How toxic is nail polish? its ingredient is harmful to reproductive health, but it has been ignored by us.

.

How much "poison" does it take to get a manicure?

In the new study, led by Canadian scholars, 45 manicurists in Toronto, Canada, were observed, and the researchers placed three kinds of air sampling devices on their shoulders, chest and wrists: an active sampler with an air pump, placed on the manicurist's left shoulder, and two passive samplers made into badges and wristbands, with badges on the right and wristbands on their habitual hands. Within an average of eight hours of sampling time, air samples from the main breathing areas of the manicurists at work and the forefront of exposure to manicure products-the hand area-were brought into the laboratory to be tested by scientists, targeting plasticizers such as phthalates (phthalates) and organophosphates (organophosphate esters) that manicurists may be exposed to. In recent years, more and more evidence shows that they are endocrine disruptors, which will affect human reproductive health and fetal neural development.

The researchers found that 12 phthalates and organophosphates were detected by active samplers on the manicurists' shoulders, 16 in badges and 19 in wristbands. In active sampling, diethyl phthalate (DEP) and diisobutyl phthalate (DiBP) with the highest content were 1.6-2 times higher than those in Canada, while TCEP and TCIPP, the two organophosphates with the highest content, were 28 times higher than those in the United States. The wristband test results are more noteworthy: except for several phthalates, the contents of TPhP, TCIPP and TDCIPP with the highest levels of organophosphate esters are 3 to 15 times higher than those of e-waste disposal workers in South Asia and North America and 20 to 60 times higher than that of household exposure in the United States.

DEP, DiBP and TPhP are all nail polish plasticizers that make nail polish more malleable and less prone to cracking-which explains why manicurists expose more DEP and DiBP than office environments, and even more TPhP than e-waste disposal workers. However, these two kinds of organophosphate esters, TCEP and TCIPP, are not additives in nail polish and other care products. They are more often used as flame retardants to add building materials, polyester foam sound insulation, sofas and bedding. The researchers believe that the TCEP and TCIPP that manicurists are exposed to are likely to come from styrofoam sofas, handrails, slippers and manicure tools (such as toe splitters and nail polishing tools) in nail salons.

In Europe and the United States, the content of phthalate plasticizer in children's products, cosmetics and electronic products is limited to 0.1%. Flame retardants TDCIPP and TCEP have been classified as carcinogens by California Act 65, and both together with TCIPP have been recognized by the Canadian government as harmful to human health. However, how much exposure will cause health damage in the process of manicure, the academic circle has not given a unified answer, and there is a lack of targeted supervision in the industry, and this kind of substance will continue to be active at people's fingertips.

"non-toxic" nail polish is not 100% safe

Since 2006, U.S. manufacturers have actively kicked three harmful compounds, formaldehyde, a primary carcinogen, toluene, an organic solvent with developmental and neurotoxicity, and dibutyl phthalate (DnBP), a plasticizer with proven reproductive and developmental toxicity, out of the nail polish list and labeled new formulations with a "3-free" label. Since then, there has been a trend of "free" implying that nail polish is "more harmless" in European and American markets, and there are more and more types of nail polish "5-free" and even "10-free". But they may not be as safe as they think, and the problem lies with plasticizers.

In 2018, a team of American scholars selected 40 "n-free"-labeled nail polishes sold locally from 12 brands to see if the "non-toxic" nail polishes were really non-toxic. The results were mixed: toxic DnBP did disappear from all 40 samples, but some manufacturers chose to use TPhP as a substitute for DnBP with "non-toxic" nail polish. In the survey, more than 60% of nail polishes were detected with TPhP, of which 13 nail polishes were marked with the presence of the substance in the composition table, and 12 nail polishes without TPhP were actually detected with TPhP, all with "5-free" or higher "non-toxic labels".

TPhP is a harmful endocrine disruptor which has been proved to be harmful in recent years. It has adverse effects on human thyroid function and reproductive health. A 2015 study found that levels of DPHP, a metabolite of TPhP in human urine, increased nearly sevenfold 10 to 14 hours after applying nail polish. The increase of DPHP level in urine has been proved to be closely related to the decrease of in vitro fertilization ability of female oocytes and the deterioration of male sperm quality, accompanied by changes in thyroid function.

In addition, many studies have observed gender differences in TPhP exposure: the level of DPHP in urine of women is generally higher than that of men. A study of organophosphate esters in the American home environment found that urine DPHP levels in women are about twice as high as those in men. Considering that TPhP is also a flame retardant widely found in living environments, and this macromolecule tends to combine with environmental dust, manicures may be one of the reasons for women's higher exposure.

How big is the health risk?

However, whether there is a safe dose of nail polish plasticizers and what standards we should use to regulate their use in cosmetics and personal care products need more research and exploration. In the pursuit of beauty, it is always right to be careful.