Biological Response to the Gold King Mine Release in the Animas and - - PowerPoint PPT Presentation

Biological Response to the Gold King Mine Release in the Animas and San Juan Rivers

Lareina Guenzel1, Richard Mitchell, PhD1, Kate Sullivan, PhD2, and Michael Cyterski, PhD2 1 U.S. Environmental Protection Agency, Office of Wetlands, Oceans and Watersheds 2 U.S. Environmental Protection Agency, Office of Research and Development

3rd Annual Conference on Environmental Conditions of the Animas and San Juan Watersheds 6/21/2018

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Presentation Overview

• Background
• Study objectives and methods
• Benthic macroinvertebrate response

– Sentinel studies – Metal concentrations in benthic tissue – Population assessment

• Fish response

– Sentinel studies – Metal concentrations in fish tissue – Population assessment

• Questions

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Background

• The Gold King Mine (GKM) release deposited metals along the Animas

and San Juan rivers for varying periods of time until the system was cleared by stormflow and snowmelt runoff by May 2016

• Aquatic biota take up and excrete metals
• Heavy metals can be toxic to aquatic biota and terrestrial wildlife and

humans which consume them

• Acute and chronic effects

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• Legacy mining impacts: highly contaminated surface water and sediment,

and known biological impairments in Upper Animas (USGS 2007, EPA 2015)

• Lower Animas and San Juan Rivers were not known to be contaminated by

historic mining in the headwaters before the GKM release.

• San Juan River is managed for the recovery of listed fish species due to

basin-wide water development projects. Upper Animas Historic Conditions: Extremely low trout populations upstream of Baker’s Bridge No aquatic life use protection in the mainstem through Silverton Limited Benthic Macroinvertebrates

Study Questions and Methods

Study Questions

• Did the GKM add to biological impairment in

the already-contaminated upper Animas River?

• Did the GKM release cause biological

impairment in other segments of the Animas and San Juan rivers that had not been known to have metal impacts? Methods

• Collected and reviewed all available

biological data in the San Juan and Animas rivers to assess how aquatic biota responded to the GKM release

• Compared pre-event and post-event

measures of four key characteristics

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Benthic Macroinvertebrates Fish Organism body burden to indicate uptake of GKM metals

X X

Community structure and population estimates to indicate mortality from exposure to GKM metals

X X

Study Area

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Upper Animas Mid Animas Lower Animas

Upper San Juan Lower San Juan

• Upper Animas

– High gradient – Cold water aquatic life – Large particle substrate size

• Lower Animas

– Gradient transition from high to low – Transition from cold water to warm water fishery – Substrate particle size becomes smaller

• San Juan River

– Low gradient – Warm water fishery – Small particle substrate size

Longitudinal Patterns in Aquatic Habitat

Longitudinal Gradient of Metals Contamination

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Metals persistently exceed water quality criteria to support aquatic life in the Animas headwaters Metals contamination from the mining district is known to impair fish and macroinvertebrate communities

Biological Data Sources

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Source

Benthic Macro Assemblage Benthic Macro Tissue Fish Population Fish Tissue Physical Habitat EPA: START Contractors

Post Animas & San Juan Animas & San Juan Animas & San Juan Animas & San Juan

EPA: Superfund/ Mountain Studies Institute (MSI)

Pre&Post Animas (upper & mid) Animas (upper & mid)

CO Parks and Wildlife (CPW)

Pre&Post Animas (Upper and Mid)

US Fish and Wildlife Service (USFWS)

Pre&Post San Juan

NM Department of Game &Fish (NMDGF)

Post Animas(lower) San Juan (upper) Animas(lower) San Juan (upper)

Southern Ute Indian Tribe (SUIT)

Pre&Post Animas (Mid) Animas (Mid)

CO Department of Environmental Quality (CDEQ)

Pre&Post Animas Animas (Mid)

EPA: NRSA

Pre San Juan San Juan

Navajo Nation EPA (NNEPA)

Post San Juan

NM Environment Department (NMED)

Pre San Juan

Bureau of Reclamation

Pre San Juan (1996)

Primary Data Sources

Aquatic Life Exposure to Metals During the GKM plume

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Below Silverton (RK 16.4) Bakers Bridge (RK 64) Durango (RK 94) NAR06 (RK 132) Aztec (RK 164) Farmington (RK 190) Farmington (RK 196) Shiprock (RK 246) Four Corners (RK 296) Bluff (RK 377) Mexican Hat (RK 421) Aluminum 9.50 5.25 5.00 5.75 2.50 0.00 18.00 18.00 0.00 0.00 8.00 Antimony 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Arsenic 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Barium 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Beryllium 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Cadmium 7.00 1.25 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Chromium 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Cobalt 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Copper 10.50 6.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Iron 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Lead 2.25 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Manganese 5.50 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Molybdenum 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Nickel 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Selenium 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Silver 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Thallium 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Vanadium 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Zinc 13.75 7.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Criteria Used: CO CO CO CO NM NM NM NM UT UT UT

Hours At or Above Criteria During Passage of GKM Plume

Aquatic Acute

Animas River San Juan River

Navajo Nation Ute Mountain Ute Tribe

A few metals approached acute WQ criteria briefly in Durango

ZINC

• Short-duration exposure exceeded water quality criteria for some

metals, primarily in the upper Animas (hours)

