Pentachlorodibenzodioxin

356.4 g/mol

355.854618 g/mol

R8LZ311J18

DTXSID3074078

18.5 Ų

6.5 (LogP)|log Kow = 6.50 (avg of 9 isomers)

220 °C

3.37e-10 M|In water, 1.20X10-4 mg/l @ 20 °C

5.60e-10 mmHg|5.60X10-10 mm Hg @ 25 °C

/Toxic equivalency factors (TEF), indicate the toxicity of a compound relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin, which itself has been assigned a TEF of 1.0. Concentration data for polychlorinated dibenzo-p-dioxins are frequently reported in units of toxic equivalency which are equal to the measured concentration of substance multiplied by its TEF./ The TEF for pentachlorodibenzo-p-dioxins (excluding 1,2,3,7,8-pentachlorodibenzo-p-dioxin) is 0. The TEF for 1,2,3,7,8-pentachlorodibenzo-p-dioxin is 0.5.

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.

WHO; Environ Health Criteria 88: Polychlorinated Dibenzo-para-dioxins and Dibenzofurans p.262 (1989)

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

Pentachlorodibenzo-p-dioxin was detected at a concn range of 0.08-9.3 ug/kg in soot from coal combustion and at concns of 140 and 120 in fly ash from municipal waste incineration sites in the United Kingdom(1). Pentachlorodibenzo-p-dioxin concns ranged from 1.4-450 ng/g in fly ash from four incinerators in Switzerland(2). Pentachlorodibenzo-p-dioxin concns ranged 0.03-9 ng/g in sewage sludge samples from municipal waste water treatment plants in Germany(3). Pentachlorodibenzo-p-dioxin was found in landfill leachate and bottom sediments at concns up to approximately 5,000 parts per trillion from a site in Germany(4). Total pentachlorodibenzo-p-dioxin concns ranged about 1,600-1,860 parts per trillion in runoff oils from a tire fire in Ontario, Canada(5). Pentachlorodibenzo-p-dioxin was detected at concns of 68, 3, and 12 ng/sq m in surface-wipe samples taken from 3 different buildings in a facility (actual site not specified) where improper incineration of Aroclor 1254 took place(6). Pentachlorodibenzo-p-dioxin was detected at concns of 24 and 6.3 ppb in combustion products from real fire accidents (actual site not specified) involving hard-polyvinylchloride (PVC) and PVC-fibers, respectively(7). Pentachlorodibenzo-p-dioxin was identified in stack emissions from a waste oil furnace in Sydney, Australia(8). Pentachlorodibenzo-p-dioxin was detected at concns of 49 and 26 parts per trillion in effluents from two pulp and paper mills in Ontario, Canada(9).|The mean concn of pentachlorodibenzo-p-dioxin in stack gas emissions was 0.24 ng/cu m (range, 0.01-1.78 ng/cu m) from a waste incineration facility in the United Kingdom(1). Emissions from a municipal waste incinerator in northeast Spain ranged from 4.55 to 44.20 ng/normal cu m (n=4) while emissions from an industrial waste incinerator ranged from 468.71 to 2161.42 ng per normal cu m (n=2)(2). Emissions of pentachlorodibenzo-p-dioxin ranged from 0.20 to 162.45 ng/normal cu m (n=16) in waste incinerators (11 municipal solid waste incinerators; 3 small incinerators; hospital waste incinerator; industrial waste incinerator) located in Korea(3). The concn of pentachlorodibenzo-p-dioxin in the emission gases from crematories in Japan ranged from 0.12 to 20 ng/normal cu m(4). In July, 1991, the concn of pentachlorodibenzo-p-dioxin in street runoff from two rain events in Bayreuth, Germany ranged from 6.6 to 23 pg/L (n=4) while the concn of pentachlorodibenzo-p-dioxin in sediment collected in storm water sediment traps ranged from 33 to 210 ng/kg(5).

