The Great Pacific Garbage Patch

THE GREAT PACIFIC GARBAGE PATCH

by Antonio C. Antonio

July 27, 2014

Have we ever wondered why there is too much garbage being collected at the (former) Baywalk area along Roxas Boulevard in Manila especially after a typhoon?  Where is all the garbage coming from? 

Are we really able to fish out and collect all the garbage from Manila Bay?... or is the Philippines a major contributor to the Great Pacific Garbage Patch?

What is the Great Pacific Garbage Patch?  The following is a researched material on this environmental problem…

“The Great Pacific Garbage Patch, also described as the Pacific Trash Vortex, is a gyre of Marine debris particles in the central North Pacific Ocean.  The patch extends over an indeterminate area, with estimates ranging very widely depending on the degree of plastic concentration used to define the affected area.

The patch is characterized by exceptionally high concentrations of pelagic plastics, chemical sludge and other debris that have been trapped by the currents of the North Pacific Gyre.  Despite its size and density, the patch is not visible from satellite photography, nor even necessarily to a casual boater or diver in the area, since it consists primarily of a small increase in suspended, often-microscopic particles in the upper water column.  Since plastics break down to even smaller polymers, concentrations of submerged particles are not visible from space, nor do they appear as a continuous debris field to human eyes. Instead, the patch is defined as an area in which the mass of plastic debris in the upper water column is significantly higher than average.

The Great Pacific garbage patch was predicted in a 1988 paper published by the National Oceanic and Atmospheric Administration (NOAA) of the United States.  The prediction was based on results obtained by several Alaska-based researchers between 1985 and 1988 that measured neustonic plastic in the North Pacific Ocean.  This research found high concentrations of marine debris accumulating in regions governed by ocean currents.  Extrapolating from findings in the Sea of Japan, the researchers hypothesized that similar conditions would occur in other parts of the Pacific where prevailing currents were favorable to the creation of relatively stable waters.  They specifically indicated the North Pacific Gyre. 

Charles J. Moore, returning home through the North Pacific Gyre after competing in the Transpac sailing race in 1997, came upon an enormous stretch of floating debris.  Moore alerted oceanographer Curtis Ebbesmeyer, who subsequently dubbed the region the "Eastern Garbage Patch" (EGP).  The area is frequently featured in media reports as an exceptional example of marine pollution.

The patch is not easily visible because it consists of very small pieces, almost invisible to the naked eye, most of its contents are suspended beneath the surface of the ocean, and the relatively low density of the plastic debris at, in one scientific study, 5.1 kilograms of plastic per square kilometer of ocean area.  A similar patch of floating plastic debris is found in the Atlantic Ocean.

It is thought that, like other areas of concentrated marine debris in the world's oceans, the Great Pacific garbage patch formed gradually as a result of marine pollution gathered by oceanic currents.  The garbage patch occupies a large and relatively stationary region of the North Pacific Ocean bound by the North Pacific Gyre (a remote area commonly referred to as the horse latitudes).  The gyre's rotational pattern draws in waste material from across the North Pacific Ocean, including coastal waters off North America and Japan. As material is captured in the currents, wind-driven surface currents gradually move floating debris toward the center, trapping it in the region.

There are no strong scientific data concerning the origins of pelagic plastics.  The figure that an estimated 80% of the garbage comes from land-based sources and 20% from ships is derived from an unsubstantiated estimate.  According to a 2011 EPA report, "The primary source of marine debris is the improper waste disposal or management of trash and manufacturing products, including plastics (e.g., littering, illegal dumping) ... Debris is generated on land at marinas, ports, rivers, harbors, docks, and storm drains. Debris is generated at sea from fishing vessels, stationary platforms and cargo ships."  Pollutants range in size from abandoned fishing nets to micro-pellets used in abrasive cleaners.  Currents carry debris from the west coast of North America to the gyre in about six years, and debris from the east coast of Asia in a year or less.  An international research project led by Dr. Hideshige Takada of Tokyo University of Agriculture and Technology studying plastic pellets, or nurdles, from beaches around the world may provide further clues about the origins of pelagic plastic. 

Logically, the land-based sources of pollutants and plastics come from the great rivers from around the world.  The Ganges, in India, is an example of a source of major sea pollution.  The major rivers of Bangladesh, Nigeria, and other developing nations collectively provide another example of marine-pollution sources.  It has been noted that the levels of pollution in and around these rivers constitute a major health hazard to people living and doing business around the water.

