6.0 4.8 5 6/1-8/31: pH=4.73-9.0 7.7 Segment 3a 4 7/6/2009 DO= 6.0 4.4 10 6/1-8/31: pH=4.73-9.0 4 Segment 3a 5 7/21/2009 DO= 6.0 2.8 11 6/1-8/31: pH=4.73-9.0 5.1 Segment 3a 6 8/21/2009 DO= 6.0 2 8 6/1-8/31: pH=4.73-9.0 4.1 Segment 3b 1 5/3/2009 DO= 6.0 3.8 3 pH=6.5-9.0 8.2 Segment 3b 2 5/27/2009 DO= 6.0 5 4 pH=6.5-9.0 8 Segment 3b 3 6/13/2009 DO= 6.0 5 5 pH=6.5-9.0 7.7 Segment 3b 4 7/6/2009 DO= 6.0 5 10 pH=6.5-9.0 7.3 Segment 3b 5 7/21/2009 DO= 6.0 3.7 12 pH=6.5-9.0 6.3 Segment 3b 6 8/21/2009 DO= 6.0 2 8 pH=6.5-9.0 4.5 Segment 3c 1 5/3/2009 DO=6.0 3.4 3 pH=6.5-9.0 8.1 Segment 3c 2 5/27/2009 DO=6.0 4 4 pH=6.5-9.0 8 Segment 3c 3 6/13/2009 DO=6.0 5 4 pH=6.5-9.0 7.5 Segment 3c 4 7/6/2009 DO=6.0 4 10 pH=6.5-9.0 6.8 Segment 3c 5 7/21/2009 DO=6.0 5.4 12 pH=6.5-9.0 7.6 Segment 3c 6 8/21/2009 DO=6.0 2 12 pH=6.5-9.0 6 Segment 3d 1 5/3/2009 DO=6.0 4 2.5 pH=6.5-9.0 7.9 Segment 3d 2 5/27/2009 DO=6.0 4 6 pH=6.5-9.0 8 Segment 3d 3 6/13/2009 DO=6.0 6.4 8 pH=6.5-9.0 8 Segment 3d 4 7/6/2009 DO=6.0 3 10 pH=6.5-9.0 7.1 Segment 3d 5 7/21/2009 DO=6.0 3.1 12 pH=6.5-9.0 7.6 Segment 3d 6 8/21/2009 DO=6.0 3.2 15 pH=6.5-9.0 6.9 1 USFWS 2005

Table 5. (cont.) May –August 2009 Dissolved Oxygen (DO), Mean Temperature and pH Readings for the Alamosa River

River Segment Trip Date Dissolved Oxygen DO (mg/L) Temperature pH Seasonal 2009 pH (DO)Regulation (mg/L)1 (°C) Requirement1

Segment 5 4 7/6/2009 No Regulations 4 10 pH=6.0-9.0 7.6 Segment 5 7 8/24/2009 No Regulations 3.8 8 pH=6.0-9.0 8.1 Segment 6 1 5/3/2009 No Regulations 3 3 No Regulations 8.2 Segment 6 2 5/27/2009 No Regulations 5.8 8 No Regulations 8 Segment 6 3 6/13/2009 No Regulations 3 5 No Regulations 7.6 Segment 6 4 7/6/2009 No Regulations 4 10 No Regulations 7.1 Segment 6 5 7/21/2009 No Regulations 3.7 11 No Regulations 7.1 Segment 6 6 8/21/2009 No Regulations 2 8 No Regulations 6.4 Segment 9 1 5/3/2009 DO=6.0 3.4 4 pH=6.5-9.0 8.4 Segment 9 2 5/27/2009 DO=6.0 3.5 6 pH=6.5-9.0 7.9 Segment 9 3 6/13/2009 DO=6.0 4.8 8 pH=6.5-9.0 8 Segment 9 4 7/6/2009 DO=6.0 4.5 10 pH=6.5-9.0 7.8 Segment 9 5 7/21/2009 DO=6.0 4 12 pH=6.5-9.0 7.6 Segment 9 6 8/21/2009 DO=6.0 3.6 16 pH=6.5-9.0 6.9

1 USFWS 2005

Figure 5. Mean Dissolved Oxygen (DO) Values from the 2009 Collections Season with Their Corresponding Standards set by the Colorado Department of Public Health and Environment (CDPHE). Above are the 2009 mean DO concentrations (1.) and the CDPHE DO Standards (2.) by segment. Mean DO concentrations in the volcanically altered area (segment 3a), the pristine site (segment 5), below the Wightman Fork mine drainage (segments 3b, 3c and 3d) and below Terrace Reservoir (segment 9) all were below the Class 1 Cold Water Aquatic Life standard. Mean DO concentrations in the volcanically altered area (segment 3a) were also below the Class 2 Cold Water Aquatic Life standard. Mean DO concentrations in all segments were in compliance with the Recreational Standard of 3 mg/L.

Figure 6. The Number of Times the Dissolved Oxygen (DO) Concentrations were Below Standards set by the Colorado Department of Public Health and Environment (CDPHE). Above is the number of times that individual DO samples during the season were not in compliance with DO standards set by the CDPHE. Samples below the Wightman Fork mine drainage (segments 3b and 3c) and below Terrace Reservoir (segment 9) were all not in compliance with the Class 1 Cold Water Aquatic Life DO standard all 6 times that they were sampled. Samples below the Wightman Fork mine drainage (segment 3d) were not in compliance with the Class 1 Cold Water Aquatic Life DO standard 5 out of the 6 times that it was sampled. Samples at the pristine site (segment 5) were not in compliance with the Class 1 Cold Water Aquatic Life DO standard 2 out of the 6 times that it was sampled. Samples in the volcanically altered area (segment 3a) were not in compliance with the Class 2 Cold Water Aquatic Life DO standard all 6 times that it was sampled. Samples in the volcanically altered area (segment 3a) were not in compliance with the Recreation DO standard 2 out of the 6 times that it was sampled. Samples below the Wightman Fork mine drainage (segments 3b and 3c) were not in compliance with the Recreation DO standard 1 out of the 6 times that they were sampled.

Life and Recreation 1a classifications come with their own dissolved oxygen requirement

(CDPHE 2007A). The same is true for the mine drainage (segment 6); it is classified as suitable for Recreation 1a and Agricultural uses. The pristine site (segment 5) was below the Class 1 Cold Water Aquatic Life standard of 6 mg/L both times it was sampled (Table

5; Figure 6). The pristine site (segment 5) and mine drainage were both in compliance with the Recreation standard of 3 mg/L and were not below this concentration during the collection season (Table 5; Figure 6).

Samples in the volcanically altered area (segment 3a), below the Wightman Fork mine drainage (segments 3b and 3c) and below Terrace Reservoir (segment 9) were below the DO requirement necessary to be classified as Class 1 Cold Water Aquatic Life and Class 1 Warm Water Aquatic Life (Table 5; Figure 6). The CDPHE requirement to be considered Class 1 Cold Water Aquatic Life is 6 mg/L and the requirement for Class 1

Warm Water Aquatic Life is 5 mg/L (Murphy 2007). Samples in the volcanically altered area (segment 3a), below the mine drainage (segments 3b and 3c) and below Terrace

Reservoir (segment 9) were below the CDPHE requirement for the Class 1 Cold Water

Aquatic Life requirement all six times they were sampled during the 2009 runoff season

(Table 5; Figure 6). Samples collected above Terrace Reservoir (segment 3d) were below the CDPHE requirement for Class 1 Cold Water Aquatic Life classification 5 out of the 6 times it was sampled during the 2009 runoff season (Table 5; Figure 6). Samples in the volcanically altered area (segment 3a) and below Terrace Reservoir (segment 9) were both below the CDPHE requirement for the Class 1 Warm Water Aquatic Life classification all 6 times that they were sampled in the 2009 runoff season (Table 5;

Figure 6). Samples below the mine drainage (segments 3b, 3c and 3d) were below the

CDPHE requirement for Class 1 Warm Water Aquatic Life classification multiple times,

segment 3b was below 3 out of the 6 times, segment 3c was below 4 out of the 6 times,

and segment 3d was below 5 out of the 6 times during the 2009 runoff season (Table 5;

Figure 6). Samples in the volcanically altered area (segment 3a) were below the CDPHE

recreation regulation of 3 mg/L, twice, during the 2009 runoff season (Table 5; Figure 6;

Murphy 2007). Samples below the mine drainage (segments 3b and 3c) were both below

the CDPHE recreation regulation once during the 2009 runoff season (Table 5; Figure 6).

AIM 1: CONCENTRATIONS OF HEAVY METALS IN WATER, SEDIMENT

AND TREE CORE SAMPLES COLLECTED UPSTREAM, AT AND

DOWNSTREAM FROM THE MINING SITE

Heavy Metal Concentrations in 2009 Water Samples

Each segment of the Alamosa River has its own metal standards set by the

Colorado Department of Public Health and Environment (CDPHE). These standards are set up by the usage of the water for each segment. Only a subset of the 27 heavy metals in water samples will be presented; they include 27Al, 55Mn, 56Fe, 60Ni, 63Cu, 66Zn, 75As,

78Se, 111Cd, and 208Pb. Summary tables have been made for aluminum, arsenic,

cadmium, copper, iron, lead, manganese, nickel, selenium and zinc; these tables include

the CDPHE standards as well as metal concentrations from previous studies if available

and are referred to when the individual metal results are reported below. The metals that

exceeded the CDPHE limits in water in 2009 were: aluminum, cadmium, copper, iron,

manganese and zinc. The following heavy metal contaminants: arsenic, lead, nickel, and

selenium, did not have any 2009 mean or maximum concentrations that exceeded any

CDPHE limits.

Samples collected at the mine drainage (segment 6) and below both the mine drainage and volcanically altered areas (segments 3b and 3d) had significantly higher concentrations of dissolved aluminum when compared with the pristine site (segment 5;

Figure 7). No other segment had concentrations of dissolved aluminum that were significantly different from the pristine site (Figure 7). The mean and maximum dissolved aluminum concentrations in the volcanically altered area (segment 3a) and directly below both the mine drainage and volcanically altered areas (segment 3b) exceeded the acute limit set by the CDPHE (Table 6; CDPHE 2007A). The 2009 maximum dissolved aluminum concentration below both the mine drainage and volcanically altered areas (segment 3c and 3d), exceeded the chronic limit set by the

CDPHE (Table 6). In addition, the 2009 mean and maximum dissolved aluminum concentrations in the volcanically altered area (segment 3a) and below both the mine drainage and volcanically altered areas (segments 3b, 3c and3d) exceeded the 85th

Percentile Seasonal Ambient Standards set by the CDPHE during both time periods (5/1-

6/30 and 7/1-4/30; Table 6; CDPHE 2007B). Seasonal ambient standards are only implemented by the CDPHE when conditions are considered naturally occurring or when dealing with conditions that are the results of irreversible human impacts.

The 2009 mean and maximum dissolved aluminum concentrations in the volcanically altered area (segment 3a) and below both the mine drainage and volcanically altered areas (segments 3b, 3c and 3d) exceeded the 95th Percentile Seasonal Ambient

Standards for the time period of 5/1-6/30 (Table 6; CDPHE 2007B). The 95th Percentile

Seasonal Ambient Standards were also exceeded during both time periods (5/1-6/30 and

7/1-4/30) by mean and maximum concentrations in the area directly below both

p=0.0051 4500 * p=0.0051 4000 * 3500 p=0.0051 * 3000

p=0.0216 2500 Al Dis * 2000 Al TR

1500 p=0.0051 * 1000 p=0.0082 p=0.0367 p=0.0122 * 500 * * 0 5 6 3a 3b 3c 3d 9

Figure 7. Aluminum Concentrations (ppb) in Water Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009 and were analyzed with an ICP-MS using EPA method 200.8. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to Mann Whitney Test. Samples collected in the volcanically altered area (segment 3a), Wightman Fork mine drainage (segment 6), below both the mine drainage and volcanically altered areas (segments 3b and 3d) and below Terrace Reservoir (segment 9) had aluminum concentrations that were significantly higher than the pristine site (segment 5; (P>0.05). Dissolved aluminum concentrations that were significantly higher than the pristine site (segment 5) occurred in the mine drainage (mine drainage), and below both the mine drainage and volcanically altered areas (segments 3b and 3d). Total recoverable concentrations that were significantly higher occurred in the volcanically altered area (segment 3a), Wightman Fork, below both the mine drainage and volcanically altered areas (segments 3b and 3d and below Terrace Reservoir (segment 9).

Table 6. Aluminum Standards for Sections Sampled Along the Alamosa River in 2009 compared to Median and Maximum Values from Previous Studies

Chemical Segment Total 2009 2009 85th Percentile 95th Percentile 2009 Median Median Median 2000 2009 Recoverable Acute Chronic Seasonal Ambient Seasonal Ambient average + Values Values Values max max = TR TVS 1 TVS Standards pertain Standards pertain SEM 1986- 1998- 2009 (ppb)5 (ppb) Dissolved = 2 3 3 (ppb) 1994 2003 (ppb) (ppb)2 (ppb) to dates below to dates below Dis (ppb)4 (ppb)4

5/1-6/30 7/1-4/30 5/1-6/30 7/1-4/30

Aluminum 9 TR No limit No limit No limit No limit No limit No limit 457 + 112 NA NA NA 2260 762 Aluminum 3d TR No limit No limit 3500 3100 5200 3700 757 + 198 NA NA NA 9730 1283 Aluminum 3c TR No limit No limit 4600 3700 6200 6700 1005 + 228 NA NA NA 9730 1585 Aluminum 3b TR No limit No limit 3000 3000 4300 3100 2948 + 1175 NA NA NA 9730 7545 Aluminum 6 TR No limit No limit No limit No limit No limit No Limit 2516 + 982 NA NA NA 32400 7243 Aluminum 3a TR No limit No limit 3100 6200 4000 19900 2092 + 759 NA NA NA NA 5619 Aluminum 5 TR No limit No limit No limit No limit 66.8 + 11.8 NA NA NA NA 123

Aluminum 9 Dis 750 87 No limit No limit No limit No limit 35 + 10.3 170 0 27 90 66 Aluminum 3d Dis 750 87 87 56 90 559 147 +116 969 10 30 1270 612 Aluminum 3c Dis 750 87 42 137 87 645 167 + 133 969 10 43 1270 698 Aluminum 3b Dis 750 No limit 41 317 41 756 983 + 880 2800 50 34 1270 4495 Aluminum 6 Dis No limit No limit No limit No limit No limit No limit 44.6 + 6.82 4645 943 48 3550 65 Aluminum 3a Dis 750 No limit 98 903 161 6005 1327 + 1075 366 211 23 NA 5558 Aluminum 5 Dis No limit No limit No limit No limit No limit No limit 18 + 2.74 NA NA 18 NA 27

1 TVS: Table value standard 2 CDPHE 2007A 3 CDPHE 2007B 4 CWCB 2005A 5 CDPHE 2001

the mine drainage and volcanically altered areas (segment 3b; Table 6). Samples

collected in the volcanically altered area (segment 3a), the mine drainage (segment 6),

below both the mine drainage and volcanically altered areas (segments 3b and 3d) and

below Terrace Reservoir had significantly higher mean concentrations of total

recoverable aluminum when compared with the pristine site (segment 5; Figure 7). 2009

mean total recoverable aluminum concentrations for all of these heavy metals were below

both the 85th and 95th Seasonal Ambient Standards (Table 6). However, the maximum total recoverable concentrations in the area directly below the mine drainage (segment

3b) and volcanically altered area (segment 3a) were above both the 85th and 95th Seasonal

Ambient Standards (Table 6). The volcanically altered area (segment 3a) also had a

maximum total recoverable aluminum concentrations that exceeded both of the 85th

Seasonal Ambient Standards and the 95th Seasonal Ambient Standard that pertained to

the 5/1-6/30 time period (Table 6.)

All of the segments did not have significantly different concentrations of

dissolved or total recoverable arsenic, than the pristine site (segment 5; Figure 8).

Dissolved arsenic concentrations in all segments were also below the CDPHE limits

(Table 7; CDPHE 2007A). In Table 7 the CDPHE standards are given for arsenic, as well

as the concentrations from previous studies and this 2009 study.

Samples collected in the volcanically altered area (segment 3a), the mine drainage

(segment 6), below both the mine drainage and volcanically altered areas (segments 3b,

3c and 3d), and below Terrace Reservoir (segment 9) had significantly higher

concentrations of mean dissolved and/or total recoverable copper than the pristine site

(segment 5; Figure 9). Below Terrace Reservoir (segment 9) was the only segment that

1.4 p>0.05

1.2

0.8

As Dis 0.6 As TR

0.4

0.2

0 5 6 3a 3b 3c 3d 9

-0.2

Figure 8. Arsenic Concentrations (ppb) in Water Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009 and were analyzed with an ICP-MS using EPA method 200.8. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to Mann Whitney Test. None of the segment had arsenic concentrations that were significantly different than the pristine site (segment 5) in either the total or dissolved concentrations.

Table 7. Arsenic Standards for Sections Sampled Along the Alamosa River in 2009 Compared to Maximum Values from Previous Studies

Chemical Segment Total Recoverable 2009 2009 2000 max 2009 max = TR Chronic mean + SEM (ppb)3 (ppb) Dissolved = Dis TVS1 (ppb) (ppb)2

Arsenic 9 TR 100 0.21 + 0.11 0.5 0.47 Arsenic 3d TR 100 0.36 + 0.14 40 0.92 Arsenic 3c TR 100 0.32 + 0.16 40 0.98 Arsenic 3b TR 100 0.60 + 0.14 40 1.13 Arsenic 6 TR No limit 0.78 + 0.40 12 2.65 Arsenic 3a TR 100 0.37 + 0.12 NA 0.82 Arsenic 5 TR 50 0.37 + 0.10 NA 0.6 Arsenic 9 Dis No limit 0.04 + 0.10 0.9 0.19 Arsenic 3d Dis No limit 0.03 + 0.11

1 TVS: Table value standard 2 CDPHE 2007A 3 CDPHE 2001 4 MDL: below minimum detection limits

160 p=0.0082 * 140

120

100

80 p=0.0051 Cu Dis Cu TR * 60 p=0.0122 p=0.0122 p=0.0131 * p=0.0082 40 p=0.0216 * p=0.0453 * p=0.0202 p=0.0122 * p=0.0122 * * 20 * * *

0 5 6 3a 3b 3c 3d 9

Figure 9. Copper Concentrations (ppb) in Water Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009 and were analyzed with an ICP-MS using EPA method 200.8. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to Mann Whitney Test. Samples collected in the volcanically altered area (segment 3a), Wightman Fork mine drainage (segment 6), below both the mine drainage and volcanically altered areas (segments 3b, 3c and 3d) and below Terrace Reservoir (segment 9) had copper concentrations that were significantly higher than the pristine site (segment 5; (P>0.05). Dissolved copper concentrations that were significantly higher than the pristine site (segment 5) occurred in the volcanically altered area (segment 3a), the mine drainage (segment 6), and below both the mine drainage and volcanically altered areas (segments 3b, 3c and 3d.) Total recoverable copper concentrations that were significantly higher occurred in the volcanically altered area (segment 3a), the mine drainage (segment 6), below both the mine drainage and volcanically altered areas (segments 3b, 3c and 3d) and below Terrace Reservoir (segment 9).

had dissolved concentrations of copper that were similar to the pristine site (segment 5;

Figure 9). Mean dissolved copper concentrations in the volcanically altered area (segment

3a) exceeded the acute and chronic CDPHE limits and directly below the mine drainage

(segment 3b) exceeded the acute CDPHE limit (Table 8; CDPHE 2007A). In Table 8 the

CDPHE standards are given for copper, as well as the concentrations from previous

studies and this 2009 study. The 2009 maximum dissolved copper concentrations in the

volcanically altered area (segment 3a), and below both the mine drainage and

volcanically altered area (segments, 3b, 3c, and 3d) all had concentrations above both the

acute and chronic Table value standard (TVS).

