Dibenzo[b,e][1,4]dioxin

184.19

184.19

205-974-2

O1B5KJ235I

3077

DTXSID8020410

Crystals from methanol

2932999099

18.5

4.4

Dibenzo-p-dioxin appears as white crystals or crystalline solid. (NTP, 1992)

1.2±0.1 g/cm3

119 °C

278.5°C

115.7±18.5 °C

1.625

In water, 0.901 mg/l @ 25 deg C

You should store this material in a refrigerator.

4.12x10-4 mm Hg at 25 deg C

1.20e-11 cm3/molecule*sec

Hydroxyl radical reaction rate constant = 1.20X10-11 cu cm/molecule sec @ 25 °C

Insoluble in water.

Ethers

DIBENZO-P-DIOXIN is an ether. Ethers may react violently with strong oxidizing agents. In other reactions, which typically involve the breaking of the carbon-oxygen bond, ethers are relatively inert.

I

9

3077

3

22-51/53

61

HP3090000

Xn,N

Stable. Combustible. Incompatible with strong oxidizing agents.

P264, P270, P273, P301+P312, P330, P391, P501

H302

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

Bioassay of Dibenzo-p-dioxin for Possible Carcinogenicity (1979) Technical Rpt Series No. 122 DHEW Pub No. (NIH) 79-1377, U.S. Department of Health Education and Welfare, National Cancer Institute, Bethesda, MD 20014

Flash point data for this chemical are not available. It is probably combustible. (NTP, 1992)

Excerpt from ERG Guide 171 [Substances (Low to Moderate Hazard)]: As an immediate precautionary measure, isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids. SPILL: Increase, in the downwind direction, as necessary, the isolation distance shown above. FIRE: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2016)

SMALL SPILLS AND LEAKAGE: If a spill of this chemical occurs, FIRST REMOVE ALL SOURCES OF IGNITION, then you should dampen the solid spill material with acetone and transfer the dampened material to a suitable container. Use absorbent paper dampened with acetone to pick up any remaining material. Seal your contaminated clothing and the absorbent paper in a vapor-tight plastic bag for eventual disposal. Solvent wash all contaminated surfaces with acetone followed by washing with a soap and water solution. Do not reenter the contaminated area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned. STORAGE PRECAUTIONS: You should store this material in a refrigerator. (NTP, 1992)

RECOMMENDED RESPIRATOR: Where the neat test chemical is weighed and diluted, wear a NIOSH-approved half face respirator equipped with an organic vapor/acid gas cartridge (specific for organic vapors, HCl, acid gas and SO2) with a dust/mist filter. (NTP, 1992)

Fires involving this chemical can be controlled using a dry chemical, carbon dioxide or Halon extinguisher.

...Dioxins may be formed during the combustion of PCBs in fires and explosions. /Dioxins/

If a spill of this chemical occurs, FIRST REMOVE ALL SOURCES OF IGNITION, then you should dampen the solid spill material with acetone and transfer the dampened material to a suitable container. Use absorbent paper dampened with acetone to pick up any remaining material. Seal your contaminated clothing and the absorbent paper in a vapor-tight plastic bag for eventual disposal. Solvent wash all contaminated surfaces with acetone followed by washing with a soap and water solution. Do not reenter the contaminated area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned.

A laboratory-based simulation of stack emissions from municipal incinerators found dibenzo-p-dioxin was contained in the fly ash(1).

Oral dibenzo-p-dioxin given to male mice once/wk for 4 wk increased sensitivity to endotoxin, whereas polychlorinated biphenyls did not. Residual polychlorinated biphenyls levels were detected in thymus; dibenzo-p-dioxin was not.