SOIL: Pentachlorodibenzo-p-dioxin was detected at a concn of 580 parts-per-trillion in one soil sample at 1.26 km from a municipal waste incinerator in Hamilton, Ontario, Canada between 1982-1983(1). The concn of pentachlorodibenzo-p-dioxin in soil was measured at several distances from a municipal solid waste incinerator in Montcada, Spain as follows (distance, km; concn, ng/kg dry wt): 1.1, 75; 2.25, 2; 3.5, 11; 4.75, 230; 5.1, 15; 6.15, 16; 7.2, 31; 8.3, 55(2). The mean concn of pentachlorodibenzo-p-dioxin in soil from the impact area of a waste incineration facility in the United Kingdom was 5.8 ng/kg (range, 1-19 ng/kg) while the background concn was 4.4 ng/kg (range, 1-7 ng/kg)(3).|SEDIMENT: Between 1980-1985, 1,2,3,7,8-pentachlorodibenzo-p-dioxin was detected at a concn of 60 parts per trillion in a sediment sample taken from a river in south-west Germany(1). 1,2,3,7,8-Pentachlorodibenzo-p-dioxin was detected in 3 sediments of the river Elbe, Germany, at a concn range of 2-10 pg/g dry weight; total pentachlorodibenzo-p-dioxin concns ranged 10-100 pg/g dry weight in 8 sediments(2). Pentachlorodibenzo-p-dioxin was detected in sediment samples taken from two rivers in Vietnam at a concn range of 0.9-87 pg/g dry weight(3). In 1982, pentachlorodibenzo-p-dioxin was detected in sediment cores taken from Siskiwit Lake on Isle Royale, an island in northern Lake Superior, at depths of 0-0.5 cm and 5-6 cm and respective concns of 5 and 2 parts per trillion; no pentachlorodibenzo-p-dioxin was detected at depths of 8-9 cm(4). Sediment cores from Lake Stechlin (northeastern Germany) were analyzed for historical contamination of chemical contaminants(5); pentachlorodibenzo-p-dioxin was measured in these cores as follows (years, concn in ng/kg): 1994-1987, 48.53; 1987-1978, 58.85; 1978-1965, 76.11; 1965-1953, 106.90; 1953-1941, 84.46; 1941-1927, 56.55; 1927-1913, 67.63; sediments at 16-26 cm depth, range, 0.0-4.56(5). Sediment cores from spring-feed forest lakes in the southwest of Germany were analyzed for historical contaminants(6). Lakes (Herrenwieser, Schurmsee, Wildsee, Huzenbachen See) from this region contained pentachlorodibenzo-p-dioxin at concn(s) as follows(6): Herrenwieser (years, concn in pg/g): 1982-1992, 354; 1960-1982, 261; 1927-1960, 16; 1886-1927, 5.2; 18th century, not detected; 17th century, not detected. Schurmsee (years, concn in pg/g): 1987-1992, 69; 1979-1987, 36; 1965-1979, 8.4; 1946-1965, 12; 19th century, 0.2; 18th century, 0.1. Wildsee (years, concn in pg/g): 1985-1992, 398; 1964-1985, 513; 1930-1964, 544; 1892-1930, 58; 1850-1892, 14; early 19th century, 14. Huzenbachen See (years, concn in pg/g): 1983-1992, 170; 1961-1983, 22; 1903-1934, 8.3; 1882-1903, 6.8; 19th century, not detected; 18th century, 7.0. River and offshore sediments contained hexachlorodibenzo-p-dioxin at avg concns of 220 (range, 3.1-1100) pg/g dry wt and 160 (range, 1.1-1,100) pg/g dry wt, respectively, sampled in November 1993 from various points in rivers and along the coast of the Fukuoka Prefecture (Japan)(7).|SEDIMENT: Between Aug 1991-Jul 1994, sediment samples from the Ya-Er lake area of China were found to contain pentachlorodibenzo-p-dioxin at concns ranging from 0.05 to 1.84X10+3 ng/kg dry wt (n=4)(1). Surficial sediments from Fukuoka Prefecture and Fukuoka City contain pentachlorodibenzo-p-dioxin at concns as follows (location, avg, range; all pg/g dry wt)(2): reservoir, 73, 13-120; irrigation pond, 44, 17-75 (n=7); irrigation pond near incinerator, 66, 26-130 (n=10); irrigation pond control, 110 (n=1); paddy field, 5300.

