High-frequency NO<sub>3</sub><sup>−</sup> isotope (<i>δ</i><sup>15</sup>N, <i>δ</i><sup>18</sup>O) patterns in groundwater recharge reveal that short-term changes in land use and precipitation influence nitrate contamination trends
<p>Poultry manure is the primary cause of nitrate (NO<sub>3</sub><sup>−</sup>) exceedances in the transboundary Abbotsford–Sumas aquifer (ASA; Canada–USA) based on synoptic surveys two decades apart, but questions remained about seasonal and spatial aspects of agricu...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2018-08-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://www.hydrol-earth-syst-sci.net/22/4267/2018/hess-22-4267-2018.pdf |
| _version_ | 1819055355119796224 |
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| author | M. Suchy L. I. Wassenaar G. Graham B. Zebarth |
| author_facet | M. Suchy L. I. Wassenaar G. Graham B. Zebarth |
| author_sort | M. Suchy |
| collection | DOAJ |
| description | <p>Poultry manure is the primary cause of nitrate (NO<sub>3</sub><sup>−</sup>) exceedances
in the transboundary Abbotsford–Sumas aquifer (ASA; Canada–USA) based on synoptic
surveys two decades apart, but questions remained about seasonal and spatial
aspects of agricultural nitrate fluxes to the aquifer to help better focus
remediation efforts. We conducted over 700 monthly <i>δ</i><sup>15</sup>N and
<i>δ</i><sup>18</sup>O of nitrate assays, focusing on shallow groundwater
(< 5 years old) over a 5-year period to gain new insight on
spatio-temporal sources and controls of groundwater nitrate contamination.
NO<sub>3</sub><sup>−</sup> concentrations in these wells ranged from 1.3 to 99 mg N L<sup>−1</sup>
(<i>n</i> = 1041) with a mean of 16.2±0.4 mg N L<sup>−1</sup>. The
high-frequency <sup>15</sup>N and <sup>18</sup>O isotope data allowed us to identify
three distinctive NO<sub>3</sub><sup>−</sup> source patterns: (i) primarily from synthetic
fertilizer, (ii) dynamic changes in nitrate due to changes in land use, and
(iii) from a mix of poultry manure and fertilizer. A key finding was that the
source(s) of nitrate in recharge could be quickly influenced by short-term
near-field management practices and stochastic precipitation events, which
ultimately impact long-term nitrate contamination trends. Overall, the
isotope data affirmed a subtle decadal-scale shift in agricultural practices
from manure increasingly towards fertilizer nitrate sources; nevertheless,
poultry-derived N remains a predominant source of nitrate contamination.
Because the aquifer does not generally support denitrification, remediation
of the Abbotsford–Sumas aquifer is possible only if agricultural N sources
are seriously curtailed, a difficult proposition due to longstanding
high-value intensive poultry and raspberry and blueberry operations over the
aquifer.</p> |
| first_indexed | 2024-12-21T13:06:12Z |
| format | Article |
| id | doaj.art-a9f664f153484ff5b64989b44fabfd22 |
| institution | Directory Open Access Journal |
| issn | 1027-5606 1607-7938 |
| language | English |
| last_indexed | 2024-12-21T13:06:12Z |
| publishDate | 2018-08-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Hydrology and Earth System Sciences |
| spelling | doaj.art-a9f664f153484ff5b64989b44fabfd222022-12-21T19:03:02ZengCopernicus PublicationsHydrology and Earth System Sciences1027-56061607-79382018-08-01224267427910.5194/hess-22-4267-2018High-frequency NO<sub>3</sub><sup>−</sup> isotope (<i>δ</i><sup>15</sup>N, <i>δ</i><sup>18</sup>O) patterns in groundwater recharge reveal that short-term changes in land use and precipitation influence nitrate contamination trendsM. Suchy0L. I. Wassenaar1G. Graham2B. Zebarth3Environment and Climate Change Canada, 201-401 Burrard St., Vancouver, BC, CanadaInternational Atomic Energy Agency, Vienna International Centre, 1400, Vienna, AustriaEnvironment and Climate Change Canada, 201-401 Burrard St., Vancouver, BC, CanadaFredericton Research and Development Centre, Agriculture