Overview
Ma et al. measured eight metals in 56 sanitary-napkin samples collected from China, Japan, South Korea, the United States, the United Kingdom, Australia, and Germany. The study reports country-level median concentrations and ranges in μg/kg for arsenic (As), Co, Cu, lead (Pb), cadmium (Cd), Zn, nickel (Ni), and chromium (Cr). Arsenic and chromium were not speciated, so this page records arsenic as total arsenic and chromium as total chromium.
Key numbers
Table 1 reports median and range values in μg/kg for composite sanitary-napkin samples on the product-as-sold mass basis. The paper reports detection frequencies across the eight metals from 30.4% to 100%; Zn was detected in 94.6% of samples and Cr in 100% of samples.
| Country | tAs | Co | Cu | Pb | Cd | Zn | Ni | Cr |
|---|---|---|---|---|---|---|---|---|
| China (n=20) | 53.1 (<2.00-137) | 50.4 (<0.20-308) | 224 (36.6-1194) | <4.00 (<4.00-3674) | 4.89 (<0.20-15.5) | 6195 (936-99,420) | 5457 (<2.00-12,810) | 10,782 (7032-32,118) |
| Japan (n=6) | 3.33 (<2.00-69.0) | 32.2 (<0.20-370) | 41.1 (3.95-165) | <4.00 (<4.00-1407) | 0.56 (<0.20-15.7) | 4653 (13.5-11,754) | 45.9 (<2.00-881) | 28,863 (16,422-31,638) |
| South Korea (n=6) | <2.00 (<2.00) | <0.20 (<0.20-244) | 0.50 (<0.40-4.76) | <4.00 (<4.00) | <0.20 (<0.20-27.1) | 3300 (<8.10-8526) | <2.00 (<2.00-878) | 26,511 (24,612-29,580) |
| United States (n=6) | <2.00 (<2.00) | <0.20 (<0.20-8.08) | <0.40 (<0.40-38.4) | 924 (<4.00-3025) | 8.15 (<0.20-36.5) | 2355 (<8.10-4206) | <2.00 (<2.00) | 6202 (2580-18,462) |
| United Kingdom (n=6) | <2.00 (<2.00) | 1.51 (<0.20-25.4) | 27.6 (<0.40-466) | <4.00 (<4.00-4298) | 3.13 (<0.20-31.4) | 8082 (<8.10-140,580) | <2.00 (<2.00) | 2795 (1315-16,830) |
| Australia (n=6) | <2.00 (<2.00-7.23) | <0.20 (<0.20-50.8) | 53.2 (<0.40-143) | <4.00 (<4.00) | 2.14 (<0.20-17.1) | 5025 (216-7686) | <2.00 (<2.00) | 27,681 (19,488-37,512) |
| Germany (n=6) | <2.00 (<2.00) | 36.5 (<0.20-345) | <0.40 (<0.40-99.3) | <4.00 (<4.00-212) | <0.20 (<0.20-5.93) | 5829 (3660-13,620) | <2.00 (<2.00-617) | 23,409 (16,716-38,754) |
The source states that As, Co, Cu, Ni, and Cr differed significantly across countries (all p < 0.05). It reports the highest median As, Co, Cu, and Ni values in China, the highest median Cr in Japan, the highest median Pb and Cd in the United States, and the highest median Zn in the United Kingdom.
For product-type comparisons, the paper reports no significant difference by pad thickness, significantly higher As, Ni, and Co in scented products than unscented products, and significantly higher Cu, Ni, As, and Co in low-priced products than high-priced products (p = 0.003, p = 0.004, p = 0.016, and p = 0.034, respectively). Cr was significantly higher in high-priced products (p = 0.047), with median Cr 24,840 μg/kg in high-priced samples and 11,658 μg/kg in low-priced samples.
Table 4’s “This study” row reports seven-country skin-contact daily exposure dose estimates in mg/kg-bw/d: As 5.52E-08, Co 1.40E-07, Cu 1.48E-06, Pb 1.10E-07, Cd 1.18E-07, Zn 1.57E-04, Ni 5.52E-08, and Cr 5.62E-04. The paper’s hazard-index calculation excludes As and Cr because dermal reference doses were not available; for the six included metals, HI ranged from 5.20 × 10-4 to 5.83 × 10-1, with median 3.50 × 10-2. The paper estimated carcinogenic risk only for Pb, reporting 5.36 × 10-10 to 6.92 × 10-7, with median 5.36 × 10-10.
Methods (brief)
The study selected representative sanitary-napkin products after questionnaire work in seven countries, then purchased three packs per selected type. Ten pieces were randomly selected from the packs, cut into 1.0 cm by 1.0 cm fragments, and composited from surface and middle layers; each composite sample had two parallel subsamples. Approximately 0.5 g of composite sample was digested with HNO3, H2O2, and HClO4 and analyzed by ICP-MS. Matrix-spike recoveries for As, Co, Cu, Pb, Cd, Zn, Ni, and Cr were 90.8%, 70.1%, 106%, 79.9%, 89.7%, 75.6%, 103%, and 97.6%, respectively, and LOQs were 0.20-8.10 μg/kg.
Implications
Microbiome: Not applicable.
Related evidence
- Menstrual pads (disposable, panty liners, intralabial pads, reusable menstrual pads)
- Arsenic, Total
- Lead
- Cadmium
- Chromium
- Nickel
- Cobalt
- Copper
- Zinc
Update history
The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git.
| Commit | Date | Change | Description |
|---|---|---|---|
| b01ec52c31 | 2026-08-04 | major | 1 section added |
| 3171d069e3 | 2026-08-02 | major | 1 section added |
| 90a2f9a38e | 2026-07-30 | major | 1 section added and 1 removed; narrative text revised |
| eaa8eeeedf | 2026-07-27 | major | 1 section added |
| 50de6ab217 | 2026-07-27 | minor | Narrative text revised |