Dioxin is a colorless, odorless and highly toxic fat-soluble substance. Dioxin is actually a short name. It refers not to a single substance, but to two organic compounds with similar structures and properties, namely polychlorinated dibenzo-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). In China's environmental standards, they are collectively referred to as dioxins.
Polychlorinated dibenzo-dioxins consist of two oxygen atoms and two benzene rings substituted by chlorine atoms. Polychlorinated dibenzofurans consist of 1 oxygen atom and two benzene rings substituted by chlorine atoms. Each benzene ring can replace 1~4 chlorine atoms, thus forming a variety of isomers, including 75 isomers of PCDDs and 135 isomers of PCDFs.
Therefore, dioxins include 265,438+00 compounds, which are very stable, have a high melting point, are extremely insoluble in water, can be dissolved in most organic solvents, and are colorless and odorless fat-soluble substances, so they are very easy to accumulate in organisms. Microorganisms and hydrolysis in nature have little influence on the molecular structure of dioxins, so it is difficult to naturally degrade and eliminate dioxins in the environment.
It includes 2 10 compounds. It is very toxic, which is 130 times that of cyanide and 900 times that of arsenic. It is called "the poison of the century".
The International Center for Research on Cancer has listed it as a human first-class carcinogen. Environmental experts say that "dioxins" often exist in the atmosphere, soil and water in the form of tiny particles, and the main pollution sources are chemical metallurgy industry, garbage incineration, paper making and pesticide production.
Plastic bags, PVC (polyvinyl chloride) soft glue and other daily necessities all contain chlorine. When these things burn, they will release dioxins and suspend them in the air. The toxicity of dioxins varies with the substitution position of chlorine atoms. Therefore, in environmental health risk assessment, the equivalent toxic dose (TEQ) is obtained by multiplying its content by the toxic equivalent factor (TEFs).
Among dioxins, 2,3,7,8-tetrachlorodibenzo-p-dioxins (2,3,7,8-tetrachlorodibenzo-p-dioxins, 2,3,7,8-TCDD) are the most toxic and studied. (1) 90% of dioxins in the atmospheric environment come from municipal and industrial waste incineration.
Lead-containing gasoline, coal, wood after antiseptic treatment, petroleum products and various wastes, especially medical wastes, are prone to produce dioxins when the combustion temperature is lower than 300-400℃. The production process of PVC plastics, paper, chlorine gas and some pesticides, iron and steel smelting, high-temperature chlorine gas activation catalyst and other processes will release dioxins into the environment.
Dioxins also exist as impurities in some pesticide products, such as pentachlorophenol, 2,4,5-T and so on. The formation mechanism of dioxins in the process of municipal industrial waste incineration is still under study.
At present, there are three main ways: 1. In the incineration process of chlorine-containing plastics such as vinyl chloride, the incineration temperature is lower than 800℃, and chlorine-containing garbage is not completely burned, which is easy to produce dioxins. Chlorobenzene is produced after combustion, which becomes the precursor of dioxin synthesis; 2. Other chlorine-containing and carbon-containing substances, such as paper, wood products, food residues, etc., are catalyzed by metal ions such as copper and cobalt to generate dioxins, without chlorobenzene.
3. It comes from the process of manufacturing chemicals including pesticides, especially chlorine-containing chemicals, such as pesticides, herbicides, wood preservatives, defoliants (used by the US military in the Vietnam War), polychlorinated biphenyls and other products. The concentration of dioxins in the atmosphere is generally low.
Compared with rural areas, the atmosphere in cities, industrial areas or areas close to pollution sources contains higher concentrations of dioxins. The amount of dioxin exposed by the general population through respiratory route is very small, that is, it is estimated that it is about 1% ingested through the digestive tract, which is about 0.03pgTEQ(kg? D) test.
In some special cases, the amount of dioxins exposed through respiratory route can not be ignored. According to the survey, the dioxin content in the blood of waste incineration employees is 806pgTEQ/L, which is about 40 times that of the normal population.
