In vitro metal leaching from tampons under simulated vaginal and menstrual pH conditions.

BACKGROUND

Approximately 100 million people worldwide use tampons to manage their menstruation. Tampons have been shown to contain toxic metals, which may contribute to cumulative exposure risk. It is unclear whether metals leach from tampons or how changes in vaginal pH during menstruation affect leaching.

OBJECTIVE

To quantify in vitro metal leaching from tampons under physiologically relevant conditions.

METHODS

We assessed metal leaching from 22 tampon products by saturating them in simulated vaginal (pH 4.2) and menstrual fluids (pH 7.4) for 8 hours at 37°C on a shaker. Extracted supernatants were analyzed for 15 metals by inductively coupled plasma triple quadrupole mass spectrometry. Metal leaching was compared across 13 brands and tampon characteristics: organic composition and absorbency. The leaching fraction-percentage of total metal content leached-was calculated using data reported by Shearston et al.

RESULTS

We found measurable amounts of 14 metals in leachates from vaginal fluid and 12 metals in menstrual fluid, including lead, arsenic, and cadmium. Most metals leached in greater amounts in vaginal fluid compared to menstrual fluid, such as lead (mean: 40.3 ng, 95% confidence interval around mean value: [6.94, 73.7] vs 15.6 ng, [6.91, 24.3]). The highest average leaching fraction in vaginal fluid was copper (233%, [95% CI: -87% to 553%]), and in menstrual fluid, nickel (53%, 95% CI: 38%-79%]). Metal leaching varied by tampon characteristics.

DISCUSSION: Under simulated physiological conditions, we found that tampons leach metals in both vaginal fluid and menstrual fluid. Since in vitro metal release does not equate to vaginal absorption or systemic exposure, further investigations are required to inform the risk of metal exposure from tampon use.