Silicon dioxide is the main component of beach sand and is commonly known as quartz in its pure crystalline form. For industrial purposes the amorphous (non-crystalline form) silicon dioxide or silica is of greater importance. Amorphous silica can be found in a range of products including varnishes, glues and paints. It is also used in foods and in dietary supplements sold in drug stores and pharmacies.

healing earth © dima pics / Fotolia.comHow can I come into contact with this material?

Dietary uptake of small amounts of silicon is important for the human body as silicon is one of the ultra-trace elements. Amorphous silicon dioxide is also being used as a food additive (labelled E551) or as a component in medicinal clay whereby it could enter the human body via the gastro-intestinal tract. Dermal uptake of silicon dioxide particles derived from contact with paints, inks or adhesives is highly unlikely. Quartz, the crystalline form of silicon dioxide, can be inhaled as fine dust that is released from underground mining activities when digging for ore, coal and other minerals. Since the overall amount of silica in the environment is very high it is difficult to distinguish between naturally occurring silica and industrially generated silicon dioxide.

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

Nanoscaled silicon dioxide occurs almost exclusively in its unstructured amorphous form which so far hasn't shown any negative characteristics in all performed experiments from animal to environmental studies. Silicon is an essential ultra-trace element for the human body and silicon dioxide in its amorphous form is considered to be non-hazardous. On the other hand the crystalline version of silicon dioxide is known to be harmful to humans: those who are permanently exposed to quartz dust, e.g. at their work place below ground, carry a high risk for chronic lung diseases (e.g. silicosis) and other pathological changes in the lung.

Conclusion

Humans come into contact with silicon dioxide particles on a daily basis: at the beach, in food products, like paints, glues and many more and this also includes silicon dioxide nanoparticles. The amorphous form of silicon dioxide is considered to be non-hazardous whereas the crystalline form has been shown to cause severe lung toxicity both in animals and humans.

By the way...

• Silicon dioxide is a constituent of many food supplements.
• Some plants and animals store silica internally in order to make themselves harder.
• Without silicon, there would be no computer chips or solar panels on the roof.