파이어마스터FF1.

The median concn of 2,2',4,4',5,5'-hexabromobiphenyl in blood from US blood donors and Swedish female cleaners were 190 pmol/g liquid wt (N=12; range, 21-2,600 pmol/g liquid wt) and 330 pmol/g liquid wt (N=20; range, 120-1,000 pmol/g liquid wt), respectively(1).

Polybrominated biphenyls (PBB) were detected in blood and adipose tissue of 1788 persons in Michigan(1). The source of the PBBs was thought to be from the accidental substitution of Firemaster (a flame retardant largely composed of 2,2',4,4',5,5'-hexabromobiphenyl) for cattle feed in the summer of 1973. Resulting in contaminated meat, butter, milk and other diary products that were eventually consumed by humans. Of the 1681 serum samples tested, 70% were positive for PBBs and of the 844 adipose tissues tested, over 97% were positive(1). Levels were highest in that part of the state where meat and diary products were most contaminated, and levels were lowest in the upper peninsula, furthest from the source.

EYES: irrigate opened eyes for several minutes under running water. INGESTION: do not induce vomiting. Rinse mouth with water (never give anything by mouth to an unconscious person). Seek immediate medical advice. SKIN: should be treated immediately by rinsing the affected parts in cold running water for at least 15 minutes, followed by thorough washing with soap and water. If necessary, the person should shower and change contaminated clothing and shoes, and then must seek medical attention. INHALATION: supply fresh air. If required provide artificial respiration.

...Female Sprague-Dawley rats were initiated on day 1 by ip administration of diethylnitrosamine. On day 7 after initiation, the rats were fed a vitamin A-deficient basal diet that was supplemented with either 2000 IU (low-vitamin A) or 200,000 IU (high-vitamin A) retinyl acetate/kg feed. From day 30 after initiation until the end of the study the following PBBs were added to the diets: Firemaster BP-6 (10 ppm), 2,4,5,2',4',5'-hexabromobiphenyl (10 ppm) or 3,4,5,3',4',5'-hexabromobiphenyl (1 ppm). The control animals received low- or high-vitamin A diets containing no PBBs. On day 180, ... numbers of gamma-glutamyl transpeptidase-positive foci/cu cm liver and the mean volumes of these foci were lower in the high-vitamin A groups than those in the corresponding low-vitamin A groups, but these differences were not significant. The percentage of the liver volume occupied by foci was significantly greater in the low-vitamin A with 345-HBB group than in the corresponding high-vitamin A group. Thus, high dietary levels of vitamin A had some inhibitory effect on the promotion of hepatic-altered foci by 345-HBB in initiated rats.

TERRESTRIAL FATE: Based on a classification scheme(1), Koc values in the range of 2138-7413(2), indicate that 2,2',4,4',5,5'-hexabromobiphenyl will have little or no mobility in soil(SRC). Volatilization from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 4.3X10-6 atm-cu m/mole(SRC), derived from a vapor pressure, 5.2X10-8 mm Hg(3), and water solubility, 0.011 mg/L(4); however, adsorption is expected to attenuate volatilization(SRC). 2,2',4,4',5,5'-Hexabromobiphenyl is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(3). 2,2',4,4',5,5'-Hexabromobiphenyl is highly persistent under aerobic conditions, but may biodegrade slowly under anaerobic conditions(2). 2,2',4,4',5,5'-Hexabromobiphenyl was not degraded when incubated in a Brookston Loam (58% sand, 27.9% silt, 14.1% clay, 3.14% organic carbon, pH 7) and a Spinks loamy sand (81.1% sand, 14.5% silt, 4.4% clay, 1.1% organic carbon, pH 5.8) for 24 weeks maintained under aerobic conditions(3).

AQUATIC FATE: Based on a classification scheme(1), Koc values in the range of 2138-7413(2), indicates that 2,2',4,4',5,5'-hexabromobiphenyl 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 4.3X10-6 atm-cu m/mole(SRC),derived from its vapor pressure, 5.2X10-8 mm Hg(4), and water solubility, 0.011 mg/L(5); however, adsorption to suspended solids and sediment is expected to attenuate volatilization(SRC). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 14 and 165 days, respectively, if adsorption is ignored(SRC). The estimated volatilization half-life from a model pond is about 160 days when adsorption is considered(6). According to a classification scheme(7), a BCF of 18,100 measured in fathead minnows (8), suggests bioconcentration in aquatic organisms is very high(SRC). 2,2',4,4',5,5'-Hexabromobiphenyl is resistant to degradation under aerobic conditions, but may slowly undergo debromination at the meta and para positions under anaerobic conditions(2). 2,2',4,4',5,5'-Hexabromobiphenyl is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(2,9). 2,2',4,4',5,5'-Hexabromobiphenyl was degraded over 60% following 12 hours of irradiation in cyclohexane solution(10), suggesting that there is potential for direct photolysis in sunlit surface waters(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 2,2',4,4',5,5'-hexabromobiphenyl, which has a vapor pressure of 5.2X10-8 mm Hg at 25 °C(2), is expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase 2,2',4,4',5,5'-hexabromobiphenyl may be removed from the air by wet and dry deposition(SRC). In solution, 2,2',4,4',5,5'-hexabromobiphenyl has been shown to undergo direct photolysis resulting in lower brominated biphenyls as photodegradation products(3,4); however, it is unclear whether direct photolysis will occur for particulate phase 2,2',4,4',5,5'-hexabromobiphenyl in the atmosphere.