Dioxins discharged into the atmospheric environment can be adsorbed on particles, settled in water and soil, and then enriched in the food chain to enter the human body. Food is the main source of dioxins in human body.
Placenta and lactation can lead to exposure of fetuses and babies to dioxins. People who have frequent contact are more likely to get cancer.
(2) Health effects Dioxin is the representative of environmental endocrine disruptors. They will interfere with the endocrine of human body and have a wide impact on health.
Dioxins can cause ovarian dysfunction in female animals, inhibit the effect of estrogen, and make female animals infertile, have fewer fetuses and miscarry. Low doses of dioxins can cause cleft palate and hydronephrosis in fetal rats.
Male animals given dioxins will suffer from sperm cell reduction, mature degeneration and feminization. Epidemiological study found that the serum testosterone level of male workers exposed to 2,3,7,8-TCDD decreased, while follicle stimulating hormone and luteinizing hormone increased, suggesting that it may have anti-androgen effect and make men feminine.
Dioxin has obvious immunotoxicity, which can cause thymus atrophy, cellular immunity and humoral immunity decline in animals. Dioxin can also cause skin damage. Hyperkeratosis, pigmentation and chloracne can be observed in exposed experimental animals and people.
Animals infected with dioxin may have hepatomegaly, hypertrophy of parenchymal cells, and degeneration and necrosis in severe cases. 2,3,7,8-TCDD is extremely carcinogenic to animals.
Exposure to 2,3,7,8-TCDD can induce tumors in many parts of experimental animals. Epidemiological studies show that exposure to dioxins will increase people's risk of cancer.
According to the results of animal experiments and epidemiological studies, the International Agency for Research on Cancer (IARC) identified 2,3,7,8-TCDD as a kind of human carcinogen in 1997. (3) Prevention and control measures 1. Actively advocate the classified collection and treatment of garbage. Control unorganized garbage incineration. Adopt new incineration technology, increase the combustion temperature (above 1200℃), and reduce dioxin emission.
3. Establish the environmental quality standard and daily allowable intake TDI of dioxins in the atmosphere. 1998 who -ECEH/IPCS reconsidered the TDI of 2,3,7,8-tcdd and suggested that the TDE of dioxins should be 1-4pgTEQ/kg.
According to the latest research progress, some countries have successively formulated or revised TDI of 2,3,7,8-TCDD or dioxin.
What is dioxin and how harmful is it?
Dioxin usually refers to a group of polychlorinated planar aromatic compounds with similar structure and physical and chemical properties, belonging to chlorinated oxygen-containing tricyclic aromatic compounds, including 75 polychlorinated dibenzo-dioxins and 135 polychlorinated dibenzofurans, abbreviated as PCDD/Fs. The most studied toxic dioxins are 17 homologues and isomers (homologues), and chlorine atoms are substituted at positions 2, 3, 7 and 8. Among them, 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) is the most toxic dioxin in all known compounds (oral). It also has many toxic effects, such as strong carcinogenicity (the dose of rat liver cancer is 10μg/g) and extremely low environmental endocrine disrupting dose. Such substances are neither artificially produced nor used, but by-products of combustion and various industrial production. At present, the main sources of dioxins in the environment are wood preservation and the use of chlorophenol to prevent evaporation caused by schistosomiasis, the discharge from incineration industry, the use of defoliants, the preparation of pesticides, the bleaching of paper and the emission of automobile exhaust.
Dioxin is a highly toxic substance, and its toxicity is equivalent to 130 times of cyanide and 900 times of arsenic. A large number of animal experiments show that very low concentration of diquat is lethal to animals. Some toxic data and clinical manifestations of dioxins have been obtained from victims of occupational exposure and industrial accidents. Exposure to the environment containing PCDD or PCDF will cause skin ulcers, headaches, deafness, depression, insomnia and other symptoms, and may lead to chromosome damage, heart failure, cancer and so on. Some research results show that dioxins may also lead to fetal development failure, a significant decrease in the number of men, and so on. The ways to harm people include diet, air inhalation and skin contact. Some experts pointed out that human exposure to dioxin pollution may lead to male fertility loss, infertility, early puberty of women, diseases of fetuses and lactating babies, decreased immune function, decreased IQ and mental illness.
