1,2,3,4,6,7,8-Heptachlorodibenzo-p-dioxin

425.31

425.31

MM6333103R

2811

DTXSID1052034

18.5 Ų

8.2 (LogP)

1.8860 (estimate)

264 °C

506.1°C (rough estimate)

1.6710 (estimate)

0.002565ug/L(26.0 ºC)

6.48e-11 mmHg|7.4X10-8 mm Hg (est)

Henry's Law constant= 2.18X10-5 atm-cu m/mole (est)

Insoluble in water.

Ethers

1,2,3,4,6,7,8-HEPTACHLORODIBENZO-P-DIOXIN may be sensitive to prolonged exposure to light. (NTP, 1992)

I

6.1(a)

2811

Skene SA et al; Hum Toxicol 8 (3): 173-204 (1989). Polychlorinated Dibenzo-P-Dioxins and Polychlorinated Dibenzofurans: The Risk to Human Health. A Review.|WHO; Environ Health Criteria 88: Polychlorinated Dibenzo-p-dioxins and Dibenzofurans (1989)|NRCC; Polychlorinated Dibenzo-p-dioxins: Limitations to the Current Analytical Techniques, Publication NRCC No 18576 (1981). A technical review and assessment of the methodology for the analysis of polychlorinated dibenzo-p-dioxins in a variety of substrates. Analytical methodology was evaluated and safety procedures were suggested.|Olson JR et al; Chemosphere 18 (1/6): 371-81 (1989). A review of the toxicological and pharmacokinetic literature on chlorinated dibenzo-p-dioxins and dibenzofurans was presented to evaluate the accuracy and currency of established toxicity equivalence factors. /Chlorinated dibenzo-p-dioxins/

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

|Warning|H319 (100%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]|P201, P202, P261, P264, P271, P273, P280, P281, P304+P340, P305+P351+P338, P308+P313, P312, P337+P313, P391, P403+P233, P405, and P501|Aggregated GHS information provided by 38 companies from 1 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Fires involving this material can be controlled with a dry chemical, carbon dioxide or Halon extinguisher. (NTP, 1992)

Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]: 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 you spill this chemical, FIRST REMOVE ALL SOURCES OF IGNITION, then dampen the solid spill material with toluene, then transfer the dampened material to a suitable container. Use absorbent paper dampened with toluene to pick up any remaining material. Your contaminated clothing and absorbent paper should be sealed in a vapor-tight plastic bag for eventual disposal. Solvent-wash all contaminated surfaces with toluene 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 protect this container from damage. Store under refrigeration at 5 degrees centigrade and protect from light. Allow only your most experienced personnel access to this aliquot. (NTP, 1992)

MINIMUM PROTECTIVE CLOTHING: If Tyvek-type disposable protective clothing is not worn during handling of this chemical, wear disposable Tyvek-type sleeves taped to your gloves. RECOMMENDED RESPIRATOR: Where the neat test chemical is weighed and diluted, wear a NIOSH-approved half face respirator equipped with a combination filter cartridge, i.e. organic vapor/acid gas/HEPA (specific for organic vapors, HCl, acid gas, SO2 and a high efficiency particulate filter). RECOMMENDED GLOVE MATERIALS: It is recommended that you wear two dissimilar glove types when working with this chemical. (NTP, 1992)