URBAN/SUBURBAN: Total pentachlorodibenzo-p-dioxin concns were 26 and 13 fg/cu-m in the gas and particulate-bound phases, respectively, in ambient air samples taken from Bloomington, Indiana in 1986(2). Avg Bridgeport, CT ambient air concns ranged 0.006-0.067 pg/cu m in samples collected in November of 1987-January of 1988(1). Monitoring conducted in Hamburg, Germany between September-October, 1989 found avg pentachlorodibenzo-p-dioxin air concns of 104.4 and 294.6 fg/cu-m in two series of tests(3). Monitoring in Windsor, Ontario from July of 1987-August of 1988 found pentachlorodibenzo-p-dioxin at a max concn of 0.15 pg/cu m(4). Monitoring of urban air in Sydney, Australia in October of 1990 found pentachlorodibenzo-p-dioxin at concns less than 1 pg/cu m(5). Pentachlorodibenzo-p-dioxin was detected in the ambient air of Niagara Falls, NY at concns of 0.21 and 0.62 pg/cu-m on January 10, 1988(6). The concn of pentachlorodibenzo-p-dioxin was measured in the ambient air of the following locations (all concns pg/cu m)(7): Bloomington, IN (0.04); Niagara Falls, NY (0.01); Indianapolis, IN (0.26); Bridgeport, CT (0.24). The levels of pentachlorodibenzo-p-dioxin in air were measured at the locations (all fg/cu m)(8): Bloomington, IN, 51; W. Germany suburban location, 50.|INDOOR: A monitoring study done in 1986 in Germany found a pentachlorodibenzo-p-dioxin concn of 0.12 pg/cu m in the indoor air of a kindergarten classroom in a school building where wood preservatives were used(1).|RURAL/REMOTE: Pentachlorodibenzo-p-dioxin was detected in 1 of 17 samples collected from McMurdo Station, Antarctica at a concn of 0.42 pg/cu m(1). The concn of pentachlorodibenzo-p-dioxin in the ambient air of Trout Lake, WI (a remote location) was 0.01 pg/cu m(2).|SOURCE DOMINATED: The concn of pentachlorodibenzo-p-dioxin in the ambient air of Niagra Falls, NY downwind from a emission source was 1.0 pg/cu m(1). Pentachlorodibenzo-p-dioxin levels were measured at the following locations (all fg/cu m)(2): two sites in W. Germany (510 and 1,100); tunnel in W. Germany (1,900); Netherlands, 1 km from municipal waste incinerator (3,400); Netherlands, 2 km from municipal waste incinerator (500).

Pentachlorodibenzo-p-dioxin was detected in mainstream and sidestream cigarette smoke at concns of 21.4 and 42.7 pg/20-cigarettes, respectively(1). Pentachlorodibenzo-p-dioxin was identified in soil from Rheinfelden, Germany that was contaminated from the use of chlorine-alkaline-electrolysis residues for land filling(2). The pentachlorodibenzo-p-dioxin median concn was 46 parts per trillion in soil samples taken from Oroville, CA in 1988 following a fire at a wood treatment plant(3). The concn of pentachlorodibenzo-p-dioxin in paper clay samples from Taiwan ranged from 0.06 to 1.26 ng/g dry matter (4). Pentachlorodibenzo-p-dioxin was found in textile samples (n=23) from Bayreuth, Germany at concns ranging from 0.17 to 11 pg/g(5); in blue-green textiles, the concn of pentachlorodibenzo-p-dioxin ranged from <0.05 to 1.1 pg/g(5). Paper products purchased locally in Ottawa, Canada contained pentachlorodibenzo-p-dioxin at concns as follows (all pg/g)(6): coffee filter, 25.6 (year 1991, 1 of 5 samples); paper cups, 1.6 (year 1988, 2 of 3 samples); paper plates, 0.7 (year 1988, 2 of 4 samples); 2.1 (year 1991, 1 of 5 samples). Commercial p- and o-chloroanils contained pentachlorodibenzo-p-dioxin at concns ranging from not detected to 130 ug/kg (n=5) and not detected to 182 ug/kg (n=3)(7). Pentachlorodibenzo-p-dioxin was detected at a concn of 2.7 ppb in a sample of nickel-phthalocyanine(8). Pentachlorodibenzo-p-dioxin was found in motor oil at a max concn of 5.9 ppb and in refined waste oil at a max concn of 6.7 ppb(9). Also, the concn range in waste oils was found to be 0.02-2.4 ug/kg and the max concn in soil contaminated by waste oil was 2.2 ug/kg(9).