In addition, there are lethal effects, "wasting syndrome", thymus atrophy, immunotoxicity, hepatotoxicity, chloracne, reproductive toxicity, developmental toxicity, teratogenicity and carcinogenicity.
Dioxin control organization: Anhui Chuzhou Smart City Environmental Protection Technology Co., Ltd.
What is dioxin and how harmful is it?
Dioxin, also known as dioxin (qǐ), is a colorless, odorless and highly toxic fat-soluble substance. Dioxin is actually the abbreviation of dioxin, which refers to two organic compounds with similar structures and properties, including many homologues or isomers.
Dioxins include 2 10 compounds, which are very stable, have a high melting point, are extremely insoluble in water, and can be dissolved in most organic solvents. They are colorless and odorless fat-soluble substances, so they are very easy to accumulate in organisms and cause serious harm to human body. Main hazards: 1. The main ways to enter the human body are respiratory tract, skin and digestive tract.
It can cause serious skin injury diseases, has strong carcinogenic and teratogenic effects, and also has reproductive toxicity, immunotoxicity and endocrine toxicity. 2. If the human body is exposed to high concentrations of dioxins for a short time, it may cause skin damage, such as chloracne and skin dark spots, and changes in liver function.
If exposed for a long time, it will damage the immune system, developmental nervous system, endocrine system and reproductive function. Studies have shown that the cancer mortality rate of workers exposed to high concentrations of dioxins is 60% higher than that of the general population.
The most sensitive consequences of dioxins entering human body include endometriosis, the influence on the behavioral development of nervous system (recognition), the influence on the development of reproductive system (* * *, the number of female genitourinary system abnormalities) and immunotoxicity. Preventive measures at present, it is difficult to treat dioxins as substances that are pollution-free to the environment and human beings.
Although other methods are still under study, incineration is still the most feasible method, which requires high temperature above 850 degrees. In order to eliminate a large number of pollutants, sometimes even the temperature of 1000 degrees or even higher is needed.
In order to reduce the harm of dioxins to human health, the most fundamental measure is to control the emission of dioxins in the environment, thus reducing their silence in the food chain. In the past decade, the measures taken by many developed countries to control dioxin emissions have greatly reduced dioxin exposure.
Since 90% people are accidentally exposed to dioxins through diet, ensuring food supply is a very critical link. Food contamination can occur at any stage from farm to table.
Ensuring food safety is a continuous process from production to consumption. In the initial process of production, processing, distribution and sales, good control and operation norms are very important for the production of safe food.
The food pollution monitoring system must ensure that dioxin does not exceed the prescribed allowable amount. Once a pollution incident is suspected, the state should take emergency measures to identify, detain and dispose of those unsafe foods.
For exposed people, check the degree and influence of exposure.
What is dioxin? How to restrain dioxins produced by garbage incineration?
Dioxin is a kind of substance that can combine with aromatic hydrocarbon receptors and cause various biochemical changes.
It is not artificially produced, has no use, is difficult to biodegrade, is enriched in the food chain, poses a serious threat to the environment and health, and has become a global environmental problem and public health problem. It is a colorless, odorless and highly toxic fat-soluble substance. It does not refer to a single substance, but to two organic compounds with similar structures and properties, including many homologues or isomers.
Including 2 10 compounds, it is very stable, has a high melting point, is extremely insoluble in water, can be dissolved in most organic solvents, and is a colorless and odorless fat-soluble substance. Dioxin produced by garbage incineration can be controlled by adding dioxin inhibitors during incineration.
Spray it into the garbage to remove some chlorine elements. 1. Spray dioxin inhibitor in the middle and low temperature area of the furnace to prevent the garbage from catalyzing and generating dioxins.