Tier 4 of the National Dioxin Study being conducted by the USEPA has analyzed for the presence of heptachlorodibenzo-p-dioxin in stack emissions and ash at 13 and 74 sites, respectively, throughout the U.S. representing many combustion source categories(1-3). Heptachlorodibenzo-p-dioxin has been detected in stack emissions from all of the 13 sites tested in Tier 4 at concn ranging from 0.22 to 5,900 ng/standard cu m of flue gas (normalized to 3% oxygen); the max level was detected in stack emissions from a secondary copper smelter(1,3). Some of the various ash samples were analyzed from all 74 sites in the Tier 4 study representing 22 combustion source categories did not contain detectable levels (detection levels varied; most were <1 ng/g)(2). The max concn found in ash were 2,340 and 478 ng/g in the settling chamber ash and bottom ash at a wire reclamation incinerator, 1012 ng/g in the ESP ash at a municipal solid waste incinerator, and 411 ng/g in the baghouse ash at a secondary copper smelter(2). The emissions found in studies similar to Tier 4 ranged from not detected to 1600 ng per standard cu m of flue gas, normalized to 3% oxygen) (detection limit not specified); the maximum emission rate was for a municipal waste combuster(3).|The amount of heptachlorodibenzo-p-dioxin found in 8 surface wipe tests at a multi-building site where it was presumed a polychlorobiphenyl transformer askarel was improperly disposed (in an incinerator in the immediate vicinity of the buildings) 12 years prior to the testing ranged from 39 to 4160 mg/sq m (avg 1,262 mg/sq m); the concn in 6 dust samples ranged from 24-2800 ng/g and averaged 865 ng/g(1). A concn of 900 ug/sq m was found in a second floor wipe test in an apartment building where a transformer fire had occurred in the basement(2). Average emission concn of 206 and 67 ng/cu m were detected in stacks from two municipal incinerators in Belgium which correspond to emission factors of 2.7 and 0.59 mg/ton of waste burned(3). A concn of >15,000 ppb was detected in oil leachates from a waste dump site in Germany which had been receiving waste oils and liquid chemical wastes; a concn of >25,000 parts/trillion was detected in sediments of a drain near the entrance to the municipal sewer and a concn of 93,000 parts/trillion was detected in sediments of a nearby stream which had received discharges from the dump until 1981 when the main drain was connected to the municipal sewer(4). Levels of 18-380 ng/cu m (normalized to 10% CO2) were detected in stack effluents from a municipal solid waste incinerator in Sweden in 1985(5).|The 1,2,3,4,6,7,9-isomer and 1,2,3,4,6,7,8-isomer of heptachlorodibenzo-p-dioxin were found at concn of 4.0 and 3.0, respectively, in soot samples from a 1981 PCB transformer fire in a Binghamton, NY, State Office Building(1). Heptachlorodibenzo-p-dioxin has been found at an avg concn of 6.0 ng/g in particulates taken from chimneys venting fireplaces burning untreated, residential wood supplies in several areas of the U.S.(2). The range of avg concn of heptachlorodibenzo-p-dioxin found in various effluent from three typical urban incinerators in Japan were 63-1120 ng/g in fly ash, 6.0-9.6 ng/g in bottom ash, and 22-1270 ng/g in sludge(3). 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin was detected in the automobile exhaust from 3 of 5 cars tested in a study in Australia at rates of emission ranging from 95-482 pg/km (avg 294 pg/km)(4). The total concn of heptachlorodibenzo-p-dioxin present in refuse samples at 2 Ontario, Canada, incinerators prior to incineration ranged from 2.0-19 and 20-87 ng/g, respectively; the avg concn were 8.8 and 45 ng/g(5).|Unidentified isomers of heptachlorodibenzo-p-dioxin were detected in chimney ash of a woodburning stove and fireplace at concn of 0.1 and 0.5 ppb, respectively; the concn in bottom ash samples ranged from 0.3 to 1.2 ppb in 2 different woodburning stoves and was 2.0 ppb in one fireplace(1). The bottom ash from an out-of-doors open-air burning device contained 11 ppb(1). The total concn of the 2 isomers of heptachlorodibenzo-p-dioxin in particulate samples centrifuged from effluent collected in Aug-Sept 1987 from 9 of 9 from Ontario, Canada, pulp and paper mills ranged from 7.7 to 430 parts/trillion (avg 104 parts/trillion); heptachlorodibenzo-p-dioxin was not detected in whole effluent samples collected from the same 9 plants in Nov 1987 (detection limits ranged from 0.01- 0.1 parts/trillion)(2). Emission rates from 4 resource recovery and incinerator facilities in Europe range from 158 to 3366 ug/ton municipal solid waste disposed (avg 1218 ug/ton; dates of sampling not specified); the emission rate in one U.S. facility was 37 ug/ton(3). Flue gas from test runs of a Swedish hazardous waste incinerator contained between 9.4 and 71 ng/cu m of total heptachlorodibenzo-p-dioxin(4).|The total emissions of heptachlorodibenzo-p-dioxin from a municipal incinerator in Florence, Italy, in Oct 1980, March 1982, and April 1985 were 100, 70, and 1400 ng/cu m of dry effluent in the condensate (organic vapors and very fine dust), respectively; the dust emission from the incinerator contained 56 and 3.0 ng/cu heptachlorodibenzo-p-dioxin in Oct 1980 and April 1985, respectively (total amounts of dust were 100 and 40 mg/cu m, respectively)(1). The concn of total heptachlorodibenzo-p-dioxin in fly ash collected from electrostatic precipitators from two municipal incinerators in 1981, one in the Midwest US and one on the East Coast, were 78 and 107 ng/g, respectively(2).

