A new airtight sampling method for sulfur hexafluoride (SF6) in groundwater
In the past 20 years, sulfur hexafluoride (SF6) has been considered a highly reliable tracer for assessing modern water (< 65 yrs old) in groundwater. However, modern-air contamination may introduce complications in interpreting data obtained using current sampling methods. A new airtight methodo...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-06-01
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| Series: | MethodsX |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2215016124005715 |
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| Summary: | In the past 20 years, sulfur hexafluoride (SF6) has been considered a highly reliable tracer for assessing modern water (< 65 yrs old) in groundwater. However, modern-air contamination may introduce complications in interpreting data obtained using current sampling methods. A new airtight methodology isolates the sample from modern ambient air; thus, returning more reproducible and reliable results when compared to two traditional (air-sensitive and non-airtight) methods. The new airtight method returned results within 0.03–0.05 fmol/L SF6 of expected SF6 concentration for pre-modern waters (0.02–0.09±0.01 fmol/L). In contrast, the air-sensitive and non-airtight traditional methods returned results within 0.00–0.90 fmol/L and 0.02–1.21 fmol/L of the expected value, respectively. It is suspected that transformers in proximity to wells leak SF6 which subsequently partitions into the samples obtained using traditional air-sensitive and non-airtight methods, thus creating erratic SF6 results. • Comparative analyses of a new airtight method with traditional methods were performed and returned lower SF6 concentrations with the new 2022 airtight method. • The new airtight method shows reproducible low-level detection of SF6 concentrations and may reduce sampling error in production wells in urban areas that are co-located with transformers which are SF6-emitting sources. |
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| ISSN: | 2215-0161 |