Tracing nitrate sources with a combined isotope approach (δ15NNO3, δ18ONO3 and δ11B) in a large mixed-use watershed in southern Alberta, Canada

Kruk, Mary K.; Mayer, Bernhard; Nightingale, Michael; Laceby, J. Patrick

doi:10.1016/j.scitotenv.2019.135043

Cited by 41 publications

(23 citation statements)

References 83 publications

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“…The large relative mass differences between 11 B and 10 B means that isotope fractionation leads to a wide range of isotopic values in nature. The combined use of δ 11 B and δ 15 N to trace NO 3 − sources has been successfully applied in terrestrial and aquatic environments (Komor, 1997;Widory et al, 2004Widory et al, , 2005Widory et al, , 2013Seiler, 2005;Bronders et al, 2012;Lindenbaum, 2012;Briand et al, 2013Briand et al, , 2017Eppich et al, 2013;Saccon et al, 2013;Ransom et al, 2016;Guinoiseau et al, 2018;Kruk et al, 2020); however, the use of δ 11 B and δ 15 N has yet to be tested in the STE of coastal systems.…”

Section: Introductionmentioning

confidence: 99%

Investigating Boron Isotopes for Identifying Nitrogen Sources Supplied by Submarine Groundwater Discharge to Coastal Waters

Tamborski

Brown

Bokuniewicz

et al. 2020

Front. Environ. Sci.

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Stable isotopes of oxygen, nitrogen, and boron were used to identify the sources of nitrate (NO 3 −) in submarine groundwater discharge (SGD) into a large tidal estuary (Long Island Sound, NY, United States). Potential contaminants such as manure, septic waste and fertilizer overlap in δ 15 N and δ 18 O but have been shown to have distinctive δ 11 B in non-coastal settings. Two distinct subterranean estuaries were studied with different land-use up gradient, representative of (1) mixed medium-density residential housing and (2) agriculture. These sites have overlapping δ 15 N and δ 18 O measurements in NO 3 − and are unable to discriminate between different N sources. Boron isotopes and concentrations are measurably different between the two sites, with little overlap. The subterranean estuary impacted by mixed medium-density residential housing shows little correlation between δ 11 B and [B] or between δ 11 B and salinity, demonstrating that direct mixing relationships between fresh groundwater and seawater were unlikely to account for the variability. No two sources could adequately characterize the δ 11 B of this subterranean estuary. Groundwater N at this location should be derived from individual homeowner cesspools, although measured septic waste has much lower δ 11 B compared to the coastal groundwaters. This observation, with no trend in δ 11 B with [B] indicates multiple sources supply B to the coastal groundwaters. The agricultural subterranean estuary displayed a positive correlation between δ 11 B and [B] without any relationship with salinity. Binary mixing between sea spray and fertilizer can reasonably explain the distribution of B in the agricultural subterranean estuary. Results from this study demonstrate that δ 11 B can be used in combination with δ 15 N to trace sources of NO 3 − to the subterranean estuary if source endmember isotopic signatures are wellconstrained, and if the influence of seawater on δ 11 B signatures can be minimized or easily quantified.

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Section: Introductionmentioning

confidence: 99%

Investigating Boron Isotopes for Identifying Nitrogen Sources Supplied by Submarine Groundwater Discharge to Coastal Waters

Tamborski

Brown

Bokuniewicz

et al. 2020

Front. Environ. Sci.

