Author: ELIZABETH ATALAY, LAURA PARKER, HEDI SCHULZ
The Philippines is world's third largest producer of marine plastic waste. In this picture, workers are sorting garbage.
Photo by RANDY OLSON, NATIONAL GEOGRAPHIC
During our research and reporting for June issue of National Geographic's trash issue, we discovered that there is a lot of confusing terminology being used in field of plastics. Even most well-intentioned consumer of plastic can find it difficult to tell good from bad. Therefore, we specifically list current terms in field of plastics in order to popularize current knowledge in this area.
In plastics manufacturing process, chemicals added to make product stronger, safer, or more (less) flexible, or to give it other desired characteristics, are collectively referred to as additives. Common additives include water repellents, flame retardants, hardeners, softeners, pigments, and UV inhibitors. Some supplements may contain potentially toxic substances.
Degradable products must be degraded by microorganisms into natural raw materials within a reasonable time. "Biodegradation" is more complete than "decomposition" or "degradation", yet today many plastic products claim to "degrade" when in fact they simply break down into smaller plastic fragments. There is no generally accepted standard for a product to be labeled as "biodegradable", meaning that there is no precise way to define what "biodegradable" means, and there is no single standard for how manufacturers use term. Some US states prohibit use of term unless clear standards are established.
Bioplastics is a very flexible term currently used for a wide range of plastics, including bio-based and fossil-based degradable plastics, as well as non-degradable bio-based plastics. In other words, no one can guarantee whether "bioplastics" are made from non-toxic, non-fossil fuel raw materials and whether they are biodegradable.
For an object to be considered compostable, it must be able to decompose into its natural elements in a "reasonable composting environment". Some plastics are compostable, although most won't biodegrade in a regular backyard compost pile. In fact, they often require more heat at certain stages in order to fully biodegrade.
According to Rhodes Jepsen of Institute for Biodegradable Products, "Standards and certifications for compostable plastics (biodegradable in a compostable environment) exist, but most of them can only degrade under commercial scale composting conditions that require temperatures not exceedingbelow 54°C. ... In big cities such as San Francisco, Seattle, Minneapolis and New York, biodegradable plastics are one of ingredients of residential and commercial food waste composting projects, but these projects are not available everywhere, and some composting projects for fear of contamination Take only food."
Most fishing tackle is made of plastic, and when thrown, discarded, or lost are often referred to as ghost nets. Ghost nets include fishing nets, fishing lines, fishing traps, buoys, and other materials. This debris typically entangles and kills marine life, including turtles, whales, sharks, dolphins, seals, fish and seabirds, and ghost nets can suffocate corals. According to one estimate, hundreds of thousands of tons of fishing gear are thrown into ocean every year.
Microplastics are plastic particles smaller than 5 mm in length, width and height. There are currently two types of microplastics in world: primary microplastics and stimulating microplastics.
Primary microplastics include resin pellets that are melted down and used to make plastic items known as plastic spheres, and micropellets that are added as abrasives to products such as cosmetics, soaps and toothpaste. Secondary microplastics come from fragments of larger plastic objects. Microfibers are plastic threads that are woven together to make fibers such as polyester, nylon, and acrylic. During normal wear and washing, microfibers are released into air and water.
Marine Debris Plot
Due to ocean currents, marine debris often accumulates in so-called garbage patches. In world's largest gyre, these "garbage patches" can stretch over 2.6 million square kilometers. The main component of trash patch is plastic.
Actually, term "patch" is a misnomer, as term refers to floating islands of debris. In fact, a patch of ocean debris is more like sweet and sour soup, because most of debris is microplastic, and debris is found in entire water layer of ocean, and not just floating on surface of ocean. One of world's largest marine garbage patches is Great Pacific Garbage Patch (or East Pacific Garbage Patch), located between California and Hawaii.
On Earth, there are five major oceanic gyres generated by global interaction of wind and tides: North and South Pacific gyres, North and South Atlantic gyres, and Indian Ocean gyres. Ocean gyres can collect marine debris into large debris patches. Currently, there are garbage patches in five major gyres of world, in addition, people often find buthigh debris patches in some small gyres.
Polyethylene terephthalate is one of most widely used plastics. It is a transparent, lightweight and durable plastic belonging to polyester family. Polyethylene terephthalate is commonly used to make common household items such as fibers, textiles, beverage bottles, and food cans.
Plastics, also known as polymers, are made by joining together small building blocks (unit cells). Chemists refer to these basic building blocks as structural units, which are mostly made up of groups of atoms. These groups of atoms come from natural products or compounds of basic chemicals in oil, gas, and coal. For some plastics, such as polyethylene, repeating unit structure may consist of one carbon atom and two hydrogen atoms. For other plastics, such as nylon, repeating link structure may include 38 or more atoms. After assembly, chain of structural unit becomes strong, durable and very useful. But if they are disposed of haphazardly, they can create big problems for environment.
Single-stream recycling means that all recyclable items such as newspapers, cardboard, plastic, metal and glass are recycled in one container. Recycled materials are sorted by machines and people at recycling center, not by homeowner. There are pros and cons to this approach. Proponents say this approach will increase public participation in recycling activities, while opponents say it will lead to more pollution, eventually leading to some recyclables ending up in landfills and making disposal more expensive. .
Disposable plastic items
As the name implies, single-use plastics are plastic items that are used only once, such as thin grocery bags and packaging film that wraps everything from food to toys. About 40% of non-fiber plastics are used in packaging. Environmentalists often urge people to cut back on single-use plastics and opt for more durable and multi-purpose items like metal water bottles and cotton shopping bags.
(Translation: Stray dog)