Edit entry

66 powder is grayish white to brown powder with unpleasant musty smell. Chemical formula C6H6Cl6.

eye

record

Overview and basic properties of 1

2 Impact on the environment

3 emergency treatment and disposal methods

Overview and basic properties of 1

edit

Chinese name: 666; 66 powder (name when powdered)

English name: hexachlorocyolohexane

Scientific name: hexachlorocyclohexane

Chemical formula: C6H6Cl6 (hence the name bhc)

Structural formula: as shown in the figure

Molecular weight: 290.82

Melting point (individual data below):

Alpha: 159- 160℃

Beta coefficient: 309-3 10℃

Gamma body:112-113℃

δ body: 138- 139℃

Stability: BHC is not easy to decompose at high temperature and sunlight, stable to acid and easy to be destroyed by alkali.

Off-white to brown powder with unpleasant musty smell.

Others: HCH is hexachloride of cyclohexane, not hexachloride of benzene, and hexachloride of benzene is hexachloride (C6Cl6). Many people are confused!

Life-related: 66 powder is highly toxic and was once used as a pesticide. The state explicitly prohibits the production, sale and use of pesticide "66 powder"

2 Impact on the environment

edit

health hazard

When people are poisoned, the nervous system is mainly characterized by headache, dizziness, excessive sweating, fatigue, tremor, epilepsy-like convulsions of upper and lower limbs, unstable standing, dyskinesia, unconsciousness and even coma, and people's livelihood may suffer from respiratory failure due to respiratory center inhibition. The digestive system will have symptoms such as salivation, nausea, vomiting, epigastric discomfort, pain and diarrhea. Respiratory and circulatory system can cause congestion of pharynx, larynx and nasal mucosa, foreign body sensation in larynx, sputum foaming, congestion, dyspnea, pulmonary edema, pallor, blood pressure drop, body temperature rise, arrhythmia, tachycardia and even ventricular fibrillation. Irritating symptoms to skin and eyes include skin flushing, papules, blisters, dermatitis, and even erosion, exudation and allergic dermatitis; Tears in eyes, spasms in eyes and face, and severe pain. The general toxic effects of bhc are nerve and parenchymal organ toxicity, and large doses can cause serious damage to the central nervous system and some parenchymal organs, especially the liver and kidneys. BHC can be absorbed through gastrointestinal tract, respiratory tract and skin and enter the body.

Toxicological data and environmental behavior

The acute toxicity of bhc is small, and compared with its isomers, γ-bhc is the largest. BHC mainly accumulates in the central nervous system and adipose tissue after entering the body, stimulating brain movement and cerebellum, and also affecting autonomic nervous system and peripheral nerves through cortex, affecting oxidative phosphorylation of cells in organs, leading to organ malnutrition and degeneration and necrosis. It can induce hepatocyte microsomal oxidase, affect endocrine activity and inhibit ATPase.

Acute toxicity (LD50): 180 mg/kg, 1 fold, the lowest lethal dose found in children; 50mg/kg, 1 time, percutaneous in rabbits; 60mg/kg, 1 time, taken orally by rabbits; 88mg/kg, 1 time, taken orally by rats; 500mg/kg, 1 time, percutaneous in rats.

Chronic toxicity: chronic bhc poisoning is characterized by neurasthenia, dizziness, headache, heavy head, loss of appetite, nausea, nightmares, insomnia and limb pain; Symptoms of polyneuritis, sensory disturbance of limbs, flaccid paralysis, dysphagia and visual adjustment paralysis; Can be used for treating blood diseases such as liver and kidney dysfunction, cardiac dystrophy, anemia, leukocytosis, and lymphopenia. Contact dermatitis, erythema and papules appear on the skin, accompanied by irritation, pain and blisters.

Carcinogenic: 80 mg/kg, 52 weeks, taken orally by mice, carcinogenic. The chronic toxicity of bhc isomers is related to the carcinogenicity observed in rodents, and the most influential is α-bhc, which has been proved to be highly carcinogenic. γ-BHC is a weak tumorigenic agent in mice, but it has not been confirmed in rats so far.

Mutagenicity: The mutagenicity report of γ-HCH proves that there is no obvious mutagenicity.

Aquatic toxicity: LC500.58mg/L, 96 hours, silver carp; 0.63mg/L, 96 hours, goldfish; 0.3 1mg/L, 48 hours, carp.

Avian toxicity: 100mg/kg, 1 times, the lowest lethal dose found by birds; LD50 120mg/kg, 1 fold, diphtheria quail was taken orally.

Metabolism and degradation: BHC can be metabolized in plants, insects, microorganisms and animals to produce a variety of products, which are excreted as the * * * combination of sulfur and glucuronic acid.

In all cases, the initial product of bhc metabolism is pentachlorocyclohexane, which has been isolated in several different forms. Phenols produced in warm-blooded animals are excreted with urine and feces in the form of acid sulfate or glucuronide. Phenols can also be produced by microorganisms, but they will be further decomposed in soil and the whole molecule will be destroyed. In animals (rats), various isomers such as dichloro, trichloro and tetrachlorophenol can be produced.

