1. Invasive routes of health hazards: inhalation, ingestion and percutaneous absorption. Health hazard: Xylene can irritate eyes and upper respiratory tract, and can anesthetize central nervous system at high concentration. Acute poisoning: Inhalation of high-concentration nuclear weapons in a short time can cause obvious irritation to eyes and upper respiratory tract, congestion of conjunctiva and pharynx, dizziness, nausea, vomiting, chest tightness, weakness of limbs, confusion and stumbling gait. In severe cases, restlessness, convulsions or coma may occur, and some of them may have hysterical attacks. Chronic effects: long-term exposure to neurasthenia syndrome, irregular menstruation of female workers, dry skin, chapped skin and dermatitis of workers. 2. Toxicological data and environmental behavior toxicity: low toxicity. Acute toxicity: LD50 1364mg/kg (mouse vein) Reproductive toxicity: the lowest toxic concentration of rats (tdl 0): 1500mg/m3, 24 hours (taken at 7 ~14th day of pregnancy), which is embryotoxic. Pollution source: Xylene is an important chemical raw material. Wastewater and waste gas from organic synthesis, synthetic rubber, paint and dye, synthetic fiber, petroleum processing, pharmacy and cellulose, as well as unsealed production equipment and ventilation in the workshop are the main sources of xylene in the environment. Overturning, leakage and fire during transportation and storage can also cause accidental pollution accidents. Metabolic degradation: in humans and animals, except for 3% ~ 6% inhaled xylene, all three isomers of xylene are metabolized into corresponding benzoic acid (60% o-xylene and 80% ~ 90% m-xylene), and then these acids react with glucuronic acid and glycine. In this process, a large amount of o-benzoic acid is combined with glucuronic acid, while p-benzoic acid is almost completely combined with glycine to generate corresponding methylhippuric acid, which is excreted. At the same time, a small amount of corresponding xylenol (phenol) and 3- hydroxy -2- methylbenzoic acid hydride may be formed (less than 2%). Residue and accumulation: In occupational contact, xylene mainly enters the body through respiratory tract. For all isomers of xylene, the vapor absorbed by the lung is the same, the total amount is 60% ~ 70%, and this absorption amount is relatively constant during the whole contact period. Xylene solution can penetrate the whole skin with an average absorption rate of 2.25? G/(cm3 min) (range 0.7 ~ 4.3? G/(cm3 min)) is absorbed, and the transdermal absorption of xylene vapor can be ignored compared with direct contact with liquid. The residual and accumulation of xylene is not serious. As we said above, in the presence of NADP (transferase II) and NAD (transferase I), xylene entering human body can generate methylbenzoic acid, and then combine with glycine to generate methylhippuric acid, which is almost completely excreted in 18 hours. Even the 3%-6% xylene remaining in the lungs after inhalation is exhaled within 3 hours after contact (half-life is 0.5 ~ 1 hour). The residual detection of xylene exposure is mainly to determine the content of methylhippuric acid in urine, and it is also suggested to determine the content of xylene in our gas or blood, but the result of the latter is often inaccurate. Because methylhippuric acid does not exist naturally in urine, and because it is almost a residual xylene metabolite, it is the best confirmation of xylene contact test to determine its existence. Xylene can exist in drinking water for a long time. When the concentration of xylene in tap water is 5mg/L, its odor intensity is equivalent to grade 5, and the unique odor of xylene will disappear after 7 ~ 8 days. When the odor intensity is level 3, it takes 4 to 5 days. The odor of xylene in river water is kept for a short time, which is related to the initial concentration, and can generally be kept for 3 to 5 days. Migration and transformation: Xylene is mainly made from crude oil in petrochemical process. It is widely used as a diluent for pigments and paints, and as a solvent for printing, rubber and leather industries. As cleaning agents and degreasing agents, components of aviation fuel, raw materials and intermediates in chemical factories and synthetic fiber industries, and coating and impregnating materials for fabric and paper. Xylene can be discharged into the atmosphere through mechanical exhaust and ventilation equipment, causing pollution. The amount of xylene discharged into the atmosphere by an oil refinery is as high as 1 3.18 ~145g/h, and xylene can enter the water body with the wastewater discharged by its production and use units, producing1ton of xylene, and the general discharge contains 300 ~1000. Because xylene has a strong volatilization tendency in aqueous solution, it can be considered that xylene is not a persistent pollutant in surface water. Xylene can also be biodegraded in the environment, but the speed of this process is much lower than that of volatilization. Xylene volatilized into the air may also be photolyzed, which is the main migration and transformation process. Adoption rate of anonymous answers: 21.7% 2009-11-0214: 21In recent years, the international community has paid great attention to the deterioration of environmental quality and the imbalance of ecological balance, and mankind is facing the most serious environmental crisis in history. Most environmental pollution is directly related to industry and industrial products. Aromatic amines, as dye intermediates, have been listed as suspected carcinogens by government agencies in some countries, and diethanolamine of benzidine has been proved to be the strongest carcinogen to human beings. Therefore, attaching importance to dye production and emphasizing environmental protection has become a top priority for all countries in the world. The United States, Europe and Japan have all established institutions to study the ecological safety and toxicology of dyes, specifically to understand and study the impact of dyes on human health and the environment, and to formulate indicators of heavy metal content in dyes. The Ecological Committee of American Dye Manufacturers Association independently studied the influence of dyes and auxiliaries on the environment, and determined the concentration range of metal impurities in various commercial dyes.