Samples collected in the volcanically altered area (segment 3a), the mine drainage

(segment 6), directly below both the mine drainage (segment 3b) and below Terrace

Reservoir (segment 9) had significantly different mean concentrations of iron than the pristine site (segment 5; Figure 10). No other segment had concentrations of dissolved or

total iron concentrations that were significantly different from the pristine site (Figure

10).The 2009 mean dissolved iron concentrations in the mine drainage (segment 6) and

below Terrace Reservoir (segment 9) were significantly lower than the pristine site

(segment 5; Figure 10). The 2009 mean total recoverable iron concentrations that were

significantly higher occurred in the volcanically altered area (segment 3a) and directly

below the volcanically altered area and the mine drainage (segment 3b; Figure 10). The

2009 mean total recoverable iron concentrations were below the acute and chronic

CDPHE limits (Table 9; CDPHE 2007A). In Table 9 the CDPHE standards are given for

iron, as well as the concentrations from previous studies and this 2009 study. The

segment directly below the mine drainage (segment 3b) and the one directly below

Table 8. Copper Standards for Sections Sampled Along the Alamosa River in 2009 Compared to Median and Maximum Values from Previous Studies

Chemical Segment Total 2009 2009 2009 Median Median Median 2000 2009 Recoverable = Acute Chronic mean + SEM Values Values Values max max TR TVS 1 TVS (ppb) 1986- 1998- 2009 (ppb)4 (ppb) Dissolved = Dis (ppb)2 (ppb)2 1994 2003 (ppb) (ppb)3 (ppb)3 Copper 9 TR No limit No limit 10.01 + 2.10 NA NA NA 40 17.04 Copper 3d TR No limit No limit 16.59 + 3.23 NA NA NA 230 23.8 Copper 3c TR No limit No limit 19.82 + 3.41 NA NA NA 230 27.09 Copper 3b TR No limit No limit 44.6 + 13.9 NA NA NA 230 96.59 Copper 6 TR No limit No limit 104.4 + 33.9 NA NA NA 1150 251.3 Copper 3a TR No limit No limit 7.98 + 2.26 NA NA NA NA 18.93 Copper 5 TR No limit No limit 3.52 + 1.64 NA NA NA NA 11.59 Copper 9 Dis 8.20 5.50 3.508 + 0.733 236 4 4.32 9 5.16 Copper 3d Dis 12.25 7.80 5.83 + 1.93 129 7 4.29 208 13.37 Copper 3c Dis 12.91 8.17 7.80 + 2.09 129 7 4.95 208 15.35 Copper 3b Dis 17.58 30.00 26.1 + 15.8 376 65 6.1 208 83.33 Copper 6 Dis No limit No limit 26.46 + 4.14 1376 560 23.59 1260 41.84 Copper 3a Dis 6.76 No limit 7.23 + 3.07 10 5 3.82 NA 18.69 Copper 5 Dis 2.14 1.65 1.724 + 0.297 NA NA 1.83 NA 2.46

1 TVS: Table value standard 2 CDPHE 2007A 3 CWCB 2005A 4 CDPHE 2001

p=0.0051 8000 * 7000 p=0.0051 6000 *

5000

4000 Fe Dis Fe TR 3000

p=0.0122 p=0.0122 2000 * 1000 *

0 5 6 3a 3b 3c 3d 9 -1000

Figure 10. Iron Concentrations (ppb) in Water Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009 and were analyzed with an ICP-MS using EPA method 200.8. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to Mann Whitney Test. Samples collected in the volcanically altered area (segment 3a), Wightman Fork mine drainage (segment 6) and below Terrace Reservoir (segment 9) had iron concentrations that were significantly different than the pristine site (segment 5; (P>0.05). Dissolved iron concentrations in the mine drainage (segment 6) and below Terrace Reservoir (segment 9) were significantly lower than the pristine site (segment 5). Total recoverable iron concentrations that were significantly higher occurred in the volcanically altered area (segment 3a) and below the volcanically altered area and the mine drainage.

Table 9. Iron Standards for Sections Sampled along the Alamosa River in 2009 Compared to Median and Maximum Values from Previous Studies

Chemical Segment Total Recoverable = 2009 2009 Median Median Median 2000 2009 TR Chronic mean + SEM Values Values Values max max Dissolved = Dis TVS1 (ppb) 1986- 1998- 2009 (ppb)4 (ppb) (ppb)2 1994 2003 (ppb) (ppb)3 (ppb)3 Iron 9 TR 1000 932 + 238 1400 837 913 2720 1761 Iron 3d TR 12000 1476 + 424 4000 3170 1679 21900 2687 Iron 3c TR 12000 1871 + 405 4000 3170 2015 21900 2778 Iron 3b TR 12000 5097 + 2428 6040 4280 2265 21900 16920 Iron 6 TR No Limit 2363 + 1090 6320 1550 793 73500 5996 Iron 3a TR 12000 4328 + 1298 5560 4830 2495 NA 9200 Iron 5 TR 1000 790.8 +75.6 NA NA 842.5 NA 950 Iron 9 Dis No limit 8.4 + 14.2 NA NA NA 110 52 Iron 3d Dis No limit 217 + 208 NA NA NA 3400 1047 Iron 3c Dis No limit 338 + 240 NA NA NA 3400 1275 Iron 3b Dis No limit 693 + 388 NA NA NA 3400 1709 Iron 6 Dis No limit 16.6 + 14.3 NA NA NA 3760 52 Iron 3a Dis No limit 1180 + 545 NA NA NA NA 3014 Iron 5 Dis No limit 256 + 73 NA NA NA NA 442

1 TVS: Table value standard 2 CDPHE 2007A 3 CWCB 2005A 4 CDPHE 2001

Terrace Reservoir (segment 9; Table 9) had maximum total recoverable iron

concentrations that were not in compliance with the chronic TVS.

Samples collected in the volcanically altered area (segment 3a), the mine drainage

(segment 6) and directly below the mine drainage (segment 3b) had 2009 mean total

recoverable lead concentrations that were significantly higher than the pristine site

(segment 5; Figure 11). No other segment had concentrations of total recoverable lead

that were significantly different from the pristine site (Figure 11). Dissolved lead

concentrations in all segments were not significantly higher than the pristine site

(segment 5; Figure 11). None of the lead concentrations were above CDPHE standards

(Table 10; CDPHE 2007A). In Table 10 the CDPHE standards are given for lead, as well as the concentrations from previous studies and this 2009 study.

Samples collected in the volcanically altered area (segment 3a), the mine drainage

(segment 6), and below both the mine drainage and volcanically altered areas (segments

3b and 3c) had 2009 mean total recoverable selenium concentrations that were significantly higher than the pristine site (segment 5; Figure 12). Total recoverable selenium concentrations above and below Terrace Reservoir were not significantly different from the pristine site (segment5; Figure 12). Total recoverable selenium concentrations that were significantly higher occurred in the volcanically altered area

(segment 3a), the mine drainage (segment 6), and below both the mine drainage and volcanically altered areas (segments 3b, 3c; Figure 12). Dissolved selenium concentrations were not significantly higher than the pristine site (segment 5; Figure 12).

None of the selenium concentrations were above CDPHE standards (Table 11; CDPHE

2007A). In Table 11 the CDPHE standards are given for selenium, as well as the

p=0.0051 p=0.0051 1.2 * *

0.8 p=0.0051

* Pb Dis 0.6 Pb TR

0.4

0.2

0 5 6 3a 3b 3c 3d 9

Figure 11. Lead Concentrations (ppb) in Water Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009 and were analyzed with an ICP-MS using EPA method 200.8. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to Mann Whitney Test. Samples collected in the volcanically altered area (segment 3a), Wightman Fork mine drainage (segment 6) and below the mine drainage (segment 3b,) had total recoverable lead concentrations that were significantly higher than the pristine site (segment 5; (P>0.05). Dissolved lead concentrations were not significantly higher than the pristine site (segment 5). Total recoverable lead concentrations that were significantly higher occurred in the volcanically altered area (segment 3a), mine drainage (segment 6), and directly below both the mine drainage and volcanically altered areas (segment 3b).

Table 10. Lead Standards for Sections Sampled along the Alamosa River in 2009 Compared to Maximum Values from Previous Studies

Chemical Segment Total 2009 2009 2009 2000 2009 Recoverable Acute Chronic mean + SEM max max = TR TVS 1 TVS (ppb) (ppb)3 (ppb) Dissolved = ( ppb)2 (ppb)2 Dis

Lead 9 TR No limit No limit 0.24 +0.07 1.1 0.47 Lead 3d TR No limit No limit 0.35 + 0.12 14.7 0.72 Lead 3c TR No limit No limit 0.41 + 0.13 14.7 0.81 Lead 3b TR No limit No limit 0.50 + 0.13 14.7 1.09 Lead 6 TR No limit No limit 0.69 + 0.43 50 2.83 Lead 3a TR No limit No limit 0.71 + 0.41 NA 2.75 Lead 5 TR No limit No limit 0.13 + 0.02 NA 0.22 Lead 9 Dis 36.50 1.42 0.04 + 0.03 0.2 0.11 Lead 3d Dis 59.14 2.30 0.14 + 0.07 0.8 0.38 Lead 3c Dis 63.02 2.46 0.11 +0.07 0.8 0.34 Lead 3b Dis 91.87 3.58 0.07 + 0.02 0.8 0.16 Lead 6 Dis No limit No limit 0.06 + 0.03 8 0.15 Lead 3a Dis 29.45 1.15 0.12 + 0.06 NA 0.33 Lead 5 Dis 7.37 0.29 0.04 +0.01 NA 0.07

1 TVS: Table value standard 2 CDPHE 2007A 3 CDPHE 2001

0.4 p=0.0453 * 0.3 p=0.0547 p=0.0547 * 0.2 * p=0.0202 * 0.1 Se Dis Se TR 0 5 6 3a 3b 3c 3d 9

-0.1

-0.2

-0.3

Figure 12. Selenium Concentrations (ppb) in Water Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009 and were analyzed with an ICP-MS using EPA method 200.8. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to Mann Whitney Test. Samples collected in the volcanically altered area (segment 3a), Wightman Fork (segment 6), and below both the mine drainage and volcanically altered areas (segments 3b and 3c) had total recoverable selenium concentrations that were significantly higher than the pristine site (segment 5; (P>0.05). Dissolved selenium concentrations were not significantly higher than the pristine site (segment 5). Total recoverable selenium concentrations that were significantly higher occurred in the volcanically altered area (segment 3a), Wightman Fork, and below both the mine drainage and volcanically altered areas (segments 3b and 3c).

Table 11. Selenium Standards for Sections Sampled along the Alamosa River in 2009 Compared to Maximum Values from Previous Studies

Chemical Segment Total 2009 Acute 2009 2009 Recoverable TVS1 Chronic mean + SEM = TR (ppb) 2 TVS (ppb) Dissolved = (ppb)2 Dis

Selenium 9 TR No limit No limit 0.06 + 0.076 Selenium 3d TR No limit No limit 0.05 + 0.084 Selenium 3c TR No limit No limit 0.18 + 0.126 Selenium 3b TR No limit No limit 0.09 + 0.037 Selenium 6 TR No limit No limit 0.06 + 0.094 Selenium 3a TR No limit No limit 0.08 + 0.094 Selenium 5 TR No limit No limit -0.09 + 0.054 Selenium 9 Dis 18.4 4.6 -0.04 + 0.087 Selenium 3d Dis 18.4 4.6 0.00 + 0.094 Selenium 3c Dis 18.4 4.6 0.03 + 0.085 Selenium 3b Dis 18.4 4.6 0.06 + 0.055 Selenium 6 Dis No limit No limit 0.00 + 0.114 Selenium 3a Dis 18.4 4.6 -0.05 + 0.096 Selenium 5 Dis 18.4 4.6 -0.10 + 0.083

1 TVS: Table value standard’ 2 CDPHE 2007A

concentrations from previous studies and this 2009 study.

All of the segments sampled had significantly higher 2009 mean concentrations of

total recoverable cadmium (Figure 13), dissolved and total recoverable manganese

(Figure 14), dissolved and total recoverable nickel (Figure 15) and dissolved and total

recoverable zinc (Figure 16), when compared to pristine site (segment 5). Not one of the

segments sampled had dissolved and total recoverable manganese, nickel or zinc

concentrations that were comparable to the pristine site (segment 5; Figures 14-16). The only segment that had a mean dissolved cadmium concentration that was not significantly different from the pristine site (segment 5) was below Terrace Reservoir (segment 9;

Figure 13). Mean total recoverable cadmium concentrations were all significantly greater than the pristine site (segment 5; Figure 13). In Tables 12-15 the CDPHE standards are given for cadmium, manganese, nickel, and zinc, as well as the concentrations from previous studies and this 2009 study (CDPHE 2007A). The 2009 maximum dissolved cadmium concentration below the mine drainage (segments 3b and 3c) was above the chronic table values set by the CDPHE (Table 12). The 2009 maximum and mean dissolved manganese concentrations for all sites including the pristine site (segment 5) were above CDPHE limits (Table 13; CDPHE 2007A). The 2009 maximum and mean dissolved nickel concentrations were below CDPHE limits for all segments (Table 14;

CDPHE 2007A). 2009 maximum dissolved zinc concentrations exceeded the CDPHE limits in the volcanically altered area (segment 3a) and directly below the mine drainage

(segment 3b; Table 15; CDPHE 2007A).

2 p=0.0122 * p=0.0122 1.5 p=0.0081 * * p=0.0163 * 1 p=0.0122 p=0.0051 p=0.0122 * p=0.0051 * p=0.0051 p=0.0051 Cd Dis 0.5 * Cd TR * * * p=0.0051 * 0 5 6 3a 3b 3c 3d 9

-0.5

-1

Figure 13. Cadmium Concentrations (ppb) in Water Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009 and were analyzed with an ICP-MS using EPA method 200.8. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to Mann Whitney Test. Samples collected in the volcanically altered area (segment 3a), Wightman Fork mine drainage (segment 6), below both the mine drainage and volcanically altered areas (segments 3b, 3c and 3d) and below Terrace Reservoir (segment 9) had cadmium concentrations that were significantly higher than the pristine site (segment 5; (P>0.05). Dissolved cadmium concentrations that were significantly higher than the pristine site (segment 5) occurred in the volcanically altered area (segment 3a), the mine drainage (segment 6), and below both the mine drainage and volcanically altered areas (segments 3b, 3c and 3d). Total recoverable cadmium concentrations that were significantly higher occurred in the volcanically altered area (segment 3a), the mine drainage (segment 6), below both the mine drainage and volcanically altered areas (segments 3b, 3c and 3d and below Terrace Reservoir (segment 9).

900 p=0.0122 * 800 p=0.0051 * 700

600 p=0.0122 500 * p=0.0051 p=0.0122 * Mn Dis 400 * p=0.0051 Mn TR * p=0.0122 p=0.0051 p=0.0051 p=0.0051 300 * * p=0.0122 * p=0.0122 * * 200 *

100

0 5 6 3a 3b 3c 3d 9

Figure 14. Manganese Concentrations (ppb) in Water Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009 and were analyzed with an ICP-MS using EPA method 200.8. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to Mann Whitney Test. Samples collected in the volcanically altered area (segment 3a), Wightman Fork (segment 6), below both the mine drainage and volcanically altered areas (segments 3b, 3c and 3d) and below Terrace Reservoir (segment 9) had dissolved and total recoverable manganese concentrations that were significantly higher than the pristine site (segment 5; (P>0.05).

14 p=0.0122 * 12 p=0.0051 * p=0.0122 10 p=0.0051 p=0.0122 * p=0.0051 * * 8 * p=0.0051 p=0.0122 Ni Dis * p=0.0122 p=0.0051 * Ni TR 6 * * p=0.0122 p=0.0051 * 4 *

0 5 6 3a 3b 3c 3d 9

Figure 15. Nickel Concentrations (ppb) in Water Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009 and were analyzed with an ICP-MS using EPA method 200.8. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to Mann Whitney Test. Samples collected in the volcanically altered area (segment 3a), Wightman Fork (segment 6), below both the mine drainage and volcanically altered areas (segments 3b, 3c and 3d) and below Terrace Reservoir (segment 9) had dissolved and total recoverable nickel concentrations that were significantly higher than the pristine site (segment 5; (P>0.05).

250

p=0.0051 p=0.0122 * * 200

150 p=0.0122 p=0.0051 Zn Dis * * Zn TR 100 p=0.0122 p=.0122 p=0.0051 p=0.0051 * * * p=0.0051 * p=0.0122 50 * * p=0.0051 p=0.0122 * *

0 5 6 3a 3b 3c 3d 9

Figure 16. Zinc Concentrations (ppb) in Water Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009 and were analyzed with an ICP-MS using EPA method 200.8. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to Mann Whitney Test. Samples collected in the volcanically altered area (segment 3a), Wightman Fork (segment 6), below both the mine drainage and volcanically altered areas (segments 3b, 3c and 3d) and below Terrace Reservoir (segment 9) had dissolved and total recoverable zinc concentrations that were significantly higher than the pristine site (segment 5; (P>0.05).

Table 12. Cadmium Standards for Sections Sampled Along the Alamosa River in 2009 Compared to Maximum Values from Previous Studies

Chemical Segment Total 2009 2009 Acute 2009 Chronic 2009 2000 2009 Recoverable = Acute (Trout) TVS TVS mean + SEM max max TR TVS 1 (ppb)2 (ppb)2 (ppb) (ppb)3 (ppb) Dissolved = Dis (ppb)2 Cadmium 9 TR No limit No limit No limit 0.08 + 0.01 1.2 0.13 Cadmium 3d TR No limit No limit No limit 0.23 + 0.04 1.7 0.35 Cadmium 3c TR No limit No limit No limit 0.27 + 0.07 1.7 0.61 Cadmium 3b TR No limit No limit No limit 0.43 + 0.14 1.7 1.06 Cadmium 6 TR No limit No limit No limit 0.92 + 0.35 4.8 2.54 Cadmium 3a TR No limit No limit No limit 0.17 + 0.09 NA 0.51 Cadmium 5 TR No limit No limit No limit -0.01 + 0.11 NA 0.01 Cadmium 9 Dis 2.14 1.33 0.29 0.04 + 0.02 0.4 0.06 Cadmium 3d Dis 3.10 1.93 0.39 0.18 + 0.04 1 0.28 Cadmium 3c Dis 3.25 2.02 0.40 0.36 + 0.96 1 0.63 Cadmium 3b Dis 4.27 2.65 0.50 0.45 + 0.18 1 1.11 Cadmium 6 Dis No limit No limit No limit 1.26 + 0.27 5.1 2.23 Cadmium 3a Dis 1.78 1.11 0.24 0.2 + 0.93 NA 0.51 Cadmium 5 Dis 0.61 0.42 0.11 -0.01 + 0.02 NA 0.02

1 TVS: Table value standard 2 CDPHE 2007A 3 CDPHE 2001

Table 13. Manganese Standards for Sections Sampled Along the Alamosa River in 2009 Compared to Median and Maximum Values from Previous Studies

Chemical Segment Total 2009 Acute 2009 2009 Median Median Median 2000 2009 Recoverable = TVS1 Chronic mean + SEM Values Values Values max max TR (ppb) 2 TVS (ppb) 1986- 1998- 2009 (ppb)4 (ppb) Dissolved = (ppb)2 1994 2003 (ppb) Dis (ppb)3 (ppb)3

Manganese 9 TR No limit No limit 136.9 + 14.0 NA NA NA 534 181.1 Manganese 3d TR No limit No limit 182.2 + 21.6 NA NA NA 937 268.4 Manganese 3c TR No limit No limit 210.6 + 30.2 NA NA NA 937 335 Manganese 3b TR No limit No limit 307.4 + 97.4 NA NA NA 937 771.3 Manganese 6 TR No limit No limit 532 + 158 NA NA NA 2970 1275 Manganese 3a TR No limit No limit 233.6 + 87.1 NA NA NA NA 650.9 Manganese 5 TR No limit No limit 36.56 + 2.54 NA NA NA NA 48.02 Manganese 9 Dis 7.82 7.22 101.7 + 11.6 445 299 87.6 546 143.7 Manganese 3d Dis 7.92 7.33 166.8 + 23.8 401 337 140.8 882 227.6 Manganese 3c Dis 7.93 7.34 200.4 + 36.9 401 337 163.3 882 318.9 Manganese 3b Dis 7.96 7.37 330 + 116 857 537 204 882 765.2 Manganese 6 Dis No limit No limit 658 + 132 2135 1600 596 3380 1113 Manganese 3a Dis 7.73 7.13 251 + 107 210 249 120 NA 656.1 Manganese 5 Dis 7.34 6.75 18.70 + 1.00 NA NA 19.19 NA 20.35

1 TVS: Table value standard 2 CDPHE 2007A 3 CWCB 2005A 4 CDPHE 2001

Table 14. Nickel Standards for Sections Sampled Along the Alamosa River in 2009 Compared to Maximum Values from Previous Studies

