Plastic number 6 - polystyrene

Plastic number 6 - polystyrene

Polystyrene is a plastic with a mixed message.  On the one hand, foamed PS is an excellent insulator and is used more and more in buildings to provide savings by reducing heat loss in winter and promoting cooler buildings in summer.  That's terrific, but other uses of foamed PS aren't so green. 

I'm old enough to remember McDonald's bringing in 'clam shell' hamburger containers to replace cardboard boxes because of concerns over how much rainforest was being cut down to make paper and cardboard, only to replace the clam shells some years later over concerns about the amount of non-biodegradable litter they generated.  When so many of the ways we use a plastic are single use then we have a problem. 

Foamed PS is used to make boxes to transport fish and vegetables (because they are light, insulating and melting ice doesn't make them soggy), takeaway food containers and cups, and packaging 'peanuts' and frames (lightweight and protective).  As you unpack your new computer or flat screen you ponder what to do with the waste packaging.  There's no way to recycle it presently, so it ends up in landfill.  And because it is lightweight, polystyrene packaging often ends up blowing into the ocean, where it floats.  PS is particularly resistant to photo-degradation, so it doesn't break down and is toxic to any animal that ingests sufficient quantities.  Large amounts of packaging from fish markets and factories where beads of PS are produced end up polluting the oceans.

A little PS is able to be recycled in the Council waste collection, mainly the foamed trays used to package meat and vegetables, yoghurt tubs and the containers used to package tomatoes and strawberries, but the vast majority of PS ends up in landfill.

Crystal CD cases, disposable cutlery, plastic wine glasses and  are made of PS. In this form, it's quite brittle and so even uses that are a little more long term, such as CD cases, tend to generate a lot of waste.

There are alternatives to many of these uses, from Keep Cups for a take away coffee, to bamboo or wooden cutlery for picnics.  We still see some polystyrene packing peanuts at ZURI, but we usually let our suppliers know that they can get the same benefit from packing peanuts made of corn.  These break down really quickly in the garden and make a good additive to compost. We are pleased to have seen some suppliers make changes in this regard. Because so much of the PS we come into contact with is non-negotiable - try buying a computer without all that foam shock absorber - it's important to think carefully about our use of PS in the areas where we can make a difference.

Plastic number 5 - Polypropylene

Polypropylene, plastic number 5, is one of the lowest hazard plastics around. You are familiar with it in ice-cream containers, drinking straws and the screw top lids of soft drink bottles.  It is also in most homes in the form of Tupperware and in rugs and carpet backings. Most domestic uses of PP are either for long term use, such as in food containers, or for food packaging, which is able to be recycled easily.  For these reasons there isn't a lot of concern about over use or misuse of PP.

Our fabulous Bokashi buckets are made of recycled PP, for example, and if you own one, will use it for many years to come.  But if lid were to split and need replacing, for example, it would be easily recycled with in the Council recycling.  This is really the ideal way to use plastic. Make sure it's for long term, not single use, and then recycle the plastic product when the useful life is over.

One use of PP that isn't so fabulous is the now ubiquitous 'green' shopping bags.   Becasue the PP in these bags looks more like a fabric bag than a plastic bag they are known as 'non-woven'.  Green bags are strong and really useful for grocery shopping.  I'd rather see a green bag than a plastic bag at the supermarket checkout any day.  But if they tear, as they sometimes do, they are just as likely to end up in landfill as a LDPE plastic bag, and they simply don't biodegrade.

There are other concerns with non-woven polypropylene  (NWPP).  Although less energy is used to create NWPP bags than it does to create cotton bags, they take more energy to manufacture than conventional plastic bags.  They need to be used many times for an environmental benefit to start to accrue - about 171 times. Sadly, many are used about half that number.

Some companies claim to be making NWPP bags from recycled material, however with current manufacturing techniques this is not possible and all NWPP bags are made from virgin material.  And although PP is very recyclable, the NWPP used in disposable nappies, surgical gear and shopping bags isn't. 

Studies have found they can become really contaminated with bacteria (meat, sweaty gym clothes - it all ends up in there) and they should be washed occasionally.  Unfortunately, as is the way with these things, many people will find that too much of a hassle and just replace them. NWPP bags are all made in China, so the carbon footprint, from crude oil as the raw material, to shipping across the globe, to ending up in landfill is not fabulous (the same can be argued for most re-useable shopping bags, but it's a particular problem here because they aren't being used over and over and many people have accumulated many more than they need).

We all need to carry our groceries in something, and there's almost always a degree of compromise in most eco-lifestyle choices.   As always, it's always better to have thought about it and made a mindful decision about what is going to work for you, rather than not thinking about it at all.