SEDIMENT: The mean daily loadings for heptachlorodibenzo-p-dioxin in the Niagara River at Niagara-on-the-Lake based upon monitoring data for between 1984 and 1986 were 6.4 and 2.3 g/day for the water column and suspended sediment, respectively(1). Heptachlorodibenzo-p-dioxin was found at a concn of 0.92 ppb in sediments samples collected from Woods Pond, MA, a pond known to be contaminated with Aroclor 1260, a PCB (date of sampling not specified)(2). The concn of total heptachlorodibenzo-p-dioxin and the 1,2,3,4,6,7,8-isomer in sediment in the surface water raw drinking water supplies of Lockport, NY, sampled in 1988 were 535 and 285 parts/trillion, respectively, in raw water pump station, wet-well sediment and 280 and 150 parts/trillion, respectively, in sedimentation basin sludge(3). Unspecified isomers of heptachlorodibenzo-p-dioxin were found in 5 of 8 samples of suspended sediments collected from the Niagara River from Dec 1984-Feb 1985 at concn up to 238 ng/g (detection limit not specified)(4).|SEDIMENT: Three samples of trapped sediments from the archipelago of Stockholm, Sweden (date of sampling not specified) contained 880, 1200 and 5700 pg/g of total heptachlorodibenzo-p-dioxin(1). Samples of pond sludge and sediment collected in 1983 from two surface impoundments that receive discharge of effluents from a wood-treating facility in Pensacola, FL (facility was closed in 1981), contained total heptachlorodibenzo-p-dioxin concn of 39.5 and 94 mg/kg, respectively(2).|SOIL: Total heptachlorodibenzo-p-dioxin concn found in soil sampled on Feb 27, 1985, near the municipal incinerator of Florence, Italy, at 5 of 6 sites (detection limit not specified) at concn ranging from 5.8 to 97 pg/g (avg concn 56 pg/g); the site which was negative was chosen as a control site to evaluate the background concn in soil(1). Total levels of heptachlorodibenzo-p-dioxin in samples of soil from 5 sites sampled Sept 18, 1985, at a farm near the incinerator contained levels ranging from 24-70 pg/g (avg concn 43 pg/g)(1). Total concn of all isomers in three samples of soil from various rural areas of Europe (sites and data of sampling not specified) ranged from <10 pg/g (quantitation limit) in 2 samples to 17 pg/g in the other sample; 2 samples from more industrialized areas of Europe contained 370 and 1600 pg/g(2). Five samples of bottom sediment from the Dong Nai River, Vietnam, collected in 1984-85 contained 63-160 pg/g dry weight of total heptachlorodibenzo-p-dioxin (avg 110 pg/g); one sample from the Saigon River contained 940 pg/g and two samples from the Red River contained 10 and 5.1 pg/g(3).|SOIL: The concn of total heptachlorodibenzo-p-dioxin in samples collected in 1983 of porous media from the unsaturated zone in an area downgradient from surface impoundments at a wood-treating facility in Pensacola, FL (facility was closed in 1981), ranged between not detected (detection limits not specified) and 874.6 ug/kg dry weight; concn in porous material from the saturated zone ranged between not detected and 80 ug/kg dry weight(1). The concn found in soil samples collected in March 1988 in the Oroville, CA advisory area 1.5 km southeast of a pentachlorophenol plant near Polermo, CA, at which a fire occurred in April 1987 was 1403 parts/trillion; the background concn detected at a rural site not near the facility was 9.0 parts/trillion(2).

RURAL/REMOTE: The concn in ambient air from rural Waihi, Australia, was 0.302 pg/cu m(1).|URBAN/SUBURBAN: Heptachlorodibenzo-p-dioxin (total isomers) was detected in the ambient air from a high traffic density motorway and from a suburban site 100 m from the nearest road in the city of Auckland, Australia at concn of 1.48 and 1.52 picogram/cu m, respectively(1). Geometric avg concn in ambient air samples taken 4 sites in the Bloomington, IN, area between Aug 1985 and July 1988 were 1.4 and 27 fg/cu m in the vapor and particulate phases, respectively, for the 1,2,3,4,6,7,9-isomer and 4.1 and 590 fg/cu m in the vapor and particulate phases, respectively(2). A total air sample taken from urban Hamburg, Germany, contained 0.60 pg/cu m total heptachlorodibenzo-p-dioxin (date not specified)(3). Air particulate samples taken in urban Gothenburg, Sweden, contained 380 fg/cu m total heptachlorodibenzo-p-dioxin when "clean air" was blowing into the street and 2900 fg/cu m during an inversion; particulate samples taken in ubran Rorvil, Sweden, contained 140 fg/cu m when "clean air" was coming from NW and 1000 fg/cu m when "contaminated air" was coming from the North(3).|URBAN/SUBURBAN: Sixteen samples of ambient air taken from an urban Niagara Falls site (upwind from most of the industrial areas of the city) between Sept 1986 and March 1987 contained total heptachlorodibenzo-p-dioxin concn ranging between not detected (detection limit 0.16 and 0.09 pg/cu m) and 0.97 pg/cu m (avg 0.5 pg/cu m)(1).|SOURCE DOMINATED: The following concn were found in total air samples from various types of sites in Hamburg, Germany (pg/cu m; date not specified): traffic tunnel, 3.4; downwind from a municipal solid waste incinerator, 5.3; and in the vicinity of a dumpsite and metal refinery, 15(1). Sixteen samples of ambient air taken from an urban Niagara Falls site (downwind from a very large industrial complex that includes a variety of industrial process sources and incinerators) between Sept 1986 and March 1987 contained total heptachlorodibenzo-p-dioxin concn ranging between 0.24 and 9.78 pg/cu m (avg 2.44 pg/cu m)(2).

LD50 Rabbit oral > 5000 mg/kg|LD50 Rat oral > 5000 mg/kg|LD50 Guinea pig oral > 600 ug/kg /1,2,3,4,6,7,8-Heptachlorodibenzo-p-dioxin/

Heptachlorodibenzo-p-dioxin is released to the environment in stack emissions and ash from many combustion source categories(1-7). Categories include (but are not limited to) many types of incinerators, including those for municipal solid waste and hazardous chemical waste(2,4), transformer fires involving polychlorobiphenyls and chlorinated hydrocarbons(5,11), fireplaces burning both treated and untreated wood(6), and automobile exhaust(7). Heptachlorodibenzo-p-dioxin has been detected in municipal solid waste(8), leachates from contaminated waste dumps(9), effluent from pulp and paper mills(10), and as a minor impurity in wood treating chemicals including pentachlorophenol(12).

