Anoxia stimulates microbially catalyzed metal release from Animas River sediments

Williams, Kenneth H.; Rodríguez-Freire, Lucía; Cerrato, José M.; Johnston, Michael D.; Saup, Casey M.

doi:10.1039/c7em00036g

Cited by 14 publications

(7 citation statements)

References 26 publications

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“…For example, hyporheic microbial communities metabolize organic matter (Ruhala et al, ; Stegen et al, ) and have been shown to be responsible for 40–93% of whole‐stream ecosystem respiration (Fellows et al, ; Fuss & Smock, ). The hyporheic zone also provides sorption sites for metals (Nagorski & Moore, ; Saup et al, ). In one mining‐contaminated stream, manganese oxidation in the hyporheic zone decreased dissolved manganese concentrations in surface water by 20% (Harvey & Fuller, ).…”

Section: Introductionmentioning

confidence: 99%

Heterogeneity in Hyporheic Flow, Pore Water Chemistry, and Microbial Community Composition in an Alpine Streambed

Sawyer

Gabor

et al. 2019

JGR Biogeosciences

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The hyporheic zone, where surface water and groundwater mix, is an important microbial habitat where biogeochemical reactions influence water quality. We show that spatial variability in hyporheic flow in the East River near Crested Butte, CO, drives heterogeneity in streambed geochemical conditions and microbial community assemblages, but the diversity of microbial assemblages remains nearly constant throughout the reach. In July 2018, we collected approximately 100 pore water samples at 20-cm depth and analyzed them for anions, cations, dissolved organic carbon, dissolved organic matter (DOM) quality, and basic water quality parameters. Vertical hydraulic head gradients were also measured to assess the potential for upward or downward flow, and heat tracing was used to quantify vertical flux rates at a subset of locations. We found that regions of the streambed that are more groundwater-dominated contain less dissolved oxygen, higher concentrations of reduced metals, and more microbially processed, recalcitrant DOM, while more surface water-dominated locations contain higher dissolved oxygen concentrations and terrestrially derived, labile DOM. 16S rRNA gene sequencing of extracted DNA revealed that microbial community composition varies with geochemical gradients related to hyporheic flow. These findings provide a better understanding of hyporheic controls on streambed biogeochemistry during the baseflow season, which is expected to lengthen with climate change in alpine watersheds due to earlier snowmelt onset and reduced snowpack.Plain Language Summary Groundwater and surface water mixing in streambeds (hyporheic exchange) is important for nutrient and carbon cycling and influences the overall quality of surface water. In this study, we aimed to map relationships between hyporheic exchange, pore water chemistry, and microbial communities in the streambed of an alpine river during low flow conditions. We found that regions of the streambed with greater surface water influence had larger concentrations of dissolved oxygen and microbially available carbon compounds. The composition of streambed microbial communities also shifted with changes in pore water chemistry, though communities were all similarly diverse. As climate change progresses, earlier snowmelt onset and reduced snowpack should alter flow and biogeochemical processes in streambeds. This study provides a baseline for exploring future changes in alpine streambeds.

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Section: Introductionmentioning

confidence: 99%

Heterogeneity in Hyporheic Flow, Pore Water Chemistry, and Microbial Community Composition in an Alpine Streambed

Sawyer

Gabor

et al. 2019

JGR Biogeosciences

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“…Jarosite dissolution can cause the release of metals in water at specific pH and redox conditions. 18,19…”

Section: Introductionmentioning

confidence: 99%

Effect of bicarbonate and phosphate on arsenic release from mining-impacted sediments in the Cheyenne River watershed, South Dakota, USA

DeVore

Rodríguez-Freire

Mehdi-Ali

et al. 2019

Environ. Sci.: Processes Impacts

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The mobilization of arsenic (As) from riverbank sediments affected by the gold mining legacy in north-central South Dakota was examined using aqueous speciation chemistry, spectroscopy, and diffraction analyses. Gold mining resulted in the discharge of approximately 109 metric tons of mine waste into Whitewood Creek (WW) near the Homestake Mine and Cheyenne River at Deal Ranch (DR), 241 km downstream. The highest concentrations of acid-extractable As measured from solid samples was 2020 mg kg−1 at WW and 385 mg kg−1 at DR. Similar sediment mineralogy between WW and DR was identified using XRD, with the predominance of alumino-silicate and iron-bearing minerals. Alkalinity measured in surface water at both sites ranged from 1000 to 2450 mg L−1 as CaCO3 (10–20 mM HCO3− at pH 7). Batch laboratory experiments were conducted under oxidizing conditions to evaluate the effects of NaHCO3 (0.2 mM and 20 mM) and NaH2PO3(0.1 and 10 mM) on the mobilization of As. These ions are relevant for the site due to the alkaline nature of the river and nutrient mobilization from the ranch. The range of As(V) release with the NaHCO3 treatment was 17–240 μg L−1. However, the highest release (6234 μg L−1) occurred with 10 mM NaH2PO3, suggesting that As release is favored by competitive ion displacement with PO43− compared to HCO3−. Although higher total As was detected in WW solids, the As(V) present in DR solids was labile when reacted with NaHCO3 and NaH2PO3, which is a relevant finding for communities living close to the river bank. The results from this study aid in a better understanding of As mobility in surface water sites affected by the mining legacy.

