(664c) Overview and Assessment of Waste Plastics in the Ocean Environment

Humans are currently contributing to a major decline in the world's biological diversity. The problem is so critical that all human impacts combined might accelerate the present extinction rates from 1000 to 10,000 times the natural rate. The threat to marine life in the oceans comes in various forms such as dumping of waste, overexploitation and harvesting, pollution, alien species, land reclamation, dredging, and global climate change. One particular type of human impact that represents a major threat to marine life is the pollution caused by plastic debris. Plastic has become one of the most common forms of pollution in the ocean and is causing problems to become more and more severe each day, impacting both the natural environment and human life.

Since the end of World War II, plastics have been produced in large and exponential quantities. They represent a diverse group of materials which are derived from petrochemicals. Their production has increased exponentially from 1,700,000 tons in 1950 to more than 280,000,000 tons in 2011. Although plastics are recyclable, they contribute to producing a significant amount of waste globally. For example, from 2010 to 2011, Australia produced 1,433,046 tons of plastics among which only 20% was recycled. Also, 37 percent of that plastic was for the single-use disposable packaging. Plastics break down slowly through a combination of oxidation, photodegradation, and mechanical abrasion. Thick plastics survive for long times even if they are subjected to direct sunlight. When plastics are submerged under water or in sediments, protected from UV radiation, they can survive for an even longer time. Although biodegradable plastics have been developed as a solution, it has not had a long-term effect yet. Plastics have a lower proportion of biodegradable materials and thus microscopic plastic fragments are left behind.

The existence of widespread plastics in the ocean was not observed until 1970. As a result, plastic pollution of oceanic waters was not a matter of concern prior to that time. The production of plastics that are not biodegradable and the amount of waste have been increasing worldwide, causing increased levels of contamination and posing an escalating threat to the marine environment. As the ocean is downstream from almost every terrestrial location, it receives most of the plastic waste generated on land. Every year, it receives several million tons of debris and much of this is discarded plastic litter.

Plastic pollution has an adverse impact on our oceans and the health of wildlife. It is causing harm to the creatures that live in the ocean, from coral reefs to turtles gagging on straws, to whales and seabirds. These creatures may starve because their bellies become so jammed with bits of plastic that there’s no room for substantial food. Another recent concern regarding plastic pollution is the impact on food webs and marine ecosystems. The concentrated toxins of plastic materials may be delivered to animals via ingestion and transferred to their food webs. At least 26 species of cetaceans have been documented to ingest plastic debris.

This paper examines reported evidence and effects of plastic pollution in oceans and the marine environment.