Most marine debris (80%) comes from trash and debris in urban runoff, i.e. land-based sources. Key components of land-based sources include litter, trash and debris from construction, ports and marinas, commercial and industrial facilities, and trash blown out of garbage containers, trucks, and landfills.1 Ocean-based sources, such as, overboard discharges from ships and discarded fishing gear, account for the other 20%.

Food containers and packaging are the largest component of the municipal solid waste stream (80 million tons or 31.7 %).2 These items, together with plastic bags, also represent the largest component of marine debris (that is, barring items less than 5mm such as pre-production plastic pellets, fragments, and polystyrene pieces).3 Packaging and single use disposable products are not only ubiquitous in marine debris, they represent an unsustainable use of precious resources (oil, trees, energy sources, water).

The quantity of marine debris is increasing in oceans world-wide. Researchers at the Algalita Marine Research Foundation documented an increase in plastic debris in the Central Pacific Gyre five-fold between 1997 and 2007, where the baseline in 1997 showed plastic pieces outnumbered plankton on the ocean surface 6:1.4

Off Japan’s coast, the quantity of pelagic plastic particles floating increased 10 fold in 10 years between the 1970s and 1980s, and then 10 fold every 2-3 years in the 1990s.5 In the Southern Ocean, plastic debris increased 100 times during the early 1990s.6 These increases in plastic debris occurred at the same time that worldwide production of plastic fibers quadrupled.

In the ocean, plastic debris injures and kills fish, seabirds and marine mammals. Marine plastic pollution has impacted at least 267 species worldwide, including 86% of all sea turtle species, 44% of all seabird species and 43% of all marine mammal species. The impacts include fatalities as a result of ingestion, starvation, suffocation, infection, drowning, and entanglement.7

In 2010, a California grey whale washed up dead on the shores of the Puget Sound. Autopsies indicated that its stomach contained a pair of pants and a golf ball, more than 20 plastic bags, small towels, duct tape and surgical gloves.

Seabirds that feed on the ocean surface are especially prone to ingesting plastic debris that floats. Adults feed these items to their chicks resulting in detrimental effects on chick growth and survival.8 One study found that approximately 98% of chicks sampled contained plastic and the quantity of plastic being ingested was increasing over time.9

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Source: The Problem of Marine Plastic Pollution