Mercury in mascara

Is there mercury in your mascara?

16 days ago, the United Nations’ Minamata Convention for Mercury was signed by about 140 countries. Among other measures to reduce the use of mercury, this global treaty specifies that the production and import of some products containing mercury will be banned.

As reported by Scientific American, 

‘Under a new global treaty that limits the use of mercury, some light bulbs will be banned. Some batteries, thermometers and medical devices will be banned too. But mascara is exempt.’

The reason is then explained:

‘But mascara and other eye makeup is exempt because “no effective safe substitute alternatives are available” and “the intention is not to cover cosmetics, soaps or creams with trace contaminants,” the treaty says.’

Not surprisingly, this news has sparked quite an outrage. What? Do you mean we have been applying mercury around our eyes? How can this continue to be allowed?!

So… Why does mascara contain mercury?

Some mascara products (as well as other products such as eyedrops & vaccines) may contain mercury in the form of thiomersal, which is used as a preservative. Thiomersal is an organomercury compound which contains approximately 50% mercury by weight.

Chemical structure of thiomersal

The US FDA allows mercury in eye cosmetics at a limit of 65 parts per million (which is 0.0065%, in case anyone was wondering).

As a preservative, thiomersal inhibits the growth of bacteria and fungi which can spoil the products and also lead to nasty eye infections.

What harm do mercury compounds cause?

The world became aware of the toxicity of methylmercury in the late 1950s, when the dumping of methylmercury into Minamata Bay, Japan by a local petrochemical and plastics company resulted in widespread consumption of mercury-contaminated fish and shellfish. The consequences were devastating. Methylmercury proved to be a neurotoxin (affecting the nerves and brain) and led to illness, foetal abnormalities and death.

Currently, the US Environmental Protection Agency has set a reference of 0.1 µg/kg/day as a guideline for safe exposure levels to methylmercury.

Much less is known about thiomersal, which is a derivative of ethyl mercury. An animal study by Magos et al. in 1985 directly compared the toxicity of ethyl- versus methylmercury in adult male and female rats. Ethylmercury was concluded to be less neurotoxic than methylmercury. Regardless, due to the lack of data, the FDA considers ethyl- and methyl-mercury to be equivalent in its risk evaluation.

Is it possible to avoid mascara and eye products containing mercury?

According to the article by Scientific American,

‘The FDA does not require ingredients that comprise less than 1 percent of a cosmetic product to be divulged on the label, so a lot more products may have thimerosal and consumers would never know, said Kristin Adams, chief executive officer of Afterglow Cosmetics, a natural and organic cosmetic company.’

This afternoon, I did a quick survey of the ingredient labels of a few mascara products at the drugstore. Some products contained phenoxyethanol and parabens (both are preservatives) as ingredients. Some other products did not specify any preservatives on their labels. Does this mean what I think it means? Clearly, all mascaras SHOULD contain preservatives (to prevent eye infections), but the preservatives are not necessarily listed on the label because their concentrations are very low. Kristin Adams was right.

To put things into perspective,

There are many other possible ways that we could be exposed to mercury. For example, eating contaminated fish (which is the most significant source of ingestion-related mercury exposure), taking some Traditional Chinese Medicine preparations, or even accidentally breaking a lab thermometer. With the signing of the Minamata Convention for Mercury treaty, we can hope to look forward to a reduction of mercury contamination in the environment.

Personally, I don’t put on makeup very often (much to the dissatisfaction of hubby), so I am not fearful for my health right now. However, I do believe (and hope) that the increased awareness among consumers will drive the cosmetic industry to use safer alternatives as preservatives for their products. 

References:
1. http://www.scientificamerican.com/article.cfm?id=in-the-public-eye-mascara-exempt-from-mercury-treaty
2. http://www.fda.gov/BiologicsBloodVaccines/SafetyAvailability/VaccineSafety/UCM096228