2. Spray dioxin inhibitor in the low temperature area of flue gas to prevent the adsorbed dioxin from being synthesized again. The physical and chemical characteristics of dioxin inhibitor are 1, water-soluble liquid 2, no heavy metal and no secondary pollution.
3. Biodegradable and environmentally friendly. For more technical and usage matters, please contact Guo Gong, an expert in Paian technology industry. .
What is dioxin? What's the use?
1. What is dioxin? How are dioxins produced? Dioxin is actually an abbreviation, which refers to two organic compounds with similar structures and properties, including many homologues or isomers. The full names are polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), which are collectively referred to as dioxins in China's environmental standards.
Polychlorinated dibenzo-dioxins consist of two oxygen atoms and two benzene rings substituted by chlorine atoms. Polychlorinated dibenzofurans consist of 1 oxygen atom and two benzene rings substituted by chlorine atoms. Each benzene ring can replace 1~4 chlorine atoms, thus forming a variety of isomers, including 75 isomers of PCDDs and 135 isomers of PCDFs.
Therefore, dioxins include 265,438+00 compounds, which are very stable, have a high melting point, are extremely insoluble in water, can be dissolved in most organic solvents, and are colorless and odorless fat-soluble substances, so they are very easy to accumulate in organisms. Microorganisms and hydrolysis in nature have little influence on the molecular structure of dioxins, so it is difficult to naturally degrade and eliminate dioxins in the environment.
2. What are the serious hazards of dioxins to human health? The biggest harm of dioxins is irreversible "three-cause" toxicity, that is, teratogenicity, carcinogenesis and mutation. May cause fetal death, organ structure destruction and permanent organ damage in early development, or developmental retardation and reproductive defects; It can interfere with the hormone secretion of reproductive system and endocrine system, leading to the decrease of male * * * quantity, the decline of male * * * quality, the interruption of testicular development, permanent sexual dysfunction, gender self-cognition disorder and so on. Causes canceration deformity of female uterus, breast cancer, etc. It may also cause permanent obstacles to children's immune ability, intelligence and sports ability, such as ADHD, dementia and low immune function.
According to the latest case reports and animal experiments, the lifetime carcinogenic probability of 2,3,7,8-TCDD can reach1100-12g. Dioxin is currently recognized as the most toxic environmental hormone.
Environmental hormone refers to an exogenous chemical substance that interferes with the normal hormone function of human body. Its structure is similar to endocrine hormone, which can cause endocrine disorder, also known as environmental hormone or endocrine disruptor. Environmental hormones enter the human body or wild animals through environmental media and food chain, interfere with their endocrine system and reproductive function system, and affect the survival and reproduction of future generations.
Dioxin is a persistent organic pollutant (persistent organic pollutants), which persists in the environment and is constantly enriched. Once ingested, organisms are difficult to decompose or excrete, and will spread and accumulate with the food chain.
Humans are at the top of the food chain and the last gathering place of this pollution. The impact of dioxins on people can be described as "tuning".
General pollutants will have obvious harmful effects (i.e. action threshold) only when they reach a certain dose, but the action threshold of dioxins has not been studied so far. As long as it is an "ultra-micro" dose, it may cause harm, and the harm to infants is more obvious and irreversible. Another feature of dioxin hazards is its long-term nature and concealment. There is a long latent process before obvious symptoms appear, which may affect human offspring.
Therefore, some scientists even worry about whether human evolution will be terminated by such substances.
What is dioxin? What's the use?
