I had stored about ten pounds of used lab materials over a period of 8 months, waiting to hear from authorities here at Scripps Institute of Oceanography at San Diego, on ways to recycle the waste. All were different types of plastics. I was informed yesterday that San Diego County does not have a facility to recycle lab materials made of plastic. I had to dump that whole mass of plastic in the trash. But where does it go from there? In fact, much plastic waste goes not to a landfill, but is dumped into the ocean.
Plastic is the most common waste in the ocean as it is lightweight, durable, and the most common disposable product of human societies, both old and new, developing and advanced. The United Nations Environmental Program (UNEP) reported in a 2005 study that there are about 13,000 pieces of debris per square kilometer of ocean; and most of the debris is plastic. It is difficult to estimate accurately, but ~ 80% of plastic debris in the ocean is land-derived materials that nations discard into the ocean, and the remaining 20% is debris discarded by ships, cruise liners, etc., in spite of strict international rules that have been imposed to check marine pollution.
Plastic waste can float for very long distances before being caught in a gyre (a large system of rotating ocean currants, similar to a vortex) and then, over time, breaking down. It takes anywhere between 80-200 years for plastic to degrade in the ocean, depending on material type, size, and thickness, temperature, wave action, exposure to sunlight, and location. During their degradation process, plastics release toxins into the ocean water. These toxins find their way into plankton, which in turn are eaten by fish, which in turn are eaten by us. But it’s not just the degradation of plastic waste that is harmful: larger marine fauna can become entangled in plastic debris, and plastic debris can become home to colonies of bacteria and other microorganisms that wouldn’t ordinarily exist in high levels, over time disturbing the natural balance of the marine ecosystem.
Although plastic marine debris is a concern for all oceans, it is nowhere as acute as in the North Pacific Gyre, also known as the “garbage patch of the ocean”. Oceanographer Charles Moore was the first to document a vast area – estimated at 700,000 to 15,000,000 square kilometers (about twice the size of continental US or ~ 8% of the entire Pacific Ocean) – literally turned into a floating garbage bin. This patch occupies a relatively stationary position in the ocean because wind circulation patterns and ocean currents trap debris from all across the Pacific in this spot. Light bulbs, bottle caps, toothbrushes, Popsicle sticks and tiny pieces of plastic, each the size of a grain of rice, inhabit the Pacific garbage patch. Scientists say the garbage patch is just one of five that may have formed in giant gyres scattered around the world’s oceans: for example, there is another off the coast of Japan, and another in the Sargasso Sea, in the middle of the Atlantic Ocean.
Researchers like Miriam Goldstein and David de Rothschild are devoted not only to understanding the accumulation of plastic in the ocean, but also to inventing innovative ways to deal with this vast amount plastic waste. Recently, Goldsten lead SEAPLEX (Scripps Environmental Accumulation of Plastic Expedition) – a 20-day research expedition based out of the Scripps Institute of Oceanography at San Diego – in order to study plastic accumulation in the Pacific garbage patch. What the group found was very interesting: they did not observe an island or a floating landfill, as they had expected. While they did witness larger pieces floating by every minute or so, most of the time they observed tiny, nearly microscopic bits of plastic, with the concentration of these minute particles increasing towards the centre of the gyre. The research team’s finding that the vast majority of the debris is actually tiny, hard-to-see pieces probably explains why such garbage patches might not be captured by satellite images of the Earth. Goldstein, along with their collaborators, are exploring the possible ways to clean up the patch, however things don’t look very bright. Goldstein’s findings identify that a major difficulty for cleaning up plastic waste from our oceans lies in the fact that most of the plastic debris is the same size as the marine life (less than 1/4?), and hence it will be difficult to remove without substantial damage to marine organisms.
While cleaning up existing debris might be difficult, one thing we can do is to limit the amount of waste that ends up in the ocean in the first place. And the way to achieve that goal, as things are at the moment, seems to be increasing awareness about ways to recycle waste plastic into sustainable products. To this end, researcher David de Rothschild and his team will sail 12,000 nautical miles across the Pacific Ocean from San Francisco to Sydney, in a boat made out of plastic bottles and recycled waste products named The Plastiki. Their voyage aims to draw attention not only to everyday human fingerprints on the natural world, but also to how pioneering and sustainable design processes, such as those used to build the Plastiki, can offer a solution to the problem of disposing of the enormous amount plastic waste that is the byproduct of human society: one person’s waste could be another person’s treasure.
–Atreyee Bhattacharya, Harvard University