Natural biodegradation happens when microorganisms such as fungi and bacteria break down organic matter into water and carbon dioxide. Most plastic bags are made of low-density polyethylene, an artificial hydrocarbon polymer that microorganisms do not recognize as food. Polyethylene is not attractive to microorganisms due to its high molecular weight, very stable three-dimensional structure, and water resistance.
As a result, plastic bags take hundreds of years to break down, and landfills take longer. Environmental problems caused by the slow biodegradation of plastics are one of the reasons why the use of single-use plastic biodegradable bags is urgent to stop and replace with reusable bags. Before polyethylene breaks down, it breaks down into smaller pieces through exposure to light in a process known as photodegradation.
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Photodegradation is not the same as biodegradation, because the microscopic plastic pieces produced are still artificial polymers. These microscopic pieces are harmful to the environment because they can be digested by animals, cause hormonal imbalances, and absorb persistent organic contaminants such as PCBs and various pesticides. In the ocean, these fragments resemble the zooplankton in many animals and significantly exceed this in some areas, so their consumption by marine animals is unavoidable.
Plastic bags have been used for over 50 years and have only been used in supermarkets for 30 years. However, they have caused significant environmental problems in the oceans, such as Garbage and landfills. According to the research, between 500 and 1 trillion plastic bags are produced worldwide each year, most of which end up in waste streams. We can reduce the bulk of plastic bags plaguing the planet by regularly using reusable bags.