Coupling the dual isotopes of water (δ 2 H and δ 18 O) and nitrate (δ 15 N and δ 18 O)
A new framework for classifying current and legacy groundwater pollution
Bibliographic Data
| ID | 15548352 |
|---|---|
| Authors | Julie N Weitzman (0000-0002-6554-4776, Environmental Protection Agency, corresponding author), J Renée Brooks (0000-0002-5008-9774, Environmental Protection Agency), Paul M Mayer (0000-0002-8550-1386, Environmental Protection Agency), William D Rugh, Jana E Compton (0000-0001-9833-8664, Environmental Protection Agency) |
| Year | 2021 |
| Volume | 16 |
| Issue | 4 |
| Pages | 045008-045008 |
| Publication date | 2021-03-24 |
| Peer Reviewed | Yes |
| Open Access | Yes |
| Type | ARTICLE |
| Venue | Environmental Research Letters (JOURNAL) |
| Journal identifiers | ISSN: 1748-9326 • E-ISSN: 1748-9326 |
| Publisher | IOP Publishing (PUBLISHER • GB) |
| DOI | 10.1088/1748-9326/abdcef |
| PMID | 33897808 |
| OpenAlex | W3137532606 |
| Language | EN |
| Citations received | 1 |
| References cited | 73 |
Nitrate contamination of groundwater is a concern globally, particularly in agricultural regions where decades of fertilizer nitrogen (N) use has led to a legacy of N accumulation in soils and groundwater. Linkages between current management practices and groundwater nitrate dynamics are often confounded by the legacy effect, and other processes unrelated to management. A coupled analysis of dual stable isotopes of water (δH 2 O = δ 2 H and δ 18 O) and nitrate (δNO 3 - = δ 15 N and δ 18 O) can be a powerful approach to identify sources and processes responsible for groundwater pollution. To assess how management practices impact groundwater nitrate, we interpreted behavior of δH 2 O and δNO 3 - , together with nitrate concentrations, in water samples collected from long-term monitoring wells in the Southern Willamette Valley (SWV), Oregon. The source(s) of nitrate and water varied among wells, suggesting that the nitrate concentration patterns were not uniform across the shallow aquifer of the valley. Analyzing the stability versus variability of a well's corresponding δH 2 O and δNO 3 - values over time revealed the mechanisms controlling nitrate concentrations. Wells with stable δH 2 O and δNO 3 - values and nitrate concentrations were influenced by one water source with a long residence time and one nitrate source. Variable nitrate concentrations of other wells were attributed to dilution with an alternate water source, mixing of two nitrate sources, or variances in the release of legacy N from overlying soils. Denitrification was not an important process influencing well nitrate dynamics. Understanding the drivers of nitrate dynamics and interaction with legacy N is crucial for managing water quality improvement. This case study illustrates when and where such coupled stable isotope approaches might provide key insights to management on groundwater nitrate contamination issues
Aquifer · Denitrification · Dilution · Fertilizer · Groundwater · Hydrology (agriculture · Isotope analysis · Nitrate · Nitrogen · Physics · Soil water · Stable isotope ratio · Chemistry · Environmental Science · Groundwater and Isotope Geochemistry · Groundwater flow and contamination studies · Hydrology and Watershed Management Studies · Ecology · Environmental Chemistry · Geology · Soil Science
| Unique citing works | 1 |
|---|---|
| Citations per year | 1 |
| Citation span | 2025 - 2025 (1) |
| Citation velocity | recent |
| Highly cited | No |
| Citation types | Neutral: 1 |