Researchers in Hong Kong are working to cut off a major source of marine plastic: polystyrene (PS) plastic foam boxes widely used in the fishing industry. Scientific research shows that PS is harmful to marine life and human health, but the fishery industry has been slow to respond. The problem is that if alternative materials want to be widely used, they must be as easy to use and cheap as PS. The most typical PS product is a white foam-like material called foam plastic, which is widely used in various food containers, coffee cups, bean bags, and even insulation materials. An industry report shows that as one of the most commonly used materials in the world, PS production reached 17.5 million tons in 2014. Among them, more than 40% are consumed in the Asia-Pacific region. Dr. Chelsea Rochman, a marine ecologist from the University of Toronto, said: "If we can avoid using one plastic product, it should be polystyrene. Styrofoam plastic is the most common type of garbage that washes up on the coast. The material is not sustainable, so there is no reason to continue using it.” The problem starts with production. PS is polymerized from two raw materials, styrene and benzene, and is made into foamed plastic after foaming treatment. It is well known that both styrene and benzene are carcinogens. In addition, toxic flame retardants are sometimes added to foam plastic products. These toxic substances will leach out of plastic products during the heating process, so environmentalists around the world recommend not using PS in food packaging. A survey by the US activist group Clean Water Action shows that approximately 80% of marine debris comes from land. Among the floating debris in the ocean, 90% are all plastic products. They "travel" around the world along with the five major circulations. Sunlight, salt and water corrode plastics, eventually breaking them down into tiny particles. These plastic particles are about the same size as plankton. They will enter the marine food chain and eventually appear on our dinner tables. As early as 30 years ago, the U.S. Environmental Protection Agency found polystyrene residues in 100% samples of human fat tissue it collected. The disposal of PS waste is a problem because no one is willing to recycle this type of waste. Plastics Recyclers Europe is an association of 120 industry members. Bernard Merkx, honorary president of the association, said: "It's not that PS cannot be recycled, but because its utilization value is so low, its weight and limited applicability make people feel that it is not worth recycling at all." Dr. Rochman said that PS, especially The quality of expanded polystyrene is too small and the volume is too large, so recycling is not cost-effective. "The tipping fee for recycling is calculated by the pound. Expanded polystyrene takes up a lot of space but is lightweight, so the actual recycling rate is very low." Plastic that cannot be recycled is eventually buried, but in countries with poor waste management , buried material often ends up in the ocean as well. Considering the challenges of recycling PS, people decided to change direction and try to replace it with another material. But PS boxes are not only lightweight and cheap, but also easy to carry. Therefore, suitable alternative materials must also have similar characteristics. Polypropylene (PP) is a plastic alternative to PS that is both ductile and insulating. Although PP packaging boxes are more expensive to produce, they are favored by recycling companies. In other words, the retained value of used PP packaging boxes is higher. The latest data from the Association of Plastics Recyclers shows that the annual post-consumer recycling rate of PP products is less than 1%, but the annual demand in North America alone is as high as 454,000 tons. According to the International Solid Waste Alliance (ISWA), there are many reasons why recycling rates are so low. Chief among these are the varying quality of recyclable materials and insufficient recycling infrastructure. ISWA also mentioned the lack of international quality standards. At present, virgin PP is generally more affordable than various recycled materials, but as more and more plastic products are recycled and reused, this situation may change in the future. The low recycling rate shows that a large part of PP will still flow into the ocean. After the coastal cleanup operation carried out in the South China Sea in 2015, researchers found that almost 60% of small plastic waste was PP. Although PP material is relatively inert and is a hydrocarbon, it does not release toxic substances like polystyrene. However, if you want to use PP to replace PS, you must first improve the recycling facilities and collection process, otherwise it will just be used One type of plastic pollution simply replaces another. Nowadays, the world is gradually beginning to use foamed PP to replace foamed PS. In particular, foamed PP is easy to use and has small impact resistance. Foamed PP has been widely used and recognized in the automotive industry. On the fisheries side, the first substitution and trial results have been very promising. Fisheries people are very receptive to our advice. After all, when it comes to the impact of marine environmental pollution, fisheries bear the brunt. Source: Chinadialogue (2017-11-15) (PIDC compilation)