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“…The headwaters of the Animas River gained publicity in August 2015 when an accidental breach of a tunnel connected to the legacy Gold King Mine led to the release of ∼11 million liters of acidic mine drainage into surface waters that persisted as far as San Juan River in New Mexico (∼200 km downstream) (Rodriguez-Freire et al, 2016). Dissolved metals associated with the Gold King Mine spill were hypothesized to have rapidly immobilized in the headwaters via adsorption onto streambed sediments and precipitation of Fe-oxyhydroxide minerals (Rodriguez-Freire et al, 2016;Saup et al, 2017). Although the Gold King Mine spill contributed a slug of metals to the system over a short period of time, numerous historic mines or mining-related sources contribute diffuse loads upwards of 20.4 million liters per day to the Animas River headwaters (USEPA, 2016).…”

Section: Introductionmentioning

confidence: 99%

Groundwater–Stream Connectivity Mediates Metal(loid) Geochemistry in the Hyporheic Zone of Streams Impacted by Historic Mining and Acid Rock Drainage

et al. 2020

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High concentrations of trace metal(loid)s exported from abandoned mine wastes and acid rock drainage pose a risk to the health of aquatic ecosystems. To determine if and when the hyporheic zone mediates metal(loid) export, we investigated the relationship between streamflow, groundwater–stream connectivity, and subsurface metal(loid) concentrations in two ~1-km stream reaches within the Bonita Peak Mining District, a US Environmental Protection Agency Superfund site located near Silverton, Colorado, USA. The hyporheic zones of reaches in two streams—Mineral Creek and Cement Creek—were characterized using a combination of salt-tracer injection tests, transient-storage modeling, and geochemical sampling of the shallow streambed (<0.7 m). Based on these data, we present two conceptual models for subsurface metal(loid) behavior in the hyporheic zones, including (1) well-connected systems characterized by strong hyporheic mixing of infiltrating stream water and upwelling groundwater and (2) poorly connected systems delineated by physical barriers that limit hyporheic mixing. The comparatively large hyporheic zone and high hydraulic conductivities of Mineral Creek created a connected stream–groundwater system, where mixing of oxygen-rich stream water and metal-rich groundwater facilitated the precipitation of metal colloids in the shallow subsurface. In Cement Creek, the precipitation of iron oxides at depth (~0.4 m) created a low-hydraulic-conductivity barrier between surface water and groundwater. Cemented iron oxides were an important regulator of metal(loid) concentrations in this poorly connected stream–groundwater system due to the formation of strong redox gradients induced by a relatively small hyporheic zone and high fluid residence times. A comparison of conceptual models to stream concentration–discharge relationships exhibited a clear link between geochemical processes occurring within the hyporheic zone of the well-connected system and export of particulate Al, Cu, Fe, and Mn, while the poorly connected system did not have a notable influence on metal concentration–discharge trends. Mineral Creek is an example of a hyporheic system that serves as a natural dissolved metal(loid) sink, whereas poorly connected systems such as Cement Creek may require a combination of subsurface remediation of sediments and mitigation of upstream, iron-rich mine drainages to reduce metal export.

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Anoxia stimulates microbially catalyzed metal release from Animas River sediments

Cited by 14 publications

References 26 publications

Heterogeneity in Hyporheic Flow, Pore Water Chemistry, and Microbial Community Composition in an Alpine Streambed

Heterogeneity in Hyporheic Flow, Pore Water Chemistry, and Microbial Community Composition in an Alpine Streambed

Effect of bicarbonate and phosphate on arsenic release from mining-impacted sediments in the Cheyenne River watershed, South Dakota, USA

Groundwater–Stream Connectivity Mediates Metal(loid) Geochemistry in the Hyporheic Zone of Streams Impacted by Historic Mining and Acid Rock Drainage

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