1992 in April, Germany wrote the content of banned dyes in the first article of the Law on Commodity, but it was not clear, so in July, it issued the second article, namely 1994, 1994, 1995 and1respectively. According to the analysis of Bayer 1994 in Germany, there are 1 18 kinds of banned dyes involved in the German market. According to the application categories, there are 77 kinds of direct dyes, 26 kinds of acid dyes, 6 kinds of disperse dyes, 5 kinds of ice dyes, 3 kinds of basic dyes and 0/kind of oxidized dyes. The SDC resource file of 1999 contains 14 1 azo dyes that can reduce and crack 22 kinds of carcinogenic aromatic amines, which were collected by German VCI (German Chemical Industry Association) according to internal research and the third edition of "Dye Index" 1994, which is the same as that proposed by Bayer Company in Germany. If VCI is combined with the banned dyes proposed by Bayer, there are 146 banned dyes, including 84 direct dyes, 29 acid dyes, 9 disperse dyes, 7 basic dyes, 5 ice dyes, 0/oxidized dyes, 2 mordant dyes and 9 solvent dyes.

According to the new edition of Eco-Tex standard 100 issued in 2000, banned dyes also include allergic dyes, direct carcinogenic dyes and acute toxic dyes, as well as chemicals containing heavy metals such as lead, antimony, chromium, cobalt, copper, nickel and mercury, with formaldehyde content exceeding the limit index, organic pesticides exceeding the limit index, environmental hormones and causing environmental pollution.

The molecular structure analysis of dyes and the actual measurement of dyed fabrics show that dyes synthesized with carcinogenic aromatic amines as intermediates, including azo dyes and other dyes, are prohibited if they are not fully purified, even if they exist in trace amounts. At present, about 70% of synthetic dyes on the market are mainly azo-structures, and the widely used direct dyes, acid dyes, reactive dyes, metal complex dyes, disperse dyes, cationic dyes and polycondensation dyes all contain azo-structures. Azo dyes are not only used for printing and dyeing textiles, but also for dyeing leather, paper and food. It should be pointed out that under normal circumstances, azo dyes themselves will not have harmful effects on human body, but some azo dyes synthesized from carcinogenic aromatic amine intermediates, after long-term contact with human skin, will combine with substances released in normal metabolism of human body and undergo reduction reaction, which will break azo groups and regenerate carcinogenic aromatic compounds. These compounds are absorbed by the human body again, and the structure and function of human cells will change after activation, which will become pathological inducing factors and increase carcinogenicity. At the same time, the banned dyes are not limited to azo dyes, but may also be banned in other dyes, such as sulfur dyes, vat dyes and some additives, because they contain these harmful aromatic amines.

1. Direct dyes Direct dyes are a large number of dyes used in cellulose fibers. Among the first batch of 1 18 banned dyes in Germany, there are 77 kinds of direct dyes, accounting for 65%. Among them, 72 kinds of direct dyes were synthesized with benzidine and dimethyl benzidine as intermediates, and 36 kinds of direct dyes were synthesized with benzidine as intermediates, accounting for almost 50% of the total output of direct dyes. According to statistics, there are 37 kinds of direct dyes banned in China in recent years, accounting for 62.7% of the total number of direct dyes produced in China.

2. Acid Dyes The consumption of acid dyes in the world is second only to sulfur dyes, direct dyes and disperse dyes. There are nearly 30 kinds of acid dyes banned in Germany. There are many kinds of harmful aromatic amines involved, which are widely distributed, such as benzidine, dimethyl benzidine, o-amino anisole, o-toluidine, p-amino azobenzene, 4- amino-3,2-dimethyl azobenzene and dyes themselves causing cancer.

Inside. Chromatograms are mainly concentrated in red and black, and others are distributed in orange, purple and brown chromatograms. Including weak acid orange R (acid orange 45), weak acid scarlet H (acid red 285), acid black NT29 (acid black 29) and so on.

