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At ConservingNow.com we are often asked about green choices. Most often people are looking for a set of hard and fast rules to live greener. Simple straightforward answers to common questions like paper or plastic, organic or not? It seems that everywhere we go we are bombarded with green choices. And it’s important to know that we are making the right choices. And yet, these seemingly simple questions are so unbelievably difficult to answer.
This past week, one fan was asking about the right choices in reusable bags. Wanting to provide the most educated answer possible – we set about researching the subject. After hours of researching the multitudes of bag choices, we discovered we don’t have an answer. How could we? So many competing principles needed to be considered. Manufacturing process, materials used, what happens after use – these questions continue. They continue to the point that we wanted to bury our heads in the sand in defeat. And then like any reasonable citizen wanting to do the right thing – we were brought back to our own bags (www.conservingnow.com/shop). Ultra-study cotton bags. It’s our best choice. A bag that will last a lifetime. A bag that will outlast trips to the farmer’s market, grocery stores, shopping malls, moving house and endless trips of school supplies and projects – to and from the house.
After all, we are about minimal impact. Consider that whatever your choice is it should be your one and only. A lifetime is surely an easy answer in an economy rooted in convenience. And isn’t it more convenient to carry one bag, to and from the same places, for a lifetime?
For discussion here are some links to various articles on the ills of plastic bags and different types of reusable bags:
Dear Pablo: I want to switch to reusable shopping bags. (Yes I should have done it years ago.) However, all the stores in my area seem to sell bags made of polypropylene. Is the manufacturing process of these bags bad for the environment too? Is canvas or nylon any better? Which do I choose?
The greening of mainstream society has added additional complexity to the age-old "paper or plastic" dilemma (read more on the paper or plastic issue here. We all understand that reusable shopping bags are more environmentally responsible than disposable paper bags or plastic bags. But which reusable shopping bag--a canvas bag, polyester bag, or polypropylene bag--is really the best eco-choice? Let's look at the options.
Shopping Bags: Canvas Bag
The first reusable shopping bag to gain popularity was the canvas bag. Canvas totes are available in conventional cotton, organic cotton, or even hemp. The environmental impact of conventional cotton cultivation is well known--a major percentage of the world's herbicides are used to defoliate cotton prior to harvesting. While organic cotton is better, both conventional and organic cotton use a significant amount of water, so the environmental impact of the fabric bag is directly proportional to its weight. One of my organic cotton shopping bags weighs 187 grams but another cotton bag that I have is made of a much thinner fabric and weighs only 75 grams. If you are looking for a canvas bag, look for a lighter one. It will still hold more weight than a plastic or paper bag.
Shopping Bags: Polyester Tote Bag
Polyester tote bags, such as the ChicoBag, are easily portable shopping bags made from a very thin but durable fabric. The bag is about the same size as a disposable plastic bag used for shipping and stows neatly in an integrated pouch that fits in the palm of your hand and clips to your purse or fits in your pocket. At 35 grams, the manufacturing of the polyester material for one bag creates 89 grams of greenhouse gas emissions, which compares to the manufacture of just seven disposable plastic shopping bags. ChicoBag now also makes a bag that is made from seven recycled soda bottles.
Shopping Bags: Polypropylene Bag
Another shopping bag that has been gaining popularity is made from polypropylene and is designed in the shape of a brown paper shopping bag. These bags, such as hose made by One Bag at a Time, can now be found at the checkout lines pretty much everywhere, from Safeway supermarkets to Ace hardware stores. One Bag at a Time's website provides some great information on the environmental benefits of using these bags. At 103 grams, the manufacturing of the polypropylene material for each bag creates 138 grams of greenhouse gas emissions, which compares to the manufacture of 11 disposable plastic shopping bags.
And the Winner for Greenest Shopping Bag Is...
The difference in environmental impact between the polyester bag and the polypropylene bag is negligible, especially when compared to the disposable paper and plastic bags. The impact of canvas bags is higher, but still negligible when compared with the disposable alternatives over time. Ultimately, what is most important, regardless of your choice, is that you use the reusable shopping bag.
Most bags are made from plastic combined with corn-based materials. Biodegradable plastic bags require more plastic per bag, because the material is not as strong. Many bags are also made from paper, organic materials, or polycaprolactone.
"The public looks at biodegradable as something magical," even though the term is mostly meaningless, according to Ramani Narayan, a chemical engineer at Michigan State University in East Lansing, and science consultant to the Biodegradable Plastics Institute. "This is the most used and abused and misused word in our dictionary right now. Simply calling something biodegradable and not defining in what environment it is going to be biodegradable and in what time period it is going to degrade is very misleading and deceptive." In the Great Pacific Garbage Patch, biodegradable plastics break up into small pieces that can more easily enter the food chain by being consumed."
This is a fantastic article about the complexities of plastic bags, biodegradability and polypropylene.
Myth: Biodegradable Bags are the Solution
Fact: At first glance, biodegradable shopping bags may seem like a good idea, but a closer look reveals significant downsides.
Biodegradable shopping bags are made of polymers that degrade, or decompose, when exposed to air, water or sunlight. There are two main types:
* The original biodegradable bags, introduced about ten years ago, are made from resins containing polyethylene, starches and heavy metals such as cadmium, lead, and beryllium. They are still on the market today.
* About five years ago, a second type was invented using starches combined with biodegradable polymers or polylactic acid. Some of these claim to be fully compostable, meaning that they would break down to organic material suitable for plant growth.
The downsides of biodegradable bags:
* Does nothing to address the consumption part of this problem which lies at the heart of this issue. Both biodegradable and regular disposable plastic bags require a similar amount of energy, natural resources and costs to produce.
* Mixing of biodegradable bags in recycling systems for conventional plastic bags creates a sorting nightmare and can render entire batches of recyclable plastic useless.
* Bag littering could easily increase as people start to believe that biodegradable bags are less harmful to the environment and will disappear quickly - it takes at least 18 months for most to breakdown.
* The breakdown of starch-based films in water consumes oxygen, resulting in oxygen depletion that contributes to algae blooms and the death of marine life.
* Water, soil, and crop contamination could result from the use of compost with chemical residues from biodegraded bags.