There are other cases however where the product is environmentally damaging but because it is used in such small quantities, it's not vital to focus on reducing its consumption. An example would be Lego blocks are made out of acrylonitrile butadiene styrene plastic, an oil-based product that can contribute to air pollution and global warming. Given the likelihood that these toys are reused and passed to other children over time, it is not as necessary to focus on eliminating the product because it is less likely to wind up cluttering landfills. On the other hand, steps to reduce landfill clutter may be as simple as comparing the use of a plastic, paper and fabric bags. (Brower and Leon, 1999, 5-12)
Paper versus Plastic:
The life-cycle of a paper and plastic bag from production to landfill: When it comes time to check out after shopping, should you use a paper bag or a plastic bag? Although it may seem like an easy choice, there are many details and inputs hidden in each bag. From durability and reusability to life cycle costs, there is much more to each bag than you may think.
Where do brown paper bags come from? Paper comes from trees. The logging industry is huge, and the process to get that paper bag to the grocery store is long and takes a heavy toll on the environment. First, the trees are found, marked and cut which results in massive habitat destruction and long-term ecological damage. Then, machinery comes in to remove the logs from what used to be forest, either by logging trucks or helicopters. This machinery requires fossil fuel to operate and roads to drive on which impacts the ecological chain in its former surrounding areas. Once trees are collected, it takes at least three years of seasoning before they can be used. More machinery is used to strip the bark, which is then chipped into one-inch squares and cooked under tremendous heat and pressure. This wood is then combined with a chemical mixture of limestone and acid, and after several hours of cooking, what was once wood becomes pulp. It takes approximately three tons of wood chips to make one ton of pulp. The pulp is then washed and bleached; both stages require thousands of gallons of clean water. Coloring is added to more water, and is then combined in a ratio of 1 part pulp to 400 parts water, to make paper. The pulp/water mixture is poured into a filtration system of bronze wires, leaving behind only the pulp. It is finally rolled into paper. (Dunn, 2008)
Along the way, energy inputs: chemical, electrical, and fossil fuel-based are used to transport the raw material, turn the paper into a bag and then transport the finished paper bag all over the world. When you're done using paper shopping bags, for shopping or other household reuses, they can be composted or they can be recycled in most mixed-paper recycling schemes if they haven't been thrown away. (Dunn, 2008)
If composted, the bags break down and go from paper to a rich soil nutrient over a period of a couple of months; if you throw them away, they will eventually break down over a period of many years. If you choose to recycle paper bags, then the paper must first be re-pulped, which usually requires a chemical process involving compounds like hydrogen peroxide, sodium silicate and sodium hydroxide, which bleach and separate the pulp fibers. The fibers are then cleaned and screened to be sure they're free of anything that would contaminate the paper-making process, and are then washed to remove any leftover ink before being pressed and rolled into paper, as before. (Dunn, 2008)
How are plastic bags made?
Unlike paper bags, plastic bags are made from oil, a non-renewable resource. Plastics are a by-product of the oil-refining process, accounting for about four percent of oil production around the globe. The biggest energy input from the plastic bag creation process is electricity, which, in this country, comes from coal-burning power plants at least half of the time; the process requires enough juice to heat the oil up to 750 degrees Fahrenheit, where it can be separated into its various components and molded into polymers. Plastic bags most often come from one of the five types of polymers: polyethylene in its low-density form (LDPE), which is also known as #4 plastic. Like paper, plastic can be recycled. Recycling involves re-melting the bags and re-casting the plastic, though, manufacturing new plastic from recycled plastic requires two-thirds of the energy used in virgin plastic manufacturing. The material however loses viability in the process of recycling which makes it hard to make new plastic bags out of old plastic bags. (McGrath, 1998)
By looking at overall energy, emissions, and other life cycle-related costs of production and recycling, one can begin to understand the implications of choosing paper versus plastic. According to a , plastic bags create fewer airborne emissions and require less energy during the life-cycle of both types of bags per 10,000 equivalent uses -- plastic creates 9.1 cubic pounds of solid waste vs. 45.8 cubic pounds for paper; plastic creates 17.9 pounds of atmospheric emissions vs. 64.2 pounds for paper; plastic creates 1.8 pounds of waterborne waste vs. 31.2 pounds for paper. Plastic therefore has lower energy requirements. Both paper and plastic bags require lots of resources and energy. Proper recycling requires due diligence from both consumer and municipal waste collector or private recycling company.
Ultimately, neither paper nor plastic bags are the best choice. Reusable canvas bags are the way to go from an energy standpoint. Canvas bags are 14 times better than plastic bags and 39 times better than paper bags, assuming that canvas bags are used 500 times during their life cycle. (McGrath, 1998)
