Summary
Household tap water after an accidental fire-fighting foam release. Later samples, fixtures and household filters are distinct matrices and sampling times.
Key numbers
Source-reported values checked against the cited page of the filed PDF. Values are reported as printed, without conversion. These are selected records, not an exhaustive transcription.
| analyte | value | unit | basis | source location | limits and qualifiers |
|---|---|---|---|---|---|
| PFOS | 254 | ng/L | one of three high household results at first sampling visit; source lists values in this order, not a household identifier | PDF p4, Results, paragraph beginning Given the concern | Instrument LODs 0.1 to 2.5 ng/mL, PDF p3, are not converted to ng/L water limits. Sample preparation and matrix basis must be considered; no conversion made. |
| PFOS | 153 | ng/L | one of three high household results at first sampling visit; source lists values in this order, not a household identifier | PDF p4, Results, paragraph beginning Given the concern | Instrument LODs 0.1 to 2.5 ng/mL, PDF p3, are not converted to ng/L water limits. Sample preparation and matrix basis must be considered; no conversion made. |
| PFOS | 16.8 | ng/L | one of three high household results at first sampling visit; source lists values in this order, not a household identifier | PDF p4, Results, paragraph beginning Given the concern | Instrument LODs 0.1 to 2.5 ng/mL, PDF p3, are not converted to ng/L water limits. Sample preparation and matrix basis must be considered; no conversion made. |
Evidence Fitness
Source classification: primary_measurement. MANIFEST tier: PRIMARY. This is a selected, bounded transcription, not an exhaustive extraction of every result in the paper. Each selected number has its own PDF page or table locator. Values for different matrices, isomers, statistics and aggregate assays are not interchangeable.
Methods (brief)
UHPLC-MS/MS according to USEPA Draft 2 Method 1633, PDF p3. Target list and detection limits in unstaged Table S1.
Detection limits and censoring: Instrument LODs 0.1 to 2.5 ng/mL, PDF p3, are not converted to ng/L water limits. Sample preparation and matrix basis must be considered; no conversion made.
Limitations
- DETECTION_LIMIT_BASIS: Instrument LOD 0.1 to 2.5 ng/mL. Comparison: Water results use ng/L. Locator: PDF pp3-4. Keep instrument versus water basis distinct; no numeric water LOD conversion.
Provenance notes
Citation metadata verified against PDF p1, title, author byline, journal citation or masthead, and DOI.. Article DOI appears in the supplied PDF and matches the MANIFEST case-insensitively. Original file: 2026_Niu_per-and-polyfluoroalkyl-substances-in-tap.pdf. SHA-256: 0eaaf270429c98bb9795be9f3a31c9a898ad996769e82e1e1ec649af61f7b505. Original MANIFEST remains in the copied packet; discrepancies are listed without modifying it. Commercial analyte synonyms, instrument brands and manufacturer names are generalized in authored index prose.