Zinc oxide is an all-rounder when it comes to technical applications: it is used in rubber production, in cement and paints, in electronics, in medical products and also as catalyst. Zinc is also an essential element indispensable to life of humans, animals and plants.

Skin lotion © Dan Race / Fotolia.comHow can I come into contact with this material?

For a healthy life, a human requires between 12 and 15 mg zinc on a daily basis obtained from the diet. In most cases zinc is taken up in form of zinc oxide coming from natural food sources which then dissolves in the body releasing zinc ions. But even zinc, if absorbed in too high concentrations, can be harmful to the body. A possible exposure scenario is the inhalation of zinc oxide fumes formed during welding activities of zinc sheets which can then lead to lung damage (metal fume fever). Zinc oxide nanoparticles are also used in cosmetic products as a mineral UV-filter. Dermal uptake of dissolved zinc ions can occur but has no potential harmful effect since the skin needs a lot of zinc for its own metabolism anyway. Most of our absorbed zinc comes from natural sources in the food.

Is there any risk from this material to humans and the environment?

Zinc as well as zinc oxide nanoparticles have a positive effect on the human body since zinc is involved in the regulation of many important biological processes. Therefore it is used in zinc ointments and other medical products. But if zinc is applied in high concentrations or in the wrong place (e.g. zinc oxide nanoparticles in the lung) it may have toxics effects causing cell death (zinc fever).

Conclusion

Humans are exposed to zinc oxide on a daily basis originating from various sources like food intake, cosmetics and many other products. Zinc is only harmful for humans in high concentrations as zinc is an essential element and zinc oxide dissolves once inside the body.

By the way...

• Zinc oxide is the 5^th most common element in the earth's crust.
• Zinc is also added to foodstuffs in the form of zinc acetate (E650) to prevent zinc deficiency in humans.