A drinking-water laboratory method for counting particles and identifying subsampled materials by infrared spectroscopy.
Source details
California State Water Resources Control Board and SCCWRP. Official document. 2022.
Findings
The procedure separates particle counting from chemical identification and requires blank controls and demonstrated laboratory performance.
The method states a lowest reliably detected particle size of 50 µm. That is a method-scope value, not a safe exposure threshold.
Methods and scope
Revised May 27, 2022. PDF pp. 2–3 §§1–2: treated drinking water, microscopic counting plus IR identification, size-fraction processing, contamination controls and laboratory-specific reporting limits.
What this source can support
An official analytical procedure within its treated-water scope.
Not a particle health threshold, packaging-release test, or assay for all nanoplastics. Spectroscopy on representative subsamples yields estimated confirmed counts.
Related evidence
Plastic food storage · Baby wipes · Infant feeding bottles · Tea bags · Bottled water · Tap water · Cutting boards · Cosmetics and personal care · Household dust and air · Textiles · How microplastics are measured · Regulatory and agency context
Reported values and source locations
| Reported value | Measurement basis | Conditions and size context | Original document location |
|---|---|---|---|
| 50 µm | Stated lowest reliably detected particle size in this method | Treated drinking water under the supplied revised May 27, 2022 method Stated lowest reliably detected size 50 µm; method upper size 5000 µm | PDF p. 2 §§1.1 and 1.3 |
Source provenance
Primary PDF SHA-256: 2f979a7f686b3f13f0775dcfb07e5dee3a6078ef14704c00c1db27393e64309f
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