A methods comparison used selected toothpastes and facial scrubs labeled as containing polyethylene to compare counts and size distributions across analytical approaches.
Source details
Kofi O. Renner, Helen A. Foster, Edwin J. Routledge, Mark D. Scrimshaw. Environmental Toxicology and Chemistry. 2022.
Findings
A methods comparison used selected toothpastes and facial scrubs labeled as containing polyethylene to compare counts and size distributions across analytical approaches.
Scroll horizontally for methods and limitations.
| Endpoint | Source-reported result | Locator |
|---|---|---|
| Selected PE-containing facial scrub FS2 | 24.9 × 10⁶ particles per 100 g | PDF p. 5 Table 2; pp. 3-4 methods |
| Facial scrub FS2 | 20 to 423 µm | PDF p. 5 Table 2; p. 3 methods |
Methods and scope
Warm-water dispersion, salt density separation, centrifugation and aliquot counting. Light microscopy, laser diffraction and imaging flow cytometry measured different size features/windows. Ten randomly selected fragments per product subjected to µFTIR, confirming PE. Complete extraction blanks analyzed; no particles seen by microscopy/laser diffraction, but imaging flow cytometry blanks high enough to prevent quantification of most products. No reference-material recovery validation; aim was comparison of counting methods.
What this source can support
Supports product-code-specific light-microscopy numbers and method-dependent size distributions. It does not support treating all flow-cytometry events as plastic.
Four deliberately PE-containing products; not prevalence or current-market survey. Chemical identity checked on subsample, not every counted object. Counts extrapolated from aliquots. Table 2 TP2 differs from narrative and flow-cytometry FS2 differs between Table 4 and narrative; accepted Table 2 facial-scrub value only. Primary volume year 2022 despite online publication/filename 2021. No dermal uptake or clinical outcomes measured.
Related evidence
Reported values and source locations
| Reported value | Measurement basis | Conditions and size context | Original document location |
|---|---|---|---|
| 24.9 × 10⁶ particles per 100 g | Table point estimate; microscopy triplicate workflow | Facial scrub FS2 after extraction; light-microscopy enumeration, no observed microscopy blank particles 20-423 µm observed FS2 light-microscopy range | PDF p. 5 Table 2; pp. 3-4 methods |
| 20 to 423 µm | Observed range, not instrument operating range | FS2 light-microscopy size analysis, longest dimension Observed microscopy range | PDF p. 5 Table 2; p. 3 methods |
Source provenance
Primary PDF SHA-256: e13c6d65105256aeab722823f38bc1c3206007f2e3b87bc573ce5c275dd672da
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