LD50 Mouse oral 866 mg/kg|LD50 Rat ip 30 mg/kg|LD50 Rat oral 1220 mg/kg

A bioassay of dibenzo-p-dioxin for possible carcinogenicity was conducted by administering the test chemical in feed to Osborne-Mendel rats and B6C3Fl mice. Groups of 35 rats of each sex were administered dibenzo-p-dioxin at one of two doses, either 5,000 or 10,000 ppm, for 110 weeks. Groups of 50 mice of each sex were administered the same doses for 87 or 90 weeks. Controls consisted of groups of 35 untreated rats of each sex and 50 untreated mice of each sex. All surviving male rats were killed at 110 weeks, all surviving male mice at 92 to 97 weeks, and all surviving female mice at 91 to 93 weeks. ... It is concluded that under the conditions of this bioassay, dibenzo-p-dioxin was not carcinogenic for Osborne-Mendel rats or B6C3Fl mice. Levels of Evidence of Carcinogenicity: Mate Rats: Negative; Female Rats: Negative; Male Mice: Negative; Female Mice: Negative.

Dibenzo-p-dioxin is not produced commercially in the USA(SRC). A laboratory-based simulation of stack emissions from municipal incinerators found dibenzo-p-dioxin was contained in the fly ash(1).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 5,200(SRC), determined from a log Kow of 4.3(2) and a regression-derived equation(3), indicates that dibenzo-p-dioxin is expected to be immobile in soil(SRC). Volatilization of dibenzo-p-dioxin from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 1.1X10-4 atm-cu m/mole(SRC), derived from its vapor pressure, 4.12X10-4 mm Hg(2), and water solubility, 0.901 mg/l(4). However, adsorption to soil is expected to attenuate volatilization(SRC). Dibenzo-p-dioxin is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(2). Although pure culture studies have shown that dibenzo-p-dioxin can be metabolized(5-8), insufficient data are available to predict the importance of biodegradation in soil(SRC).|AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 5,200(SRC), determined from a log Kow of 4.3(2) and a regression-derived equation(3), indicates that dibenzo-p-dioxin is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 1.1X10-4 atm-cu m/mole(SRC), derived from its vapor pressure, 4.12X10-4 mm Hg(2), and water solubility, 0.901 mg/l(4). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 9 hrs and 9 days, respectively(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column(SRC). The estimated volatilization half-life from a model pond is 293 days if adsorption is considered(5). According to a classification scheme(6), an estimated BCF of 410(SRC), from its log Kow(2) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is high(SRC). Exposure of pure aqueous solutions of dibenzo-p-dioxin in pyrex tubes to outdoor October sunlight resulted in decompositions of up to 6% in three days of exposure(8); however, addition of small amounts of nitrate ion to the aqueous solutions resulted in disappearances of 70% in one day and 92% in three days(8). Although pure culture studies have shown that dibenzo-p-dioxin can be metabolized(9-12), insufficient data are available to predict the importance of biodegradation in water(SRC).|ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), dibenzo-p-dioxin, which has a vapor pressure of 4.12X10-4 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere(SRC). However, it has been shown that dibenzo-p-dioxin can become irreversibly adsorbed to incinerator stack emissions of fly ash under certain operating conditions(3); therefore, particulate phase dibenzo-p-dioxin may also occur in the ambient environment(SRC). Vapor-phase dibenzo-p-dioxin is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 1.3 days(SRC), calculated from its rate constant of 12X10-12 cu cm/molecule-sec at 25 °C(4). Particulate-phase dibenzo-p-dioxin may be removed from the air by wet and dry deposition(SRC). Dibenzo-p-dioxin has a strong absorption maximum at 290 nm in methanol(5) and has the potential for direct photolysis in the atmosphere(SRC).

ULTIMATELY HETEROCYCLIC RING WAS RUPTURED WHEN IRRADIATED BY LIGHT OF LAMBDA= 300 NM OR SUNLIGHT|The rate constant for the vapor-phase reaction of dibenzo-p-dioxin with photochemically-produced hydroxyl radicals is 1.2X10-11 cu cm/molecule-sec at 25 °C(1). This corresponds to an atmospheric half-life of about 1.3 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Dibenzo-p-dioxin is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(2). Exposure of pure aqueous solutions of dibenzo-p-dioxin in pyrex tubes to outdoor October sunlight resulted in decompositions of up to 6% in three days of exposure(3); however, addition of small amounts of nitrate ion to the aqueous solutions resulted in disappearances of 70% in one day and 92% in three days(3). Dibenzo-p-dioxin has a strong absorption maximum at 290 nm in methanol(4) and has the potential for direct photolysis(SRC). Irradiation of a methanol solution with a UV light produced 2-hydroxydiphenyl ether and 2,2-dihydroxydiphenyl as reaction products(4).

