Identification of Groundwater Nitrate Contamination from Explosives Used in Road Construction: Isotopic, Chemical, and Hydrologic Evidence

Degnan, James R.; Böhlke, John K.; Pelham, Krystle; Langlais, David M.; Walsh, Gregory J.

doi:10.1021/acs.est.5b03671

Cited by 33 publications

(25 citation statements)

References 45 publications

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“…Larger amounts of nitrate are commonly present in actual aquifers (Degnan et al, 2016), and so the interaction of nitrate with V(V) should be considered whenever practical bioremediation is conducted with hydrogen as the sole electron donor.…”

Section: Influences Of Operating Factorsmentioning

confidence: 99%

Synchronous microbial vanadium (V) reduction and denitrification in groundwater using hydrogen as the sole electron donor

et al. 2018

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Groundwater co-contaminated by vanadium (V) (V(V)) and nitrate requires efficient remediation to prevent adverse environmental impacts. However, little is known about simultaneous bio-reductions of V(V) and nitrate supported by gaseous electron donors in aquifers. This study is among the first to examine microbial V(V) reduction and denitrification with hydrogen as the sole electron donor. V(V) removal efficiency of 91.0 ± 3.2% was achieved in test bioreactors within 7 d, with synchronous, complete removal of nitrate. V(V) was reduced to V(IV), which precipitated naturally under near-neutral conditions, and nitrate tended to be converted to nitrogen, both of which processes helped to purify the groundwater. Volatile fatty acids (VFAs) were produced from hydrogen oxidation. High-throughput 16S rRNA gene sequencing and metagenomic analyses revealed the evolutionary behavior of microbial communities and functional genes. The genera Dechloromonas and Hydrogenophaga promoted bio-reductions of V(V) and nitrate directly coupled to hydrogen oxidation. Enriched Geobacter and denitrifiers also indicated synergistic mechanism, with VFAs acting as organic carbon sources for heterotrophically functional bacteria while reducing V(V) and nitrate. These findings are likely to be useful in revealing biogeochemical fates of V(V) and nitrate in aquifer and developing technology for removing them simultaneously from groundwater.

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Section: Influences Of Operating Factorsmentioning

confidence: 99%

Synchronous microbial vanadium (V) reduction and denitrification in groundwater using hydrogen as the sole electron donor

et al. 2018

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“…Reported values are relative to the standard air (AIR) and Vienna Standard Mean Ocean Water (VSMOW), respectively. Reported literature values for potential NO 3 − isotope end members such as fertilizer, soils (Kendall et al, ), explosives (Degnan et al, ), and coal (Holloway & Dahlgren, ) were used in the analysis (Figure S1). The precipitation endmember was derived from measured rainfall samples taken during storm periods.…”

Section: Methodsmentioning

confidence: 99%

“…To investigate source dynamics, a subset of stream and rainfall samples from the June 2016 storm was analyzed for 15 N and 18 O values by the bacterial denitrification method (Sigman et al, 2001) (Kendall et al, 2008), explosives (Degnan et al, 2016), and coal (Holloway & Dahlgren, 2002) were used in the analysis ( Figure S1). The precipitation endmember was derived from measured rainfall samples taken during storm periods.…”

Section: No 3 − Source Dynamicsmentioning

confidence: 99%

Excess Nitrate Export in Mountaintop Removal Coal Mining Watersheds

et al. 2019

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Throughout the Central Appalachian ecoregion, mountaintop removal coal mining (MTM) is the predominant form of land use change. The streams draining MTM impacted watersheds have been reported to contain high stream nitrate (NO3−) concentrations, yet the source and persistence of elevated NO3− remains unknown. Here we compiled data from multiple sources to conduct a regional evaluation of the impact of mining on stream NO3−, examine NO3− persistence after mining cessation, and identify potential N sources. Using water quality data from six large watersheds, we observe elevated NO3− in watersheds with the highest active mining density. At four small MTM watersheds with repeat sampling, we found that high levels of NO3− concentrations declined after mining cessation but remain elevated above reference after several decades. At MTM watersheds, we found annual mass flux of NO3− was 3.68 to 26.4 kg N ha−1 year−1, which is 1 to 2 orders of magnitude higher than a nearby forested reference watershed. Stream water NO3− isotopic ratios at these sites did not match previously suggested NO3− sources such as explosives used during mining and fertilizer applied during reclamation but were highly enriched in both δ15N and δ18O compared to the reference watershed suggesting high rates of NO3− retention. Explosive residue could account for the bulk of watershed NO3− export during active mining phases but other mining related N sources including fertilizer and rock‐derived N, the construction of valley fills, and alterations in watershed NO3‐ cycling likely contribute to the persistence of elevated NO3− export observed in this study.

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“…Mohalik et al (2017), Sloss (2013), Wu et al (2012), and Yang et al (2017) used environmental tracers and stable isotopes to identify the susceptibility of coal mines to the phenomenon of 'spontaneous combustion'. In addition, N and O isotopes have been investigated particularly to trace the environmental impact of explosives used in mining and construction (Degnan et al 2016;Hendry et al 2018;Nilsson 2013).…”

Section: Specific Isotopic Toolsmentioning

confidence: 99%

Guidance for the Integrated Use of Hydrological, Geochemical, and Isotopic Tools in Mining Operations

et al. 2020

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This paper summarizes international state-of-the-art applications and opportunities for employing and deploying hydrological, geochemical, and isotopic tools in an integrated manner for investigations of mining operations. It is intended to aid formulation of more integrated approaches for evaluating the overall sustainability of mining projects. The focus is particularly on mine waters, including: environmental water sources, mine water dynamics, and as a source and vector for pollution in the wider environment. The guidance is generic to mining projects and not just reflective of a particular extraction (e.g. coal, metalliferous, uranium) industry. A mine life cycle perspective has been adopted to highlight the potential for more integrated investigations at each stage of a mining operation. Three types of mines have been considered: new (i.e. those in the planning stage), active (i.e. working mines), and historical mines (i.e. inactive and abandoned mines). The practical usage of geochemical analyses and isotopic studies described here emphasise characterisation, dynamics, and process understanding for water quality considerations in tandem with water resource and environmental impact implications. Both environmental (i.e. ambient) and applied (i.e. injected) tracers are considered. This guide is written for scientists (including isotope specialists) who have limited or no mine water experience, environmental managers, planners, consultants, and regulators with key interests in planned, active, and legacy mining projects.

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Identification of Groundwater Nitrate Contamination from Explosives Used in Road Construction: Isotopic, Chemical, and Hydrologic Evidence

Cited by 33 publications

References 45 publications

Synchronous microbial vanadium (V) reduction and denitrification in groundwater using hydrogen as the sole electron donor

Synchronous microbial vanadium (V) reduction and denitrification in groundwater using hydrogen as the sole electron donor

Excess Nitrate Export in Mountaintop Removal Coal Mining Watersheds

Guidance for the Integrated Use of Hydrological, Geochemical, and Isotopic Tools in Mining Operations

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