Chemical Segment Total Recoverable = TR 2009 2009 2000 2009 Dissolved = Dis Acute mean + SEM max max TVS1 (ppb) (ppb)3 (ppb) (ppb)2

Nickel 9 TR No limit 3.19 + 0.89

1 TVS: Table value standard 2 CDPHE 2007A 3 CDPHE 2001 4 MDL: below minimum detection limits 5 Value is anomalously high and judged to be unusable by the EPA

Table 15. Zinc Standards for Sections Sampled Along the Alamosa River in 2009 Compared to Median and Maximum Values from Previous Studies

Chemical Segment Total 2009 2009 2009 Median Median Median 2000 2009 Recoverable Acute Chronic mean + SEM Values Values Values max max = TR TVS 1 TVS (ppb) 1998- 1994- 2009 (ppb)4 (ppb) Dissolved = (ppb)2 (ppb)2 2003 1986 (ppb) Dis (ppb)3 (ppb)3

Zinc 9 TR No limit No limit 15.63 + 2.92 NA NA NA 70 22.18 Zinc 3d TR No limit No limit 33.37 + 5.55 NA NA NA 180 52.55 Zinc 3c TR No limit No limit 46.38 +8.94 NA NA NA 180 83.68 Zinc 3b TR No limit No limit 76.8 + 25.5 NA NA NA 180 195.7 Zinc 6 TR No limit No limit 155 + 53.4 NA NA NA 860 395.5 Zinc 3a TR No limit No limit 38.8 +12.9 NA NA NA NA 101.3 Zinc 5 TR No limit No limit 4.66 + 1.50 NA NA NA NA 9.49 Zinc 9 Dis 91.46 79.30 4.41 + 1.13 169 37 3.94 70 8.01 Zinc 3d Dis 130.26 112.95 27.35 + 4.54 108 70 25.02 200 38.25 Zinc 3c Dis 136.42 118.28 45.3 + 10.0 108 70 36.8 200 80.87 Zinc 3b Dis 176.65 153.17 75.1 + 30.0 201 120 41.1 200 188.6 Zinc 6 Dis No limit No limit 162.3 + 39.6 704 460 145.6 890 308.3 Zinc 3a Dis 76.31 66.17 38.6 + 16.0 37 20 18.2 NA 99.28 Zinc 5 Dis 27.12 23.52 1.028 + 0.524 NA NA 1.13 NA 2.69

1 TVS: Table value standard 2 CDPHE 2007A 3 CWCB 2005A 4 CDPHE 2001

Heavy Metal Concentrations in Sediment in 2009

A subset of the 27 heavy metals in sediment samples will be presented; they include 27Al, 51V, 55Mn, 56Fe, 59Co, 60Ni, 63Cu, 66Zn, 75As, 78Se, 111Cd, and 208Pb. None of the segment had aluminum (Figure 17), iron (Figure 18) or vanadium (Figure 19) concentrations that were significantly different than the pristine site (segment 5) at either the 0-5 centimeters (cm) or 5-15 cm depths. In Figures 17-19 the sediment concentrations for aluminum, iron, and vanadium at the 0-5 and 5-15 cm depths are compared with concentrations at the pristine site (segment 5). There are no requirements established for aluminum or iron concentrations in sediment (Tables 16 and 17; USEPA 2003A; USEPA

2003B). There are no Ecological Soil Screening Levels (ECSSL) given for aluminum and iron. Tables 16 and 17 provide concentrations from previous studies and this 2009 study. All segments including the pristine site (segment 5) had vanadium concentrations at the 0-5 cm and 5-15 cm depths that are not in compliance with the ECSSL for avian life (Table 18; USEPA 2005A). In Table 18 the ECSSL standards are given for vanadium, as well as the concentrations from previous studies and this 2009 study.

Samples collected in the mine drainage (segment 6) had arsenic concentrations at the 0-5 cm depth that were significantly higher than the pristine site (segment 5; Figure 20).

Samples collected in the mine drainage (segment 6) and directly below both the mine drainage and volcanically altered areas (segment 3b) had arsenic concentrations that were significantly higher at the 5-15 cm depths than the pristine site (segment 5; Figure 20).

No other segment had arsenic concentrations at the 0-5 or 5-15 cm depths that were significantly different from the pristine site (segment 5; Figure 20). Arsenic concentrations at both depths in the mine drainage (segment 6) were not in compliance

20000 p>0.05 18000

16000

14000

12000

10000 5cm 8000 15cm

6000

4000

2000

0 5 6 3a 3b 3c 3d 9

Figure 17. Aluminum Concentrations (ppm) in Sediment Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009. Samples were digested using EPA method 3052 and were analyzed with an ICP-MS using EPA method 6020A. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to ANOVA Test. None of the segments had aluminum concentrations that were significantly different than the pristine site (segment 5) at either the 0-5 cm or 5-15 cm depths.

50000 p>0.05 45000

40000

35000

30000

25000 5cm 15cm 20000

15000

10000

5000

0 5 6 3a 3b 3c 3d 9

Figure 18. Iron Concentrations (ppm) in Sediment Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009. Samples were digested using EPA method 3052 and were analyzed with an ICP-MS using EPA method 6020A. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to ANOVA Test. Samples collected had iron concentrations that were not significantly different than the pristine site (segment 5) at both the 0-5 cm and 5-15 cm depths.

90 p>0.05 80

50 5cm 40 15cm

0 5 6 3a 3b 3c 3d 9

Figure 19. Vanadium Concentrations (ppm) in Sediment Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009. Samples were digested using EPA method 3052 and were analyzed with an ICP-MS using EPA method 6020A. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to ANOVA Test. None of the segments had vanadium concentrations that were significantly different than the pristine site (segment 5) at either the 0-5 cm or 5-15 cm depths.

Table 16. May–August 2009 Aluminum Concentrations at 0-5 cm and 5-15 cm Depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Aluminum Designated for each Segment of the Watershed

Location/ Segment Segment 9 Segment 3d Segment 3c Segment 3d Segment 6 Segment 3a Segment 5 Toxicant Aluminum Aluminum Aluminum Aluminum Aluminum Aluminum Aluminum Ecological Soil Screening Level None None None None None None None Maximum Contaminate Level (mg/kg)1 Depth

2009 Mean 13730.37 + 11739.65 + 12899.30 + 11064.15 + 10962.66 + 12088.36 + 11559.29 + 0-5 + SEM 706 425 1045 490 416 795 5603 2009 Mean 12449.80 + 11258.48 + 11771.52 + 11488.40 + 10770.41 + 11302.98 + 14167.44 + 5-15 + SEM 177 468 692 996 625 695 4480 2000 Data2 Unknown 11400.00 10100.00 8810.00 10100.00 14300.00 NA NA 2009 11446.68- 10660.16- 10303.20- 9456.97- 9652.83- 8867.59- 5956.59- 0-5 Range 15425.93 13059.29 16866.04 12481.51 12334.53 14691.19 17161.99 2009 11901.34- 10038.35- 10316.55- 9180.99- 8608.38- 9159.88- 9687.48- 5-15 Range 13011.43 12817.22 15050.97 16204.64 13161.61 13451.64 18647.40 2000 Unknown 7260-8610 6270-9790 6270-9791 6270-9792 6470-7620 NA NA Range3

1 USEPA 2003A 2 CWCB 2005A 3 CDPHE 2001

Table 17. May–August 2009 Iron Concentrations at 0-5 cm and 5-15 cm Depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Iron Designated for each Segment of the Watershed

Location/ Segment Segment 9 Segment 3d Segment 3c Segment 3b Segment 6 Segment 3a Segment 5 Toxicant Iron Iron Iron Iron Iron Iron Iron Ecological Soil Screening Level None None None None None None None Maximum Contaminate Level (mg/kg)1 Depth 2009 Mean 25933 + 0-5 33799 + 979 37647 + 2571 35059 + 1331 37632 + 1013 37112 + 2039 33918 + 966 + SEM 9601 2009 Mean 27146 + 5-15 39176 + 4078 38287 + 2858 36753 + 1222 41133 + 2986 41591 + 3117 33373 + 723 + SEM 14022 2000 Data2 Unknown 60200 39100 40700 44100 47300 NA NA 2009 30903.86- 29255.73- 31700.34- 34111.19- 28296.82- 30942.03- 16331.57- 0-5 Range 36272.73 48212.73 38908.29 41008.64 41415.20 36465.40 35534.27 2009 26920.83- 32783.23- 32151.30- 34949.64- 34429.35- 30697.25- 13123.52- 5-15 Range 54051.82 51206.13 41255.07 55282.69 54714.80 35576.34 41167.63 2000 Unknown 29600-44300 30900-42500 30900-42500 30900-42500 33400-41500 NA NA Range3

1 USEPA 2003B 2 CWCB 2005A 3 CDPHE 2001

Table 18. May–August 2009 Vanadium Concentrations at 0-5 cm and 5-15 cm Depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Vanadium Designated for each Segment of the Watershed

Location/ Segment Segment 9 Segment 3d Segment 3c Segment 3b Segment 6 Segment 3a Segment 5 Toxicant Vanadium Vanadium Vanadium Vanadium Vanadium Vanadium Vanadium

Ecological Soil PL2= NA PL = NA PL = NA PL = NA PL = NA PL = NA PL = NA Screening Level SI3 = NA SI = NA SI = NA SI = NA SI = NA SI = NA SI = NA Maximum Contaminate AV4 = 7.8 AV = 7.8 AV = 7.8 AV = 7.8 AV = 7.8 AV = 7.8 AV = 7.8 Level (mg/kg)1 MA5 = 280 MA = 280 MA = 280 MA = 280 MA = 280 MA = 280 MA = 280

Depth 2009 Mean + 0-5 52.38 + 3.26 56.54 + 7.25 47.65 + 3 44.1 + 2.61 38.39 + 2.83 38.49 + 1.71 35.7 + 13.1 SEM 2009 Mean + 5-15 70.6 + 12.4 57.34 + 8.4 51.24 + 4.43 51.58 + 4.47 43.38 + 4.51 38.95 + 2.41 38.8 + 13.7 SEM 2009 Range 0-5 41.35-62.94 39.08-88.26 38.75-55.47 36.10-55.11 28.67-47.22 31.62-43.15 22.57-48.83 2009 Range 5-15 39.56-117.98 40.33-95.07 36.74-70.00 43.03-72.41 32.00-62.74 33.21-49.48 25.02-52.50

1 USEPA 2005A 2 PL = plants 3 SI = Soil Invertebrates 4 AV = Avian 5 MA = mammalian

p=0.00

50 *

40 p=0.00 p=0.00 * 30 * 5cm 15cm p=0.00

20 *

0 5 6 3a 3b 3c 3d 9

Figure 20. Arsenic Concentrations (ppm) in Sediment Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009. Samples were digested using EPA method 3052 and were analyzed with an ICP-MS using EPA method 6020A. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to ANOVA Test. Samples collected in Wightman Fork mine drainage (segment 6) and directly below both the mine drainage and volcanically altered areas (segment 3b) had arsenic concentrations that were significantly higher at both the 0-5 cm and 5-15 cm depths than the pristine site (segment 5).

With the ECSSL for plants, and were significantly greater when compared with the pristine site (Table 19; USEPA 2005B). In Table 19 the ECSSL standards are given for arsenic, as well as the concentrations from previous studies and this 2009 study.

Samples collected below Terrace Reservoir (segment 9) had cadmium concentrations that were significantly higher at the 0-5 cm depth than the pristine site

(segment 5; Figure 21). None of the other segments sampled, at the 0-5cm depth, had significantly different concentrations when compared with the pristine site (segment 5;

Figure 21). All of the segments, at the 5-15 cm depth, were not significantly different from the pristine site (segment 5; Figure 21). The 2009 mean cadmium concentration below Terrace Reservoir (segment 9) were not in compliance with the ECSSL for mammals (Table 20; USEPA 2005C). In Table 20 the ECSSL standards are given for cadmium as well as the concentrations from previous studies and this 2009 study.

Samples collected below Terrace Reservoir (segment 9) had cobalt concentrations that were significantly higher at both the 0-5 cm and 5-15 cm depths than the pristine site

(segment 5; Figure 22). No other segments sampled at either depth were found to have significantly different concentrations of cobalt when compared with the pristine site

(segment 5; Figure 22).The 2009 mean cobalt concentrations below Terrace Reservoir

(segment 9) were not in compliance with the ECSSL for plants (Table 21; USEPA

2005D). In Table 21 the ECSSL standards are given for cobalt, as well as the concentrations from previous studies and this 2009 study.

Samples collected in the mine drainage (segment 6), below both the mine drainage and volcanically altered areas (segments 3b, 3c, and 3d) and below Terrace

Reservoir (segment 9) had copper concentrations that were significantly higher than the

Table 19. May–August 2009 Arsenic Concentrations at 0-5 cm and 5-15 cm depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Arsenic designated for each segment of the watershed

Location/ Segment Segment 9 Segment 3d Segment 3c Segment 3b Segment 6 Segment 3a Segment 5 Toxicant Arsenic Arsenic Arsenic Arsenic Arsenic Arsenic Arsenic

Ecological Soil Screening PL4 = 18 PL = 18 PL = 18 PL = 18 PL = 18 PL = 18 PL = 18 Level Maximum SI5 =NA SI =NA SI =NA SI =NA SI =NA SI =NA SI =NA Contaminate Level AV6 = 43 AV = 43 AV = 43 AV = 43 AV = 43 AV = 43 AV = 43 (mg/kg)1 MA7 = 46 MA = 46 MA = 46 MA = 46 MA = 46 MA = 46 MA = 46

Depth 2009 Mean + 0-5 13.04 + 2.18 10.74 + 0.67 11.38 + 0.944 13.46 + 1.32 26.16 + 3.33 6.72 + 0.294 3.23 + 0.388 SEM 2009 Mean + 5-15 12.87 + 1.86 9.33 + 0.719 11.63 + 0.626 21.38 + 3.25 42.74 + 5.89 6.40 + 0.304 3.37 + 0.163 SEM 2000 Data2 Unknown 6.4 8.2 10.9 9.3 5.5 NA NA 2009 Range 0-5 4.82-19.34 8.04-12.45 8.34-14.04 8.83-17.87 12.90-34.88 5.69-7.57 2.84-3.61 2009 Range 5-15 4.56-18.41 6.84-11.87 10.65-14.59 8.13-31.73 16.16-59.88 5.58-7.54 3.21-3.54 2000 Range3 Unknown 7-9.3 5.3-16.8 5.3-16.8 5.3-16.8 34.4-87.2 NA NA

1 USEPA 2005B 2 CWCB 2005A 3 CDPHE 2001 4 PL = plants 5 SI = Soil Invertebrates 6 AV = Avian 7 MA = mammalian

0.6 p=0.00 *

0.5

0.4

0.3 5cm 15cm 0.2

0.1

0 5 6 3a 3b 3c 3d 9

-0.1

Figure 21. Cadmium Concentrations (ppm) in Sediment Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009. Samples were digested using EPA method 3052 and were analyzed with an ICP-MS using EPA method 6020A. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to ANOVA Test. Samples collected below Terrace Reservoir (segment 9) had cadmium concentrations that were significantly higher at the 0-5 cm depth than the pristine site (segment 5).

Table 20. May–August 2009 Cadmium Concentrations at 0-5 cm and 5-15 cm Depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Cadmium Designated for each Segment of the Watershed

Location/ Segment Segment 9 Segment 3d Segment 3c Segment 3b Segment 6 Segment 3a Segment 5 Toxicant Cadmium Cadmium Cadmium Cadmium Cadmium Cadmium Cadmium

Ecological Soil PL4 = 32 PL = 32 PL = 32 PL = 32 PL = 32 PL = 32 PL = 32 Screening Level SI 5 = 140 SI = 140 SI = 140 SI = 140 SI = 140 SI = 140 SI = 140 Maximum Contaminate AV6 = 0.77 AV = 0.77 AV = 0.77 AV = 0.77 AV = 0.77 AV = 0.77 AV = 0.77 Level (mg/kg)1 MA7 = 0.36 MA = 0.36 MA = 0.36 MA = 0.36 MA = 0.36 MA = 0.36 MA = 0.36

Depth 2009 Mean 0.1272 + 0.1319 + 0.2178 0.0405 + 0.0538 + 0-5 0.49 + 0.10 0.19 + 0.0461 + SEM 0.0187 0.0288 +0.0547 0.0156 0.0211 2009 Mean 0.2184 + 0.1442 + 0.1408 0.2043 + 0.1074 + 0.0346 + 5-15 0.114 + 0.0470 + SEM 0.0490 0.0266 +0.0330 0.0317 0.0372 0.0104 2000 Data2 Unknown 2.2 0.7 1.2 0.6 0.4 NA NA 2009 0-5 0.06-0.71 0.09-0.35 0.05-0.17 0.12-0.20 0.11-0.47 0.00-0.09 0.03-0.07 Range 2009 5-15 0.06-0.33 0.08-0.25 0.07-0.28 0.04-0.18 0.08-0.3 0.04-0.21 0.02-0.05 Range 2000 Unknown 3.9-4.7 3-4.3 3-4.3 3-4.3 <0.3-4.3 NA NA Range3

1 USEPA 2005C 2 CWCB 2005A 3 CDPHE 2001 4 PL = plants 5 SI = Soil Invertebrates 6 AV = Avian 7 MA = mammalian

p=0.00 * 25

20 p=0.00

* 15 5cm 15cm

0 5 6 3a 3b 3c 3d 9

Figure 22. Cobalt Concentrations (ppm) in Sediment Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009. Samples were digested using EPA method 3052 and were analyzed with an ICP-MS using EPA method 6020A. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to ANOVA Test. Samples collected below Terrace Reservoir (segment 9) had cobalt concentrations that were significantly higher at both the 0-5 cm and 5-15 cm depths than the pristine site (segment 5).

Table 21. May–August 2009 Cobalt Concentrations at 0-5 cm and 5-15 cm Depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Cobalt Designated for each Segment of the Watershed

Location/ Segment Segment 9 Segment 3d Segment 3c Segment 3b Segment 6 Segment 3a Segment 5 Toxicant Cobalt Cobalt Cobalt Cobalt Cobalt Cobalt Cobalt

Ecological Soil PL2 = 13 PL = 13 PL = 13 PL = 13 PL = 13 PL = 13 PL = 13 Screening Level SI3 = NA SI = NA SI = NA SI = NA SI = NA SI = NA SI = NA Maximum Contaminate AV4 = 120 AV = 120 AV = 120 AV = 120 AV = 120 AV = 120 AV = 120 Level (mg/L)1 MA5 = 230 MA = 230 MA = 230 MA = 230 MA = 230 MA = 230 MA = 230

Depth 2009 Mean + 0-5 22.76 + 2.54 10.17 + 0.525 10.223 + 0.536 11.08 + 1.24 11.29 + 1.48 6.841 + 0.581 7.07 + 2.01 SEM 2009 Mean + 5-15 14.04 + 1.14 11.229 + 0.347 9.747 + 0.434 10.813 + 0.607 8.4 + 1.15 8.92 + 2.03 6.14 + 1.43 SEM 2009 Range 0-5 12.15-30.47 8.33-11.58 8.35-11.97 6.09-14.84 7.58-15.58 4.27-8.63 5.06-9.08 2009 Range 5-15 9.35-18.00 9.92-12.32 8.73-11.42 9.28-13.51 5.28-12.95 4.31-18.63 4.71-7.57

1 USEPA 2005D 2 PL = plants 3 SI = Soil Invertebrates 4 AV = Avian 4 MA = mammalian

pristine site (segment 5, Figure 23). All of the other segments had copper concentrations

that were comparable to the pristine site (segment 5; Figure 23). At the 0-5 cm depth

copper concentrations that were significantly higher than the pristine site (segment 5)

occurred in the mine drainage (segment 6) and below Terrace Reservoir (segment 9;

Figure 23). At the 5-15 cm depth copper concentrations that were significantly higher

occurred in the mine drainage (segment 6), below both the mine drainage and

volcanically altered areas (segment 3a), and below Terrace Reservoir (segment 9; Figure

23). The 2009 mean copper concentrations in the mine drainage (segment 6), below both

the mine drainage and volcanically altered areas (segment 3c) and below Terrace

Reservoir (segment 9) did not comply with the ECSSL for plant, soil invertebrate, avian

and mammalian life (Table 22; USEPA 2007A). In Table 22 the ECSSL standards are

given for copper as well as the concentrations from previous studies and this 2009 study.

