Environmental impact analysis of the hottest plast

Environmental impact analysis of plastic packaging

plastic products have been seen everywhere in our daily life, and have entered all walks of life and thousands of households on a large scale, which has brought a profound impact on many aspects of our life. However, due to the great relevance of plastic products, especially to daily life, the plastic packaging created by cosys for material suppliers has brought a series of environmental problems [1]. "White pollution" has become a household name for environmental pollution caused by plastic packaging [2]. Therefore, since the late 1980s, countries around the world have attached great importance to plastic packaging and environmental issues [3]. At present, the current situation of the use and treatment of plastic packaging constitutes environmental problems mainly in the following aspects: plastic packaging is abused and discarded everywhere, causing white pollution; Stacking, landfilling and crushing residues in the soil environment cause harm; Incineration is easy to discharge waste, causing secondary pollution to the atmosphere [4]. The following is an item by item analysis of their impact on the environment to clarify their pollution degree and occurrence probability, so as to attract the attention of relevant parties

1 the abuse of plastic packaging materials is discarded everywhere, causing white pollution

now on both sides of the road in the urban-rural fringe, plastic bags and plastic films are floating on the branches, and all kinds of discarded plastic bags, fast-food boxes, and beverage bottles can be seen everywhere on the road slopes along the railway, commercial streets, stations, wharves, and around the farmers' markets. According to relevant information, the total output of plastic products in China in 1995 was close to 7million tons, of which 25% (1.7 million tons) were used for packaging, of which 500000 tons of packaging will be discarded as waste [5]. According to the sampling survey of Beijing, Tianjin and Shanghai, there are 1.8 ~ 2.5 billion plastic bags, one per capita per day; 150 ~ 220 million disposable fast food boxes per year, about 500000 ~ 600000 per day; Agricultural film covers an area of 6.75 million square meters and hundreds of millions of beverage bottles every year. Although the total weight of these varieties ranges from 50000 to 60000 tons throughout the year, accounting for 7% to 10% of the total weight of municipal solid waste (garbage), most of them enter the municipal solid waste treatment system due to their large volume, wide range, light weight and low recycling value [6,7]. The other part is the daily public littering of plastic packaging that cannot be treated with the garbage treatment system, which constitutes plastic garbage, affects the city's appearance and landscape, and constitutes the main source of white pollution. Due to the non degradability of its plastic waste, its random disposal will have varying degrees of impact on the environmental landscape, public health, urban facilities and ecological balance

1.1 plastic packaging materials are discarded at random or stacked, and poor management has an impact on the environmental landscape

as such materials are light in weight, they will bring dirt and chaos to the tourist attractions of the city and the author's unit: Tianjin Institute of labor health and occupational diseases (300204) [6]. A large number of plastic packages scattered in the busy streets and tourist attractions are flying with the wind, either falling on the roadside green space or hanging high on the branches, causing trouble to the sanitation workers and making the price of finished products far higher than the current price of ordinary mulching film, which is extremely incompatible with a civilized and tidy city. Therefore, the treatment of white pollution is an important aspect of maintaining a healthy city and establishing a clean and tidy world big city image

1.2 waste plastic packaging is a breeding ground for mosquitoes, flies and bacteria

[8] due to the residues on waste plastic packaging, such as food residues in fast-food boxes, sugar in beverage bottles, etc., will provide a breeding ground for mosquitoes, flies and bacteria to survive and reproduce, especially in spring and summer, some common microorganisms such as bacillus, Achromobacter, octococcus Old cocci can grow rapidly on the plastic packaging stacked or scattered in the city. At the same time, it can also cause a large number of mosquitoes and flies to breed, endanger the health of the urban public and affect environmental health. According to the monitoring around the stacking of solid wastes such as waste plastics, the total number of bacteria in the airborne microorganisms can reach 8542cfu/m2, and mosquitoes and flies breed in large numbers. Therefore, white pollution should be eliminated for our living environment

1.3 randomly discarding and stacking plastic packages flying with the wind not only hinders the appearance of the city, but also causes failures to urban facilities. In spring, Tianjin is a windy season, and plastic bags flying with the wind can be wrapped around overhead power lines to cause short circuit accidents. According to the statistics of the power industry department, in 1996, more than 10 power outages occurred in Tianjin, causing undue losses to industrial and agricultural production and people's lives. 1.4 random discarding and stacking of plastic packaging can lead to the death of livestock and wild animals. In rural areas and some nature reserves, due to the random discarding of broken plastic packaging, which is eaten by livestock and wild animals or inadvertently mixed into food, it will cause gastric or intestinal obstruction of animals, affect digestive function, and seriously lead to death. Large animals often die from eating plastic products in urban zoos, which makes rare wild animals die needlessly and causes great losses to the country [5,7]

2 the impact of the burial treatment of waste plastic packaging on the environment

2.1 the burial treatment of waste plastic or solid waste is a technology suitable for China's national conditions. However, plastic packaging itself is a polymer material, which is strong and durable, difficult to degrade, and slow to be decomposed by biology or sunlight. The National Journal of environment and Health reported that the blood in the hospital surgical catheter buried for many years had not yet coagulated; The words and patterns of newspapers buried for more than 40 years can still be seen clearly [9]. This is because the burial site is buried in a compact way after being covered with soil. It is difficult for microorganisms to decompose organic matter in the dark and in the air and environment. Microorganisms usually decompose organic matter effectively under the conditions of 32 ~ 35 ℃ and suitable air and humidity. At the same time, too many space-time gaps will cause ground instability. Some abandoned food containers are mostly adhered to residual food, and the residual food will produce malodorous sewage after corruption, which will also seriously pollute the environment