In insects, HCH and pentachlorocyclohexene first react with sulfhydryl groups of amino acids to produce cyclohexane, cyclohexene and aromatic derivatives, and thiophenol and its derivatives are the final products of these reactions.

The decomposition of pesticides in the environment is carried out through biological and chemical ways, and the biodegradation of pesticides is an important reason for the disappearance of pesticides. BHC in the environment will be degraded by microorganisms. It is generally believed that the biodegradation of BHC under anaerobic conditions is faster than that under aerobic conditions. Many microorganisms can decompose BHC, such as Fusobacterium and Pseudomonas. The chemical decomposition of organochlorine pesticides is carried out under the action of many physical and chemical factors, including sunlight, alkaline environment, air and humidity, among which sunlight plays an important role in the decomposition of organochlorine pesticides. Generally speaking, it takes six and a half years for HCH in organochlorine pesticides to disappear in soil.

Residue and accumulation: BHC in the environment can be bioaccumulated through the food chain. Based on the investigation of pesticide content in rice in Japan, it is found that rice has the same properties as ordinary aquatic plants, and both of them have enrichment effect. The residue of bhc in rice straw is high, which is about 4-6 times that in the soil where it is planted. The absorption rate of γ -bhc by beans is particularly high, and its content is dozens of times that in soil. The pollution of bhc in the environment and ecosystem has reached as far as penguins in antarctica, ice cubes in Greenland in the arctic and snow on the top of the mountain more than 2000 meters.

The investigation shows that BHC is mainly accumulated in human fat, and β-BHC is the longest and has the strongest accumulation effect. For example, it can be excreted continuously for 6 months after oral administration, while γ-BHC can be excreted within 1 ~ 2 weeks.

Migration and transformation: HCH, like other organochlorine pesticides, will eventually disappear under the action of various physical, chemical and biological factors after entering the environment. The final disappearance of pesticides in the environment is achieved through diffusion, decomposition and biological enrichment.

The diffusion of bhc in the environment has several forms, such as dissolution, suspension, volatilization, sedimentation and infiltration. The research shows that at 25℃; The solubility of α-HCH in water is 65438 0630 μ g/L, β-HCH is 700 μ g/L, γ-HCH is 7900 μ g/L, and δ-HCH is 265438 0300 μ g/L. Pesticides entering the water environment can be adsorbed by suspended substances (including soil, organic particles and plankton) in water. Pesticides entering the surface of water and soil can also enter the surface atmosphere by volatilization, and particulate matter or gaseous pesticides in the air can be carried to a certain distance with the dust in the airflow and settled in the sediment environment; Pesticides in soil can also penetrate from the upper soil to the lower soil through infiltration, thus polluting groundwater.

3 emergency treatment and disposal methods

edit

1, emergency treatment of leakage

Isolate the leakage and pollution area, set warning signs around it, and cut off the fire source. Emergency personnel should wear gas masks and general fire protection clothing. Collect it with a clean shovel in a dry and clean container with a lid and transport it to the waste disposal site. Such as a large number of leaks, collected and recycled or discarded after harmless treatment.

Waste treatment method: using activated carbon containing 5 ~ 10% copper chloride, ferric chloride and zinc chloride (or activated carbon containing 5 ~ 10% aluminum chloride) as catalyst, HCH is destroyed and thermally decomposed at 400 ~ 500℃.

IRPTC suggested that a small amount of HCH-contaminated containers can be treated according to FAO guidelines on the disposal of waste pesticides and their containers on farms, and a large amount of HCH waste should be treated by incineration.

2, protective measures

Respiratory system protection: Wear a respirator when it may come into contact with its dust. It is recommended to use self-contained breathing apparatus in emergency rescue or evacuation.

Eye protection: Wear chemical safety glasses when necessary.

Protective clothing: wear work clothes.

Hand protection: Wear chemical resistant gloves.

Others: Smoking and eating are prohibited in the workplace. After work, clean thoroughly. Change work clothes in time.

3. First aid measures

Skin contact: Wash with soapy water and apply hydrocortisone ointment to the affected area.

Eye contact: Use 2% procaine hydrochloride drops.

Inhalation: Give oxygen to people with dyspnea and inject sodium benzoate, caffeine, nikethamide and theophylline. During convulsion, paraformaldehyde can be injected intramuscularly, with the dosage of 3-5ml for adults and 0. 1mg/kg for children, and 10% glucose infusion can be injected to accelerate the excretion of poisons.

Ingestion: If you are poisoned by HCH by mistake, you should immediately induce vomiting, first drink normal saline, then induce vomiting with 1% copper sulfate or inject apomorphine, lavage your stomach with 2% sodium bicarbonate or normal saline, and then inject 20-30 grams of magnesium sulfate to induce diarrhea. Be careful not to use oil for gastric lavage, so as not to promote the absorption of pesticides.

Entry label:

Chemicals? Insecticide