The exact mechanism of toxicty of PBBs varies depending on the specific congener. The predominant interaction is believed to involve the aryl hydrocarbon receptor (AhR). PBBs bind to and activate the AhR, which in turn initiates the transcriptional upregulation of a number of genes, affecting biochemical and endocrine pathways, cell cycle regulation, morphogenesis, oxidative stress response, and various other processes. This results in the numerous toxic responses characteristic of PBBs. Some of the known induced genes include the cytochrome P-450-dependent monooxygenases CYP1A1 and CYP1A2. (L628)

A major source of environmental contamination of hexabromobiphenyl occurred in the lower peninsula of Michigan where Firemaster BP-6 was accidentally substituted for a cattle nutrient in feed sent to a number of farms in 1973(1). The disposal of contaminated feed, animal carcasses (poultry, dairy cattle, swine) and animal products such as meat, eggs, and diary products was a major source of hexabromobiphenyl emitted to the environment(1).

Used as a fire retardant for ABS plastics, coatings, lacquers, and polyurethane foams; Hexabromobiphenyl is resistant to degradation in the environment. It was a major constituent of Firemaster BP-6 and Firemaster FF-1 used in plastic components in televisions and computers. Commercial production and use ceased in the US in 1974; [HSDB]

Painting (Pigments, Binders, and Biocides) [Category: Paint]

Ingredient in flame retardants. /Former use/

Formerly a fire retardant for ABS plastics, coatings, lacquers and polyurethane foams

PBBs can be used as flame retardants and may be added to the plastics used to make products like computer monitors, televisions, textiles, and plastic foams to make them difficult to burn. However, the use of PBBs is banned or restricted in most areas due to their toxicity and persistence in the environment. (L628, L629)

Flame retardant (Firemaster BP-6 ) was subjected to chem and toxicological analyses to establish whether brominated dibenzo-p-dioxin or dibenzofuran impurities were present. No bromodibenzofurans or bromodibenzo-p-dioxins were found.

Firemaster BP-6 contains 25 ppm hexabromonaphthalene and 1 ppm pentabromonaphtalene as impurities. Firemaster BP-6 has been found to contain 70 ppm hexabromonaphthalene and 150 ppm pentabromonaphthalene.

(1972) PROBABLY GREATER THAN 4.54X10+5 GRAMS

(1974) 2.2X10+9 GRAMS (ESTIMATE)

NO US PRODUCTION SINCE 1974

Bromination of biphenyl

/PBBs are/ produced by bromination of biphenyl with bromine chloride in presence of iron or friedel-crafts catalyst in closed vessel.

2,2',4,4',5,5'-Hexabromobiphenyl (is pure grade of chem). Hexabromodiphenyl also known as Firemaster BP-6 and Firemaster FF-1 is technical grade. Firemaster FF-1 is pulverized form of Firemaster BP-6 containing 2% by wt of anticaking agent, calcium polysilicate, produced in limited quantities as developmental product in 1971 and 1972.

Bromine content.../is/ about 77% for /commercial/ hexabromobiphenyl... technical grade...(Firemaster BP-6) produced in US contains 63% hexabromobiphenyl (principally 2,2',4,4',5,5'-isomer), 14% heptabromobiphenyl (mostly 2,2',3,4,4',5,5'-isomer), 10% pentabromobiphenyl, 2% tetrabromobiphenyl and 11% other bromobiphenyls.

All use of hexabromobiphenyl in US was discontinued in 1974...

Before its production was stopped /in US/ in November 1974, this chemical was used as fire retardant in 3 main commercial products: 1) acrylonitrile-butadiene-styrene (ABS) plastics; 2) coatings and lacquers; and 3) polyurethane foams. ... Use ... as flame retardant in thermoplastics was confined to those products which do not come into contact with food or feed and which were not used in fabrics to which humans are exposed.

In July 1973, cattle feed was contaminated with about 1000 kg of hexabromobiphenyl /believed to be Firemaster FF-1/, resulting in contamination levels of from over 4000-13500 mg/kg. Contaminated feed was used by farmers in Michigan between July 1973 and May 1974...

The sole US producer depleted their remaining stock /of hexabromobiphenyl/ in April 1975