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Heavy Metal Index

Development of a generic safety assessment strategy for feminine intimate products

Overview

Marcelis’s PhD thesis develops a safety-assessment workflow for feminine intimate products, combining extractables/leachables testing, menstrual/vaginal fluid simulants, fragrance-allergen QRA, and in vitro mixture testing. Chapter 2 contains the same chemical-characterization program later published as Marcelis et al. 2025, so its metal leachables should be treated as overlapping provenance rather than an independent occurrence replicate. The thesis is C-tier thesis evidence; the later peer-reviewed Environment International article remains the preferred primary occurrence anchor for the Chapter 2 metal table.

Key numbers

The thesis market survey purchased 64 feminine intimate products: tampons (n=9), sanitary napkins (n=6), adult novelties (n=15), menstrual cups (n=15), Kegel-exercise devices (n=14), and menstrual sea sponges (n=5). Product origin/source criteria included EU, US, and Asia; the thesis discussion later describes the sample as including the European Union, United States, and China.

Chapter 2 reports an inorganic leachables pilot using 5 samples from each of four product categories: adult novelties, Kegel-exercise devices, menstrual sea sponges, and menstrual cups. Tampons and sanitary napkins are part of the broader 64-product chemical-characterization study, but they are not quantified in Table 2-10’s inorganic leachables grid. Table 2-10 expresses leachate values in ng/mL.

Category-level maxima from Table 2-10 were:

Product categoryAlCrNitAsCdSbPbSntHg
Menstrual sea sponges1661.8 ng/mL28.9 ng/mL1850.2 ng/mL28.6 ng/mL1.0 ng/mL0.3 ng/mL3.8 ng/mL11.4 ng/mL0.6 ng/mL
Adult novelties< LOQ< LOQ< LOQ0.1 ng/mL0.8 ng/mL< LOQ17.7 ng/mL2159.1 ng/mL< LOQ
Menstrual cups338.7 ng/mL3.2 ng/mL< LOQ< LOQ0.7 ng/mL0.3 ng/mL32.9 ng/mL238.6 ng/mL< LOQ
Kegel-exercise devices504.7 ng/mL1.0 ng/mL< LOQ< LOQ< LOQ< LOQ1.5 ng/mL0.4 ng/mL< LOQ

For menstrual sea sponges, Table 2-10 also reports maximum Li 2.6 ng/mL, Mn 117.2 ng/mL, Fe 4930 ng/mL, Co 28.0 ng/mL, Cu 22.4 ng/mL, Zn 95.9 ng/mL, Se 7.1 ng/mL, and Ba 9.8 ng/mL. Adult novelties had maximum Li 15.1 ng/mL, Mn 1.1 ng/mL, Cu 1.9 ng/mL, Zn 122.7 ng/mL, and Ba 3.2 ng/mL. Menstrual cups had maximum Mn 1.1 ng/mL, Co 3.5 ng/mL, Cu 6.1 ng/mL, and Ba 14.9 ng/mL; Kegel-exercise devices had maximum Ba 2.4 ng/mL.

The thesis narrative highlights menstrual sea sponges as having the highest metal(loid) leaching among the tested product categories. It reports maximal sea-sponge values for aluminum 1661.8 ng/mL, chromium 28.9 ng/mL, manganese 117.2 ng/mL, iron 4930 ng/mL, cobalt 28 ng/mL, nickel 1850.2 ng/mL, copper 22.4 ng/mL, arsenic 28.6 ng/mL, selenium 7.1 ng/mL, cadmium 1ng/mL, antimony 0.3ng/mL, and mercury 0.6ng/mL; the source’s spacing around 1ng/mL and 0.3ng/mL is preserved in this note.

Table 2-9 reports 19 organic chemicals leaching from the 64 products under simulated-use conditions. Maximum organic leachable values included heliotropine 1.79 µg/mL, triethyl citrate 18 µg/mL, di-n-octyl phthalate 100 ng/mL, diethyl phthalate 70 ng/mL, bis(2-ethylhexyl) phthalate 25 ng/mL, dibutyl phthalate 22 ng/mL, cyclohexanone 0.23 µg/mL, benzophenone 0.19 µg/mL, and menthyl salicylate 0.90 µg/mL. Benzyl butyl phthalate had positive tampon, sanitary-pad, and panty-liner samples, but the maximum is reported as < LLOQ.

Chapter 3 uses the Chapter 2 leachables data for a fragrance-allergen QRA in 8 scented menstrual hygiene products from the Belgian market: 5 tampons, 2 sanitary pads, and 1 panty liner. The thesis states that the detected fragrance substances were not disclosed on product labels. Table 3-6 reports consumer exposure levels in µg/cm²/day for an exposure scenario of 6 products per day, each used for 4 hours; the highest reported CEL was heliotropine in tampon T5 at 5.25 µg/cm²/day. Table 3-7 reports AEL/CEL ratios from 0.94 for heliotropine in tampon T5 to 7637.48 for geraniol in panty liner TS1.

Methods (brief)

The thesis adapts ISO 10993 extractables/leachables concepts for feminine intimate products. Exaggerated extractables testing used cut product pieces, headspace GC-MS, GC-MS, and LC-HRMS. Simulated-use leachables testing used menstrual fluid simulant (MFS) and vaginal fluid simulant (VFS) at 37°C; menstrual cups used 25 mL MFS, while adult novelties and Kegel-exercise devices leached into 50 mL VFS. The inorganic pilot measured Li, aluminum (Al), chromium (Cr), Mn, Fe, Co, nickel (Ni), Cu, Zn, arsenic (As) (O2), Se, cadmium (Cd), Sb, Ba, lead (Pb), tin (Sn), and mercury (Hg) by ICP-MS with H2 reaction gas, a 0.005-10 ppb calibration range, NIST1568b certified reference material, procedural blanks, reagent blanks, and drift checks every 20 samples.

Implications

Microbiome: The thesis discusses the vulvovaginal environment and uses menstrual/vaginal fluid simulants, but it does not measure a vaginal microbiome endpoint.

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.

CommitDateChangeDescription
b01ec52c312026-08-04major1 section added
3171d069e32026-08-02major1 section added
90a2f9a38e2026-07-30major1 section added and 1 removed; narrative text revised
eaa8eeeedf2026-07-27major1 section added
50de6ab2172026-07-27minorNarrative text revised