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“…Riverine boron concentrations provide an additional indicator of anthropogenic impacts. Boron fluxes display a more gradual increase with distance from headwater and continues to increase further downstream of Calgary, declining again towards the confluence with the Oldman River (Kruk, Mayer, Nightingale, & Laceby, 2020 riverine nitrate (Fig. 5C).…”

Section: Spatial Variation In Nutrient Flux and Sourcementioning

confidence: 99%

“…5C). To distinguish nitrate from these two sources, boron isotope ratios have proven to be a useful co-tracer (Kruk et al, 2020). Boron isotope ratios in Bow River water revealed that samples from the midstream section are dominated by WWTP-derived nutrients (Fig.…”

Section: Spatial Variation In Nutrient Flux and Sourcementioning

confidence: 99%

“…The approximate contributions from each nitrate source (soil nitrification, WWTP effluent, and manure-derived agricultural nitrate) to samples from each section of the river was estimated based on dual isotope mixing models using  15 N and  18 O values by Chao (2011) and  15 N and  11 B values by Kruk et al (2020;Fig. 5B) and revealed that nitrate in headwater samples were predominantly derived from nitrification in soils with some minimal input from WWTPs.…”

Section: Spatial Variation In Nutrient Flux and Sourcementioning

confidence: 99%

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Considering multiple anthropogenic threats in the context of natural variability: Ecological processes in a regulated riverine ecosystem

et al. 2020

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“…The watersheds in a temperate continental monsoon climate are more beneficial in developing dryland agriculture. For instance, nitrogen fertilizer was the primary nitrate source of nitrate due to the use of nitrogen fertilizer in the North China and West Canada (Bu et al, 2017;Peters et al, 2019;Kruk et al, 2020). While in South China and North Malaysia (Hu et al, 2019;Fadhullah et al, 2020), nitrogen fertilizer was not the primary source of nitrate.…”

Section: Comparison Of the Nitrate Source With Other Twenty-five Similar Watershedsmentioning

confidence: 99%

Contribution of Nitrogen Sources to Streams in Mixed-use Watershed Varies Seasonally in a Temperate Region

Lin

Liu

Xiao

et al. 2021

Preprint

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The Beiyun river flows through a hot spot region of Beijing-Tianjin-Hebei in China that serves a majority of occupants. However, the region experiences severe nitrate pollution, posing a threat to human health due to inadequate self-purification capacity. In that context, there is an urgent need to assess nitrate levels in this region. Herein, we used δ15N-NO3, δ18O-NO3 isotopes analysis, and stable isotope analysis model to evaluate the nitrate source apportionment in the Beiyun river. A meta-analysis was then used to compare the potential similarity of nitrate sources among the Beiyun riverine watershed and other watersheds. Results of nitrate source apportionment revealed that nitrate originated from the manure & sewage (contribution rate: 89.6%), soil nitrogen (5.9%), and nitrogen fertilizer (3.9%) in the wet season. While in the dry season, nitrate mainly originated from manure & sewage (91.6%). Further, different land-use types exhibited distinct nitrate compositions. Nitrate in urban and suburban areas mostly was traced from manure & sewage (90.5% and 78.8%, respectively). Notably, the different nitrate contribution in the rural-urban fringe and plant-covered areas were manure & sewage (44.3% and 32.8%), soil nitrogen (26.9% and 35.7%), nitrogen fertilizer (23.5% and 29.4%), and atmospheric deposition (5.3% and 2.0%). Through a meta-analysis, we found nitrogen fertilizer, soil nitrogen, and manure & sewage as the main nitrate sources in the Beiyun riverine watershed or the other similar complex watersheds in the temperate. Thus, this study provides a scientific basis for nitrate source apportionment and nitrate preventive management in watersheds with complex land-use types in temperate regions.

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Tracing nitrate sources with a combined isotope approach (δ15NNO3, δ18ONO3 and δ11B) in a large mixed-use watershed in southern Alberta, Canada

Cited by 41 publications

References 83 publications

Investigating Boron Isotopes for Identifying Nitrogen Sources Supplied by Submarine Groundwater Discharge to Coastal Waters

Investigating Boron Isotopes for Identifying Nitrogen Sources Supplied by Submarine Groundwater Discharge to Coastal Waters

Considering multiple anthropogenic threats in the context of natural variability: Ecological processes in a regulated riverine ecosystem

Contribution of Nitrogen Sources to Streams in Mixed-use Watershed Varies Seasonally in a Temperate Region

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