If you don鈥檛 have children, you may well be unaware that slime is a thing. A huge thing, and many kids love to spend hours making slime using a plethora of internet recipes. But concerns have been raised that it can contain potentially toxic levels of chemicals. Should parents be worried about their children playing with it?
A report by consumer group Which? has found that some slimes bought online in the UK contain up to four times the permitted concentration of an element called boron, in the form of sodium borate, or borax. What the report does not say is that home-made slime could well contain even higher levels. The report sparked alarming headlines, but actually the risks are very low.
Polymers such as PVA glue are the main ingredient in slimes. They are molecules made of long chains of repeating units. Mix them with water and you get a liquid. To turn that liquid into slime, you add an 鈥渁ctivator鈥� that makes the chains stick together despite being in water 鈥� and borax is commonly used.
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So is toy slime safe? The states that 鈥淓xposure to excessive levels of boron could cause irritation, diarrhoea, vomiting and cramps in the short term鈥�. While this is true, what the report does not say it is that children are exceedingly unlikely to have excessive levels of boron even after playing with the slime found to have 1400 milligrams of boron per kilogram, way above the European Union safety limit of 300 mg/kg for toys of this kind.
No accumulation
Borax and other boron compounds are regarded as non-toxic at low levels. Adults eat a milligram or two a day because most food contains low levels of boron. Unlike some heavy metals such as lead, boron does not accumulate in the body. You urinate it out within a day.
Much higher levels . The lethal dose for children is unclear, but has been estimated to be 5000 mg per day.
It is repeated exposure to high doses that is dangerous, rather than one-off events, says David Schubert of AvidChem, an expert on borates. 鈥淚f you were to eat a few grams of borax, you would get sick to your stomach and throw up, and that would be the only harm that would come to you.鈥�
A more likely route of exposure is absorption via the skin. However, according to a 1998 study, 鈥� less than the daily dosage from food. There is a caveat, though: 鈥渢he findings of this study do not apply to abraded or otherwise damaged skin.鈥�
This suggests it would be safest not to let kids with cuts, rashes or sores play with slimes unless they wear rubber gloves. This also makes sense because there have also been 鈥� although this may be nothing to do with borax.
Care also needs to be taken if pure borax in powder form is used as an ingredient for slime. Chemist and slime maker 鈥� in a clearly labelled container 鈥� rather than letting children handle it themselves.
She also suggests parents limit slime time, and always make sure children wash their hands thoroughly afterwards.
Read more: Slime听