LD50 Guinea pig oral 3.1 ug/kg /1,2,3,7,8-Pentachlorodibenzo-p-dioxin/|LD50 Guinea pig oral 1,125 ug/kg /1,2,4,7,8-Pentachlorodibenzo-p-dioxin/|LD50 Mouse oral 337.5 ug/kg /1,2,3,7,8-Pentachlorodibenzo-p-dioxin/|LD50 Rat (Sprague-Dawley, male) oral 206 ug/kg /1,2,3,7,8-Pentachlorodibenzo-p-dioxin/

/FIELD STUDIES/ Studying liver samples of 16 adult male polar bears /(Ursus maritimus)/ ...workers found that CYP1A protein content correlated strongly with the concentration of PCBs, polychlorinated dibenzodioxins (PCDDS) and polychlorinated dibenzofurans (PCDFs) in the liver... . /Polychlorinated dibenzodioxins/

Pentachlorodibenzo-p-dioxin is released to the environment in emissions from wood combustion(1), waste oil furnaces(2), fires of PVC-containing materials(3), and fires of electrical equipment containing polychlorinated biphenyls (PCBs)(4); and cigarette smoke(5). Pentachlorodibenzo-p-dioxin is found in 2,4,5-T and other pesticides(6) and may be released during their use. It is also released in effluents from the pulp and paper industry(7), and in sewage from municipal waste(8). In the UK, estimated emissions of pentachlorodibenzo-p-dioxin from domestic coal combustion and municipal waste incinerators are 0.09 and 1.27 kg/yr, respectively(9). Industrial synthesis of nickel-phthalocyanine could lead to the production of pentachlorodibenzo-p-dioxin(10).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 82,000(SRC), determined from a log Kow of 6.50(2) and a regression-derived equation(3), indicates that pentachlorodibenzo-p-dioxin is expected to be immobile in soil(SRC). Volatilization of pentachlorodibenzo-p-dioxin from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 2.2X10-6 atm-cu m/mole(SRC), derived from its vapor pressure, 5.6X10-10 mm Hg(4), and water solubility, 1.2X10-4 mg/l(5). However, adsorption to soil is expected to attenuate volatilization(SRC). Pentachlorodibenzo-p-dioxin is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(4). Pentachlorodibenzo-p-dioxin is susceptible to direct photolysis based on a half-life of 7.6 hr in n-hexadecane solution for 1,2,3,7,8-pentachlorodibenzo-p-dioxin(6). Therefore, some photodegradation may occur on surfaces exposed to sunlight(SRC), although the relative importance of surface photodegradation is unknown(SRC). Biodegradation of pentachlorodibenzo-p-dioxin in soil is expected to be very slow(SRC). 100 percent of pentachlorodibenzo-p-dioxin (as 1,2,3,7,8-pentachlorodibenzo-p-dioxin) applied to a sandy loam soil, at pH 8.1, remained in the soil after a 15 month period(7).|AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 82,000(SRC), determined from a log Kow of 6.50(2) and a regression-derived equation(3), indicates that pentachlorodibenzo-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 2.2X10-6 atm-cu m/mole(SRC), derived from its vapor pressure, 5.60X10-10 mm Hg(4), and water solubility, 1.20X10-4 mg/l(5). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 21 and 236 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 52 years if adsorption is considered(6). According to a classification scheme(7), BCF values of 810(8) and 1,434(9) are high and very high, respectively(SRC). Pentachlorodibenzo-p-dioxin in water is susceptible to direct photolysis in sunlight(9); however, adsorption to sediment and suspended solids may minimize any importance of aquatic photodegradation(SRC). Based on a soil field study(10), biodegradation of pentachlorodibenzo-p-dioxin in water is expected to be very slow(SRC). 100 percent of pentachlorodibenzo-p-dioxin (as 1,2,3,7,8-pentachlorodibenzo-p-dioxin) applied to a sandy loam soil, at pH 8.1, remained in the soil after a 15 month period(10).|ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), pentachlorodibenzo-p-dioxin, which has a vapor pressure of 5.60X10-10 mm Hg at 25 °C(2), is expected to exist solely in the particulate phase in the ambient atmosphere(SRC). However, monitoring data suggest that pentachlorodibenzo-p-dioxin will also exist in the vapor-phase in the ambient atmosphere(3). Vapor-phase pentachlorodibenzo-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 28 days(SRC), calculated from its rate constant of 5.8X10-13 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(4). Particulate-phase pentachlorodibenzo-p-dioxin may be removed from the air by wet and dry deposition(SRC). Particle-bound pentachlorodibenzo-p-dioxin is removed from the atmosphere in rain and has been identified in precipitation samples(5,6). Dry deposition also has been observed(6). Photodegradation of pentachlorodibenzo-p-dioxin bound to fly ash is not an important atmospheric removal mechanism(7).