The size of the patch is unknown, as large items readily visible from a boat deck are uncommon.  Most debris consists of small plastic particles suspended at or just below the surface, making it impossible to detect by aircraft or satellite. Instead, the size of the patch is determined by sampling.  Estimates of size range from 700,000 square kilometres to more than 15,000,000 square kilometres (0.41% to 8.1% of the size of the Pacific Ocean), or, in some media reports, up to "twice the size of the continental United States".  Such estimates, however, are conjectural given the complexities of sampling and the need to assess findings against other areas.  Further, although the size of the patch is determined by a higher-than-normal degree of concentration of pelagic debris, there is no standard for determining the boundary between "normal" and "elevated" levels of pollutants to provide a firm estimate of the affected area.

The Great Pacific garbage patch has one of the highest levels known of plastic particulate suspended in the upper water column.  As a result, it is one of several oceanic regions where researchers have studied the effects and impact of plastic photodegradation in the neusonic layer of water.  Unlike organic debris, which biodegrades, the photodegraded plastic disintegrates into ever smaller pieces while remaining a polymer.  This process continues down to the molecular level.  As the plastic flotsam photodegrades into smaller and smaller pieces, it concentrates in the upper water column.  As it disintegrates, the plastic ultimately becomes small enough to be ingested by aquatic organisms that reside near the ocean's surface.  In this way, plastic may become concentrated in neuston, thereby entering the food chain.

Some plastics decompose within a year of entering the water, leaching potentially toxic chemicals such as bisphenol A, PCBs and derivatives of polystyrene.

The process of disintegration means that the plastic particulate in much of the affected region is too small to be seen.  In a 2001 study, researchers (including Charles Moore) found concentrations of plastic particles at 334,721 pieces per km² with a mean mass of 5,114 grams per km², in the neuston.  Assuming each particle of plastic averaged 5 mm x 5 mm x 1 mm, this would amount to only 8 m² per km² due to small particulates.  Nonetheless, this represents a very high amount with respect to the overall ecology of the neuston.  In many of the sampled areas, the overall concentration of plastics was seven times greater than the concentration of zooplankton.  

Some of these long-lasting plastics end up in the stomachs of marine birds and animals, and their young, including sea turtles and the Black-footed Albatross.  Midway Atoll receives substantial amounts of marine debris from the patch.  Of the 1.5 million Laysan Albatrosses that inhabit Midway, nearly all are found to have plastic in their digestive system.  Approximately one-third of their chicks die, and many of those deaths are due to being fed plastic from their parents.  Twenty tons of plastic debris washes up on Midway every year with five tons of that debris being fed to Albatross chicks. 

Besides the particles' danger to wildlife, on the microscopic level the floating debris can absorb organic pollutants from seawater, including PCBs, DDT and PAHs.  Aside from toxic effects, when ingested, some of these are mistaken by the endocrine system as estradiol, causing hormone disruption in the affected animal.  These toxin-containing plastic pieces are also eaten by jellyfish, which are then eaten by larger fish.  Many of these fish are then consumed by humans, resulting in their ingestion of toxic chemicals.  Marine plastics also facilitate the spread of invasive species that attach to floating plastic in one region and drift long distances to colonize other ecosystems.

On the macroscopic level, the physical size of the plastic kills birds and turtles as the animals’ digestion cannot break down the plastic inside their stomachs.  A second effect of the macroscopic plastic is to make it much more difficult for animals to see and detect their normal sources of food.  Research has shown that this plastic marine debris affects at least 267 species worldwide and a few of the 267 species reside in the North Pacific Gyre.

Bacteria have been found in the plastic polluted waters of the Sargasso sea that consume plastic; however, it is unknown whether these bacteria ultimately clean up poisons or simply spread them elsewhere in the marine microbial ecosystem.  Plastic debris can absorb toxic chemicals from ocean pollution, potentially poisoning anything that eats it.” (http://en.wikipedia.org/wiki/Great_Pacific_garbage_patch)

It is hard to imagine serving fish on the dinner table that tastes like plastic.  The many research conducted so far seems to validate this possibility.  The Philippines is part of the Asia-Pacific Rim and could very well be a contributor to this dire phenomenon.  Let us be responsible in the disposition of our solid household waste lest we want (in the future) to experience eating plastic-tasting fish caught at the Great Pacific Garbage Patch.

Just my little thoughts…

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