Common plastic racetracks are divided into polyurethane (composite, hybrid and permeable), prefabricated rubber coiled material and water-based plastic. Polyurethane is relatively cheap, easy to lay, the largest market use, but also the protagonist of the recent "poison runway."
How "poisonous" is the "poisonous runway"?
Where are the "poison runway" and "poison"?
In fact, chemicals are toxic to some extent. As long as toxic substances are defined within certain limits and will not cause harm to human body and environment, they belong to environmental protection products. The national standard GBT14833-2011restricts the toxic substances in the runway. As long as the plastic track meets the national standards, it will generally not endanger health.
At present, all the manufacturers that meet the production standards use qualified polyurethane particles, but most of the recently exposed plastic runways are black-hearted businesses driven by interests, and a large number of waste materials such as recycled polyether, industrial toxic paraffin wax and drier are used. In the construction, the process is not standardized, a large number of diluents (such as toluene, xylene and other heavy and toxic diluents, natural water and gasoline) are used, and cheap inorganic fillers are added, which finally reduces the cost of plastic materials and makes some of them toxic.
Recently, CCTV Financial Channel also reported several "black-hearted" dens that use waste tires and optical cables to process runway raw materials. Piles of waste tires, plus some chemicals, are converted into one of the main raw materials for the runway.
Many exposed "poisonous runways" contain irritating smells. Shi Jianhua, one of the main drafters of the national standard of "Plastic Runway" in China, explained that the odor of plastic runways mainly comes from chloride, residual free diisocyanate (TDI), residual organic lead, residual sulfide in EPDM color particles and residual sulfide in black particles in polyurethane (PU) glue.
Once these toxic substances exceed the standard, they will lead to dizziness, vomiting, fainting and even cancer, which is harmful to human beings, animals and plants and the environment. Moreover, after this inferior runway is paved, harmful substances may not be clean for several years, especially in hot weather or strong ultraviolet radiation, which will accelerate the release of malodorous gases and poison the campus and the atmosphere.
How "poisonous" is the "poisonous runway"?
Who did the "poisonous runway" hurt?
Students in the center of the whirlpool of "poison runway" are the first to respond to "poison".
Parents of students in many schools report that their children have nosebleeds, persistent cough and itchy skin due to the new "toxic runway" on campus. In some classes, more than half of the students feel unwell. Some parents worry that their children will get leukemia because of these toxic substances.
Exposure time and concentration will directly affect the impact of harmful substances on children's health. Generally short-term contact will metabolize some harmful substances in the body's immune function. But if you don't consciously contact for a long time, it may cause chronic poisoning.
As for the leukemia problem that parents are worried about, some immunologists said that it is difficult to make a clear conclusion because they have not seen the child's blood sample, but according to the symptoms reported in the news, it is unlikely that they will suffer from leukemia. Nosebleeds are probably irritating gases released by toxic chemicals, such as hydrogen chloride and ammonia, which cause nasal mucosa irritation, capillary congestion and rupture of students.