The rate constant for the vapor-phase reaction of pentachlorodibenzo-p-dioxin with photochemically-produced hydroxyl radicals has been estimated as 5.8X10-13 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 28 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Pentachlorodibenzo-p-dioxin is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(2). The photolysis half-life of 1,2,3,7,8- pentachlorodibenzo-p-dioxin in n-hexadecane solution was measured to be 7.6 hr(3). No photodegradation was observed for polychlorodibenzo-p-dioxins found on five different fly ashes ranging in color from black to yellow(4).

BCF values for 1,2,3,4,7-pentachlorodibenzo-p-dioxin of 810 for rainbow trout (Salmo gairdneri) and 1,434 for fathead minnows (Pimephales promelas) were measured in a flow-through test using a 5-day exposure period(1). The BCF for pentachlorodibenzo-p-dioxin was determined to be 432.8 in blue mussel (Mytilus edulis) after a 64-day exposure period to 0.759 parts per trillion pentachlorodibenzo-p-dioxin in 50 liter tank of artificial sea water(2). According to a classification scheme(3), BCF values of 810 for rainbow trout(1) and 1,434 for fathead minnows(1) are high and very high, respectively(SRC). Monitoring data in fish also indicate that pentachlorodibenzo-p-dioxin will bioconcentrate in aquatic organisms(4,5).

The Koc of pentachlorodibenzo-p-dioxin is estimated as 82,000(SRC), using a log Kow of 6.50(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that pentachlorodibenzo-p-dioxin is expected to be immobile in soil(SRC).

The Henry's Law constant for pentachlorodibenzo-p-dioxin is estimated as 2.2X10-6 atm-cu m/mole(SRC) derived from its vapor pressure, 5.6X10-10 mm Hg(1), and water solubility, 1.2X10-4 mg/l(2). This Henry's Law constant indicates that pentachlorodibenzo-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 21 days(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 236 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 52 years if adsorption is considered(4). Pentachlorodibenzo-p-dioxin's estimated Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). However, volatilization from moist soil surfaces is expected to be attenuated by adsorption to soil(SRC). Pentachlorodibenzo-p-dioxin is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(1).

SURFACE WATER: Pentachlorodibenzo-p-dioxin concns ranged <0.7-22.3 pg/cu m in water at three remote coastal and six offshore stations in the Baltic sea(1).|RAIN/SNOW: Pentachlorodibenzo-p-dioxin was identified in a precipitation sample taken in Toronto, Canada during September 6 - November 1(1). Monitoring in Rheinfelden, Germany during May-October of 1991 found pentachlorodibenzo-p-dioxin at concns < 100 pg/(sq-m d) in wet and dry deposition combined(2). Avg pentachlorodibenzo-p-dioxin concns in the dissolved and particle-bound phases were determined to both be 0.2 pg/L in rain samples taken in Bloomington, IN during August 1985-July 1988(3).

