The world lacks natural resources and due to our carelessness in the way of treating them, we are speeding contamination of the environment. These impacts can be determined from the health problems, biodiversity loss, adverse effect on ecosystem and many other environmental problems. To overcome this problem and to control the extent of these pollutants, we are required to take action towards their degradation by implementing Best Available Techniques (BAT) and Best Environmental Practices (BEP), through which we will be able to save the life of our future generation.
As massive amounts of waste is produced, it accumulates through improper disposal, causing build up and leaching into natural environments. Dumping and littering on land accumulates in landfills, posing problems in places where they are poorly maintained, and contribute to leaching of plastic waste. The chemical runoff and physical waste can end up in the ocean, harming the ecosystem, worsening the already present marine pollutants impact on wildlife and stressing populations.
In attempts to address plastic waste, different forms of biodegradation are explored, such as those involving bacteria, enzymes, and fungi, used as agents to break down plastics, making them less persistent in the environment. This includes a look into pre-treatment, how labs can account for abiotic degradation, and other measures to facilitate the process for the organisms, or combination of methods, possibly to even use the waste. Some bacteria can help degrade when they are able to use the plastic as a source of carbon, and can contain enzymes able to degrade those plastics. Enzymes can be used for biodegradation for their ability to break those polymer bonds that make it especially stable. Fungi is known to be able to break through the hydrophobic surface of these plasticsb and weaken the structure with its hyphae, while releasing enzymes that similarly are able to degrade it.
Challenges in this field are also explored, since polyethylene will be fiercely protected by its producers and marketers from any changes in composition or campaigns to restrict its use. A goal of this investigation was to find experiments that gave visible results and concrete validation of their processes. Our philosophical look at the problem explores the economic point of view on the issue, since the greatest opposition to changes in plastic use comes from it being a staple product that markets can’t afford to change. We refute this explanation and call for a stricter view of businesses and their apparent needs for plastics against their damaging presence in the world.
The study aims to understand different problems faced because of plastics in ecosystem, its environmental impacts, the sources, production, fate of plastics in environment, composition, quality and degradability as well as alternative source to identify the challenges and to develop new strategy depending upon the previous and present techniques.
1.1 General Information of plastics and polyethylene
During the past decades, plastics have been increasingly used in various parts of ecosystem from household to industrial use. Globally, plastic waste generation is about 56 million tons annually. Particularly in developing countries more than 1 – 2 million tons of plastic waste has found ways into various fields in the years 1999 and 2000 respectively (statistics of foreign trade of India, March 2000 and March 2001, DGFT, GoI). Mostly plastics are thrown away after single use, specially the one used for packaging and sheeting, but because they are durable, they persist in the environment. The rate of accumulation of such synthetic materials per year increasing at rate of 20-30% in terrestrial as well as in marine environment (Byuntae et al. 1991). Mostly plastics are thrown away after single use, specially the one used for packaging and sheeting, but because they are durable, they persist in the environment.
Plastics can be defined as overall range of synthetic or semisynthetic materials that can be molded into matter of diverse shapes. These are the polymers composed of carbon, silicon, oxygen, hydrogen, nitrogen, and chloride. Most common forms of plastics are polyolefins, polypropylene, polystyrene etc. Polyolefins are used in a wide variety of applications, including grocery bags, containers, toys, adhesives, home appliances, engineering plastics, automotive parts, medical applications, and prosthetic implants. They behave as thermoplastics, elastomers or thermosets which can be either amorphous or highly crystalline. Polyolefins with entire new properties can be newly produced with bonding of ethylene, propylene, and higher ?-olefins in the polymer chain. Polyolefins can be divided into two main types, polyethylene and polypropylene, which are subdivided into several forms for different applications.
The most commonly used polyolefins are polyethylene which are subdivided into High Density Polyethylene (HDPE) and Low Density Polyethylene (LDPE). These polymers are so handy, durable, lightweight, and low cost which make it so valuable. They are widely used as plastic bags, packaging material, milk and water bottles etc, that are contributing in posing different environmental problems (Byuntae et al. 1991).