TERRESTRIAL FATE: If heptachlorodibenzo-p-dioxin is released to soil, it will be expected to be immobile based upon an estimated Koc of 7.8X10+5 which can be calculated(SRC) from a measured water solubility of 1.9X10-3 mg/l(2) using a recommended regression equation(1,SRC). It should not, therefore, leach through soil(3). It will not hydrolyze in soil(1). Based solely upon an estimated Henry's Law constant of 2.18X10-5 atm-cu m/mole(4,SRC), volatilization from near-surface soil may be expected to be significant(SRC). However, strong adsorption to soil is expected to greatly attenuate the rate of volatilization from near-surface soil(SRC). It is not known whether heptachlorodibenzo-p-dioxin biodegrades in soil(SRC).|AQUATIC FATE: If heptachlorodibenzo-p-dioxin is released to water, it will be expected to strongly adsorb to sediment and suspended particulate matter based upon an estimated Koc of 7.8X10+5 which can be calculated(SRC) from a measured water solubility of 1.9X10-3 mg/l(2) using a recommended regression equation(1,SRC). Bioconcentration in aquatic organisms may be important based upon measured BCF ranging between 89.1-1700(3-5). It may be susceptible to direct photolysis in near-surface surface water based upon the adsorption of light at wavelengths >290 nm exhibited by other polychlorodibenzo-p-dioxins including hexachloro- and octachlorodibenzo-p-dioxins(6). Hydrolysis is not expected to be important(1). It is not known whether heptachlorodibenzo-p-dioxin biodegrades in water under environmental or laboratory screening test conditions. The half-life for volatilization of heptachlorodibenzo-p-dioxin from a river one meter deep flowing 1 m/sec with a wind velocity of 3 m/sec is estimated to be 3.7 days at 25 °C(1) based on an estimated Henry's Law constant of 2.18X10-5 atm-cu m/mole(7,SRC). Strong adsorption to sediment and suspended particulate matter, however, is expected to greatly attenuate the rate of volatilization in many natural waters(SRC). A half-life of >51 years for volatilization from a model pond can be estimated using a three-compartment EXAMS model which considers the effect of adsorption(8,SRC).|ATMOSPHERIC FATE: If heptachlorodibenzo-p-dioxin is released to the atmosphere, it can be expected to exist both in the vapor and particulate phases in ambient air(1,SRC) based upon an estimated vapor pressure of 7.4X10-8 mm Hg calculated(SRC) from a measured water solubility of 1.9X10-3 mg/l at 25 °C(2) and an estimated Henry's Law constant of 2.18X10-5 atm-cu m/mole at 25 °C(3,SRC). It has been estimated that polychlorodibenzo-p-dioxins such as heptachlorodibenzo-p-dioxin are likely to be associated with air particulate matter(4). The rate constant for the vapor phase reaction of heptachlorodibenzo-p-dioxin with photochemically produced hydroxyl radicals has been estimated to be 1.3X10-12 cu cm/molecule-sec at 25 °C(4,SRC) which corresponds to an atmospheric half-life of 12.3 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(SRC). Heptachlorodibenzo-p-dioxin may be susceptible to direct photolysis in the atmosphere and in near-surface surface water based upon the adsorption of light at wavelengths >290 nm exhibited by other polychlorodibenzo-p-dioxins including several hexachloro- isomers and octachlorodibenzo-p-dioxin(5).

The rate constant for the vapor phase reaction of heptachlorodibenzo-p-dioxin with photochemically produced hydroxyl radicals has been estimated to be 1.3X10-12 cu cm/molecule-sec at 25 °C(1,SRC) which corresponds to an atmospheric half-life of 12.3 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(SRC). Heptachlorodibenzo-p-dioxin may be susceptible to direct photolysis in the atmosphere and in near-surface surface water based upon the adsorption of light at wavelengths >290 nm exhibited by other polychlorodibenzo-p-dioxins including hexachloro-isomers and octachlorodibenzo-p-dioxin(2). Hydrolysis is not expected to be an environmental important process(3).

4.68e+03|An experimental BCF of 128.5 was measured for unspecified isomers of heptachlorodibenzo-p-dioxin in blue mussels (Mitilus edulis) after 64 days in seawater under static conditions(1). The BCF continuously rose throughout the exposure period, rising from 22.6 at 22 days to 89.1 at 50 days(1). The BCF for rainbow trout were 1100 and 1700 after 5 days at exposure concn of 11 and 55 picograms/l, respectively(2). The BCF for fathead minnows was 500 after 5 days at both exposure concn tested (8 and 39 picograms/l)(2,3). These BCF indicate that bioconcentration of heptachlorodibenzo-p-dioxin may be an important process in both fresh and saltwater aquatic organisms(SRC).

An estimated Koc of 7.8X10+5 can be calculated(SRC) from a measured water solubility of 1.9X10-3 mg/l(2) using a recommended regression equation(1,SRC). Based upon this estimated Koc, heptachlorodibenzo-p-dioxin will be expected to be immobile in soil(3,SRC). Therefore, leaching through soil to groundwater is not expected to occur(3,SRC).

