Plastics are indigestible and non-biodegradable and once produced, one cannot get rid of them. The majority of the world’s plastics end up in the garbage, rivers, and eventually in lakes and oceans. Large plastics float across oceans and sometimes collect together to form garbage patches such as the Great Pacific Garbage Patch. Microplastics, on the other hand, exist on beaches and deeper waters. Large plastics cause physical damage to marine animals and can result in death. However, the biggest problems are microplastic. They are mistaken for food by marine animals and ingested. They block the digestive system of animals and result in low levels of oxygen and consequently result in reduced energy levels. Some plastics are so tiny that they embed in the animal tissues. They are passed across the food chain, and some find their way to humans. Microplastics find their way to humans through ingestion or respiration. Today, the sources of microplastics are so essential to humans that we cannot live without them. The best alternative to controlling microplastic remains proper handling of plastic and thorough treatment of wastewater.

Plastic is a material made to last forever, yet 33 percent of all plastic - water bottles, bags and straws - are used just once and thrown away. Plastic cannot biodegrade; it breaks down into smaller and smaller pieces.
Disposed plastic materials can remain in the environment for up to 2,000 years and longer.

Plastic affects human health.
Toxic chemicals leach out of plastic and are found in the blood and tissue of nearly all of us. Exposure to them is linked to cancers, birth defects, impaired immunity, endocrine disruption and other ailments.
Two broad classes of plastic-related chemicals are of critical concern for human health—bisphenol-A or BPA, and additives used in the synthesis of plastics, which are known as phthalates. 

Plastic spoils our groundwater.
There are thousands of landfills in the United States. Buried beneath each one of them, toxic chemicals from plastics drain out and seep into groundwater, flowing downstream into lakes and rivers.
There are long-term risks of contamination of soils and groundwater by some additives and breakdown by-products in plastics, which can become persistent organic pollutants.
Plastic attracts other pollutants.
Chemicals in plastic which give them their rigidity or flexibility (flame retardants, bisphenols, phthalates and other harmful chemicals) are oily poisons that repel water and stick to petroleum-based objects like plastic debris.  So, the toxic chemicals that leach out of plastics can accumulate on other plastics.  This is a serious concern with increasing amounts of plastic debris accumulating in the world's oceans. 
Fish, exposed to a mixture of polyethylene with chemical pollutants absorbed from the marine environment, bioaccumulate these chemical pollutants and suffer liver toxicity and pathology. 

Plastic threatens wildlife.
Wildlife become entangled in plastic, they eat it or mistake it for food and feed it to their young, and it is found littered in even extremely remote areas of the Earth.  In our oceans alone, plastic debris outweighs zooplankton by a ratio of 36-to-1.
Over 260 species, including invertebrates, turtles, fish, seabirds and mammals, have been reported to ingest or become entangled in plastic debris, resulting in impaired movement and feeding, reduced reproductive output, lacerations, ulcers and death.
Plastic piles up in the environment.
Americans discard more than 30 million tons of plastic a year. Only 8 percent gets recycled. The rest ends up in landfills, is burned or becomes litter.
More than 5 trillion plastic pieces weighing over 250,000 tons afloat at sea.
Plastic poisons our food chain.
Even plankton, the tiniest creatures in our oceans, are eating microplastics and absorbing their hazardous chemicals.  The tiny, broken down pieces of plastic are displacing the algae needed to sustain larger sea life who feed on them.
Contaminated plastics when ingested by marine species present a credible route by which the POPs can enter the marine food web. 
Plastic costs billions to abate.
Everything suffers: tourism, recreation, business, the health of humans, animals, fish and birds—because of plastic pollution. The financial damage continuously being inflicted is inestimable.

Interest in making plastics arose in the 1800s to replace scarce materials such as ivory and tortoise shell. The first synthetic plastics were derived from cellulose, a substance found in plants and trees. Cellulose was heated with chemicals and resulted in a new material that was extremely durable.

The raw materials for today’s plastics come from many places (some even use salt!), but most plastics can be made from the hydrocarbons that are readily available in natural gas, oil and coal.