If you've ever dissected a disposable diaper -- or been unlucky enough to have one break apart on you -- you'll have noticed that the modern disposable variety is filled with squishy white crystals. Sometimes you'll find these bead-like particles stuck to the surface of your baby's skin, too. Such a discovery can make a parent worry about the safety of such space-age material. Plenty of parents have opted for cloth diapers or gel-fee disposables just in case. But in general, this absorbent gel is considered nontoxic and free from any major safety risks.
Those little gel beads are made from super-absorbent polymers, or SAPs. Specifically, most disposable diapers on the market today use a chemical compound known as sodium polyacrylate, which is used frequently in gardening, too, to help soil retain water. It also can be found in loose-powder form at hardware stores, in cosmetics and even toys.
Sodium polyacrylate can absorb several hundred-times its own weight in water. It starts out as a powder and as it comes into contact with moisture, it swells into its gel form. Unlike other absorbent materials, you cannot squeeze the moisture out of this gel. This is what makes it perfect for use in diapers -- your child can sit on it, roll around, sleep for hours in a wet diaper and there will still be no leaks.
Sodium polyacrylate is considered a safe and nontoxic product. The powder form poses an inhalation danger and can also irritate the eyes, but that's not generally a concern when it comes to diapers. A few contact allergies have been reported, where the gel or powder causes a rash on the skin. Author and pediatrician Carla Natterson writes in her book, "Worry Proof," that the crystals you see on your baby's skin after a diaper change may not be sodium polyacrylate at all, but dehydrated urine residue. It's also true that sodium polyacrylate is so effective at moisture absorption that it can over dry the skin and cause irritation -- in other words, it may contribute to diaper rash. Finally, there is some question as to the safety of sodium polyacrylate when ingested. While classified as nontoxic by ingestion, it may cause organ damage as well as digestive irritation if swallowed.
It turns out that the biggest concern about SAPs in general, and sodium polyacrylate in particular, is not toxicity, but their environmental friendliness. Sodium polyacrylate is a petroleum product, meaning it's made using non-renewable resources and it does not break down readily in landfills. Thus, it's not a particularly eco-friendly or sustainable product. Cloth diapers or even disposables using cellulose materials for absorbency may be better choices in this regard.
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