The half-life for volatilization of heptachlorodibenzo-p-dioxin from a river one meter deep flowing 1 m/sec with a wind velocity of 3 m/sec is estimated(SRC) to be 3.7 days at 25 °C(1) based on a Henry's Law constant of 2.18X10-5 atm-cu m/mole which has been estimated using a structure-based estimation method(2). Strong adsorption to sediment and suspended particulate matter, however, is expected to greatly attenuate the rate of volatilization in many natural waters(SRC). A half-life of >51 years for volatilization from a model pond can be estimated using a three-compartment EXAMS model which considers the effect of adsorption(3).

DRINKING WATER: No heptachlorodibenzo-p-dioxin isomers were detected in finished drinking water from 20 NY locations (detection limits ranged from 0.4 to 12 pg/g in the soluble fraction and 0.4-15.4 pg/g in the particle-bound fraction)(1).|GROUNDWATER: The concn of total heptachlorodibenzo-p-dioxin in samples of groundwater collected in 1983 near surface impoundments at a wood-treating facility in Pensacola, FL (facility was closed in 1981), were 1500, 4.6, 34, not detected, and 0.4 ng/l at depths of 6.1, 12.2, 18.3, 24.4, and 30.5 m, respectively (detection limit not specified)(1).|SURFACE WATER: No heptachlorodibenzo-p-dioxin isomers were detected in raw water entering the sedimentation basin at the Lockport, NY, drinking water treatment plant sampled in 1988 (detection limit 2.8 picogram/l)(1). Unspecified isomers of heptachlorodibenzo-p-dioxin were found in 1 of 6 samples of the dissolved fraction of water collected from the Niagara River from Dec 1984-Feb 1985 at a concn of 1.4 ng/l (detection limit not specified)(2).|RAIN/SNOW: Unspecified isomers of heptachlorodibenzo-p-dioxin were found in rain collected in a remote rural location (Dorset, Ontario, Canada) over a 4 week period in Nov/Dec 1986 at a concn of 70 pg/l; the compound was not detected in samples collected in March/April or July/Aug 1987 (detection limit not specified(1).

A survey of 25 composite samples from 10 food classes including meats, eggs, milk, fruits, and vegetables collected at an unspecified time in the US and Canada indicated that total concn of heptachlorodibenzo-p-dioxin was below detection limits (detection limits 1-4 parts/trillion) in plant derived foods and in all animal derived foods tested except in chicken samples from Quebec which contained a maximum concn of 15 parts/trillion (fresh weight basis)(1). The following concn (fat basis) were found in chicken eggs collected from farms and stores in March 1988 in the vicinity of a pentachlorophenol plant near Polermo, CA, at which a fire occurred in April 1987: Polermo (4.5 km south of facility), 157 pg/g; Oroville, CA advisory area (1.5 km southeast of facility), 443 pg/g; and general commercial eggs from facility in Oroville and local stores, 7.7 pg/g; chicken fat and liver concn in chickens from the advisory area contained 495 and 835 pg/g median concn(2).

Heptachlorodibenzo-p-dioxin was detected at concn of 8.5 and 89 parts/trillion (wet weight and lipid basis, respectively) in one of 9 samples of human breast milk taken from South Vietnam in 1973; the compound was not detected in the other 8 samples (detection limit 2 parts/trillion(1). The concn in breast milk taken from 2 of 3 U.S. women in the 1970s ranged from 1.7 to 2.5 parts/trillion (wet weight basis) and 44 to 61 parts/trillion (lipid basis)(1). The 1,2,3,4,6,7,8-isomer was found in 9 of 11 samples of human milk collected in South Vietnam in 1985 at concn in the positive samples ranging from 19 to 172 parts/trillion (lipid basis) (detection limit generally between 0.1 and 0.2 parts/trillion); two of the samples were composites of three samples and one was a composite of 4 samples(1). The 1,2,3,4,6,7,8-isomer was found in 2 samples of human breast milk collected in 1986 in Binghamton, NY, at concn of 1.26 and 1.74 parts/trillion (wet weight basis) and 44 and 60 parts/trillion (lipid basis)(1). The avg total concn in the fat fraction of human milk were 59.5 picogram/g in 4 samples from Sweden, 72.8 picogram/g in 5 samples from Germany, and 174 picogram/g in 1 sample from Denmark(2).|Pool samples of human milk collected in 1988 from Birmingham and Glasgow, UK, (40 mothers each city) contained 76 and 65 parts/trillion 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (fat basis), respectively(1). The concn found in a WHO/EURO Interlaboratory Comparison of a pooled 1987 sample of European human milk from a number of mothers and locations that were not specified contained 46 parts/trillion (fat basis)(1).