The 2009 mean copper concentrations below both the mine drainage and volcanically

altered areas (segment 3b and 3d) did not comply with the ECSSL for plant, avian and

mammalian life (Table 22).

Samples collected in the mine drainage (segment 6), below both the mine

drainage and volcanically altered areas (segments 3b and 3c) and below Terrace

Reservoir (segment 9) had lead concentrations that were significantly higher than the

pristine site (segment 5; Figure 24). The other segments all had lead concentrations that

were comparable to the pristine site (segment 5; Figure 24). At the 0-5 cm depth lead concentrations that were significantly higher than the pristine site (segment 5) occurred in the mine drainage (segment 6) and below Terrace Reservoir (segment 9; Figure 24). At the 5-15 cm depth lead concentrations that were significantly higher occurred in the

275 p=0.00 * p=0.00 225 p=0.00 * * 175 p=0.00 p=0.00 * 125 p=0.00 5cm * p=0.00 * 15cm *

5 6 3a 3b 3c 3d 9 -25

Figure 23. Copper Concentrations (ppm) in Sediment Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009. Samples were digested using EPA method 3052 and were analyzed with an ICP-MS using EPA method 6020A. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to ANOVA Test. Samples collected in Wightman Fork mine drainage (segment 6), below both the mine drainage and volcanically altered areas (segments 3b, 3c and 3d) and below Terrace Reservoir (segment 9) had copper concentrations that were significantly higher than the pristine site (segment 5; (P>0.05). At the 0-5 cm depth copper concentrations that were significantly higher than the pristine site (segment 5) occurred in the mine drainage and below Terrace Reservoir (segment 9). At the 5-15 cm depth copper concentrations that were significantly higher occurred in the mine drainage (segment 6), below both the mine drainage and volcanically altered areas (segment 3b, 3c,and 3d), and below Terrace Reservoir (segment 9).

Table 22. May–August 2009 Copper Concentrations at 0-5 cm and 5-15 cm Depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Copper Designated for each Segment of the Watershed

Location/ Segment Segment 9 Segment 3d Segment 3c Segment 3b Segment 6 Segment 3a Segment 5 Toxicant Copper Copper Copper Copper Copper Copper Copper

Ecological Soil PL4 = 70 PL = 70 PL = 70 PL = 70 PL = 70 PL = 70 PL = 70 Screening Level SI5 = 80 SI = 80 SI = 80 SI = 80 SI = 80 SI = 80 SI = 80 Maximum Contaminate AV6 = 28 AV = 28 AV = 28 AV = 28 AV = 28 AV = 28 AV = 28 Level (mg/kg)1 MA7 = 49 MA = 49 MA = 49 MA = 49 MA = 49 MA = 49 MA = 49

Depth 2009 Mean 0-5 157.8 + 35.5 78.79 + 3.86 82.82 + 4.92 77.8 + 13.2 210 + 27.6 20.82 + 2.03 12.49 + 4.6 + SEM 2009 Mean 5-15 106.9 + 20.5 83.62 + 2.72 86.73 + 4.53 95.02 + 8.86 161.1 + 18.9 22.12 + 2.07 14.62 + 3.7 + SEM 2000 Data2 Unknown 307 208 147 129 545 NA NA 28.16- 2009 Range 0-5 63.57-88.80 66.51-93.07 53.42-138.71 128.99-328.27 15.59-29.05 7.89-17.09 293.46 35.12- 10.92- 2009 Range 5-15 73.56-90.79 69.71-100.80 57.20-117.11 113.95-231.53 17.66-29.43 191.27 18.32 2000 Unknown 159-206 20-132 20-132 20-132 191-362 NA NA Range3

1 USEPA 2007A 2 CWCB 2005A 3 CDPHE 2001 4 PL = plants 5 SI = Soil Invertebrates 6 AV = Avian 7 MA = mammalian

70 p=0.00 * 60

p=0.00 p=0.004 50 p=0.004 * p=0.00 * * 40 * 5cm

30 15cm

0 5 6 3a 3b 3c 3d 9

Figure 24. Lead Concentrations (ppm) in Sediment Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009. Samples were digested using EPA method 3052 and were analyzed with an ICP-MS using EPA method 6020A. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to ANOVA Test. Samples collected in Wightman Fork mine drainage (segment 6), below both the mine drainage and volcanically altered areas (segments 3b and 3c) and below Terrace Reservoir (segment 9) had lead concentrations that were significantly higher than the pristine site (segment 5). At the 0-5 cm depth lead concentrations that were significantly higher than the pristine site (segment 5) occurred in the mine drainage (segment 6) and below Terrace Reservoir (segment 9). At the 5-15 cm depth lead concentrations that were significantly higher occurred in the mine drainage (segment 6) and both the mine drainage and volcanically altered areas (segment 3b and 3c).

mine drainage (segment 6) and below both the mine drainage and volcanically altered

areas (segments 3b and 3c; Figure 24). Lead concentrations in all segments except the pristine site (segment 5) at both the 0-5 cm and 5-15 cm depths were not in compliance with the ECSSL for avian life (Table 23; USEPA 2005E). In Table 23 the ECSSL standards are given for lead, as well as the concentrations from previous studies and this

2009 study.

Every segment sampled had manganese concentrations that were not significantly different than the pristine site (segment 5) at either the 0-5 cm or 5-15 cm depths (Figure

25). All of the segments including the pristine site (segment 5) were not in compliance with one or both ECSSL for plant or soil invertebrate life (Table 24; USEPA 2007B). In

Table 24 the ECSSL standards are given for manganese, as well as the concentrations from previous studies and this 2009 study.

Samples collected below both the mine drainage and volcanically altered areas

(segments 3c and 3d) and below Terrace Reservoir (segment 9) had nickel concentrations that were significantly higher than the pristine site (segment 5; Figure 26). None of the other segments, at either depth, had nickel concentrations that were significantly different from the pristine site (Segment 5; Figure 26). At the 0-5 cm depth nickel concentrations that were significantly higher than the pristine site (segment 5) occurred below both the mine drainage (segment 6) and volcanically altered areas (segments 3c and 3d) and below

Terrace Reservoir (segment 9; Figure 26). At the 5-15 cm depth nickel concentrations that were significantly higher occurred below both the mine drainage (segment 6) and volcanically altered areas (segment 3d) and below Terrace Reservoir (segment 9; Figure

26). Nickel concentrations in all segments were below ECSSL (Table 25; UESPA

Table 23. May–August 2009 Lead levels at 0-5 cm and 5-15 cm depths collected along the Alamosa River and the Ecological Soil Screening Levels for Lead designated for each segment of the watershed

Location/ Segment Segment 9 Segment 3d Segment 3c Segment 3b Segment 6 Segment 3a Segment 5 Toxicant Lead Lead Lead Lead Lead Lead Lead Ecological Soil PL4 = 120 PL = 120 PL = 120 PL = 120 PL = 120 PL = 120 PL = 120 Screening Level SI5 = 1700 SI = 1700 SI = 1700 SI = 1700 SI = 1700 SI = 1700 SI = 1700 Maximum Contaminant AV6 = 11 AV = 11 AV = 11 AV = 11 AV = 11 AV = 11 AV = 11 Level (mg/kg)1 MA7 = 56 MA = 56 MA = 56 MA = 56 MA = 56 MA = 56 MA = 56 Depth 2009 Mean 0-5 34.14 + 8.24 25.5 + 2.54 25.12 + 1.45 24.53 + 2.43 36.68 + 4.017 16.24 + 1.64 6.82 + 1.78 + SEM 2009 Mean 5-15 3.63 2.5 1.4 4.19 4.78 1.83 2.47 + SEM 2000 Data2 Unknown 17 21 21 30 23 NA NA 2009 0-5 11.65-69.58 18.86-32.76 19.55-28.44 19.39-33.07 21.85-51.72 11.51-21.49 5.04-8.60 Range 2009 5-15 10.49-35.09 13.66-29.05 23.89-32.00 24.46-51.15 31.12-62.90 11.70-23.54 4.40-9.39 Range 2000 Unknown 16-17 14-33 14-33 14-33 51-137 NA NA Range3

1 USEPA 2005E 2 CWCB 2005A 3 CDPHE 2001 4 PL = plants 5 SI = Soil Invertebrates 6 AV = Avian 7 MA = mammalian

1800 p>0.05 1600

1400

1200

1000 5cm 800 15cm

600

400

200

0 5 6 3a 3b 3c 3d 9

Figure 25. Manganese Concentrations (ppm) in Sediment Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009. Samples were digested using EPA method 3052 and were analyzed with an ICP-MS using EPA method 6020A. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to ANOVA Test. None of the segment had manganese concentrations that were significantly different than the pristine site (segment 5) at either the 0-5 cm or 5-15 cm depths.

Table 24. May–August 2009 Manganese Concentrations at 0-5 cm and 5-15 cm Depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Manganese Designated for each Segment of the Watershed

Location/ Segment Segment 9 Segment 3d Segment 3c Segment 3b Segment 6 Segment 3a Segment 5 Toxicant Manganese Manganese Manganese Manganese Manganese Manganese Manganese Ecological Soil PL4 = 220 PL = 220 PL = 220 PL = 220 PL = 220 PL = 220 PL = 220 Screening Level SI5= 450 SI = 450 SI = 450 SI = 450 SI = 450 SI = 450 SI = 450 Maximum AV6 = 4300 AV = 4300 AV = 4300 AV = 4300 AV = 4300 AV = 4300 AV = 4300 Contaminate Level MA7 = 4000 MA = 4000 MA = 4000 MA = 4000 MA = 4000 MA = 4000 MA = 4000 (mg/kg)1 Depth 2009 Mean + 0-5 948 + 125 429.7 + 20.9 436.4 + 30.1 553.3 + 62.6 1065 + 555 392.9 + 44.7 659.8 + 63.8 SEM 2009 Mean + 5-15 616.5 + 57.2 469.5 + 12.8 427.9 + 24.8 552.7 + 45.6 396.4 + 75 524 + 135 364.2 + 55.6 SEM 2000 Unknown 1610 412 442 381 350 NA NA Data2 2009 483.06- 365.71- 374.73- 0-5 355.97-481.64 395.31-584.70 207.55-492.72 595.98-723.53 Range 1405.09 785.20 3818.88 2009 449.15- 225.10- 193.10- 5-15 382.08-768.66 420.91-500.04 375.17-508.02 308.66-419.77 Range 727.51 724.23 1154.92 2000 Unknown 787-1480 351-520 351-520 351-520 479-797 NA NA Range3

1 USEPA 2007B 2 CWCB 2005A 3 CDPHE 2001 4 PL = plants 5 SI = Soil Invertebrates 6 AV = Avian 7 MA = mammalian

14 p=0.00 p=0.00 12 * * p=0.00 10 p=0.00 p=0.00 8 * * * 5cm 6 15cm

0 5 6 3a 3b 3c 3d 9

Figure 26. Nickel Concentrations (ppm) in Sediment Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009. Samples were digested using EPA method 3052 and were analyzed with an ICP-MS using EPA method 6020A. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to ANOVA Test. Samples collected below both the mine drainage and volcanically altered areas (segments 3c and 3d) and below Terrace Reservoir (segment 9) had nickel concentrations that were significantly higher than the pristine site (segment 5). At the 0-5 cm depth lead concentrations that were significantly higher than the pristine site (segment 5) occurred below both the mine drainage and volcanically altered areas (segments 3c and 3d) and below Terrace Reservoir (segment 9). At the 5-15 cm depth lead concentrations that were significantly higher occurred below both the mine drainage and volcanically altered areas (segment 3d) and below Terrace Reservoir (segment 9).

Table 25. May–August 2009 Nickel Concentrations at 0-5 cm and 5-15 cm depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Nickel Designated for each Segment of the Watershed

Segment 9 Segment 3d Segment 3c Segment 3b Segment 6 Segment 3a Segment 5

Toxicant Nickel Nickel Nickel Nickel Nickel Nickel Nickel Ecological Soil PL4 = 38 PL = 38 PL = 38 PL = 38 PL = 38 PL = 38 PL= 38 Screening Level SI5 = 280 SI = 280 SI = 280 SI = 280 SI = 280 SI = 280 SI = 280 Maximum Contaminate AV6 = 210 AV = 210 AV = 210 AV = 210 AV = 210 AV = 210 AV = 210 Level (mg/kg)1 MA7 = 130 MA = 130 MA = 130 MA = 130 MA = 130 MA = 130 MA = 130 Depth 2009 Mean 0-5 10.72 + 0.74 7.10 + 0.38 6.36 + 0.11 5.00 + 0.32 5.66 + 0.32 3.74 + 0.14 0.12 + 0.06 + SEM 2009 Mean 0.128 + 5-15 9.79 + 0.91 7.22 + 0.47 6.13 + 0.16 5.49 + 0.26 5.53 + 0.27 3.92 + 0.28 + SEM 0.07 2000 Data2 Unknown 20 11 9 6 6 NA NA 2009 Range 0-5 7.81-12.93 5.80-8.11 5.96-6.74 3.58-5.92 4.43-6.41 3.28-4.14 2.24-4.78 2009 Range 5-15 5.51-11.39 6.17-9.21 5.70-6.77 4.87-6.54 4.74-6.46 3.18-5.13 3.22-5.13 2000 Unknown 13-17 5-9 5-9 5-9 6-9 NA NA Range3

1 USEPA 2007C 2 CWCB 2005A 3 CDPHE 2001 4 PL = plants 5 SI = Soil Invertebrates 6 AV = Avian 7 MA = mammalian

2007C). In Table 25 the ECSSL standards are given for nickel, as well as the

concentrations from previous studies and this 2009 study.

Samples collected in the volcanically contaminated area (segment 3a) and below both the mine drainage (segment 6) and volcanically altered areas (segments 3b and 3c) had selenium concentrations that were significantly higher than the pristine site (segment

5; Figure 27). The areas above and below Terrace Reservoir (segments 3d and 9) had comparable selenium concentrations when compared with the pristine site (segment 5;

Figure 27). At the 0-5 cm depth selenium concentrations that were significantly higher than the pristine site (segment 5) occurred in the volcanically altered area (segment 3a)

and directly below the mine drainage (segment 3b; Figure 27). At the 5-15 cm depth selenium concentrations that were significantly higher occurred in the volcanically contaminated area (segment 3a), directly below the mine drainage (segment 3b) and below both the mine drainage (segment 6) and volcanically altered areas (segment 3c;

Figure 27). Selenium concentrations in all segments except for the pristine site (segment

5) were not in compliance with one or all three ECSSL for plant, avian and mammalian life (Table 26; USEPA 2007D). In Table 26 the ECSSL standards are given for selenium, as well as the concentrations from previous studies and this 2009 study.

The only area that had a 2009 mean zinc concentration that was not significantly

different than the pristine site (segment 5) occurred in the volcanically altered area

(segment 3a) at a depth of 5-15 cm (Figure 28); all of the other segments had mean zinc

concentrations that were significantly different from the pristine site (segment 5; Figure

28). Zinc concentrations in all segments except the pristine site (segment 5) were not in

compliance with one or both of the ECSSL for avian or mammalian life (Table 27;

2.5 p=0.00 p=0.00 * p=0.00 * 2 * p=0.00 p=0.00 * * 1.5

5cm 1 15cm

0.5

0 5 6 3a 3b 3c 3d 9

-0.5

Figure 27. Selenium Concentrations (ppm) in Sediment Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009. Samples were digested using EPA method 3052 and were analyzed with an ICP-MS using EPA method 6020A. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the pristine site (segment 5) at the 5% level according to ANOVA Test. Samples collected in the volcanically altered area (segment 3a) and below both the mine drainage and volcanically altered areas (segments 3b and 3c) had selenium concentrations that were significantly higher than the pristine site (segment 5). At the 0-5 cm depth lead concentrations that were significantly higher than the pristine site (segment 5) occurred in the volcanically altered area (segment 3a) and directly below the mine drainage (segment 3b). At the 5-15 cm depth lead concentrations that were significantly higher occurred in the volcanically contaminated area (segment 3a) and below both the mine drainage and volcanically altered areas (segments 3b and 3c).

Table 26. May–August 2009 Selenium Concentrations at 0-5 cm and 5-15 cm Depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Selenium Designated for each Segment of the Watershed

Location/ Segment Segment 9 Segment 3d Segment 3c Segment 3b Segment 6 Segment 3a Segment 5 Toxicant Selenium Selenium Selenium Selenium Selenium Selenium Selenium PL2 = 0.52 PL = 0.52 PL = 0.52 PL = 0.52 PL = 0.52 PL = 0.52 PL = 0.52 Ecological Soil Screening SI3 = 4.1 SI = 4.1 SI = 4.1 SI = 4.1 SI = 4.1 SI = 4.1 SI = 4.1 Level Maximum Contaminate AV4 = 1.2 AV = 1.2 AV = 1.2 AV = 1.2 AV = 1.2 AV = 1.2 AV = 1.2 Level (mg/k)1 MA5 = 0.63 MA = 0.63 MA = 0.63 MA = 0.63 MA = 0.63 MA = 0.63 MA = 0.63 Depth 2009 Mean + SEM 0-5 1.32 + 0.48 1.09 + 0.04 1.28 + 0.08 1.75 + 0.14 0.61 + 0.11 1.92 + 0.29 0.17 + 0.10 2009 Mean + SEM 5-15 0.69 + 0.04 1.04 + 0.06 1.27 + 0.05 1.45 + 0.15 0.68 + 0.006 1.74 + 0.31 0.20 + 0.15 2009 Range 0-5 0.51-3.67 0.99-1.21 1.06-1.60 1.47-2.39 0.28-0.96 0.26-3.07 0.08-0.27 2009 Range 0-15 0.55-0.79 0.87-1.28 1.14-1.49 1.19-2.16 0.54-0.92 1.07-3.19 0.05-0.34

1 USEPA 2007D 2 PL = plants 3 SI = Soil Invertebrates 4 AV = Avian 5 MA = mammalian

160 p=0.00 p=0.00 * 140 p=0.00 p=0.00 p=0.00 p=0.00 * p=0.00 * * 120 * p=0.00 * p=0.00 * 100 * p=0.00 * * 80 5cm 15cm

0 5 6 3a 3b 3c 3d 9

Figure 28. Zinc Concentrations (ppm) in Sediment Samples Along the Alamosa River. Samples were collected between 5/3/2009 and 8/24/2009. Samples were digested using EPA method 3052 and were analyzed with an ICP-MS using EPA method 6020A. Bars above the means denote standard errors. Means with an asterisk (*) are statistically significantly different from the prestine site (segment 5) at the 5% level according to ANOVA Test. The only sample that was not significantly different than the pristine site (segment 5) occurred in the volcanically altered area (segment 3a) at a depth of 5-15 cm.

Table 27. May–August 2009 Zinc Concentrations at 0-5 cm and 5-15 cm Depths Collected Along the Alamosa River and the Ecological Soil Screening Levels for Zinc Designated for each Segment of the Watershed

Location/ Segment Segment 9 Segment 3d Segment 3c Segment 3b Segment 6 Segment 3a Segment 5 Toxicant Zinc Zinc Zinc Zinc Zinc Zinc Zinc

PL4 = 160 PL = 160 PL = 160 PL = 160 PL = 160 PL = 160 PL = 160 Ecological Soil Screening SI5 = NA SI = NA SI = NA SI = NA SI = NA SI = NA SI = NA Level Maximum Contaminate AV6 = 46 AV = 46 AV = 46 AV = 46 AV = 46 AV = 46 AV = 46 Level (mg/k)1 MA7 = 79 MA = 79 MA = 79 MA = 79 MA = 79 MA = 79 MA = 79

Depth 2009 Mean + 0-5 125.30 + 12.8 103.01 + 8.73 85.69 + 3.46 74.09 + 5.03 109.66 + 6.98 47.89 + 3.91 27.93 + 6.86 SEM 2009 Mean + 5-15 105.80 + 12.2 98.30 + 6.97 87.82 + 5.93 79.06 + 3.44 107.74 + 8 52.93 + 6.97 33.95 + 2.99 SEM 2000 Data2 Unknown 198 135 120 57 56 NA NA 2009 Range 0-5 73.61-153.42 75.74-136.03 72.76-98.33 51.33-88.11 90.79-133.07 29.27-56.95 21.07-34.79 2009 Range 5-15 68.95-138.79 80.89-125.21 72.69-111.56 68.35-88.80 85.46-138.42 29.97-80.27 30.96-36.94 2000 Range3 Unknown 131-170 46-119 46-119 46-119 106-166 NA NA

1 USEPA 2007F 2 CWCB 2005A 3 CDPHE 2001 4 PL = plants 5 SI = Soil Invertebrates 6 AV = Avian 7 MA = mammalian

USEPA2007F). In Table 27 the ECSSL standards are given for zinc, as well as the concentrations from previous studies and this 2009 study.