In addition, there are four kinds of prohibited acid dyes in the new edition of Eco-Tex standard 100 published in 2000: there are two kinds of known direct carcinogenic dyes, namely C.I. Acid Red 26 and C.I. Acid Violet 49; The allergic dye involved is C.I. Acid Black 48; The acute toxic dyes involved are C.I. Acid Orange 156, C.I. Acid Orange 165, etc.

3. Among the 1 18 dyes banned in Germany, 6 disperse dyes were banned, and 14 disperse dyes were not listed, but were banned due to the influence of 22 harmful aromatic amines, excluding the components of composite dyes. Among the banned dyes, C.I. Disperse Yellow 23 is a red and yellow disazo disperse dye, which is called Disperse Yellow RGFL in China. Other banned disperse dyes include: Disperse Yellow E-5R (C.I. Disperse Yellow 7), Disperse Orange 2g (C.I Disperse Yellow 56) and C.I. Disperse Orange 149, C.I. Disperse Red 15 1 and C.i.

In the new edition of ECO-TEX standard 100 released in 2000, 26 kinds of allergic dyes were involved. In addition, it is known that there are two kinds of disperse dyes in carcinogenic dyes, namely C.I. Disperse Yellow 3 and C.I. Disperse Blue 1.

4. Many chromophores used in chromophore and chromophore-insoluble azo dyes are MAK (Ⅲ) A1(MAK stands for maximum workplace concentration) and A2 group carcinogenic or suspected carcinogenic aromatic amines, which should be banned. Germany announced the first batch of banned color base ***5, omitting 1 color base. According to incomplete statistics, there are 9 kinds of chromophores harmful to the synthesis of aromatic amines. In addition, there are chromophores containing isomers harmful to aromatic amines. For example, orange-based GC (C.I. chromophore 2) and yellow-based GC (C.I. chromophore 44) are isomers of carcinogenic aromatic amine p-chloroaniline, respectively. Other prohibited color bases: red base TR (C.I Ice Dye Base 1 1), red base G (C.I Ice Dye Base 12), blue base B (C.I Ice Dye Base 48) and deep blue base R (C.I Ice Dye).

There are only 1 species listed in the banned dyes in Germany, namely C.I. chromophore 14, or C.I. chromophore 20(76035), namely 2,4-diaminotoluene.

The acute toxic dyes involved are C.I. chromophore 20, C.I. chromophore 24 and C.I. chromophore 4 1.

5. Basic Dyes The first three basic dyes listed as banned dyes in Germany are: Basic Brown 4, Basic Red 42 and Basic Red11. Among them, C.I. basic red 1 1 1 contains amino azobenzene; C.i. Basic Red 42 contains o-aminophenol methyl ether; C.i. Basic Brown 4 contains 2,4-diaminotoluene. VCI in Germany announced four other basic dyes, which were banned because they contained harmful aromatic amines. For example, C.I. Basic Yellow 82 contains p-aminoazobenzene; C.i. Basic Yellow 103 contains 4,4'-diaminodiphenylmethane; C.i. Basic Red 76 contains anthraniline; C.i. basic red 1 14 contains o-aminoanisole.

Among the acute toxic dyes involved, there are six kinds of basic dyes, namely C.I. Basic Yellow 2 1 2, C.I. Basic Red 12, C.I. Basic Violet 16, C.I. Basic Blue 3, C.I. Basic Blue 7 and C.i.

6. Reactive dyes and vat dyes 1 18 There are no reactive dyes and vat dyes in the banned dyes, but 22 harmful aromatic amines are taken as the benchmark. Individual varieties of these two dyes will be affected. Such as reactive yellow K-R, reactive blue KD-7g, reactive yellow brown K-GR and reactive yellow Ke-4RNI in reactive dyes. Wait a minute.

There are few vat dyes banned, but for example, vat magenta R (C.I vat red 1 73360) is made of o-aniline, and vat red violet RH (C.I vat violet 2,73385) is also made of o-aniline, so it is also affected by the ban. Indigo pink IR and indigo red violet IRH in the corresponding soluble vat dyes will also be affected. They are sulfate esters of vat pink R and vat red violet RH leuco respectively.

7. Other types of dyes In addition to the above dyes, some aromatic amine intermediates are also used in other commonly used dyes, which makes them banned dyes. For example, sulfur dyes include yellow brown sulfide 5g (C.I Brown Sulfide 1 0,53055), yellow brown sulfide 6g (C.I Orange Sulfide153050) and yellow sulfur GC (C.I Yellow Sulfide 2,53120).

Dyes made of azo dyes are also prohibited in pigment pastes. Include Gu Yong orange G (C.I pigment orange13,2110), 8205 dye golden FGRN, 6 103 dye golden FG and 81/kloc-0.