An estimated BCF of 410 was calculated for dibenzo-p-dioxin(SRC), using a log Kow of 4.3(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is high(SRC).

The Koc of dibenzo-p-dioxin is estimated as 5,200(SRC), using a log Kow of 4.3(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that dibenzo-p-dioxin is expected be immobile in soil(SRC).

The Henry's Law constant for dibenzo-p-dioxin is estimated as 1.1X10-4 atm-cu m/mole(SRC) derived from its vapor pressure, 4.12X10-4 mm Hg(1), and water solubility, 0.901 mg/l(2). This Henry's Law constant indicates that dibenzo-p-dioxin is expected to volatilize from water surfaces(3). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(3) is estimated as 9 hours(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(3) is estimated as 9 days(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column(SRC). The estimated volatilization half-life from a model pond is 293 days if adsorption is considered(4). Dibenzo-p-dioxin is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(1).

The general population may be exposed to dibenzo-p-dioxin through inhalation of fly ash particulates and emissions from municipal waste incinerators. (SRC)

Dibenzo-p-dioxin is rapidly metabolized after ip dose to mice into unknown polar products. Liver microsomes (reduced nicotinamide adenine dinucleotide) from mouse, rat, and rabbit also transformed /it/ very efficiently.|In rats, primary hydroxylation of dibenzo-p-dioxins takes place exclusively at 2, 3, 7, or 8 position.|Dioxins were administered to rats. Urine and feces were collected and analyzed. Dibenzo-p-dioxin yielded the 2-hydroxy analog, one methylthio and one dihydroxy analog.|Metabolic transformation of the dibenzo-p-dioxins in the guppy (Poecilia reticulata) appears to involve hydroxylation, probably mediated by the mixed function oxidase system. /Dibenzo-p-dioxins/

Excerpt from ERG Guide 171 [Substances (Low to Moderate Hazard)]: Inhalation of material may be harmful. Contact may cause burns to skin and eyes. Inhalation of Asbestos dust may have a damaging effect on the lungs. Fire may produce irritating, corrosive and/or toxic gases. Some liquids produce vapors that may cause dizziness or suffocation. Runoff from fire control may cause pollution. (ERG, 2016)

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop. SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. If symptoms such as redness or irritation develop, IMMEDIATELY call a physician and be prepared to transport the victim to a hospital for treatment. INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. If symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop, call a physician and be prepared to transport the victim to a hospital. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used; if not available, use a level of protection greater than or equal to that advised under Protective Clothing. INGESTION: DO NOT INDUCE VOMITING. If the victim is conscious and not convulsing, give 1 or 2 glasses of water to dilute the chemical and IMMEDIATELY call a hospital or poison control center. Be prepared to transport the victim to a hospital if advised by a physician. If the victim is convulsing or unconscious, do not give anything by mouth, ensure that the victim's airway is open and lay the victim on his/her side with the head lower than the body. DO NOT INDUCE VOMITING. IMMEDIATELY transport the victim to a hospital. (NTP, 1992)

Emergency and supportive measures. Treat skin, eye, and respiratory irritation symptomatically. /Dioxins/|Specific drugs and antidotes. There is no specific antidote. /Dioxins/|Decontamination. 1. Inhalation. Remove victims from exposure and give supplemental oxygen if available. 2. Eyes and skin. Remove contaminated clothing and wash affected skin with copious soap and water; irrigate exposed eyes with copious tepid water or saline.Personnel involved in decontamination should wear protective gear appropriate to the suspected level of contamination. 3. Ingestion. a. Prehospital. Administer activated charcoal if available. Ipecac-induced vomiting may be useful for initial treatment at the scene (eg, children at home) if it can be given within a few minutes of exposure. b. Hospital. Administer activated charcoal. Gastric emptying is not necessary if activated charcoalcan be given promptly. /Dioxins/|Enhanced elimination. There is no known role for these procedures. /Dioxins/

dibenzo(1,4)dioxin