Heavy Metal Concentrations in Cottonwood Tree Cores in 2009

Tree core samples were collected at all of the water and sediment sampling sites except for the pristine site (segment 5) since the collection site was at an elevation where deciduous trees do not grow. Two different species of small deciduous trees were sampled along the Alamosa River since only certain deciduous trees will grow at certain elevations. The two tree types that were sampled were cottonwoods and aspens. The cottonwood tree cores correspond with sampling locations above and below Terrace

Reservoir (segments 3d and 9). The aspen tree cores correspond with the volcanically altered area (segment 3a), the area below the mine drainage and the mine drainage itself

(segments 3a, 3b, 3c and 6.) The tree cores were analyzed by tree species and were not compared to each other. A subset of the 27 heavy metals in tree core samples will be presented; they include 55Mn, 56Fe, 59Co, 60Ni, 63Cu, 66Zn, 75As, 78Se, 107Ag, 111Cd, and

208Pb. Arsenic, cadmium, cobalt, copper, lead, manganese, nickel, selenium, silver and zinc were the only heavy metals that are required to meet certain Ecological Soil

Screening Levels (ECSSL).

An Analysis of Variance Test (ANOVA) was used to determine if metal concentrations of an individual metal in cottonwood trees were significantly different between segments within a one decade time period (p-value<0.05; Figures 29-38). Paired

T-Tests were used to determine if the concentrations of an individual metal in cottonwood trees were significantly different among decades at one segment. Arsenic was the only heavy metal that had concentrations that were significantly different (p-

0.06 p>0.05 p>0.05 Analysis of Variance (ANOVA) Paired T-Test Comparing segments 3d and 9 Comparing decades within segment 9 0.05

0.04 p=0.009 Paired T-Test Comparing decades * within segment 3d Mean As 1980-1989 0.03 Mean As 1990-1999 Mean As 2000-2009 * 0.02

0.01

0 3d 9

Figure 29. Arsenic Concentrations (ppm) in Cottonwood Tree Cores Above and Below Terrace Reservoir. Arsenic concentrations were significantly higher above Terrace Reservoir (segment 3d) during the 2000-2009 decade when compared to the 1980-1989 decade.

0.45 p>0.05 Analysis of Variance (ANOVA) and Paired T- Test 0.4 Comparing segments 3d and 9

0.35

0.3

0.25 Mean Cd 1980-1989 Mean Cd 1990-1999 0.2 Mean Cd 2000-2009

0.15

0.1

0.05

0 3d 9

Figure 30. Cadmium Concentrations (ppm) in Cottonwood Tree Cores Above and Below Terrace Reservoir. Cadmium concentrations were determined to be not significantly different among segments or among decade comparisons.

0.3 p>0.05 Analysis of Variance (ANOVA) and Paired T- Test Comparing segments 3d and 9 0.25

0.2

Mean Co 1980-1989 0.15 Mean Co 1990-1999 Mean Co 2000-2009

0.1

0.05

0 3d 9

Figure 31. Cobalt Concentrations (ppm) in Cottonwood Tree Cores Above and Below Terrace Reservoir. Cobalt concentrations were determined to be not significantly different among segments or among decade comparisons.

7 p>0.05 Analysis of Variance (ANOVA) and Paired T- Test Comparing segments 3d and 9 6

4 Mean Cu 1980-1989 Mean Cu 1990-1999 3 Mean Cu 2000-2009

0 3d 9

Figure 32. Copper Concentrations (ppm) in Cottonwood Tree Cores Above and Below Terrace Reservoir. Copper concentrations were determined to be not significantly different among segments or among decade comparisons.

0.25 p>0.05 Analysis of Variance (ANOVA) and Paired T- Test Comparing segments 3d and 9

0.2

0.15

Mean Pb 1980-1989 Mean Pb 1990-1999 Mean Pb 2000-2009 0.1

0.05

0 3d 9

Figure 33. Lead Concentrations (ppm) in Cottonwood Tree Cores Above and Below Terrace Reservoir. Lead concentrations were determined to be not significantly different among segments or among decade comparisons.

35 p>0.05 Analysis of Variance (ANOVA) and Paired T- Test Comparing segments 3d and 9 30

20 Mean Mn 1980-1989 Mean Mn 1990-1999 15 Mean Mn 2000-2009

0 3d 9

Figure 34. Manganese Concentrations (ppm) in Cottonwood Tree Cores Above and Below Terrace Reservoir. Manganese concentrations were determined to be not significantly different among segments or among decade comparisons.

1.2 p>0.05 Analysis of Variance (ANOVA) and Paired T- Test 1 Comparing segments 3d and 9

0.8

0.6

Mean Ni 1980-1989 0.4 Mean Ni 1990-1999 Mean Ni 2000-2009

0.2

0 3d 9

-0.2

-0.4

Figure 35. Nickel Concentrations (ppm) in Cottonwood Tree Cores Above and Below Terrace Reservoir. Nickel concentrations were determined to be not significantly different among segments or among decade comparisons.

0.025 p>0.05 Analysis of Variance (ANOVA) and Paired T- Test Comparing segments 3d and 9

0.02

0.015

Mean Se 1980-1989 Mean Se 1990-1999 Mean Se 2000-2009 0.01

0.005

0 3d 9

Figure 36. Selenium Concentrations (ppm) in Cottonwood Tree Cores Above and Below Terrace Reservoir. Selenium concentrations were determined to be not significantly different among segments or among decade comparisons.

0.035 p>0.05 Analysis of Variance (ANOVA) and Paired T- Test Comparing segments 3d and 9 0.03

0.025

0.02 Mean Ag 1980-1989 Mean Ag 1990-1999 0.015 Mean Ag 2000-2009

0.01

0.005

0 3d 9

Figure 37. Silver Concentrations (ppm) in Cottonwood Tree Cores Above and Below Terrace Reservoir. Silver concentrations were determined to be not significantly different among segments or among decade comparisons.

100

120 p>0.05 Analysis of Variance (ANOVA) and Paired T- Test Comparing segments 3d and 9 100

Mean Zn 1980-1989 60 Mean Zn 1990-1999 Mean Zn 2000-2009

0 3d 9

Figure 38. Zinc Concentrations (ppm) in Cottonwood Tree Cores Above and Below Terrace Reservoir. Zinc concentrations were determined to be not significantly different among segments or among decade comparisons.

101

value <0.05). Arsenic concentrations above Terrace Reservoir (segment 3d) in the 2000-

2009 decade were significantly greater than the 1980-1989 decade (p-value of 0.009;

Figure 29), but were not significantly from the 1990-1999 decade.

Heavy Metal Concentrations in Aspen Tree Cores

An Analysis of Variance Test (ANOVA) was used to determine if metal concentrations

of an individual metal in aspen trees were significantly different between segments within

a one decade time period (p-value<0.05; Figures 39-48). Arsenic concentrations in the

mine drainage (segment 6) in the 2000-2009 decade were significantly lower than

concentrations below the mine drainage (segment 3a and 3c; p-value of 0.010; Figure

39). Cadmium concentrations below the mine drainage (segment 3c) in 1980-1989 were

significantly greater than concentrations directly below the mine drainage (segment 3b)

(p-value of 0.043; Figure 40). Lead concentrations directly below the mine drainage

(segment 3b) were significantly greater than concentrations in the volcanically altered area (segment 3a) and below the mine drainage (segment 3c; p- value of 0.025; Figure

41). Zinc concentrations below the mine drainage (segment 3c) in the 2000-2009 decade

were significantly lower than concentrations in the volcanically altered area (segment 3a;

p- value of 0.041; Figure 42).

Paired T-Tests were used to determine if the concentrations of an individual metal

in aspen trees were significantly different among decades at one segment. Arsenic

concentrations directly below the mine drainage (segment 3b) in the 2000-2009 decade

were significantly greater than the 1990-1999 decade (p-value of 0.049; Figure 38), but

were not significantly different from the 1980-1989 decade. Cadmium concentrations

below the mine drainage (segment 3c) in the 1990-1999 decade were significantly lower

102

p=0.01 0.0400 Analysis of Variance (ANOVA) Comparing * segments 3a, 3c and 6 p=0.049 0.0350 * Paired T-Test Comparing decades in segment 3b 0.0300 p>0.05 Paired T-Test * Comparing decades 0.0250 in segment 3a, 3c and 6 * Mean As 1980-1989 0.0200 Mean As 1990-1999 * Mean As 2000-2009 0.0150

0.0100

0.0050

0.0000 6 3a 3b 3c

Figure 39. Arsenic Concentrations (ppm) in Aspen Tree Cores Above and Below Wightman Forks junction with the Alamosa River. Samples in the volcanically altered area (segment 3a) and below the Wightman Fork mine drainage (segment 3c) had significantly higher concentrations than Wightman Fork (segment 6). Arsenic concentrations were significantly higher directly below Wightman Fork (segment 3b) in the 1990-1999 decade when compared to the 2000-2009 decade.

103

0.7000 p>0.05 p=0.05 Analysis of Variance (ANOVA) Paired T-Test Comparing segments 3a and 6 * Comparing decades 0.6000 * in segment 3c p>0.05 Paired T-Test 0.5000 Comparing decades in segment 3a, 3b and 6 p=0.043 Analysis of Variance (ANOVA) 0.4000 Comparing segments 3b and 3c * Mean Cd 1980-1989 Mean Cd 1990-1999 0.3000 Mean Cd 2000-2009 *

0.2000

0.1000

0.0000 6 3a 3b 3c

Figure 40. Cadmium Concentrations (ppm) in Aspen Tree Cores Above and Below Wightman Forks Junction with the Alamosa River. Samples from the 1980-1989 decade below the Wightman Fork mine drainage (segment 3c) had significantly higher cadmium concentrations than directly below Wightman Fork the mine drainage (segment 3b). Cadmium concentrations were significantly higher below the mine drainage (segment 3c) in the 1980-1989 decade when compared to the 1990-1999 decade.

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0.2500 p>0.05 p=0.025 Paired T-Test Analysis of Variance (ANOVA) Comparing decades Comparing segments 3a, 3b and 3c in segment 3a, 3b and 3c 0.2000 *

p=0.009 0.1500 Paired T-Test Comparing decades Mean Pb 1980-1989 in segment 6 Mean Pb 1990-1999 * Mean Pb 2000-2009 0.1000 * *

* 0.0500

0.0000 6 3a 3b 3c

Figure 41. Lead Concentrations (ppm) in Aspen Tree Cores Above and Below Wightman Forks Junction with the Alamosa River. Lead concentrations in the 1990-1999 decade directly below Wightman Fork mine drainage (segment 3b) had significantly higher lead concentrations than the volcanically contaminated area (segment 3a) and below Wightman Fork (segment 3c). Lead concentrations were significantly higher in Wightman Fork mine drainage (segment 6) in the 1990-1999 decade when compared to the 2000-2009 decade.

105

140 p=0.041 Analysis of Variance (ANOVA) Comparing segments 3a and 3c 120 * p>0.05 p>0.05 Paired T-Test Analysis of Variance (ANOVA) Comparing decades Comparing segments 3b and 6 100 in segment 3a, 3b and 6 p=0.024 Paired T-Test Comparing decades 80 in segment 3c * Mean Zn 1980-1989 * Mean Zn 1990-1999 60 Mean Zn 2000-2009

40 *

0 6 3a 3b 3c

Figure 42. Zinc Concentrations (ppm) in Aspen Tree Cores Above and Below Wightman Forks Junction with the Alamosa River. Samples collected in the volcanically altered area (segment 3a) had significantly higher concentrations of zinc when compared to concentrations below Wightman Fork (segment 3c). Zinc concentrations were significantly higher below Wightman Fork (segment 3c) in the 1980-1989 decade when compared to the 2000-2009 decade.

106

0.3500 p>0.05 Analysis of Variance (ANOVA) and Paired T- Test Comparing segments 3a, 3b, 3c and 6 0.3000

0.2500

0.2000 Mean Co 1980-1989 Mean Co 1990-1999 0.1500 Mean Co 2000-2009

0.1000

0.0500

0.0000 6 3a 3b 3c

Figure 43. Cobalt Concentrations (ppm) in Aspen Tree Cores Above and Below Wightman Forks Junction with the Alamosa River. Cobalt concentrations were determined to be not significantly different among segments or among decade comparisons.

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9.000 p>0.05 Analysis of Variance (ANOVA) and Paired T- Test 8.000 Comparing segments 3a, 3b , 3c and 6

7.000

6.000

5.000 Mean Cu 1980-1989 Mean Cu 1990-1999 4.000 Mean Cu 2000-2009

3.000

2.000

1.000

0.000 6 3a 3b 3c

Figure 44. Copper Concentrations (ppm) in Aspen Tree Cores Above and Below Wightman Forks Junction with the Alamosa River. Copper concentrations were not significantly different among segments or among decade comparisons.

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25.000 p>0.05 Analysis of Variance (ANOVA) Comparing segments 3a, 3b, 3c and 6 20.000 p>0.05 Paired T-Test Comparing decades in segment 3a, 3b and 6 15.000 p=0.025 Paired T-Test Mean Mn 1980-1989 Comparing decades Mean Mn 1990-1999 in segment 3c Mean Mn 2000-2009 10.000 *

* 5.000

0.000 6 3a 3b 3c

Figure 45. Manganese Concentrations (ppm) in Aspen Tree Cores Above and Below Wightman Forks Junction with the Alamosa River. Manganese concentrations were significantly higher below Wightman Fork (segment 3c) in the 2000-2009 decade when compared to the 1990-1999 decade.

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1.6000 p>0.05 Analysis of Variance (ANOVA) and Paired T- Test 1.4000 Comparing segments 3a, 3b, 3c and 6

1.2000

1.0000

Mean Ni 1980-1989 0.8000 Mean Ni 1990-1999 Mean Ni 2000-2009 0.6000

0.4000

0.2000

0.0000 6 3a 3b 3c

Figure 46. Nickel Concentrations (ppm) in Aspen Tree Cores Above and Below Wightman Forks Junction with the Alamosa River. Nickel concentrations were not significantly different among segments or among decade comparisons.

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0.0140 p>0.05 Analysis of Variance 0.0120 (ANOVA) and Paired T- Test Comparing segments 3a, 3b, 3c and 6 0.0100

0.0080

0.0060 Mean Se 1980-1989 0.0040 Mean Se 1990-1999 Mean Se 2000-2009 0.0020

0.0000 6 3a 3b 3c -0.0020

-0.0040

-0.0060

Figure 47. Selenium Concentrations (ppm) in Aspen Tree Cores Above and Below Wightman Forks Junction with the Alamosa River. Selenium concentrations were not significantly different among segments or among decade comparisons.

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0.0700 p>0.05 Analysis of Variance (ANOVA) and Paired T- Test p>0.05 0.0600 Comparing segments 3a, 3b, 3c and 6 Paired T-Test Comparing decades in segment 3a, 3b and 3c 0.0500 p=0.033 0.0400 Paired T-Test Comparing decades in segment 6 0.0300 * Mean Ag 1980-1989 Mean Ag 1990-1999 0.0200 Mean Ag 2000-2009

* 0.0100

0.0000 6 3a 3b 3c

-0.0100

-0.0200

Figure 48. Silver Concentrations (ppm) in Aspen Tree Cores Above and Below Wightman Forks Junction with the Alamosa River. Silver concentrations were significantly higher in the Wightman Fork mine drainage (segment 6) in the 1990-1999 decade when compared to the 1980-1989 decade.

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than the 1980-1989 decade (p-value of 0.050; Figure 39), but did not significantly change

in the 2000-2009 decade. Lead concentrations in the mine drainage (segment 6) in the

2000-2009 decade were significantly lower than the 1990-1999 decade (p-value of 0.009;

Figure 42) but were not significantly different than the 1980-1989 decade. Manganese

concentrations below the mine drainage (segment 3c) in the 2000-2009 decade were

significantly greater than the 1990-1999 decade (p-value of 0.025; Figure 43); however,

they were not significantly greater than the 1980-1989 decade. Silver concentrations in

the mine drainage (segment 6) in the 1990-1999 decade were significantly greater than

the 1980-1989 decade (p-value of 0.033; Figure 46), but were not significantly different

from the 2000-2009 decade. Zinc concentrations below the mine drainage (segment 3c)

in the 2000-2009 decade were significantly greater than the 1980-1989 decade (p-value

of 0.024; Figure 47), but were not significantly greater than the 1990-1999 decade.

Concentrations of cobalt, copper, nickel and selenium were all found to be not

significantly different among decade comparisons between segments (Figures 43-44 and

46-47).

AIM 2: COMPARISON OF CONCENTRATIONS OF INORGANIC ELEMENTS

AT THE MINING SITE IN 2009 TO CONCENTRATIONS PREVIOUSLY

RECORDED

The pH in all segments with previous data (segments 3a, 3b, 3c, 3d, 6 and 9) increased when compared to the pH in 1998-2003 (Figure 49; Table 28; CWCB 2005A).

There are no 1998-2003 data for the pristine site (segment 5) so we do not know if it’s mean increased like the other segments. The mean pH for all of the segments sampled in

2009 and the mean pH for the segments sampled in a study done in 1998-2003 can be

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Figure 49. Mean pH Values from the 2009 Collections Season with the Corresponding Standards set by the Colorado Department of Public Health and Environment. Above is the 1. 2009 mean pH values, 2. the 1998-2003 mean pH values and 3. the Colorado Department of Public Health and Environment (CDPHE) pH Standards by segment. All of the 2009 mean pH values increased when compared to the 1998-2003 mean pH values. All of the 2009 mean pH values were in compliance with the standards set by the CDPHE.

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Table 28. 2009 Median and Average pH Values Compared to Previously Reported Values

Segment 9 3d 3c 3b 6 3a 5 1986-1994 median pH1 6.13 6.22 6.22 4.91 5.61 5.19 NA 1998-2003 median pH1 6.9 6.49 6.49 5.86 5.32 5.08 NA 2009 median pH 7.85 7.75 7.55 7.5 7.35 6.4 7.85 1998-2003 average pH1 6.17 5.99 4.89 5.01 4.87 3.83 NA 2009 average pH 7.77 7.58 7.33 7 7.4 6.12 7.85

1 CWCB 2005A

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seen in Figure 49, as well as the Colorado Department of Public Health (CDPHE) pH

standards. The average pH in 2009 ranged from 6.12-7.85 across all sites and was 2-3

orders of magnitude higher than the average 1998-2003 pH range of 3.83-6.17 (CWCB

2005A; Table 28). Even though the mean pH increased for all of the segments, some

segments still exceeded the acidic limits set by the CDPHE for specific times during the

collection season (Figure 50). Samples collected in the volcanically altered area

(segment 3a) had pH readings that were below the acidic limit of 4.73, twice during the

time period of 6/1-8/31 (Table 5; Figure 50). Table 5 includes all of the pH levels

recorded in the 2009 collection season and may be seen on pages 31-32. On 7/6/09 the volcanically altered area (segment 3a) was a pH of 4.0 and on 08/21/09 it was a pH of 4.1

(Table 5). Samples directly below the mine drainage (segment 3b) exceeded the acidic limit of 6.5 twice during the collection season (Table 5; Figure 49). On 07/21/09 the sample directly below the mine drainage (segment 3b) was a pH of 6.3 and on 08/21/09 it was a pH of 4.5 (Table 5). On 08/21/09 the sample below the mine drainage (segment 3c) was a pH of 6.0, which was below the acidic limit of 6.5 (Table 5; Figure 49). Samples above and below Terrace Reservoir (segments 3d and 9) did not have any pH readings during the collection season that were below their reflective pH standard (Table 5; Figure

49). Segment 6 does not have any pH standards that it must meet (Table 5; Figure 49).

Heavy Metals in Water Samples Compared to Previous Concentrations

The volcanically altered area (segment 3a) and the pristine site (segment 5) do not

have comparable historic data available for water and sediment data; therefore they will

not be discussed in this portion of the results. The metal standards in water are specific to

each metal; therefore, some metals only have either dissolved or total recoverable

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Figure 50. The number of times the pH values were below standards set by the Colorado Department of Public Health and Environment. Above is (1.) the Colorado Department of Public Health and Environment (CDPHE) pH standards by segment and (2.) the number of times that individual pH samples during the season were not in compliance with CDPHE pH standards. The pristine site (segment 5), and above and below Terrace Reservoir (segments 3d and 9) were in compliance with the pH standards throughout the 2009 runoff sampling period (5/3/2009-8/24/2009). A sample below the Wightman Fork mine drainage (segment 3c) was below the pH standard once during the season. 2 samples in the volcanically altered area (segment 3a) and 2 samples directly below the Wightman Fork mine drainage (segment 3b) were below pH standards during the 2009 runoff season.