The concn of pentachlorodibenzo-p-dioxin averaged 28, 1,509, 164, and 186 parts per trillion in apple, chicken, egg, and sugar samples, respectively, purchased during the period of October 1985-March 1986 in Akita city, Japan(1). In the same study, the concn ranged from <10-208 parts per trillion in cereals, 16-204 parts per trillion in beans, and 13-38 parts per trillion in vegetables(1). Pentachlorodibenzo-p-dioxin median concns were 38 pg/g in egg, 246 pg/g in chicken liver and 198 pg/g in chicken fat in samples taken from Oroville, CA in 1988 following a fire at a wood treatment plant(2). The concn of pentachlorodibenzo-p-dioxin in vegetable, chicken, and egg samples collected in Japan during June of 1986 were 0.1, 1.3, and 0.9 pg/g, respectively(3). Pentachlorodibenzo-p-dioxin was found at concns < 2 ng/kg dm in apples and pears from trees in Rheinfelden, Germany(4).

The average concn of pentachlorodibenzo-p-dioxin in milk samples purchased during the period of October 1985-March 1986 in Akita city, Japan was 121 parts per trillion(1).|1,2,3,7,8-Pentachlorodibenzo-p-dioxin has been detected in human milk; avg levels in human milk fat are <30 parts per trillion(1). In 1989, the avg pentachlorodibenzo-p-dioxin concn in human milk samples taken from 100 nursing mothers from Stockholm, Sweden was approximately 10 pg/g fat(2). The concn of pentachlorodibenzo-p-dioxin in breast milk samples was measured in mothers from Kazakstan in 1994(location, concn in pg/g fat): rural, 14.60 (n=7); Almaty, 2.39 (n=5); Aralsk, 1.91 (n=6); Atyrau, 3.97 (n=6); Shymkent, 2.43 (n=5); Qyzyl-Orda, 1.38(n=5)(3).

Occupational exposure to pentachlorodibenzo-p-dioxin may occur through inhalation of dust and dermal contact with compounds (e.g. PCP, pesticides) contaminated with pentachlorodibenzo-p-dioxin at workplaces where these compounds are produced or used(SRC). Workers involved in chlorophenol production and metal reclamation will be exposed to pentachlorodibenzo-p-dioxin by inhalation of contaminated air or by dermal exposure(1). In 1988-1991, the mean concn of 1,2,3,7,8-pentachlorodibenzo-p-dioxin in workers whole blood samples were 10.7 parts per trillion from a trichlorophenol production plant, 28.3 parts per trillion from a pentachlorophenol production plant, 19.2 parts per trillion from a metal reclamation facility, and 56.3 parts per trillion from a herbicide plant(2). 1,2,3,7,8-Pentachlorodibenzo-p-dioxin concn ranged from approximately 10-200 mg/kg in fat tissue from workers of a herbicide production plant(2). Monitoring data indicate that the general population may be exposed to pentachlorodibenzo-p-dioxin via inhalation of ambient air, ingestion of food and dermal contact with compounds contaminated with pentachlorodibenzo-p-dioxin(SRC). Pentachlorodibenzo-p-dioxin is found in urban air(3); and human exposure in urban settings will occur by inhalation of ambient air(SRC). Monitoring data suggest that direct exposure to pentachlorodibenzo-p-dioxin will occur with the ingestion of contaminated food(4-6) and inhalation of cigarette smoke(7). Both adults and infants may be exposed to pentachlorodibenzo-p-dioxin through ingestion of contaminated milk(4,8,9). Exposure may also occur by inhalation of contaminated indoor air in buildings where materials containing pentachlorodibenzo-p-dioxin are used(10,11).

