NANOSILVER – no silver lining to this pollution
Silver has always had a special place with royalty, the common man and even in medicine. In fact it is one of the first five metals to be discovered and used by humans. Virtually indestructible at the molecular level with antibacterial properties long known to man. Ancient civilisations stored food and water in silver containers to prevent spoilage.
SO WHAT IS NANOSILVER?
When you bundle minuscule little particles and put them in places they’ve never been able to get before; measuring approximately one billionth of a meter – a human hair is 100,000 nanometers wide!
Nanosilver is not a new discovery – it has been used in various products for over a hundred years. Known as colloidal silver, where silver particles down to the nano scale were suspended in liquid and used for health and medical reasons since early 20th century. Currently, silver impregnated zeolite and silver nano particles are effectively and extensively being used as antimicrobials because they release silver ions, which are lethal to target organisms. As silver reacts with oxygen – oxidises – it releases ions – charged atomic particles – that kill bacteria and yeasts.
BORN FROM EXPLODING STARS AND NOW A PART OF ALMOST EVERYTHING!
These antibiotic particles are showing up all over.
Silver ion coatings are increasingly used in hardware, switches, window treatments, cubicle curtains and textiles to provide antimicrobial properties. Silver nanoparticles are in upholstery fabrics, hardware, touchable surfaces, ceramic tiles, countertops, adhesives, sealants, paints, carpets, textiles. Silver zeolites are in paints, carpet fibres, wallpaper. adhesives, fabrics and textiles.
Nanosilver has appeared in electric shavers, athletic clothing, bed and bath linens, cosmetics, baby bottles, stuffed animals, keyboards, paints, food containers … in hospital equipment – catheters, stents, bandages, wound dressing, surfaces of wheelchair seats, door handles…
A TROJAN HORSE?..
Nanosilver is an effective antimicrobial, just like engineered nano materials that provide great benefits. However we know very little about the potential effects on human health and the environment. Nano-sized particles can enter the human body through inhalation, ingestion and through the skin. In fact paints, countertops, fabrics, furniture, hardware – virtually any product considered an interior finish – may contain antimicrobial additives. These agents are considered pesticides.. will talk more on these nano materials in another post. Nanosilver too is considered toxic, to the aquatic ecosystems, persistent in the environment and hazardous to organ systems. These silver particles leach – wash down the drain and enter the water treatment facilities. Waste water sludge is sometimes spread as crop fertiliser or used in landscaping, where they enter the surrounding ecosystem.
A LOT OF THE LITTLE
The expansion of nanosilver in new applications may contribute to unique risks. The other side effect is that widespread use of nanosilver will contribute to silver resistance in bacteria – just like it happened with common antibiotics like penicillin, tetracycline, triclosan. Nanosilver can promote not just silver resistance but also antibiotic resistance. Also, nanosilver has different effects than silver. The minute sized nanoparticles have different properties than larger particles of the same material. They have greater surface area, so are more reactive than the bulk material and produce more silver ions than solid silver. These silver ions are toxic to bacteria.
HOW MUCH IS TOO MUCH
Who would have thought we’d consider washing our clothes with nanoparticles of the metal we once wore as prized jewellery? Whether in laundry detergents or in paints, it has become a material of innovation and is now appearing in a number of unexpected places and products. There are hundreds of products in circulation that contain silver nanoparticles. Every year almost 320 tonnes of nanosilver are used worldwide – some released into waste water – find their way into natural water circulation systems. More than 90% remains bound in the sewage sludge as silver sulphide – which is extremely insoluble.
Is it wise to dispatch such a powerful weapon against bacteria in everyday contents where bacteria pose a relatively minor concern? It’s one thing if we are using a little bit of nanosilver in the shoes of a diabetic, it’s another thing if we’re putting it in all athletic clothing, every bed, every countertop, every coating or finish… This will lead to exponential increase in the amount of nanosilver into the environment. Nanosilver should be used cautiously and not in a hysterical and frivolous way..
“Silver is a big line of defence against microbes. We don’t want to waste it on socks.” – Andrew Maynard, environmental health scientist at University of Michigan, Ann Arbor.
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