What Is The Main Danger of Environmental Pollution With Plastic?

Plastic is one of the most dangerous materials that adorn the earth. Increasing number of plastic waste is a growing concern globally. Plastic is dumped in land areas, discarded to open water ways; openly burned all of which results in pollution.

The word plastic comes from the Greek word plastikos, which means ‘able to be molded into varied shapes (Joel 1995). There are numerous types of plastic now but they can be basically classified into seven types namely high density polyethylene (HDPE), low density polyethylene (LDPE), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polystyrene, polypropylene, and different mixes of the above. Plastic is made up of carbon, hydrogen, oxygen, silicon, chloride and nitrogen (Seymour 1989).

Plastics are formed by monomers which are bound together by chemical bonds. Of the total plastics present in the world 64% is polythene. The common formula of polyethylene is CⴖH₂ⴖ, n is the number of carbon atoms (Sangale et al ., 2012). Polythene can be categorized mainly into two- LDPE and HDPE, both of which are thermoplastic polymer. And LDPE materials are used as thin films and sheets for packaging. Due to their light weight, strength and durability, it is widely used around the world (Kumar et al ., 2013).

The rate of plastic usage around the world increases by 12% per year. The use of plastic has been increasing over the past decades. Its use ranges from industrial, agricultural, packaging, transportation and much more. Plastics are preferred more than other materials due to its light weight and inertness. It has high strength and durability which makes them more dependable. Also plastic requires less production cost. But they are difficult to degrade naturally causing a concern in pollution. (Swapnil K K et al ., 2015)

Plastic wastes are highly persistent and it takes decades, or centuries for its complete removal. Weathering and environmental factors such as humidity, temperature, pH, salinity, the presence or absence of oxygen, sunlight, water and stress affect the structure of plastic and leads to its degradation. These factors play an important role in the microbial population and their enzyme activity (Gu 2003).

Removal of plastic has been attempted by many methods. Microbial degradation of plastic completely is difficult. Various parameters such as weight loss, SEM, DMR, HT-GPC, Thermogravimetric analysis, DSC, X-diffraction, Small and Wide angle X ray Scattering, Fourier Transformed Infra red Spectroscopy (FTIR), Thin layer Chromatography (TLC), Gas Chromatography (GC), Nuclear Magnetic Resonance (NMR), Matrix Assisted Laser Desorption Ionization-Time Of Flight(MALDI-TOF), Chemilluminesence, Gas Chromatography-Mass Spectrometry (GC-MS), Adenosine triphosphate (ATP), Fluorescien Diacetate (FDA), protein analysis etc are currently used for assessment of plastic degradation.

The current experiment was done to study the biodiversity of bacteria from sediments of Andaman Islands and to identify the bacteria which has the ability to degrade plastic. For this study low density polyethylene (LDPE) was selected and the experiment was kept for 120 days. The bacteria were grown in minimal salt media (MSM broth) and plastic was given as the only carbon source. The organisms which can utilize LDPE will only survive in these extreme conditions. The bacteria showing degradation activity was identified by comassie brilliant blue (CBB) method, emulsification method and weight loss of plastic. The identified colonies were individually studied. The individual study was done to check whether the bacteria have the ability to degrade plastic by themselves or if it’s the combined activity of the consortium.

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