1,2,3,7,8-Pentachlorodibenzo-p-dioxin has been detected in human milk; avg levels in human milk fat are <30 parts per trillion(1). In 1989, the avg pentachlorodibenzo-p-dioxin concn in human milk samples taken from 100 nursing mothers from Stockholm, Sweden was approximately 10 pg/g fat(2). The concn of pentachlorodibenzo-p-dioxin in breast milk samples was measured in mothers from Kazakstan in 1994(location, concn in pg/g fat): rural, 14.60 (n=7); Almaty, 2.39 (n=5); Aralsk, 1.91 (n=6); Atyrau, 3.97 (n=6); Shymkent, 2.43 (n=5); Qyzyl-Orda, 1.38(n=5)(3). In 1988-1991, the mean concn of 1,2,3,7,8-pentachlorodibenzo-p-dioxin in workers whole blood samples were 10.7 parts per trillion from a trichlorophenol production plant, 28.3 parts per trillion from a pentachlorophenol production plant, 19.2 parts per trillion from a metal reclamation facility, and 56.3 parts per trillion from a herbicide plant(4). 1,2,3,7,8-Pentachlorodibenzo-p-dioxin concn ranged from approximately 10 to 200 mg/kg in fat tissue from workers of a herbicide production plant(5).

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/|Incomplete and variable absorption of 1,2,3,7,8-pentaCDD in corn oil was reported in rats, with 19 to 71% of the dose absorbed within the first 2 days after oral exposure.|Studies in the rat, guinea pig, hamster, and mouse have found that essentially all of the TCDD-derived radioactivity excreted in the urine and bile corresponds to metabolites of TCDD. The apparent absence of TCDD metabolites in liver and fat suggests that once formed, the metabolites of TCDD are excreted readily. Thus, urinary and biliary elimination of TCDD depends on metabolism of the toxin. The more limited data for other compounds also suggest that this relationship may be true for 1,2,3,7,8-pentaCDD, 2,3,7,8-TBDD, 2,3,7,8-TCDF, 1,2,3,7,8-pentaCDF, 2,3,4,7,8-pentaCDF, and 3,3',4,4'-TCB.|...The role of dietary fiber or Chlorella in the fecal excretion of PCDDs and PCDFs in rats /was investigated/. Rice bran fibers enhanced the fecal excretion of PCDDs form 0.6 to 2.3 and of PCDFs from 0.5- to 10.4 fold above that of rats on a control diet. Chlorella is a unicellular green algae sold as a health food or health supplement. Chlorella in the diet of rats also enhanced the fecal excretion of PCDDs from 0.8 to 5.6 and PCDFs from 0.9- to 11.1-fold above that of rats on a control diet. Dietary fiber, chlorophyll, and /or lipid in the Chlorella may be factors responsible for the enhanced fecal excretion of PCDDs and PCDFs observed in this study. Thus, fiber and/or Chlorella may be other dietary factors capable of increasing the fecal excretion of PCDDs and PCDFs. /Polychlorinated dibenzo-p-dioxins and dibenzofurans/

Little is known about the metabolism of these compounds in mammalian systems. The half-life of some of these compounds in humans can be measured not in hours, days, weeks, or months, but in years. /Polychlorodibenzodioxins/

/In a/... study of 48 workers at a German pesticide facility, elimination half times were estimated for several CDD congeners. The estimated half-/life was/ 15.7 years for 1,2,3,7,8-PeCDD... . /1,2,3,7,8-Pentachlorodibenzo-p-dioxin/|An elimination half-life of 29.5 days was estimated for 1,2,3,7,8-PCDD in Sprague-Dawley rats following a single oral exposure. /1,2,3,7,8-Pentachlorodibenzo-p-dioxin/

Persons with recent exposure to polychlorodibenzodioxins ... should have the chemicals removed from their skin as quickly as possible to prevent additional absorption of the compounds. Exposed person should be asked for an exposure history, including onset of exposure, duration of exposure, and type of exposure. Physical examinations, including a thorough examination of the skin, should be given. Routine blood and liver laboratory tests should be carried out. In most situations, however, evidence of exposure and disease relatable to the exposure will be lacking. Because chloracne is the only human effect documented thus far, no other specific abnormality can be considered pathognomonic for exposure. /Polychlorodibenzodioxins/|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/