• Aluminum exceeded more widely
• No evidence of wide-spread fish kills

Sentinel CPW Fish Studies

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• Toxicity: caged trout fry (8/6-10/2015)

– 1.5 inch rainbow trout fry placed in cages at three sites in the Animas River for four-days – Of the 108 deployed fish, 2 mortalities were attributed to handling

• Small fish survey (9/2015)

– Mottled sculpin are sensitive to metals, especially zinc – Young trout are more sensitive than adults

N = number of surveys

Sentinel Macroinvertebrates

EPA/MSI Benthic Macroinvertebrates

– Mountain Studies Institute sampled macroinvertebrate communities before and after the GKM plume

• Found no decline in

species or relative abundance

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Months After the GKM Event

• Aquatic studies were conducted in the

weeks following the GKM release to determine whether fish consumption advisories were needed

• Colorado Parks and Wildlife; Durango area
• New Mexico Game and Fish; lower Animas

and upper San Juan

• Sampled in August 2015 and again before

the onset of snowmelt runoff in 2016

• Sampled tissue for metals body burden

– Fish (muscle and liver) – Macroinvertebrates (NM)

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Animas sites had significant deposits of GKM release material in the river channel during the August sampling Deposits resulted in measurably elevated metals in sediment during August sampling, at background in March

Benthic Macroinvertebrate Tissue

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• Metals in benthic macroinvertebrate

tissue track the longitudinal patterns in sediment and water concentrations

• In the Lower Animas, elevated

concentrations of some metals were

• bserved immediately post-release
• Concentrations returned to background by

spring 2016

• Differences in field collection and

analytical methods by various entities limit comparative data analyses

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Metals in Fish: New Mexico Fish Data

• Liver tissue had higher concentrations than muscle
• Some individuals had very high concentrations while most were at non-detect levels
• Some species were more responsive to individual metals than others
• Unknown whether there was any fish mortality due to this exposure
• Fish took up metals

in the weeks immediately after the GKM event

• Uptake was very

complex at the individual level

Note log scale

• Average metals concentrations in fish followed the

longitudinal pattern of GKM deposition in the Animas River

• Metals in fish were at background in the Animas

during March 2016 sampling

• There was little change in water and sediments in the

San Juan River after the release and this was reflected in the low metals concentrations in both samplings of macroinvertebrate and fish communities

• Muscle concentration did not exceed advisory

consumption concentrations.

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Metals in Fish: New Mexico Fish Data

• Body burdens of 8 metals from

SUIT and EPA data taken at the same locations in Fall 2016 were very similar to pre-event samples

• EPA’s monitoring data supports

the conclusion that biological conditions were at background by Fall 2016

• The NMDGF spring data taken

30 km downstream were also very similar to the SUIT and EPA data for most details

Return to Background Conditions After GKM

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Benthic Macroinvertebrate Assemblage

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• Upper Animas River

– Substantial pre-existing degradation pre-GKM release – No difference in community indices immediately after the event – No difference in indices a year+ after the event

• Lower Animas and San Juan Rivers

– Moderate to no degradation pre-GKM release – No difference in community indices a year+ after the event

Multi-metric index scores based on macroinvertebrate communities

Animas River Fish Populations

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Durango-Area CPW Adult Fish Survey Results

• Much year-to-year variability in numbers caught
• Native, naturally reproducing fish abundance

(sculpin, suckers) in 2015/2016 falls within historic data ranges

• Stocked trout populations (rainbow, brown)

showed above-average population abundance in post-GKM 2015 survey Bluehead Sucker length-frequency data from 2016 show absence of fish < 200mm; however, these are typically < 5% of total fish caught

San Juan River Fish Populations: US Fish and Wildlife Survey Results

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Primary Findings

• Abundance of Speckled Dace, Bluehead Sucker and

Flannelmouth Sucker in 2015/2016 generally falls within historic ranges, except in the mid-San Juan

• Rising abundance of native endangered species under managed

recovery plans (Razorback Sucker and Colorado Pikeminnow)

Summary by Location

Upper Animas River

• Historic mining activities in the headwaters have contaminated water and sediments with high concentrations
• f heavy metals and impacted aquatic life for decades
• Although the upper Animas River experienced the most exceedances of aquatic life criteria and the GKM

release left behind deposits that persisted for 8 months after the release, this did not have significant effects

• n the already-impacted aquatic community that has not historically supported fish

Middle and Lower Animas River

• Moving away from the historic mining operations, macroinvertebrate and fish assemblages expand in the

middle Animas River

• Some fish accumulated metals immediately after the GKM event, however fish survey data for naturally

reproducing populations in the middle Animas show that longer-term chronic effects have not been observed

• Changes in the aquatic community structure were not observed
• The Colorado Parks and Wildlife determined that the spill did not cause short term acute effects (fish mortality)

as the plume passed through the Durango, CO section of the river San Juan River

• Concentrations of metals are generally much lower and showed little response to the GKM release
• Metals that could be attributed to the GKM Release were not observed in fish or macroinvertebrates in the San

Juan River

• No effect on fish or macroinvertebrate community composition or populations within the San Juan River were

detected due to the GKM release.

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