2.2 the impact of waste plastic packaging on Soil and crops

mainly comes from the use of plastic greenhouses and mulching films. The cultivation technology of agricultural film mulching has developed rapidly since its introduction, which has brought good economic benefits. At the same time, the fragmentation and littering of plastic film has brought great harm to the soil [10,11]. At present, the agricultural film used in our country is difficult to recover and decompose under natural conditions. Moreover, the development of plastic film in our country is getting thinner and thinner, and the tension is small. The used film is easy to be broken after aging. If it is not cleaned in time, it will form a large number of residual film fragments left in the field, forming a barrier layer to the soil, reducing the ventilation and permeability of the cultivated soil, deteriorating the cultivated land, and hindering the development of plant roots and the absorption of water and nutrients. Beijing Agricultural Environmental Protection Department has conducted artificial simulation experiments and large-scale investigations on the harm of agricultural film to soil, and concluded that the yield of farmland crops with broken film is generally lower than that without broken film, and the range of low is different from crop to crop, among which rape is 54.2% lower; Chinese cabbage is 9.8% lower; Wheat is short of seedlings and ridged more, and the total base number and particle weight are greatly reduced. At the same time, it is also pointed out that the amount of residual broken film in farmland is generally one-third of the amount used. If plastic film is used for five consecutive years, the residual broken film per mu can reach 32kg. Planting wheat on this soil generally reduces the yield by 26% - 30%. In this regard, experts call for: save the soil and leave fertile land for future generations [12]

3 impact of incineration of waste plastic packaging on the environment

incineration of solid waste is the most fundamental treatment to solve the pollution, but there may be some problems that cannot be solved technically in the incineration of plastic products, which will constitute a new environmental pollution problem [13]

3.1 general plastics are organic polymers, mostly composed of carbon, hydrogen, oxygen and other elements, so they have high heating characteristics. The calorific value of a single piece of plastic is between 500 ~ 10000 kcal per kilogram [14]. Too high temperature makes the incinerator easy to burn the castor, and the molten plastic may also block the eyelet of the castor. Because there is a certain upper limit on the maximum heating capacity of the incinerator design, too high heating capacity will lead to the melting of refractory materials in the incinerator, affecting the service life and efficiency of the incinerator

3.2 during the combustion of organic matter, two chemical reactions occur with different temperatures, namely thermal decomposition and combustion. Thermal decomposition can be divided into thermal decomposition and thermal oxygen decomposition due to different conditions. Taking the combustion of fast food box as an example, when the temperature is lower than 80 ℃, the substance can be kept unchanged, and the location of cracks in the sample may occur at the time of strong force, and most of them are at the position of fracture force. When the temperature rises to 280 ℃, thermal decomposition begins to occur, its molecular weight begins to decline, and volatile substances are produced, including styrene units (44%), dimers (22%) Trisomy and a small amount of toluene ethyl benzene, etc. Table 1 lists the decomposition of fast food boxes at different temperatures: Table 1 name of plastic decomposition at different temperatures 425 ℃ 525 ℃ 625 ℃ 725 ℃ 825 ℃ 1025 ℃ 1125 ℃ styrene 64.367.574.483.973.762.964.3 ethyl benzene toluene trace trace 0.92.55.65.8 benzene trace 8.113.413.0 acetylene trace 4.16.96.8 ethylene trace 4.16.96.8 residual 35.732.525.614.47.54.33.3 it is also reported that some monomers are produced in the incineration of chlorinated plastics such as PVC The monomer and dimer can also produce toxic substances and carcinogens, such as hydrogen chloride and dioxin (TCDD) [14]. These organic monomers and some highly toxic substances have a great impact on human body. 3.3 in addition, in the process of incineration, different oxygen supplies can also produce some toxic substances, especially in the case of insufficient oxygen supply, it will produce a large amount of carbon monoxide, causing hemoglobin in human blood to become carbon monoxide heme, making the blood lose its oxygen carrying function. Some people have carried out combustion experiments on natural and synthetic materials, and conducted animal experiments on complete combustion products to observe the survival rate of mice as an assessment of the toxicity of combustion products. The results are shown in table 2[14]. It can be seen from table 2 that the combustion products of PS have the least impact on rats, while some plastic combustion products, in addition to carbon monoxide, have enough products to kill rats. Table 2 Effects of different combustion products on animals material number of animal deaths (animals) average co Hb concentration in blood Yangshan 538.7fr synthetic board 548.4pvc5221.2pv524.3ps023.9 in addition, some toxic metals of plastic coloring pigments enter the environment during incineration and cause pollution

4 conclusion

to sum up, in the current industrialized countries, plastic packaging is more and more closely related to people's daily life, which has posed a certain harm to the environment. Choose new plastic materials, including photosensitive degradation, biodegradation and other degradation composites [15,16], and choose various design and recycling methods to solve the problem of white pollution according to the principles of reduction, recycling and harmlessness. According to this principle and in combination with China's national conditions, we should take the path of environmental protection, which is mainly recycling, supplemented by carbon structural steel GB 700 (8), treated differently, and comprehensive and reasonable, so that white pollution can be overcome in a short time, protect our beautiful environment, and benefit future generations

author/Wang yanrang, Wang Qian