Biological Response to the Gold King Mine Release in the Animas and San Juan Rivers Lareina Guenzel 1 , Richard Mitchell, PhD 1 , Kate Sullivan, PhD 2 , and Michael Cyterski, PhD 2 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 1
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 2
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 Extremely low trout populations upstream of humans which consume them Baker’s Bridge Upper - Acute and chronic effects Animas Limited Benthic Macroinvertebrates • Legacy mining impacts: highly contaminated surface water and sediment, Historic No aquatic life use Conditions: and known biological impairments in Upper Animas (USGS 2007, EPA 2015) protection in the • Lower Animas and San Juan Rivers were not known to be contaminated by mainstem through Silverton 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. 3
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 Benthic impairment in other segments of the Macroinvertebrates Fish Animas and San Juan rivers that had not been known to have metal impacts? Organism body burden to indicate uptake of GKM X X metals Methods Community structure and • Collected and reviewed all available population estimates to biological data in the San Juan and Animas X X indicate mortality from rivers to assess how aquatic biota exposure to GKM metals responded to the GKM release • Compared pre-event and post-event measures of four key characteristics 4
Study Area Longitudinal Patterns in Aquatic Habitat • Upper Animas High gradient – Upper Animas – Cold water aquatic life – Large particle substrate size • Lower Animas Mid Animas Gradient transition from – high to low – Transition from cold water Lower Animas to warm water fishery – Substrate particle size becomes smaller • San Juan River Low gradient – – Warm water fishery Upper San Juan Lower San Juan – Small particle substrate size 5
Longitudinal Gradient of Metals Contamination 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 6
Biological Data Sources Source Benthic Macro Benthic Macro Fish Fish Physical Assemblage Tissue Population Tissue Habitat Animas Animas Animas Animas EPA: START Contractors Post Primary Data Sources & San Juan & San Juan & San Juan & San Juan EPA: Superfund/ Animas Animas Pre&Post (upper & mid) (upper & mid) Mountain Studies Institute (MSI) CO Parks and Wildlife Animas Pre&Post (CPW) (Upper and Mid) US Fish and Wildlife Service Pre&Post San Juan (USFWS) NM Department of Game &Fish Animas(lower) Animas(lower) Post (NMDGF) San Juan (upper) San Juan (upper) Southern Ute Indian Tribe Pre&Post Animas (Mid) Animas (Mid) (SUIT) CO Department of Environmental Animas Pre&Post Animas (Mid) Quality (CDEQ) EPA: NRSA Pre San Juan San Juan Navajo Nation EPA (NNEPA) Post San Juan NM Environment Department Pre San Juan (NMED) Bureau of Reclamation Pre San Juan (1996) 7
Aquatic Life Exposure to Metals During the GKM plume A few metals approached acute WQ criteria briefly in Durango Aquatic Hours At or Above Criteria During Passage of GKM Plume Acute Animas River San Juan River Below Bakers Silverton Bridge Durango NAR06 Aztec Farmington Farmington Shiprock Four Corners Bluff Mexican Hat ZINC (RK 16.4) (RK 64) (RK 94) (RK 132) (RK 164) (RK 190) (RK 196) (RK 246) (RK 296) (RK 377) (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 Navajo Nation Ute Mountain Ute Tribe • 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 8
Sentinel CPW Fish Studies • 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 N = number of surveys metals, especially zinc Young trout are more sensitive – than adults 9
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 10
Months After the GKM Event • Aquatic studies were conducted in the weeks following the GKM release to determine whether fish consumption Animas sites had significant advisories were needed deposits of GKM release material in the river channel - Colorado Parks and Wildlife; Durango area during the August sampling - 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) Deposits resulted in measurably elevated metals in sediment during August sampling, at background in March 11
Benthic Macroinvertebrate Tissue • Metals in benthic macroinvertebrate tissue track the longitudinal patterns in sediment and water concentrations • In the Lower Animas, elevated concentrations of some metals were observed immediately post-release • Concentrations returned to background by spring 2016 • Differences in field collection and analytical methods by various entities limit comparative data analyses 12
Metals in Fish: New Mexico Fish Data • Fish took up metals in the weeks immediately after the GKM event Note log scale • Uptake was very complex at the individual level • 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 13
Metals in Fish: New Mexico Fish Data • 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. 14
Return to Background Conditions After GKM • 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 15
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