Batteries, washing soda and dental floss
New Zealanders use thousands of disposable batteries every year. What should we do with them when they go flat? Plus: How microwaves work
I believe microwaves are bad for your health and food, but can you tell me exactly how they work?
Nuking something in a microwave oven doesn’t really involve radioactivity. ‘Microwaves’ are electromagnetic waves, part of the same electromagnetic spectrum used by radars, satellite communications and mobile phones (they all operate at different frequencies—microwaves at 2.5 gigahertz—so they don’t interfere with each other).
Microwaves are everywhere, says microwave expert Mirjana Bogosanovic. “If you don’t believe me, check your mobile phone: what is called ‘coverage’ means that microwaves are launched in the space all around us. The same applies to GPS or wireless networks at home and at work.”
When high-power microwaves pass through food and drink, they make the water and fat molecules vibrate and rotate. These spinning molecules rub up against each other, generating heat through friction and cooking the food. Conventional ovens actually cook food in a similar way, using infrared radiation to get food molecules rubbing up against each other. Microwave ovens cook food more quickly and at a lower temperature because the microwaves penetrate deeply into food, heating it all at once instead of from the outside in.
Are microwaves dangerous? Mirjana says the only serious risk is the same as a conventional oven: being burned—but since microwaves can’t penetrate metal, microwaves ovens are safe as long as they have undamaged doors and seals.
Another danger is accidentally overheating food: microwaved containers can seem cool to the touch even though the food within is extremely hot. Heating babies’ bottles in microwave ovens isn’t recommended for this reason.
It’s also not a good idea to heat food in containers not labelled microwave-safe, since plasticisers (see good.net.nz/bpa) can leach into the food.
But microwaving food has some benefits, too. It reduces the risk of fire (remember those ‘don’t drink and fry’ TV ads? It’s okay to microwave drunk!) and it eliminates the carcinogens caused by charring meat. Any cooking will destroy some of the nutrients in food, but the less water you use and the lower the temperature you cook at, the more nutrients your food will retain—no matter how you cook it.
I extend my laundry detergent by adding washing soda crystals to the wash. Is there a brand of washing crystals you recommend?
‘Washing soda’ and ‘soda crystals’ are common names for sodium carbonate, a non-toxic salt that can be used to make bleach- and enzyme-free cleaners. Washing soda is biodegradable. It acts as a water s oftener and is safe to use on clothes, in the dishwasher and elsewhere around the house. It can remove tea stains from china, stubborn stains from clothes and act as a descaling agent for your coffee machine. It can also be added to other cleaners to make them go further.
Put half a cup in your washing machine and it will clean the machine as well as your clothes. Tip a cupful into your toilet to clean it, or dissolve a handful of crystals in warm water and add some eco-detergent to clean concrete paths and driveways. The most cost-effective way to buy washing soda is in bulk at Bin Inn stores nationwide (www.bininn.co.nz) for around 29 cents per 100 grams ($2.90 per kilo).
Why don’t we recycle AA batteries? If this is done, then where?
Batteries make power portable, by converting chemical energy into electricity—and there’s no denying how handy that is. Problem is, batteries contain toxic heavy metals such as mercury, lead and cadmium that, if dumped, can pollute soil and groundwater, endangering humans and wildlife. Cadmium is a known human carcinogen; long-term exposure can cause liver and lung disease. Mercury can also cause damage to the brain, spinal system, kidneys and liver. Sulphuric acid in lead acid batteries can cause severe skin burns. Batteries are so toxic, it’s incredible we’re allowed to simply biff them when we’re done.
You can’t recycle AA batteries in New Zealand, but there are better things to do with them than throw them in a landfill. Aucklanders can dispose of household batteries using the mobile collection service HazMobile. It sets up shop in various public car parks around Auckland about 15 times a year.
Rechargeable batteries, such as nickel cadmium, lithium-ion and nickel-metal batteries, can be recycled. Christchurch City Council has an online recycling directory for finding recyclers for various types of batteries (www.targetsustainability.co.nz). Contact your local authority for details on local battery collectors and recyclers, or check the RONZ National Recycling Directory at www.ronz.org.nz. Vodafone and Telecom stores accept old mobile phone batteries for recycling, and Sony stores can accept all types of batteries used in its products.
For a list of local battery collectors we’ve come across, go to good.net.nz/batteries.
Is there an eco-friendly alternative to standard plastic dental floss?
Flossing is the best way to get at the plaque, stains and annoying bits of food that get stuck in the gaps between your teeth. And as my dentist is always reminding me, flossing is the also best way to prevent between-the-teeth decay and gum disease. The only problem is what to do with umpteen unrecyclable plastic floss containers (approximately 700 million a year, worldwide), the wasteful secondary packaging and the floss itself—usually made from a non-biodegradable substance such as nylon or Teflon.
One alternative is GentleFloss by Eco-dent. It’s not perfect: made in the US, the floss itself is not biodegradable, but at least the cardboard and soy ink packaging is, and the floss is vegan-friendly, as it’s made without beeswax or mineral wax. To order, contact Piko Wholefoods, Christchurch (ph 03 366-8116).
Alternatively, if you’re feeling experimental, you could try washed linen thread—or for a totally local and renewable option, said to have an antibacterial effect, try thin strips of freshly scraped flax.