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concentrations and others may have both dissolved and total recoverable concentrations

that apply. Therefore, only the specific type of metal concentrations that apply to the

Alamosa River will be discussed below.

When the maximum dissolved aluminum concentrations for 2009 were compared

to the maximum dissolved aluminum concentrations for 2000, there was a drastic

decrease (Table 6) All of the sampling sites with comparable data (segments 3b, 3c, 3d, 6

and 9) had concentrations in 2009 that were lower than previously measured in 2000,

except for site directly below the mine drainage (segment 3b; Table 6). The segment

directly below the mine drainage (segment 3b) had a maximum dissolved aluminum

value for 2009 that had increase by 3.54 times (Table 6). The other sampling sites

decreased within a range of 1.36-54.6 times (Table 6). The area that had the greatest

decrease was the mine drainage (segment 6; Table 6). The extremely high maximum

value that was seen directly below the mine drainage (segment 3b) was much larger than

all of the other concentrations that were seen in this segment throughout the season.

However, without more analysis we cannot determine if it is a good representative for the

time period and area, or an outlier (Table 6).

When the 2009 median dissolved aluminum concentrations were compared to

median dissolved aluminum concentrations from 1986-1994 and 1998-2003 an increase

was seen in the areas below the mine drainage (segment 3c) and above and below Terrace

Reservoir (segments 3d and 9; Table 6). These areas (segments 3c, 3d and 9) were below

the 1986-1994 concentrations, but exceeded the 1998-2003 concentrations (Table 6).

When the 2009 maximum total recoverable arsenic concentrations were compared

to the maximum total recoverable arsenic concentrations presented in 2000 all of the

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segments had concentrations that decreased (Table 7). The decreases that were seen in

these segments ranged from 1.06-43.48 times (Table 7). The segment with the smallest

decrease was the area below Terrace Reservoir (segment 9) and the segment with the

largest decrease was above Terrace Reservoir (segment 3d; Table 7).

When the 2009 maximum dissolved cadmium concentrations were compared to

the maximum dissolved cadmium concentrations presented in 2000 all of the segments

had decreased concentrations (segment 3b; Table 12).

When the maximum dissolved copper concentrations for 2009 were compared to

the maximum dissolved copper concentrations for 2000, a large decrease was seen in the

amount of dissolved copper for each segment (Table 8). When the 2009 median dissolved

copper concentrations were compared to the median concentrations from 1986-1994 and

1998-2003 the only segment that exceeded any previous median concentration was from

the site below Terrace Reservoir (segment 9), which exceeded the 1998-2003

concentration (Table 8).

When the maximum total recoverable iron concentrations for 2009 were

compared to the maximum total recoverable iron concentrations for 2000 all of the

segments had decreased concentrations (Table 9). The decreases seen in these segments

ranged from 1.29-12.3 times (Table 9). When the 2009 median total recoverable iron

concentrations were compared to the median concentrations from 1986-1994 and 1998-

2003 the only segment that exceeded its previous 1998-2003 value was below Terrace

Reservoir (segment 9; Table 9). The 2009 median total recoverable iron concentration below Terrace Reservoir (segment 9) was 913 mg/kg, exceeded the 1998-2003 value of

837 mg/kg (Table 9).

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When the maximum dissolved lead concentrations for 2009 were compared to the

maximum dissolved lead concentrations for 2000 all of the segments had decreased concentrations (Table 10). The decreases seen in these segments ranged from 1.81-53.33

times (Table 10). The segment with the smallest decrease was below Terrace Reservoir

(segment 9) and the segment with the largest decrease was the mine drainage (segment 6;

Table 10).

Despite the 2009 mean dissolved manganese concentrations in all segments

exceeding both the chronic and acute TVS, there were decrease relative to the

concentrations measured in 2000 (Table 13). When the 2009 median dissolved

manganese concentrations were compared to the median concentrations from 1986-1994

and 1998-2003, a decrease was observed at all comparable segments, none of the

segments manganese concentrations had risen above previous concentrations (Table 13).

When the maximum dissolved nickel concentrations for 2009 were compared to

the maximum dissolved nickel concentrations from 2000, all of the segments decreased

in concentrations (Table 14). The decreases seen in these segments ranged from 2.40-

126.93 times (Table 14).

When the maximum dissolved zinc concentrations for 2009 were compared to the

maximum dissolved zinc concentrations for 2000 all of the segments decreased in

concentrations (Table 15). The decreases seen in these segments ranged from 1.06-8.74

times (Table 15). Likewise, there was a decrease in the 2009 median dissolved zinc concentrations in all segments (Table 15).

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Heavy Metal Concentrations in Sediment Compared to Previously Reported

Concentrations

The mean sediment samples taken at the 0-5 cm and 5-15 cm depths were compared to mean sediment samples from the same segment taken in 2000 of an unknown depth; therefore, both depths will be compared to the same mean from 2000.

When the mean aluminum concentrations in sediment for 2009 were compared to the aluminum concentrations collected in 2000, there was an increase in all of the segments at both the 0-5 cm and 5-15 cm depths (Table 16; CWCB 2005A). When the aluminum ranges in 2009 at both depths were compared to the range reported in 2000, all of the segments had greater 2009 maximum and minimum concentrations than previously reported (Table 16; CDPHE 2001).

Arsenic means observed in 2009 were below means previously reported (Table

19; CWCB 2005A). The mine drainage (segment 6) and directly below the mine drainage

(segment 3b) had means that were significantly greater than the pristine site (segment 5;

Figure 20). Arsenic ranges in 2009 were comparable to previous data, except for the areas below the mine drainage (segment 3b) and below Terrace Reservoir (segment 9); both areas had maximum concentrations at the 0-5 cm and 5-15 cm depths that were above previous data (Table 19; CDPHE 2001).

When the mean cadmium concentrations in the sediment samples from 2009 were compared to those measured in 2000, they all decreased (Table 20; CWCB 2005A). The only 2009 cadmium mean concentration that exceeded an ECSSL occurred below

Terrace Reservoir (segment 9) at the 0-5 cm depth (Table 20). However, the cadmium mean of 0.49 mg/kg at the 0-5 cm depth below Terrace Reservoir (segment 9) was below

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the 2000 mean cadmium value of 2.2 mg/kg (Table 20). The cadmium ranges seen in

2009 all had maximum concentrations that were below the maximum concentrations previously reported. (Table 20; CDPHE 2001)

The 2009 mean copper concentrations were lower than those measured in 2000 for all segments (Table 22; CWCB 2005A). The 2009 copper ranges at the 0-5 cm depth for the areas directly below the mine drainage (segment 3b) and below Terrace Reservoir

(segment 9) had maximum concentrations that exceeded their previous maximum collected in 2000 (CWCB 2005A). All of the segments had 2009 maximum copper concentrations, at the 5-15 cm depth, that were below the maximum copper concentration in the previously reported range (Table 22).

The mean iron concentrations in sediment at the 0-5 cm and 5-15 cm depth in all of the segments sampled were lower than previously measured in 2000 (Table 17; CWCB

2005A). The iron ranges observed in 2009, at the 0-5 cm depth, were lower than the 2000 ranges in all of the segments except for site above Terrace Reservoir (segment 3d) where the maximum concentration in 2009 was above the maximum concentration in 2000

(Table 17; CDPHE 2001). The iron ranges in 2009 at a 5-15 cm depth were all higher than the 2000 ranges except for the area below the mine drainage (segment 3c), this segment had a lower maximum concentration than the maximum concentration previously reported (Table 17).

All of the segments except for the site directly below the mine drainage (segment

3b) had 2009 mean lead concentrations at the 0-5 cm depth that exceeded the concentrations collected in 2000 (Table 23; CWCB 2005A). All of the segments at the 5-

15 cm depth had 2009 mean lead concentrations that exceeded the concentrations

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collected in 2000 (Table 23). The lead ranges at both depths in the mine drainage

(segment 6) had maximum and minimum concentrations that decreased when compared

with the previous range (Table 23; CDPEH 2001). The lead ranges at both depths below

Terrace Reservoir (segment 9) had maximum concentrations greater than previously

reported (Table 23). The lead ranges at the 0-5 cm depth in the areas below the mine

drainage (segment 3b, 3c and 3d) had maximum concentrations similar to previously

reported concentrations, however, the minimum values in these areas increased (Table

23). Lead ranges at the 5-15 cm depth in the areas below the mine drainage (segment 3c

and 3d) had maximum and minimum concentrations that were similar to previously

reported concentrations, but the area directly below the mine drainage ( segment 3b) had maximum and minimum concentrations that increased (Table 23).

The mine drainage (segment 6), directly below the mine drainage (segment 3b) and below the mine drainage (segment 3d) had 2009 mean manganese concentrations that increase, at both the 0-5 cm and 5-15 cm depths, when compared to concentrations previously reported (Table 24; CWCB 2005A). The manganese ranges in 2009 at the 0-5 cm depth had maximum concentrations that increased, in the mine drainage (segment 6), directly below the mine drainage (segment 3b) and below the mine drainage (segment 3c;

Table 24; CDPHE 2001). All of the manganese ranges in 2009 at the 5-15 cm depth except for the area directly below the mine drainage (segment 3b) had maximum concentrations that decreased when compared to maximum concentrations in 2000

(Table 24).

The mean nickel concentrations, at both depths, in sediment, at all of the segments sampled had lower nickel concentrations than when previously collected in 2000 (Table

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25; CWCB 2005A). The 2009 nickel ranges in all of the segments sampled at both depths

had lower maximum nickel concentrations than previously reported (Table 25; CDPHE

2001).

The 2009 mean zinc concentrations at both depth in the mine drainage (segment

6) and directly below the mine drainage (segment 3b) exceeded the zinc concentrations that were collected in 2000 (Table 27; CWCB 2005A). The 2009 maximum and minimum concentrations at both depths, for the mine drainage and below Terrace

Reservoir decreased when compared to the maximum and minimum concentrations previously reported (Table 27; CDPHE 2001).The 2009 maximum concentrations at both depths in the areas below the mine drainage (segments 3b and 3c) increased, and both of their minimum concentrations decreased when compared with previously reported data

(Table 27). Both the maximum and minimum concentrations at both depths above

Terrace Reservoir (segment 3d) increased when compared with previous reported concentrations (Table 27).

DISCUSSION

2009 pH Conditions in the Alamosa River

The pH of the water at the mine drainage (segment 6) had increased relative to previous median concentrations in 1986-1994 and 1998-2003 (Table 28). The increased pH leads us to conclude that the remediation has reduced the production of acid mine drainage (AMD) at Summitville Mine and thus reduced the amount of AMD entering into

Wightman Fork. As the pH decreased in the volcanically altered area (segment 3a; during 7/6/2009-8/21-2009), more acidic conditions were observed downstream (Table

5). Acidic conditions in the mine drainage were not recorded until the last sampling date

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(8/21/2009). The pH directly below the mine drainage (segment 3b) began to be acidic at the same time that pH decreased in the volcanically altered area (segment 3a). Because of this we conclude that the volcanically altered area (segment 3a) is now the major source of acid drainage for the Alamosa River not Summitville Mine, however further testing is recommended.

2009 Dissolved Oxygen Concentrations in the Alamosa River

The majority of dissolved oxygen (DO) concentrations in all segments of the

Alamosa River were not in compliance with the DO regulations set specifically for the

Alamosa River. The Alamosa River segments have water use classifications for all sections; however, the DO requirements were not meet in almost all instances. The segments directly below the mine drainage (segment 3b), below the mine drainage

(segment 3c) and above and below Terrace Reservoir (segment 9), were all below the DO requirement, that is necessary to be classified as Class 1 Cold Water Aquatic Life as they currently are (Table 5). The segments directly below the mine drainage (segment 3b), below the mine drainage (segment 3c) and above and below Terrace Reservoir (segment

9) were all below the DO standard for Class 1 Warm Water Aquatic Life as well (Table

5). Most of these segments were below these DO standards multiple times throughout the

2009 runoff season. The volcanically altered area (segment 3a), directly below the mine drainage (segment 3b) and below the mine drainage (segment 3c) were even below the

DO Colorado Department of Public Health and Environment (CDPHE) recreation regulation of 3 mg/L at least once during the 2009 runoff season (Table 5). A low DO concentration is a characteristic that is present in many polluted rivers (Lloyd 1961). DO concentrations have been shown to decrease when high concentrations of ferrous sulfate

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are present; this is true of the Alamosa River (Oba and Poulson 2008). DO concentrations decrease in the presence of high ferrous sulfate with neutral or acidic pHs due to reduction by ferrous ions). As mentioned above the DO does not interact directly with pyrite, but its reduction causes the oxidation of pyrite by generating reactive ferric ions on the pyrite surface (Moses and Herman 1991). This process removes DO from the water by reducing DO to H2O. The low concentrations of DO observed during this study maybe a result of this process. We hypothesize that the cause of the low DO concentrations in the Alamosa River is due to it containing high concentrations of ferrous sulfate. Iron concentrations remain elevated in the Alamosa River; two segments of the

Alamosa River had concentrations of iron in 2009 that were not in compliance with

CDPHE standards (Table 9; CDPHE 2007A). The two segments that were not in compliance were the area directly below the mine drainage (segment 3b) and below

Terrace Reservoir (segment 9; Table 9). The low DO concentrations that were seen in the

Alamosa River during the 2009 runoff season were not supportive of a reintroduction of trout species to the area since the optimal DO concentrations for an adult trout is between

9-12 mg/L (Murphy 2007). Most fish species are unable to survive in areas that have DO concentrations below 3 mg/L and throughout the 2009 runoff season DO concentrations ranged between 2-6.4 mg/L (Murphy 2007; Table 5).

2009 Heavy Metal Concentrations in Water Samples Along the Alamosa River

Overall, the condition of the water in the Alamosa River appears to have improved, having less acidity and decreased heavy metal concentrations; however, more studies will be needed to ensure that safe concentrations of heavy metals are met in the

Alamosa River. Decreases were seen in the 2009 maximum presence of arsenic,

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cadmium, lead, nickel and zinc in the waters of the Alamosa River. The 2009 median dissolved aluminum, copper, iron and manganese concentration also reported decreases in their presence in water samples; however, they were still above the requirements that have been set specifically for the Alamosa Watershed.

Dissolved aluminum concentrations were still exceeding standards in the Alamosa

Watershed during the 2009 runoff season. It appears that the high dissolved aluminum concentrations are not coming from the mine drainage (segment 6) and are instead coming from the volcanically altered area (segment 3a; Table 6). ) The volcanically altered area (segment 3a) had a pH (4.0-8.0) during the 2009 runoff season that allowed aluminum to remain in solution. Concentrations of aluminum in solution are dependent on pH (Eby 2004). Aluminum is soluble in both acidic and basic conditions both of which were seen in the volcanically altered segment 3a (Schemel et al. 2000; Eby 2004;

Table 5). Aluminum, as various species, is most soluble in solutions with a pH ranging from 2.00-5.00 and 7.00-13.00. In the beginning of the season the volcanically altered area (segment 3a) had a pH concentration around 7.83 and at the end of the season around 4.40 (Table 5). Both of these values fall within the optimal solubility for aluminum. The mine drainage (segment 6) had pH levels throughout the 2009 runoff season that were fairly consistent and ranged from 6.40-8.20, these values are roughly in the area where aluminum is not as soluble and may precipitates out of solution (Table 5).

Dissolved aluminums dependence on pH can be seen when the total recoverable concentrations of aluminum are compared with the dissolved aluminum concentrations in the volcanically altered area (segment 3a) and the mine drainage (segment 6). The mine drainage (segment 6) has total recoverable aluminum concentrations that are much higher

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than the dissolved concentrations (Figure 7). The volcanically altered area (segment 3a)

has dissolved aluminum concentrations that are just over half of the total recoverable

aluminum concentrations in that area (Figure 7). This suggests that a large portion of the

aluminum in the volcanically altered area (segment 3a) is remaining in solution due to the

pH. Since, both the volcanically altered area (segment 3a) and the mine drainage

(segment 6) had similar concentrations of total aluminum; together they are the main

contributors of total recoverable aluminum concentrations in the Alamosa River.

However, the volcanically altered area (segment 3a) is the main contributor of dissolved

aluminum.

When the maximum dissolved aluminum concentrations from a study performed

in 2000 were compared to the 2009 maximum dissolved aluminum concentrations there

was a large decrease for most segments (Table 6; CDPHE 2001). However, directly

below the mine drainage (segment 3b) had a 2009 dissolved aluminum maximum value

that was 3.54 times higher than the 2000 maximum value (Table 6). We conclude that

this increase could be due to the volcanically altered area (segment 3a). The volcanically

altered area (segment 3a) had the greatest maximum and mean concentrations for

dissolved aluminum in 2009 and is located above the area directly below the mine

drainage (segment 3b; Table 6). The increase in the maximum dissolved aluminum

concentration observed directly below the mine drainage (segment 3b) was not due to the

mine drainage itself (segment 6), since maximum dissolved aluminum concentrations in the mine drainage (segment 6) have decreased by 54.6 times since measured in 2000.

When the 2009 median dissolved aluminum concentrations were compared to median concentrations from 1986-1994 a decrease was seen in all segments (Table 6;

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CWCB 2005A). However, when the 2009 median dissolved aluminum concentrations

were compared to the median concentrations from 1998-2003, an increase was seen in the volcanically altered area (segment 3a) and above and below Terrace Reservoir (segments

3d and 9; Table 6). We believe that the elevated median concentrations above and below

Terrace Reservoir (segment 9) are due to the formation of aluminum colloids. In this study 0.45μm filters were used to determine the dissolved and total recoverable concentrations of metals in the water samples. However, it has been shown that filtration membranes with a pore size of 0.1 μm can permit the passage of aluminum colloids/species, thus a portion of the aluminum that should have been measured as total

recoverable aluminum may have been measured as dissolved aluminum (Barnes 1975;

Kimball, et al. 1995).

Aluminum colloids are formed when acidic waters containing dissolved

aluminum (the volcanically altered area, segment 3a) combine with streams that have

increased pH (like the junction of the Alamosa River coming from volcanically altered

area, segment 3a, and the Wightman Fork mine drainage, segment 6). The combination of such waters results in the solubility of aluminum decreasing, resulting in formation of precipitates (Schemel et al. 2000). When junctions of water tributaries like this occur, colloids can be formed in the water column and form coatings on the stream bed. The colloids can be transported downstream very long distances prior to them precipitating out of the water column. Since aluminum colloids are able to be transported long distances downstream we hypothesize that the transport of aluminum colloids is why we are seeing elevated median concentrations in areas below the mine drainage (segment 3c) and above and below Terrace Reservoir (segments 3d and 9; Schemel et al. 2000).

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When the 2009 maximum total recoverable arsenic concentrations were compared to the arsenic concentrations presented in 2000 all of the segments had concentrations that decreased; we conclude that the decrease could be attributed to the increased river pH caused by the remediation efforts (Hornberger et al. 2009; Cheng et al. 2008; Lien and Wilkin 2005; Table 7; CDPHE 2001). The mine drainage (segment 6) had the highest maximum and mean total recoverable arsenic concentrations for 2009; however, we conclude that this is negligible since all of the segments had maximum and mean total recoverable and dissolved arsenic concentrations that were below CDPHE standards

(Figure 8; Table 7; CDPHE 2007A). The greatest decrease in maximum total recoverable arsenic was seen above Terrace Reservoir (segment 3d); therefore, we conclude that the remediation has helped to reduce the amount of arsenic entering Terrace Reservoir. Even though the area below Terrace Reservoir (segment 9) had the smallest decrease in maximum total recoverable arsenic concentrations, it is not a great concern since the maximum total recoverable arsenic concentration in this area were already much lower than all of the other segments in 2000. All of the 2009 arsenic concentrations were well below the CDPHE chronic table values (TVS) limit (Table 8).This being said the main contributor of arsenic in the Alamosa River Watershed is still Summitville Mine (Figure

7).

