For those of you who don’t know this, plastics are made from long chains called polymers which are created out of petroleum or crude oil. These do not biodegrade and even after they’re torn, cracked or broken, remain intact in landfills for hundreds of years. However, given the current focus on environment, biodegradable plastics have made their way into commercial use. For example, SunChips, a brand of potato crispies in the US comes in a bag that if buried in a compost pit, biodegrades leaving no poisonous residue. Similarly, the outer shell of Papermate pens can be broken down by burying, but not its inner components.
The commercial use of bioplastics has great benefits for the environment. Apart from the fact that they will save thousands of acres of landfill that gets poisoned every year, bioplastics produce fewer greenhouse gases in the manufacturing process than normal oil-based plastics. Also, these biomaterials don't contain an allegedly hormone-disrupting chemical, bisphenol A (BPA) that some regular plastics do. But is society green enough to use bioplastics?
Bioplastics are not new to the world, having been first used in car parts for the Ford model T, and were made from corn oil and soya bean oil. Interest in bioplastics has tended to fluctuate with the price of oil. Of the two promising new varieties of bioplastic, one type — dubbed polylactic acid, or PLA — is clear in color and costs manufacturers about 20% more to use than petroleum-based plastic. The other — called polyhydroxyalkanoate, or PHA — biodegrades more easily but is more than double the price of regular plastic. The base ingredient for both these forms is fermented corn sugar, which allows them to degrade fast when buried.
The PLA form of plastic is finding a lot of takers, with widespread use from bags to water bottles. Companies are also trying to make PLA from potatoes and algae, as well as certain varieties of grass. PHA on the other hand, being more expensive, has several advantages. It is able to stand higher temperatures and will decompose in either water or soil. The problem with them right now is that they can be eliminated only under certain conditions. Otherwise, they can still create problems. For example, if leakage seeps in, the plastic could degrade into methane gas. But discarded bioplastic is not the only potential methane emitter in landfills. Kitchen scraps and yard waste emit the gas, which is one reason many garbage dumps have started capturing methane output and using it for energy.
Another hassle is learning to distinguish between normal plastic and bioplastics. Many of these disposal issues could be sorted out if the manufacturers could come up with some kind of color coding scheme for the plastics, but it won’t be easy getting everyone attention and co-operation. For many, convenience still takes precedence over the environment.