and Agri-Food Canada, 850 Lincoln Rd., P.O. Box 20280 Fredericton, NB, E3B 4Z7, Canada<p>Poultry manure is the primary cause of nitrate (NO<sub>3</sub><sup>−</sup>) exceedances in the transboundary Abbotsford–Sumas aquifer (ASA; Canada–USA) based on synoptic surveys two decades apart, but questions remained about seasonal and spatial aspects of agricultural nitrate fluxes to the aquifer to help better focus remediation efforts. We conducted over 700 monthly <i>δ</i><sup>15</sup>N and <i>δ</i><sup>18</sup>O of nitrate assays, focusing on shallow groundwater (< 5 years old) over a 5-year period to gain new insight on spatio-temporal sources and controls of groundwater nitrate contamination. NO<sub>3</sub><sup>−</sup> concentrations in these wells ranged from 1.3 to 99 mg N L<sup>−1</sup> (<i>n</i> = 1041) with a mean of 16.2±0.4 mg N L<sup>−1</sup>. The high-frequency <sup>15</sup>N and <sup>18</sup>O isotope data allowed us to identify three distinctive NO<sub>3</sub><sup>−</sup> source patterns: (i) primarily from synthetic fertilizer, (ii) dynamic changes in nitrate due to changes in land use, and (iii) from a mix of poultry manure and fertilizer. A key finding was that the source(s) of nitrate in recharge could be quickly influenced by short-term near-field management practices and stochastic precipitation events, which ultimately impact long-term nitrate contamination trends. Overall, the isotope data affirmed a subtle decadal-scale shift in agricultural practices from manure increasingly towards fertilizer nitrate sources; nevertheless, poultry-derived N remains a predominant source of nitrate contamination. Because the aquifer does not generally support denitrification, remediation of the Abbotsford–Sumas aquifer is possible only if agricultural N sources are seriously curtailed, a difficult proposition due to longstanding high-value intensive poultry and raspberry and blueberry operations over the aquifer.</p>https://www.hydrol-earth-syst-sci.net/22/4267/2018/hess-22-4267-2018.pdf |
| spellingShingle | M. Suchy L. I. Wassenaar G. Graham B. Zebarth High-frequency NO<sub>3</sub><sup>−</sup> isotope (<i>δ</i><sup>15</sup>N, <i>δ</i><sup>18</sup>O) patterns in groundwater recharge reveal that short-term changes in land use and precipitation influence nitrate contamination trends Hydrology and Earth System Sciences |
| title | High-frequency NO<sub>3</sub><sup>−</sup> isotope (<i>δ</i><sup>15</sup>N, <i>δ</i><sup>18</sup>O) patterns in groundwater recharge reveal that short-term changes in land use and precipitation influence nitrate contamination trends |
| title_full | High-frequency NO<sub>3</sub><sup>−</sup> isotope (<i>δ</i><sup>15</sup>N, <i>δ</i><sup>18</sup>O) patterns in groundwater recharge reveal that short-term changes in land use and precipitation influence nitrate contamination trends |
| title_fullStr | High-frequency NO<sub>3</sub><sup>−</sup> isotope (<i>δ</i><sup>15</sup>N, <i>δ</i><sup>18</sup>O) patterns in groundwater recharge reveal that short-term changes in land use and precipitation influence nitrate contamination trends |
| title_full_unstemmed | High-frequency NO<sub>3</sub><sup>−</sup> isotope (<i>δ</i><sup>15</sup>N, <i>δ</i><sup>18</sup>O) patterns in groundwater recharge reveal that short-term changes in land use and precipitation influence nitrate contamination trends |
| title_short | High-frequency NO<sub>3</sub><sup>−</sup> isotope (<i>δ</i><sup>15</sup>N, <i>δ</i><sup>18</sup>O) patterns in groundwater recharge reveal that short-term changes in land use and precipitation influence nitrate contamination trends |
| title_sort | high frequency no sub 3 sub sup sup isotope i δ i sup 15 sup n i δ i sup 18 sup o patterns in groundwater recharge reveal that short term changes in land use and precipitation influence nitrate contamination trends |
| url | https://www.hydrol-earth-syst-sci.net/22/4267/2018/hess-22-4267-2018.pdf |
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