When the 2009 maximum dissolved cadmium concentrations were compared to the maximum dissolved cadmium concentrations presented in 2000 all of the segments had concentrations that decreased (Table 12; CDPHE 2001). Research has shown that cadmium concentrations in water will decrease as pH increases (Gundersen and Steinnes

2003). Therefore, we hypothesize that the increased pH in the Alamosa River, which was

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caused by the remediation, is the reason why dissolved cadmium concentrations

decreased (Table 12; CDPHE 2007A). Even though dissolved cadmium concentrations

decreased, the area directly below the mine drainage (segment 3b) had maximum

dissolved cadmium concentrations during the 2009 season that exceeded the chronic TVS

(Table 12). The mine drainage (segment 6) had the greatest maximum dissolved

cadmium concentration of all segments; however, there are no cadmium limits in the

mine drainage (segment 6). We conclude that the area directly below the mine drainage

(segment 3b) exceeded the chronic TVS because of cadmium inputs from the mine

drainage (segment 6). Even though cadmium concentrations have been reduced due to the

remediation, the main contributor of cadmium in the Alamosa River Watershed is still

Summitville Mine (Figure 13).

The 2009 mean dissolved copper concentrations exceeded the CDPHE limits at

the pristine site (segment 5) the volcanically altered area (segment 3a) and directly below

the mine drainage (segment 3b; Table 8). Both the pristine site (segment 5) and

volcanically altered area (segment 3a) were only slightly higher than the CDPHE limits in their segments (Table 8; CDPHE 2007A). Directly below the mine drainage (segment

3b) was much higher than the limits set for its segment (Table 8).Segment 3b directly

below the mine drainage had mean dissolved copper concentrations that were interestingly similar to the mean dissolved copper concentrations in the mine drainage

(segment 6; Table 8). The mine drainage (segment 6) has no limits set for its section. We

conclude that since the concentrations directly below the mine drainage (segment 3b) are

much higher than the concentrations seen in the pristine and volcanically altered areas

(segment 3a), the dissolved copper concentrations directly below the mine drainage

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(segment 3b) could only be coming from the mine. In a 2005 update on the remediation

efforts written by the EPA, the EPA reported that due to storage capacity and treatment

limits Summitville Mine was still discharging contaminated water with metal

concentrations in excess of limits (CDPHE 2005). Despite treating a record 298 million gallons of contaminated water in 2004, the EPA said that approximately 65 million gallons of untreated water were released into Wightman Fork. The 2005 update confirms that copper concentrations have decreased since the remediation began, however it also indicates that the inability to store and treat all contaminated water generated from the site is likely why copper concentrations are exceeded copper standards. Therefore, we conclude that the release of copper contaminated water has still not been resolved completely since the 2009 data indicates that some of the segments are still not in compliance with dissolved copper regulations.

The transportation of copper from the mine drainage (segment 6) to directly below the mine drainage (segment 3b) could easily be done by colloidal transport.

Research on the effects of acid mine drainage (AMD) on rivers in Colorado has shown that colloidal loads are capable of transporting copper ions over 50 kilometers (Kimball, et al. 1995). Copper colloids are formed by co-precipitation with aluminum, iron or manganese. Differentiation in most studies between dissolved and particulate phases have used 0.45μm membranes to distinguish between the two. However, 0.1μm filters may allow for iron colloids (with co-precipitated copper) to pass through the filter and be measured in conjunction with the dissolved phase (Kimball, et al. 1995; Davis et al.

1991).

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Copper concentrations fluctuated in different sections of the Alamosa River at

different times. The maximum copper concentrations that exceeded CDPHE limits below

the mine drainage (segment 3c) and above Terrace Reservoir (segments 3d) occurred

early in the runoff season when high water flow is able to re-suspended colloidal loads

and wash them further downstream (Kimball, et al. 1995; Table 8; CDPHE 2007A). The

maximum copper concentrations that exceeded CDPHE limits directly below the mine drainage (segment 3b), in the volcanically altered area (segment 3a) and in the pristine

site (segment 5) all occurred late in the runoff season with lower water flow resulting in

the colloidal loads not being washed further downstream to segments 3c and 3d (Table

8). Therefore, we conclude that copper concentrations in the Alamosa River are effected greatly by the amount of water flowing in the river.

Despite the fact that the majority of the copper is still be coming from the mine, the 2009 maximum copper concentrations only exceeded the 1986 copper concentration of 30μg/L a total of 2 times. The mine drainage (segment 6) and directly below the mine drainage (segment 3b) were the two areas that had 2009 maximum concentrations that exceeded the 1986 value in total and dissolved copper measurements (Table 8). Three out of the four times during the season when the concentrations exceeded the 1986 concentration; they were also above the 96-hour LC50 for copper (the concentration of copper that will kill 50 percent of the test species in four days) for the rainbow trout

species of 52 µg/L (Rupert 2001).

When the 2009 median dissolved copper concentrations were compared to the

median concentrations from 1986-1994 and 1998-2003 the only segment that exceeded

its previous 1998-2003 value was the sampling site below Terrace Reservoir (segment 9;

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Table 8; CWCB 2005A). Even though there was a rise in the dissolved copper median

value for 2009 it was not large enough of an increase to be above the CDPHE limits

(Table 8). The main contributor of copper in the Alamosa River Watershed is still

Summitville Mine (Figure 9).

When the maximum total recoverable iron concentrations for 2009 were

compared to the maximum total recoverable iron concentrations for 2000 all of the

segments demonstrated a decrease in concentrations (Table 9; CDPHE 2001). Iron

concentrations have been shown to be affected by pH and will precipitate out of rivers between a pH range of 4-7 (Theobald et al. 1963). The remediation has worked to

increase the pH of the Alamosa River and during the 2009 collection season the pH of the

Alamosa River ranged from 4 to 8.4 (Table 5). The current pH range of the Alamosa

River is conducive to the precipitation of iron out of the river water. Due to this, we

hypothesize that the decreased maximum total recoverable iron concentration in the

Alamosa River is directly related to the increased pH caused by the remediation. Despite

having maximum total recoverable iron concentrations that decreased, segments directly

below the mine drainage (segment 3b) and below Terrace Reservoir (segment 9), had

maximum total recoverable concentrations that exceeded the CDPHE Limits (Table 9;

CDPHE 2007A). We hypothesize that both of these segments had maximum total

recoverable concentrations that exceeded the CDPHE standards for different reasons. We

hypothesize that the area directly below the mine drainage (segment 3b) was over the

CDPHE limits due to the volcanically altered area and the mine drainage having the

second and third highest total recoverable iron concentrations of all of the segments. Due

to this we conclude that the area directly below the mine drainage (segment 3b) had the

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smallest decrease in maximum total recoverable iron due to the combination of the mine

drainage and the volcanically altered areas being located above it (segment 3a, Figure

10). We hypothesize that maximum total recoverable iron concentrations below Terrace

Reservoir exceeded CDPHE limits due to large portions of iron inputs being retained in

the sediment of lakes and reservoir and due to the flushing of sediments from Terrace

Reservoir when water levels are decreased (Giblin 2009; CWCB 2005B).

When the 2009 median total recoverable iron concentrations were compared to

the median concentrations from 1986-1994 and 1998-2003 the only segment that

exceeded its previous 1998-2003 concentration was below Terrace Reservoir (segment 9;

Table 9; CWCB 2005A). Terrace Reservoir was also one of the two segments that had

the maximum total recoverable iron concentrations that were not in compliance with the

chronic TVS set by the CDPHE, the other occurred directly below the mine drainage

(segment 3b; Table 9). The earlier part of the collection season had much higher total

recoverable iron concentrations when compared to the concentrations from the end of the

season, elevating the maximum and median concentrations. We hypothesize that the

increase in maximum and median total recoverable iron concentrations below Terrace

Reservoir (segment 9) is due to colloids. The area below Terrace Reservoir (segment 9)

had a maximum total recoverable concentration that was recorded during the first

sampling of the season. This sampling occurred during the high flow portions of the year,

this is when colloids are re-suspended causing a flushing of metals downstream (Kimball et al. 1995). During low flow portions of the year the iron colloids settle to the streambed, this was reflected by the area directly below the mine drainage (segment 3b), it had a maximum value that occurred during the second to last sampling indicating that the

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colloids were not being flushed downstream (Kimball et al. 1995). We conclude that

natural seasonal flow is occurring, determining when and where these elevated

concentrations of iron are along the Alamosa River. The main contributor of iron in the

Alamosa River Watershed is the volcanically altered area (segment 3a; Figure 10).

When the maximum dissolved lead concentrations for 2009 were compared to the

maximum lead concentrations for 2000 all of the segments demonstrated a decrease in

concentrations that ranged between 1.81-53.33 times (Table 10; CDPHE 2001). All of the

segments lead concentrations were well below the CDPHE limits (Table 10; CDPHE

2007A). A 1996 study demonstrated when pH increased from 3 to 6 in river water, lead adsorption to river sediments increased, thereby decreasing lead concentrations in the water (Jain and Ram 1996). Consequently, we hypothesize that the decreases that were seen in the maximum dissolved lead concentrations are in direct correlation with the increased pH caused by the remediation. The mine drainage (segment 6) was the segment with the largest decrease in dissolved lead concentrations (Table 10) resulting in the mine drainage now being a contributor of lead to the Alamosa River Watershed and not the main source. The main contributor of lead in the Alamosa River Watershed is the combination of the volcanically altered area (segment 3a) and Summitville Mine (Figure

11). Lead concentrations were significantly higher in the area directly below the mine drainage when compared with the pristine site. We hypothesize that these high concentrations of lead directly below the mine drainage were caused by inputs from both the mine drainage and the volcanically altered areas (segment 3a; Figure 11).

Research has shown that manganese does not follow any systematic dependence on pH (Laxen et al. 1984). Since manganese is not depended on pH, like some of the

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other metals in this study, we hypothesize that median and maximum manganese

concentrations decreased along the Alamosa River due to the precipitation process used

to remove heavy metals at the water treatment plant at Summitville Mine. Even though

manganese concentrations decreased in all of the segments sampled, manganese

concentrations were still above the ECSSL in 2009 (Table 13; CDPHE 2007A,; CWCB

2005A; CDPHE 2001) When mean dissolved manganese concentrations at the pristine

site (segment 5) and the volcanically altered area (segment 3a) were compared to the

mine drainage (segment 6), the mine drainage was 2.44 times higher than the

combination of the pristine site (segment 5) and volcanically altered area (segment3a;

Table 13). The maximum dissolved manganese concentrations followed this trend as well; the mine drainage (segment 6) had a maximum dissolved concentration that was

1.65 times higher than the combination of the pristine and volcanically altered areas

(segment 3a; Table 13). Since dissolved mean and maximum manganese concentrations in the mine drainage (segment 6) were both greater than concentrations in the pristine and volcanically altered areas (segment 3a) we conclude that the mine is still the major contributor of manganese to the Alamosa River. It has also been well documented that

Summitville mine has had to release untreated water due to storage constraints; we hypothesize that dissolved manganese concentrations remain extremely high due to the combination of untreated water being released and due to manganese not being affected by pH (Laxen et al. 1984; CDPHE 2005). We would expect that the other metals concentrations in the water would also be elevated due to the release of untreated water; however, the other metals such as aluminum, arsenic, and zinc are affected by the increased pH in the Alamosa River, which causes them to precipitate out of the water into

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the sediment (Cheng et al. 2008; Lien and Wilkin 2005; Schemel et al. 2000; Eby 2004;

Gundersen and Steinnes 2003 ). Dissolved manganese concentrations have a pattern that

is similar to dissolved copper concentrations and since mean and maximum manganese

concentrations are still exceeding CDPHE limits; we hypothesize that dissolved

manganese concentrations are likely being influenced by the release of untreated water

from Summitville Mine (CDPHE 2005).

When the maximum dissolved nickel concentrations for 2009 were compared to

the maximum nickel concentrations for 2000 all of the segments demonstrated a decrease

in concentrations that ranged between 2.40-126.93 times (Table 14; CDPHE 2001). A recent study, showed that nickel complexation with organic matter in sediments will increase as pH increases (Doig and Liber 2006.We hypothesize that decreased nickel concentrations in the waters of the Alamosa River are in direct correlation with the increased pH caused by the remediation work being done by the CDPHE and EPA. The mine drainage (segment 6) had the smallest decrease and was the segment with the highest concentrations of total recoverable and dissolved nickel; therefore, we conclude that Summitville mine is still the main contributor of nickel to the Alamosa Watershed

(Table 14; Figure 15). Despite the mine being the main contributor of nickel to the

Alamosa River, nickel concentrations in all of the segments were below the CDPHE limits (Table 14; CDPHE 2007A).

When the maximum and median dissolved zinc concentrations for 2009 were compared to the previously collected data all of the segments demonstrated a decrease in concentrations (Table 15; CWCB 2005A; CDPHE 2001). Research has demonstrated that

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as river water pH increases from 3 to 7 adsorption of zinc to the river sediment will also

increase, thereby decreasing zinc concentrations in the river water (Gundersen and

Steinnes 2003). We conclude that maximum and median dissolved zinc concentrations

have decreased in the river water due to the remediation efforts causing increased pH in

the Alamosa River. Even though a decrease was seen in zinc concentrations, two of the segments sampled had maximum dissolved zinc concentrations that did not comply with acute and chronic TVS (Table 15; CDPHE 2007A). These segments were the volcanically altered area (segment 3a) and directly below the mine drainage (segment 3b;

Table 15). During the Schemel (2000) study when low stream flow conditions existed,

zinc colloid loads decreased and dissolved zinc loads predominated. We hypothesize that this is what happened during the 2009 runoff season, since the high maximum dissolved zinc concentrations in the volcanically altered area (segment 3a) and directly below the mine drainage (segment 3b) were during the end of the season and low water flow. The segment that had the greatest maximum zinc concentration was the mine drainage

(segment 6), which occurred during the same time period. The volcanically altered area

(segment 3a) also had an elevated dissolved zinc presence during this time; however, the

mine drainage (segment 6) had a maximum value that was 3.11 times that of the

volcanically altered area (segment 3a; Table 15). Summitville Mine remains the main

contributor of zinc to the Alamosa Watershed (Table 15). This is reflected by both the

dissolved and total recoverable concentrations of zinc (Figure 16).

2009 Heavy Metal Concentrations in Sediment Along the Alamosa River

Aluminum concentrations in 2009 river bank core samples increased at the 0-5 cm

and 5-15 cm depth in all segments that had comparable data from previous years, except

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the mine drainage (segment 6; Table 16; CWCB 2005A; CDPHE 2001). None of the aluminum concentrations, at the 0-5 cm or 5-15 cm depths, at any of the sites were significantly different from the mine drainage (segment 6) or pristine site (segment 5).

We conclude that aluminum concentrations have increased in the sediment due to colloidal transport of aluminum in the river and the increased pH of the river due to the remediation. Precipitation of aluminum out of solution is highly dependent on pH (Eby

2004). As mentioned previously aluminum colloids are formed in rivers when acidic waters containing dissolved aluminum (the volcanically altered area, segment 3a) combine with streams that have increased pH (like the junction of the Alamosa River coming from volcanically altered area, segment 3a, and the Wightman Fork mine drainage, segment 6). The combination of such waters results in the solubility of aluminum decreasing, resulting in formation of precipitates (Schemel et al. 2000). When junctions of water tributaries like this occur, colloids can be formed in the water column and form coatings on the stream bed. The colloids can be transported downstream very long distances prior to them being lost from the water column and entering the sediment.

Since aluminum colloids have the capacity to be transported over long distances downstream; we hypothesize that when the water in the mine drainage (segment 6) and volcanically altered area (segment 3a) combine it causes the formation of aluminum colloids that precipitate out of the water column along the Alamosa River because of elevated pH in the segments below this junction (Schemel et al. 2000). Even though aluminum concentrations have increased in the sediment of the Alamosa River, currently aluminum concentrations in sediment are not under any regulations. This is most likely

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due to aluminum being the third most abundant element in the earths crust (Freda 1991;

Folsom et al. 1986).

Mean arsenic concentrations in 2009 river bank core samples increased compared to previous measurements at the 0-5 cm and 5-15 cm depths (Table 19; CWCB 2005A).

The segment with the highest sediment arsenic concentrations was the mine drainage

(segment 6; Table 19). In the mine drainage (segment 6) at the 0-5 cm depth mean

arsenic concentrations increased by 8 times and at the 5-15 cm depth mean arsenic

concentrations increased by 12.7 times in just 4 years (Table 19). The arsenic

concentrations that were measured in the mine drainage (segment 6) did exceed the

enforceable ECSSL limits for plants (Table 19; USEPA 2005B). The greater presence of

arsenic in the Alamosa River sediment cannot be blamed on sections above Wightman

Fork. The pristine and volcanically altered areas (segment 3a) both had significantly less

mean arsenic concentrations in sediment at both depths when compared the mine

drainage (segment 6; Table 19). Dissolved and total recoverable arsenic concentrations

in water samples were also not significantly different when the mine drainage (segment

6) was compared with the pristine site (segment 5; Figure 8). This indicates that the high

arsenic concentrations in the sediment of Wightman fork are not coming from the water

since arsenic concentrations were not significantly different above or below the mine. We

hypothesize that the rise in arsenic concentrations in the sediment is due to an increase in

the pH of Wightman Fork (Hornberger et al. 2009). The remediation caused an increase

in pH in the mine drainage (segment 6) to near-neutral conditions. In neutral conditions a

rapid decrease in dissolved arsenic concentrations will be seen due to precipitation of

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arsenic with iron hydroxides via precipitation, co-precipitation and sorption (Cheng et al.

2008; Lien and Wilkin 2005).

Therefore we conclude that the rise in arsenic concentrations in the sediment at the mine drainage (segment 6) is due to precipitation. However, we recommend further testing since arsenic species can vary substantially in the areas of toxicology, mobility, and adsorpitivity (Bednar et al. 2002). Inorganic species of arsenic such as arsenates, arsenites and arsenines are typically the most toxic forms (Jedynak et al. 2009). Organic arsenic species such as arsenobetaine, arsenocholine are considered to be non-toxic.

Arsenite has the ability to be more mobile due to it adsorbing less strongly than arsenate in the typical pH range of natural water (Cheng et al. 2008). Portions of adsorbed arsenic species can be remobilized due to exchange with anions especially phosphate and sulfate.

Therefore understanding the speciation of arsenic in the Alamosa River is very important for designing plans to reduce the risks associated with arsenic contamination.

Cadmium concentrations in 2009 river bank core samples revealed that the site below Terrace Reservoir (segment 9) had the highest amount of cadmium contamination

(Figure 18). The highest cadmium concentration was present in the top 0-5 cm of sediment (Table 19). Research has shown when there is competitive sorption between heavy metals; lead, chromium and copper are typically retained in greater concentrations than cadmium by the sediment (Oh et al. 2009; Echeverria et al. 1998; Appel, et al.

2008). This is consistent with what was observed in the 2009 sediment data, concentrations of copper and lead were much greater than cadmium concentrations in the sediment. Therefore we conclude that cadmium is being out competed by lead and copper due to the fact that there are much greater concentrations of lead and copper in the water,

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thus leaving them more available to enter into the sediment and also because some sediment types have greater binding affinities for lead and copper due to their chemical characteristics (Echeverria et al. 1998; Appel et al. 2008).

Even though cadmium concentrations in sediment decreased in 2009, cadmium concentration below Terrace Reservoir (segment 9) exceeds the enforceable ECSSL limit for mammals (Table 19; USEPA 2005C). Below Terrace Reservoir (segment 9) is the closest to vacation homes and has a higher potential for mammalian contact through grazing and farmland downstream. We hypothesize the higher concentrations of cadmium below Terrace Reservoir (segment 9) are caused by the reservoir itself.

Research on the Azlate Reservoir has shown that metal concentrations in the water decreased in the reservoir when samples were taken further away from the water source to the reservoir (Avila-Perez et al. 1999). This indicates that the metals will precipitate out of the water and be available to enter the sediment. It was reported by the Colorado

Water Conservation Board in 2005 that large quantities of sediment in Terrace Reservoir are flushed when water is released from the reservoir (CWCB 2005B). The combination of these two facts lead us to conclude that the higher cadmium concentrations below

Terrace Reservoir (segment 9) are due to metals precipitating into the reservoirs sediment and subsequent release of that sediment when water is released from the reservoir.

