#60 Why does plastic degrade slower than other substances (English)

Why does plastic degrade slower than other substances

                  An important definition to know when talking about degrading is the term, biodegradable. Biodegradable means materials that can be broken down by microorganisms into organic matter. For example, vegetables may degrade in a month or so, while metals might take longer than a month. This shows that one of the factors affecting biodegradability is the type of material that makes up the object. Another factor affecting biodegradability is the environment. Air, water, and light all affect the biodegradability. In the case of plastics, they are not affected by air, water, or light, and therefore do not biodegrade to any significant degree. One of the reasons that plastics degrade slowly, is because the links joining the atoms are linked more intricately. In things like wood or cotton, the atoms are linked to each other naturally, therefore allowing bacteria to easily break down the links. The conditions for plastic to decompose is limited to ultraviolet light or heat, neither of which are found naturally in landfills where plastic is discarded after its use.

             When we normally consider biodegradables, we think of the materials degrading in landfills. However, it has recently been found that certain plastics degrade in water. Not only that, but they also break down within a year of contact with water. Although this may seem positive for people finding ways to speed up the degradation of plastic, it poses a threat to the underwater ecosystems. The plastics that break down in the water are made up of a molecule called polystyrene, a chemical pollutant. The plastic not only releases this dangerous molecule into the water, it also introduces chemicals not found near the water, to the water. These chemicals have the power to create cancer in humans, and simpler creatures in the water may be more susceptible to these harsh chemicals. In the food chain, the animals at the top would be consuming the highest amount of these dangerous chemicals, potentially threatening the entire ecosystem as we know it.

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