Exposure to heptachlorodibenzo-p-dioxin will occur mainly through inhalation of contaminated air(1-5,SRC) and ingestion of contaminated foods(6,7,SRC). Minor exposure will occur through the ingestion of contaminated soil(SRC).|The avg personal breathing zone concn of heptachlorobenzo-p-dioxin for 6 job areas in a US plant were 0.014-0.083 ug/cu m; the overall mean was 0.038 ug/cu m(1).|Workers involved in the production of pentachlorophenol may be exposed to one of its contaminants, hexachlorobenzene. Pentachlorophenol is produced commercially in the USA by direct chlorination of phenol with chlorine gas in the presence of a catalyst at gradually risin temperatures up to 200 degrees C. Other contaminants formed in pentachlorophenol production are isomers of hexa-, hepta- and octachlorodibenzo-para-dioxin and isomers of tetra-, penta-, hexa-, hepta- and octachlorodibenzofuran.

1,2,3,4,6,7,9-Heptachlorodibenzo-p-dioxin was found at concn ranging from 1.6 to 580 parts/trillion (whole, wet weight basis) in 46 adipose tissue samples collected in 1976 from the general Canadian adult population; all of the samples contained the compound and the mean concn was 135 parts/trillion(1). Concn of 1,2,3,4,6,7,9- and 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin ranged from not detected to 5.3 and from 39.4 to 119 parts/trillion, respectively, in 5 sc tissue samples taken in 1983-1984 from the Binghamton, NY, general population; the concn of the two isomers were 9.6 and 209 parts/trillion, respectively, in sc tissue samples from one Binghamton, NY, State Office Building worker exposed following the 1981 PCB transformer fire(1). The avg total heptachlorodibenzo-p-dioxin concn in human adipose tissue were 97 parts/trillion in 31 samples taken in Sweden in 1982-83, 137 parts/trillion in 13 samples taken in Canada in 1976, 116 parts/trillion in 46 samples taken in Canada in 1980, and 164 parts/trillion in 8 samples taken in the U.S. in 1982-83(2). The avg total concn in the fat fraction of human milk were 59.5 picogram/g in 4 samples from Sweden, 72.8 picogram/g in 5 samples from Germany, and 174 picogram/g in 1 sample from Denmark(2).|Heptachlorodibenzo-p-dioxin was detected at concn of 8.5 and 89 parts/trillion (wet weight and lipid basis, respectively) in one of 9 samples human breast milk taken from South Vietnam in 1973; the compound was not detected in the other 8 samples (detection limit 2 parts/trillion(1). The concn in breast milk taken from 2 of 3 U.S. women in the 1970s ranged from 1.7 to 2.5 parts/trillion (wet weight basis) and 44 to 61 parts/trillion (lipid basis)(1). The 1,2,3,4,6,7,8-isomer was found in 9 of 11 samples of human milk collected in South Vietnam in 1985 at concn in the positive samples ranging from 19 to 172 parts/trillion (lipid basis) (detection limit generally between 0.1 and 0.2 parts/trillion); two of the samples were composites of three samples and one was a composite of 4 samples(1). The 1,2,3,4,6,7,8-isomer was found in 2 samples of human breast milk collected in 1986 in Binghamton, NY, at concn of 1.26 and 1.74 parts/trillion (wet weight basis) and 44 and 60 parts/trillion (lipid basis)(1). The concn of 1,2,3,4,7,8,9-heptachlorodibenzo-p-dioxin in composite samples of human adipose tissue as measured in the EPA fiscal year 1982 National Human Adipose Tissue Survey (NHATS) ranged from not detected (detection limit 23 picogram/g) to 390 picogram/g and the avg concn was 87 pg/g; the average concn was approximately 140, 80, and 42 picogram/g in samples from individuals >45 years old, 15-44 years old, and 0-14 years old, respectively(2).|The total concn of heptachlorodibenzo-p-dioxin in tissue from 28 adults from the Munich, Germany, area ranged from 35.1-246 parts/trillion (avg 106.7 parts/trillion) in adipose tissue and 95.7-3463.1 parts/trillion (avg 1002.4 parts/trillion) in liver tissue; the concn of heptachlorodibenzo-p-dioxin in adipose tissue from 8 infants ranged from 11.8-51.1 parts/trillion (avg 27.1 parts/trillion)(1). Pool samples of human milk in 1988 from Birmingham and Glasgow, UK, (40 mothers each city) contained 76 and 65 parts/trillion 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (fat basis), respectively(2). The concn found in a WHO/EURO Interlaboratory Comparison of a pooled 1987 sample of European human milk from a number of mothers and locations that were not specified contained 46 parts/trillion (fat basis)(2). The 1,2,3,4,6,7,9-isomer was detected in samples of adipose tissue collected in 1985 from 9 of 13 Japanese cancer patients at concn ranging from 14-53 picogram/g (wet weight basis; 28 picogram/g avg concn); the 1,2,3,4,6,7,8-isomer was found in 12 of the 13 samples at concn ranging from 29-180 pg/g (77 picogram/g avg) (detection limits not specified)(3).|The range of avg concn of total heptachlorodibenzo-p-dioxin found in many of the studies of human adipose tissue from various industrial countries (excluding China and the north of Vietnam) is 87-230 parts/trillion(1).