Cobalt concentrations in 2009 river bank core samples revealed that below

Terrace Reservoir (segment 9) had the highest amount of cobalt contamination (Figure

19). The contamination concentrations below Terrace Reservoir (segment 9) at both depths exceeded the ECSSL limits for plants (Table 21; USEPA 2005D). The site below

Terrace Reservoir (segment 9) was the only segment to have cobalt contamination

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concentrations that exceeded an ECSSL (Table 21). Below Terrace Reservoir (segment 9)

had cobalt concentrations that were 3.22 times higher than the pristine site (segment 5) at

the 0-5 cm depth and were 2.29 times higher than the pristine site (segment 5) at a 5-15

cm depth (Table 21). We hypothesize that cobalt concentrations, like cadmium

concentrations, are greater below Terrace Reservoir due to the combination of the

reservoir effect and sediment flushing when water is released from Terrace Reservoir

(Avila-Perez et al. 1999; CWCB 2005B).

Mean copper concentrations in 2009 river bank core samples at both depths

decreased from data reported in 2000 (Table 22; CWCB 2005A). We conclude that

copper concentrations have decreased in the sediment due to the precipitation removal

process used by remediation. The increased pH in the water of the Alamosa River would

cause copper to enter into the sediment, therefore, for copper concentrations to have

decreased in the sediment there must have been a drastic decrease in the amount of

copper available to enter into the sediment, and the only mechanism that reduces the

availability of copper is the precipitation process (Gundersen and Steinnes 2003). Even

though copper concentrations have decreased in all of the segments below the junction of

Wightman Fork and the Alamosa River they were still exceeding multiple ECSSL

(plants, sediment invertebrates, avian and mammalian (Table 22; USEPA 2007A).

Above this junction no ECSSL were being exceeded (Table 22). Since the mine drainage

(segment 6) had the highest 2009 mean copper concentrations that in both water and sediment samples, we conclude that Summitville Mine is still the main contamination source of copper for the Alamosa River Watershed.

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The majority of mean lead concentrations in 2009 river bank core samples increased when compared with data collected in 2000 (Table 23; CWCB 2005A; CDPHE

2001). Research has shown that lead adsorption to bed sediment will increase as the river pH increases (Jain and Ram 1996). Over the years the remediation efforts have resulted in increased pH of the Alamosa River; therefore, we hypothesize that this is why we observed increased lead concentrations in sediment. The mine drainage (segment 6) had the highest amount of mean lead contamination (Table 23). The volcanically altered area

(segment 3a) also had elevated mean concentrations of lead; however, mean concentrations downstream were all higher than the mean concentrations present in the volcanically altered area (segment 3a; Table 23). All segments except for the pristine site

(segment 5) were above the ECSSL for avian species (Table 23; USEPA 2005E). This is especially important because the water from the Alamosa River feeds wetlands that have multiple migratory and endangered bird species that visit them during the year. The high mean dissolved lead concentrations at the 0-5 cm depth below Terrace Reservoir

(segment 9) were not significantly different than the high lead concentrations that were present in the mine drainage (segment 6) coming from the mine (Figure 24). Since this is true we recommend that the sediment concentrations further downstream closer to the wetlands be sampled to determine if the lead contamination is now affecting that area and potentially affecting avian species. Since it has been demonstrated in other literature that colloids are capable of long distance transport and have high adsorption capacities for lead; we believe it possible that lead contamination could make it downstream to the wetlands (Kimball, et al. 1995; Hassellov and Frank 2008).

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Mean manganese concentrations in 2009 river bank core samples decreased in all

segments that had previous data from 2000 except for the mine drainage (segment 6;

CWCB 2005A) and directly below the mine drainage (segment 3b; Table 24). Both of

these segments saw increases in there mean manganese concentrations at the 0-5 cm

depth (Table 24). We hypothesize that the increased concentrations of manganese that

were seen in 2009 can be attributed to Summitville Mine (Figure 25). We believe this

since both total recoverable and dissolved manganese concentrations were the highest in

the mine drainage (segment 6), that seeing high concentrations in the sediment of both of

these areas is not surprising (Figure 14). The pristine site (segment 5) above the mine

drainage also had very high mean concentrations of manganese in its sediment samples.

However, the pristine site’s concentrations of total recoverable and dissolved manganese

were the lowest of all of the sites sampled, showing that the manganese in the sediment in

the pristine site (segment 5) is not being mobilized and released further downstream to

Summitville Mine. Therefore we conclude that the elevated concentrations of manganese

must be coming Summitville Mine.

Nickel concentrations in sediment were not exceeding any ECSSL or previously

reported concentrations in 2000 either (Table 25; USEPA 2007C; CWCB 2005A;

CDPHE 2001). The 2009 results showed that nickel concentrations have continued to decrease at both depths since data that was collected in 2000 (Table 25). We hypothesize that nickel concentrations are being positively effected by the remediation efforts ongoing at Summitville Mine.

Selenium concentrations in sediment exceeded multiple plant, avian and mammalian ECSSLs at the 0-5 cm and 5-15 cm depth (Table 26; USEPA 2007D). We

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hypothesize that the high concentrations of selenium in sediment maybe attributed to

natural conditions. Despite the possibility that selenium concentrations may possibly be

attributed to natural conditions, the concentrations that were seen were above ECSSLs

(Table 26). Selenium concentrations in water samples were almost nonexistent (Figure

12); however, selenium concentrations in sediment were very high (Figure 27).

Most of the selenium that is present in aquatic environments usually accumulates

in the top layer of sediment (Lemly 1999). Sediments can typically be a temporary home

for selenium, aquatic systems are able to recycle selenium from sediments into the biota

thru oxidation and methylation processes and these concentrations can remain elevated

for years after waterborne inputs have ceased. Further testing downstream of Terrace

Reservoir in the wetlands and farmlands is strongly recommended due to selenium’s

ability to reenter the aquatic system and cause long term dietary effects to plant, avian

and mammalian species downstream.

Vanadium concentrations in sediment exceeded the avian ECSSL at the 0-5 cm depth, however this contaminant was high in all of the segments and we hypothesize it could be a natural contaminant of the area (Table 18; USEPA 2005A). We believe that vanadium is a natural contaminate of the area due to the data being rather uniform. All of the sites sampled did not have significantly different concentrations at the 0-5 and 5-15 cm depth when compared with the pristine site (segment 5; Figure 19). Despite vanadium being a natural contaminate it was above the avian ECSSLs and we recommend further testing below Terrace Reservoir (segment 9) to determine if the high concentrations are reaching the wetlands below this section.

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Even though zinc concentrations in the sediment have decreased, they still remain above both avian and mammalian ECSSLs in almost all of the segments sampled (Table

27; USEPA 2007F). Research has shown that zinc can be adsorbed to bed sediment, like lead, and both lead and zinc concentrations in the sediment will increase as river pH increases (Jain and Ram 1996). We hypothesize that the increased pH of the Alamosa

River has caused zinc to precipitate out of the water, resulting in increased zinc concentrations in the sediment.

Because zinc concentrations in sediment exceeded the avian ECSSLs throughout the Alamosa River, we recommend that further testing downstream of Terrace Reservoir be completed to ensure that the downstream wetlands have not become contaminated and that zinc concentrations are not potentially affecting migratory and endangered bird species (Figure 27). Zinc concentrations exceeding the mammalian ECSSL is also very worrisome due to the agricultural land uses further downstream (Table 28). We recommend further sediment testing downstream of Terrace Reservoir to ensure that metal contaminates are not effecting the agricultural practices and peoples livelihoods.

2009 Heavy Metal Concentrations in Tree Cores Along the Alamosa River

Tree cores are a very useful tool that can be used to determine changes in their surrounding environment overtime. Trees are suitable organisms for the analysis of pollution history, because they meet several criteria; they are long-lived, static, possess a mechanism for heavy metal uptake, demonstrate regular annual growth, can be easily aged and can easily be sampled without killing the organism (Lepp 1975). We chose the cottonwood and aspen species due to their proximity to the Alamosa River and because both species are typically found in close proximity to a water source since they require

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moist sites with adequate drainage for growth and seed germination (USDA 2002; USDA

2003). Small changes in sediment chemistry can be seen by examining the metal concentrations present in tree rings (USGS 1995A). This is due to root uptake of heavy metals by the trees from the sediment (Lepp 1975). Absorption of heavy metals through the roots is regulated by edaphic and biological factors such as sediment pH, chemical composition sediment texture, sediment drainage, sediment aeration, patchy landscapes, moisture, organic matter and ion availability (USDA, 1985; Rajakaruna and Boyd 2008;

Donahue et al. 1983; USDA 2002; Bhattacharjee et al. 2007).

Thus interpretation of heavy metals in tree cores must be done very carefully; especially since heavy metals have the ability to move between rings especially when initial concentrations vary greatly between years (USGS 1995A). Since there are many contributing factors that determine the absorption and location of heavy metals within a tree, the use of tree cores for pollution history is not an exact science yet. We tried to account for the movement of heavy metals between the tree rings by looking at multiple year sections (Watmough and Hutchinson 1995).We hypothesized that if we looked ten year segments it would help reduce errors caused by metals movement between rings, since metal concentrations over ten year periods should be fairly consistent, however we cannot rule out the possibility that heavy metal transport among rings did not occur. All of the tree core samples and segments (3a, 3b, 3c, 3d, 6 and 9) were found to be in compliance with the ECSSL plant limits that they were compared to.

Heavy Metal Concentrations in Cottonwood Tree Cores

Mean arsenic concentrations in tree cores above Terrace Reservoir (segment 3d) in the 2000-2009 decade were significantly greater than the 1980-1989 decade with a p-

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value of 0.009 (Figure 29). There are many reasons for the rise in arsenic, these include, changes in sediment chemistry, changes in macro-nutrient elements or changes in sediment pH (Lepp 1975). The later of these is the most important since increases in sediment pH can result in metal uptake by tree roots being suboptimal, further resulting in the metal burdens of the sediment not being passed on to the plant life (Lepp 1975;

Pulford and Watson 2003). There was also an increase in the mean presence of arsenic in sediment at the same location, above Terrace Reservoir (segment 3d; Table 19).

However, we can not conclude that arsenic concentrations increased in tree cores based only on the fact that arsenic concentrations in sediment also increased in 2009. Further research is needed to help clarify if the increased arsenic concentrations in tree cores were due to increased arsenic concentrations in the sediment, at the sampling location above Terrace Reservoir (segment 3d). For instance, studies aimed at examining sediment pH, sediment texture, sediment drainage, and compartmentalization of metals with in trees could help understand translocation of arsenic in the leaves, shoots, bark and roots (Pulford and Watson 2003; Vervaeke et al. 2003). Many studies have shown that the location of metals with in a tree will depend on seasonal variation. Various studies have shown that metal concentrations will accumulate in actively growing tissue and early vegetative growth, such as, shoots and young leaves (Pulford and Watson 2003;

Dinelli and Lombini 1996; Laureysens et al. 2004; and Hagemyer and Schafer 1995).

Studies have also shown that tree species grown in soil with high metal content will increase their metal content in their leaves in the autumn months as a detoxification method in connection with defoliation (Pulford and Watson 2003; Dinelli and Lombini

1996; and Laureysens et al. 2004).

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A complete explanation of what might possibly be occurring at the sampling location above Terrace Reservoir (segment 3d) is beyond the realm of this study. What we can say about the increase in mean arsenic concentrations in the cottonwood tree cores above

Terrace Reservoir (segment 3d) is it shows that the plant life will absorb heavy metals traveling downstream; this result corresponds with the increases that were seen in mean arsenic concentrations in other segments by aspens trees as well (Figure 39).

Heavy Metals Concentrations in Aspen Tree Cores

The mean arsenic concentrations in aspen tree cores directly below the mine drainage (segment 3b) in the 2000-2009 decade were significantly greater than the 1990-

1999 decade (Figure 39). The increase in arsenic concentration in aspen tree cores also correlated with an increase in sediment data for this segment when the 2000 data was compared to the 2009 data, this was also seen in cottonwood tree cores above Terrace

Reservoir (segment 3d). The mean arsenic concentrations in aspen tree cores in the mine drainage (segment 6) in the 2000-2009 decade were significantly lower than mean arsenic concentrations in the volcanically altered area (segment 3a) and below Wightman Fork

(segment 3c; Figure 39). However, the mine drainage (segment 6) had the highest total recoverable mean arsenic concentrations in water samples and highest arsenic concentrations in sediment samples, indicating that the reduced concentrations of arsenic in aspens in the mine drainage (segment 6) could be due to arsenic speciation (Cheng et al. 2008). Arsenic species are known to vary substantially in the areas of toxicology, mobility, and adsorpitivity (Bednar et al. 2002). Inorganic species of arsenic such as arsenates, arsenites and arsenines are typically the most toxic forms (Jedynak et al. 2009) where as some of the organic arsenic species such as arsenobetaine, arsenocholine are

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considered to be non-toxic. Arsenic species will change as acidic pH is neutralized, as it was in the waters of the mine drainage (segment 6) due to the remediation effort, thus changing arsenics fate and transport through the mine drainage (segment 6; Cheng et al.

2008). As mentioned above we hypothesize that the rise in arsenic concentrations in the sediment is due to an increase in pH of the water in the mine drainage (segment 6;

Hornberger et al. 2009). Although arsenic concentrations in sediment did rise in all segments with previous data the metal concentrations jumped drastically in the mine drainages sediment (segment 6; Table 18). The remediation caused an increase in pH in the mine drainage (segment 6) to near-neutral conditions. In neutral conditions a rapid decrease in dissolved arsenic concentrations is seen due to precipitation of arsenic with iron hydroxides via precipitation, co-precipitation and sorption (Cheng et al. 2008; Lien and Wilkin 2005). We hypothesize that the remediation caused a change in arsenic speciation in the mine drainage (segment 6) due to changes in Wightman Forks pH.

The increased water pH could have caused the sediment pH to rise to basic conditions.

When sediment pH increases heavy metals can be immobilized and remain in the sediment, thus not allowing the trees to absorb arsenic and have reduced arsenic concentrations in the mine drainage (segment 6; Lepp 1975). As shown in Figure 39. the arsenic concentrations in aspen tree cores in the areas below the mine drainage (Segments

3b and 3c) are not significantly different from the volcanically altered area (segment 3a), but are significantly higher than the mine drainage (segment 6). This finding could indicate that the sediment pH has not increased in any of the other sampling areas thus leaving the trees in those areas able to uptake arsenic (Lepp 1975). Most toxicity studies involving tree studies use cultured seeds or cuttings thus little is actually known about the

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toxicological relationship in mature trees that are exposed to higher amounts of metals

(Barrick and Noble 1993). Future research on arsenic absorption in cottonwoods could be extended further upstream to deal with aspens and provide a clearer understanding arsenic absorption in the plant life.

The mean cadmium concentrations in tree cores below the mine drainage

(segment 3c) in 1980-1989 were significantly greater than mean cadmium concentrations directly below the mine drainage (segment 3b; Figure 40). We hypothesize that the area below the mine drainage (segment 3c) had elevated cadmium concentrations during the

1980-1989 decade when compared to the area directly below the mine drainage (segment

3b) due to it receiving water from both the mine drainage (segment 6) and volcanically altered area (segment 3a), whereas the area directly below the mine drainage (segment

3b) only receives water from the mine drainage (segment 6). The mean cadmium concentrations in tree cores below the mine (segment 3c) drainage in the 1990-1999 decade were significantly lower than the 1980-1989 decade (Figure 40). Since cadmium is known to be one of the more mobile heavy metals subsequent to root uptake this could have possibly resulted in its movement within, as well as in and out of the trees (Lepp

1975). We hypothesize that the changes in cadmium concentrations between decades is most likely due to its mobility within the tree and not the remediation. Cadmiums mobility within a tree could also be why no distinctive patterns were seen in the aspen data.

The mean lead concentrations in the 1990-1999 decade directly below the mine drainage (segment 3b) were significantly greater than the mean lead concentrations in the volcanically altered area (segment 3a) and below the mine drainage (segment 3c; Figure

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41). The elevated concentrations of lead in the tree cores from 1990-1999 in the area directly below the mine drainage (segment 3b) could have been due to a greater presence of lead desorption from aluminum and iron colloids in the river (Schemel et al. 2000).

Desorption of metals from aluminum and iron colloids occurs in acidic pHs, as reported in the area from 1986-2003 (Table 6). We hypothesize that desorption of lead may have resulted in a greater presence of lead in that area of the river during the 1990’s thus leaving lead able to enter into the sediment and trees in that area.

The mean lead concentrations in the mine drainage (segment 6) in the 2000-2009 decade were significantly lower than the 1990-1999 decade (Figure 41). This is contradictory to what was seen in the sediment when data from 2000 was compared to

2009. During 2000-2009 the lead concentrations actually increased in the sediment. Since regulation of root uptake of heavy metals is dependent on many factors dealing with conditions in the sediment such as pH and macro nutrients presences we conclude that these factors could be affecting the trees lead concentrations due to changes caused by the remediation (Lepp 1975). In addition to edaphic factors, heavy metals are also known to form ligands with arginine and asparagines, which comprise over 75% of total amino acids present in xylem. Lead is specifically known to form ligands with arginine. This is important because amino acids in the xylem undergo season-dependent variation

(Malaguti et al. 2001; Hagemyer and Schafer 1995). This has the ability to change the amounts of lead within the tree depending on when the tree cores were taken (Lepp

1975). Therefore, we hypothesize that lead concentrations could have been significantly different between the 1990-1999 and 2000-2009 decades simply based on seasonal changes in the amino acids of the xylem.

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The mean manganese concentrations below the mine drainage (segment 3c) between the 2000-2009 decade were significantly greater than the 1990-1999 decade

(Figure 45). The 2009 mean manganese concentrations in sediment below the mine drainage (segment 3c) was below the manganese concentrations collected in 2000. It is unclear whether or not the increase in manganese concentrations in tree cores below the mine drainage (segments 3c) in the 2000-2009 decade are due to the remediation efforts or if the changes are due to evolution in the symbiotic relationship of mychorrhizal fungi that are associated with aspen trees (Cripps 2003). The mutuallistic relationship between mychorrhizal fungi and aspens allows them to inhabitate areas of low pH, high metal content, low fertility and drought. We hypothesize that since it has been shown that mychorrhizal fungi have the capacity to increase and change concentration of manganese in other tree species of similar diffuse porous tissue; that this is likely what is occurring at the sampling location below the mine drainage (segment 3c; Lepp 1975; Wilkins 1991).

The mean silver concentrations in the mine drainage (segment 6) in the 1990-

1999 decade were significantly greater than the 1980-1989 decade (Figure 48), but were not significantly different in the 2000-2009 decade. We hypothesize that the increase of silver in the 1990-1999 decade could have been a result of the mining activity at

Summitville mine since it was mined for silver prior to SCMCI beginning their operation.

The changes that were seen in zinc concentrations in the aspen trees over the decades could be due to natural variation since all of the concentrations seen were below the ECSSL. Toxicological concentrations of zinc have been shown to be modulated by mychorrhizal fungi, thus we hypothesize that the variation in zinc concentrations among

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the aspen trees in all of the segments maybe nothing more than normal concentrations for

the metal conditions present in the surrounding area (Wilkins 1991).

Despite the reduction of heavy metal concentrations in the waters of the Alamosa

River, and the fact that heavy metal concentrations in tree cores were below ECSSL

limits; we recommend further testing of sediment be conducted further downstream due

to the large increases that were seen in the presence of heavy metals in sediment when

compared to previous results. Overall the Alamosa River ecosystem has shown

improvements in the presence of heavy metal contamination in water samples since the

remediation began in 1992, this supported our hypothesis that the water quality of the

Alamosa River had improved since remediation had begun. The source of the heavy metals actually depends on the specific metal, however; Summitville mine was still the major source for a majority of the heavy metals. The 2009 sediment samples revealed

that heavy metal concentrations have increased in recent years and further testing of

speciation and colloidal transport must be done to determine the toxicological effects that

these heavy metals could be having further downstream. The tree samples demonstrated

that concentrations of heavy metals were not above ECSSLs. However, since heavy metal

concentrations are known to have the capacity to vary depending on the season and since

mychorrhizal fungi are known to reduce concentrations of metals in their host trees, we

suggest that further studies including plants be done (Wilkins 1991). We recommend that

the plant sources that are sampled be sources where annual growth can be looked at

without having to worry about the metals being able to disperse in the sample, such as

grass clippings along the river. The results from this study have shown that the

remediation efforts at Summitville Mine have helped to reduce the heavy metal loads in

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the Alamosa River, however more remediation and research is required in the sediment to ensure that Summitville’s problems are not being washed further downstream and causing entirely new problems.

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APPENDICES

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