/HUMAN EXPOSURE STUDIES/ Workers exposed to dioxin had adipose tissue levels with a mean of 246 ppt. Unexposed workers had levels of 86 ppt. Nine workers with a history of exposure to PCDD's and chloracne in 1971 to 1973 had TCDD serum levels of 340 pg per gram blood lipid in 1990.|/HUMAN EXPOSURE STUDIES/ The most prominent acute manifestation of toxicity that has been shown in humans is chloracne, an acne-like condition that takes months or years to disappear. Clinically, this skin lesion is characterized by hyperplasia and hyperkeratosis of the interfollicular epidermis, hyperkeratosis of the sebaceous follicles, and the squamous metaplasia of the sebaceous glands that form cysts and keratinaceous comedones in a typical distribution. Data are not yet available to determine the amount, route, or duration of exposure that is necessary to cause chloracne. /Polychlorodibenzodioxins/|/HUMAN EXPOSURE STUDIES/ All members of a Spanish family (father, mother and six children) developed chloracne. The causative agent was found to be the family's stock of olive oil, which had become contaminated with polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, pentachlorophenol, and hexachlorobenzene. The more highly chlorinated polychlorinated dibenzo-p-dioxins, in particular octachlorodibenzo-p-dioxin, were the predominant congeners in the oil. Three members of the family exhibited either an overt or a sub-clinical disturbance of kidney function. The father also had a chronic respiratory problem. These changes could not be unequivocally attributed to the polychlorinated dibenzo-p-dioxins. Experimental toxicity of the oil was limited to the development of hepatic porphyria in mice. A serum sample taken after the consumption of the oil ceased, contained high levels of the polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans. Extrapolation back to ingested dose was used to validate dosage estimates. The use of toxicity equivalence factors provided estimates of cumulative dosage to produce chloracne as 0.13-0.31 ug 2,3,7,8-tetrachlorodibenzodioxin/kg (using EPA toxicity equivalence factors) or 6.7-16 ug 2,3,7,8-tetrachlorodibenzodioxin/kg (using Nordic/NATO toxicity equivalence factors). This is the first incident in which human toxicity is related primarily to ingestion of polychlorinated dibenzo-p-dioxins and for which estimates of dosage can be made.|/HUMAN EXPOSURE STUDIES/ Due to their lipophilicity, /Chlorinated dibenzo-p-dioxins/ (CDDs) can concentrate in human breast milk and can be transferred to infants through nursing. In general, the amount of individual congeners in breast milk decreased as chlorination decreases. Excretion via milk is highest during the first weeks after delivery. Also, the concentration of CDDs in milk is higher in mothers breast-feeding their first child than in those breast-feeding their second child. CDDs transferred to infants through nursing are readily absorbed by the infants. A pharmacokinetic model predicted that the increased body burden in infants that results from breast-feeding does not translate into raised lifetime body burden. /Chlorinated dibenzo-p-dioxins/|For more Human Toxicity Excerpts (Complete) data for PENTACHLORODIBENZO-p-DIOXIN (8 total), please visit the HSDB record page.

Thermal or chemical degradation of chlorophenols can produce as a byproduct ... . /Polychlorodibenzoparadioxins/

Commercial chlorophenols were analyzed for chlorodibenzo-para-dioxins by fractionation on an aluminum oxide column, followed by GC with ECD and confirmation by MS. Di-, tri-, tetra-, penta-, hexa-, hepta- and octachlorodibenzo-para-dioxins were determined, with a detection limit of 20 ug/kg.|EPA Method 8280A, The Analysis of Polychlorinated Dibenzo-p-Dioxins and Polychlorinated Dibenzofurans by High Resolution Gas Chromatography/Low Resolution Mass Spectrometry; Analyte: hexachlorodibenzo-p-dioxin; Matrix: water, soil, fly ash, and chemical wastes. /Total Pentachlorodibenzo-p-dioxin/|Method: EPA-EAD 1613, Tetra-through Octa-Chlorinated Dioxins and Furans by Isotope Dilution High Resolution Gas Chromatography/High Resolution Mass Spectrometry; Analyte: pentachlorodibenzo-p-dioxin; Matrix: water, soil, sediment, sludge, tissue, and other sample matrices; Detection Level: not provided.