1. What is dioxin? How are dioxins produced? Dioxin is actually an abbreviation, which refers to two organic compounds with similar structures and properties, including many homologues or isomers. The full names are polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), which are collectively referred to as dioxins in China's environmental standards. Polychlorinated dibenzo-dioxins consist of two oxygen atoms and two benzene rings substituted by chlorine atoms. Polychlorinated dibenzofurans consist of 1 oxygen atom and two benzene rings substituted by chlorine atoms. Each benzene ring can replace 1~4 chlorine atoms, thus forming a variety of isomers, including 75 isomers of PCDDs and 135 isomers of PCDFs. Therefore, dioxins include 265,438+00 compounds, which are very stable, have a high melting point, are extremely insoluble in water, can be dissolved in most organic solvents, and are colorless and odorless fat-soluble substances, so they are very easy to accumulate in organisms. Microorganisms and hydrolysis in nature have little influence on the molecular structure of dioxins, so it is difficult to naturally degrade and eliminate dioxins in the environment. 2. What are the serious hazards of dioxins to human health? The biggest harm of dioxins is irreversible "three-cause" toxicity, that is, teratogenicity, carcinogenesis and mutation. May cause fetal death, organ structure destruction and permanent organ damage in early development, or developmental retardation and reproductive defects; It can interfere with the hormone secretion of reproductive system and endocrine system, leading to the decrease of male * * * quantity, the decline of male * * * quality, the interruption of testicular development, permanent sexual dysfunction, gender self-cognition disorder and so on. Causes canceration deformity of female uterus, breast cancer, etc. It may also cause permanent obstacles to children's immune ability, intelligence and sports ability, such as ADHD, dementia and low immune function. According to the latest case reports and animal experiments, the lifetime carcinogenic probability of 2,3,7,8-TCDD can reach1100-12g.
Dioxin is currently recognized as the most toxic environmental hormone. Environmental hormone refers to an exogenous chemical substance that interferes with the normal hormone function of human body. Its structure is similar to endocrine hormone, which can cause endocrine disorder, also known as environmental hormone or endocrine disruptor. Environmental hormones enter the human body or wild animals through environmental media and food chain, interfere with their endocrine system and reproductive function system, and affect the survival and reproduction of future generations.
Dioxin is a persistent organic pollutant (persistent organic pollutants), which persists in the environment and is constantly enriched. Once ingested, organisms are difficult to decompose or excrete, and will spread and accumulate with the food chain. Humans are at the top of the food chain and the last gathering place of this pollution.
The impact of dioxins on people can be described as "tuning". General pollutants will have obvious harmful effects (i.e. action threshold) only when they reach a certain dose, but the action threshold of dioxins has not been studied so far. As long as it is an "ultra-micro" dose, it may cause harm, and the harm to infants is more obvious and irreversible.
Another feature of dioxin hazards is its long-term nature and concealment. There is a long latent process before obvious symptoms appear, which may affect human offspring. Therefore, some scientists even worry about whether human evolution will be terminated by such substances.
How are dioxins produced?
Plastic bags, PVC (polyvinyl chloride) soft glue and other daily necessities all contain chlorine. When these things burn, they will release dioxins and suspend them in the air. Lead-containing gasoline, coal, wood after antiseptic treatment, petroleum products and various wastes, especially medical wastes, are prone to produce dioxins when the combustion temperature is lower than 300-400℃. The production process of PVC plastics, paper, chlorine gas and some pesticides, iron and steel smelting, high-temperature chlorine gas activation catalyst and other processes will release dioxins into the environment. Dioxins also exist as impurities in some pesticide products, such as pentachlorophenol, 2,4,5-T and so on.
At present, there are three main ways: 1. In the incineration process of chlorine-containing plastics such as vinyl chloride, the incineration temperature is lower than 800℃, and chlorine-containing garbage is not completely burned, which is easy to produce dioxins. Chlorobenzene is produced after combustion, which becomes the precursor of dioxin synthesis; 2. Other chlorine-containing and carbon-containing substances, such as paper, wood products, food residues, etc., are catalyzed by metal ions such as copper and cobalt to generate dioxins, without chlorobenzene. 3. It comes from the process of manufacturing chemicals including pesticides, especially chlorine-containing chemicals, such as pesticides, herbicides, wood preservatives, defoliants (used by the US military in the Vietnam War), polychlorinated biphenyls and other products.
In addition, if the TV set is not cleaned in time, dioxin bromide will usually be detected in the dust accumulated in the TV set.