After 21 daily doses of 100 ug octachlorodibenzo-p-dioxin containing 12.6 picograms (35)S-thio-heptachlorodibenzo-p-dioxin to male Sprague-Dawley rats, the radioactivity was mainly recovered in the feces and urine, the percentages of the ingested radioactive doses being 93 (+ or - 6) and 5.2 (+ or - 0.8)% respectively. The high fecal excretion suggests poor absorption. Of the radioactive body burden, 50% was contained in the liver. The microsomal fractioncontained 96.3 (+ or - 8.2)% of the hepatic radioactivity.|The polychlorinated dibenzo-p-dioxins and the polychlorinated dibenzofurans are predominantly stored in fat, but they are also excreted in milk and pass the placenta. They also appear in the blood and vital organs at lower concentrations. /Polychlorinated dibenzo-p-dioxins/|A defined mixture of polychlorinated dibenzo-p-dioxins and dibenzofurans was subcutaneously administered to a pregnant marmoset monkey (Callithrix jacchus) 11 wk prior to delivery. Transfer of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans via placenta and mother's milk was investigated by measurement of concn in a newborn 1 day after birth and in an infant of the same litter after a lactation period of 33 days. Furthermore, comparative measurements were performed in different tissues of the mother at the end of the lactation period, and in addition, in two groups of four adult monkeys each 1 and 6 wk after treatment. Deposition of the polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans into fell liver was very low for most of the 2,3,7,8-substituted congeners. Highest deposition was observed for 2,3,7,8-tetrachlorodibenzo-p-dioxins and 1,2,3,7,8-pentachlorodibenzo-p-dioxins. For all other compounds concn in the hepatic tissue of newborn shortly after birth were lower than one tenth of corresponding concn in adults. Fetal liver isapparently largely unable to accumulate polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans. In contrast to liver, concn of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans in adipose tissue of the newborn were at least one third of the levels in adults. However, concn of octachlorodibenzo-p-dioxin and octachlorodibenzofuran were about three times higher in the newborn than in adult adipose tissue. Transfer of some of the 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans to the offspring via mother's milk was considerable, leading to hepatic concn in the suckled infant at the end of the 33-day nursing period well above corresponding concn in the dam. When hepatic concn in the infant and dam were compared 2- to 4-fold higher concn were found in the infant's liver for 2,3,7,8-tetrachlorodibenzo-p-dioxins/furans and for 1,2,3,7,8-pentachlorodibenzo-p-dioxins. In the case of the 2,3,7,8-substituted hexachlorodibenzo-p-dioxins, hepatic concn in the infant and dam were in the same range at the end of the suckling period. In contrast to this, less than one tenth the concn of octachlorodibenzo-p-dioxin was found in the infant's liver when compared with adult liver. /Hexachlorodibenzo-p-dioxins/|The tissue distribution of 2,3,7,8-chlorine substituted dibenzo-p-dioxins was conducted in 11 patients who died of cancer. The concn of octachlorodibenzo-p-dioxin was the highest in each organ and tissue and heptachlorodibenzo-p-dioxins was also found at relatively high levels, second only to octachlorodibenzo-p-dioxin. The levels of 1,2,3,7,8-pentachlorodibenzo-p-dioxins and 1,2,3,6,7,8-hexachlorodibenzo-p-dioxins in the spleen were the highest, respectively. 2,3,7,8-Tetrachlorodibenzo-p-dioxins was also detected and its concn was the highest in the gonad (0.8-3.2 picogram/g range). From the 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalent calculations, the highest equivalent value was obtained from a 54-year old female who died of cancerous goiter. This individual had the highest concn of 2,3,7,8-substituted penta- and hexa-chlorodibenzo-p-dioxinss among the 11 patients. /Heptachlorodibenzo-p-dioxins/|For more Absorption, Distribution and Excretion (Complete) data for HEPTACHLORODIBENZO-P-DIOXIN (8 total), please visit the HSDB record page.

The effects of subchronic octachlorodibenzo-p-dioxin exposure was examined in rats over a 13 wk period. Male Fischer 344 rats were treated with 50 ug/kg (14)C labeled octachlorodibenzo-p-dioxin by gavage for 10, 20, 40, or 65 doses (once per day 5 days per wk) and sacrificed 3 days postexposure. Hepatic accumulation was associated with alterations of several biochemical parameters. In animals treated 65 times, ethoxyresorufin-O-deethylase activity was elevated 40 fold over controls; total cytochrome p450 content doubled and exhibited a 2 nanometer blue shift in the Soret maximum for the reduced hemoprotein-CO complex. Cytochrome p450c and cytochrome p450d were significantly increased, while cytochrome p450b levels were unaltered. Nearly all the dioxin congeners present in liver were represented by octachlorodibenzo-p-dioxin, with a slight amount ofheptachlorinated dioxin present. It was concluded that subchronic octachlorodibenzo-p-dioxin exposure causes toxic effects similar to those observed with other dioxins, but with far less potency than 2,3,7,8-tetrachlorodibenzo-p-dioxin. /Octachlorodibenzo-p-dioxin/

16.22 Days|The half-lives of 1,2,3,6,7,8-Hexachlorodibenzo-p-dioxin, 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin, and octachlorodibenzo-p-dioxin /were calculated/ to be about 3.5, 3.6 and 2 years, respectively. The estimation was based on the analysis of fat tissue biopsies collected with an interval of 28 months from one 14 year old girl who for a period of about 2-3 years had been exposed to technical pentachlorophenol.

SYMPTOMS: Symptoms of exposure to this compound may include eye irritation, chloracne and liver damage. ACUTE/CHRONIC HAZARDS: This chemical is extremely toxic. Ingestion of small quantities can cause toxic effects. It can also be absorbed through the skin. Allow only your most experienced personnel to work with this chemical. All non-essential personnel should leave the laboratory. (NTP, 1992)

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. IMMEDIATELY call a hospital or poison control center even if no symptoms (such as redness or irritation) develop. IMMEDIATELY transport the victim to a hospital for treatment after washing the affected areas. INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. IMMEDIATELY call a physician and be prepared to transport the victim to a hospital even if no symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop. 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: 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. Generally, the induction of vomiting is NOT recommended outside of a physician's care due to the risk of aspirating the chemical into the victim's lungs. However, if the victim is conscious and not convulsing and if medical help is not readily available, consider the risk of inducing vomiting because of the high toxicity of the chemical ingested. Ipecac syrup or salt water may be used in such an emergency. IMMEDIATELY transport the victim to a hospital. 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)

Results confirm that chloracne is associated with exposure to pentachlorophenol contaminated with hexachlorinated, heptachlorinated, and octachlorinated dibenzo-p-dioxins and dibenzofurans.|There are 12 isomers /of 2,3,7,8-tetrachlorodibenzo-p-dioxin/ that display high toxicity, ie, the tetra-, penta-, hexa-, and hepta-chlorodibenzo-p-dioxins ... with four chlorine atoms in the symmetrical lateral positions 2,3,7,and 8.|To evaluate the association between exposure to pentachlorophenol and the occurrence of chloracne, the medical and personnel records for individuals employed in the manufacturing of pentachlorophenol /were examined/. Forty seven cases of chloracne were identified among 648 workers (7.0%) assigned to pentachlorophenol production at a single plant between 1953 and 1978. The annual incidence rate varied considerably, ranging from 0 (in 1953) to 1.46 (in 1978). No linear trend in the risk of chloracne was observed with the duration of employment in the pentachlorophenol department. Workers with a documented episode of direct skin contact with pentachlorophenol had a significantly increased risk of chloracne compared with workers who did not have a documented episode of direct skin contact (cumulative incidence ratio = 4.6; 95% confidence interval 2.6-8.1). Our results confirm that chloracne is associated with exposure to pentachlorophenol contamined with hexachlorinated, heptachlorinated, and octachlorinated dibenzo-p-dioxins and dibenzofurans.

1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin

One of the 21 tetrachlorophenol samples /that were analyzed/ contained ... 5.1 mg/kg ... /of/ heptachlorodibenzo-p-dioxin. ... Analysis /of 8 commercial pentachlorophenols/ ... showed ... heptachlorodibenzo-p-dioxins ... in the range of 0.5 to 39 mg/kg in 7 samples, and 3.3 to 15 mg/kg ... in 5 samples.|/Samples analyzed by mass fragmentography/ were found to contain ... 55 mg/kg of heptachlorodibenzo-p-dioxins /in commercial 2,3,4,6-tetrachlorophenol (TCP) and/ 235 mg/kg heptachlorodibenzo-p-dioxins /in technical pentachlorophenol (PCP)/. The positional isomers of the dioxins were not identified.|Heptachlorodibenzo-p-dioxins were found in both technical and analytical grades of commercial pentachlorophenol, as determined by gas chromatography coupled with several detection methods. When an electron capture detector was used, the technical grade product was found to contain 24 mg/kg ... and the analytical grade product had 0.04 mg/kg /of heptachlorodibenzo-p-dioxins/.

EPA Method 1613. Determination of heptachlorobenzo-p-dioxin using GC with high resolution mass spectrometry.|Fat, oil, fatty acid, or lipid is treated with sulfuric acid and extracted with petroleum ether. Extract is purified on an aluminum oxide column, further treated with sulfuric acid, and examined by EC/GC. Peaks with retention times relative to aldrin (Ra) between 8 and 45 ... /indicate/ hexa-, hepta-, and octachlorodibenzo-p-dioxins. ... 2 Peaks at 17-22 /are due/ to the 2-hepta- isomers.|Commercial chlorophenols were analyzed ... by fractionation on an aluminum oxide column, followed by GC with ECD confirmation by MS. Hepta-chlorodibenzo-p-dioxins were determined, with a detection limit of 20 ug/kg.

A method for multicomponent determinations of organochlorine contaminants in human milk is described. The lipophilic gel Lipidex 5000 was used for extraction of lipids and organochlorine cmpds. Further purification and separation was achieved by chromatography on partly deactivated aluminum oxide, Lipidex, silica gel, and active basic and acidic aluminum oxide. The concentrations of pesticides and PCBs were determined by EC/GC. Polychlorinated dibenzo-p-dioxins were determind by selected-ion monitoring capillary column Gc/MS at a resolution of 8000-9000. Ten polychlorinated dibenzo-p-dioxins /including heptachlorodibenzo-p-dioxin/ reported to occur in milk were added at levels between 0.5 and 50 pg/ml milk. Recoveries of these cmpds were on an average 79-91%.