6-Bromobenzo(a)pyrene

The Koc of 6-bromobenzo(a)pyrene is estimated as approximately 153,000(SRC), using an estimated log Kow of 7.0(1) and a regression-derived equation(2,SRC). According to a recommended classification scheme(3), this estimated Koc value suggests that 6-bromobenzo(a)pyrene is expected to be immobile in soil(SRC).

...NUMEROUS CARCINOGENS OF ELECTROPHILIC REACTANT TYPE...BIND TO DNA. ... WITH...B(A)P, THROUGH ITS ACTIVATED FORM, 7,8-DIHYDRODIOL-9,10-EPOXIDE, /ALKYLATION/ REACTION IS THRU 10 CARBON...TO THE 2-AMINO POSITION IN GUANYLIC ACID. IN ADDN, THERE ARE MINOR INTERACTIONS WITH OTHER PURINES & PYRIMIDINES... /BENZO(A)PYRENE/

Mortality studies have demonstrated that exposure to coke oven emissions, which contain a variety of PAHs, caused increased incidences of lung and genitourinary cancer mortality in coke oven workers ... . /Polycyclic aromatic hydrocarbons/

Workers exposed to creosote containing numerous PAHs developed skin tumors ... . /Polycyclic aromatic hydrocarbons/

Exposures to other chemical mixtures that contain PAHs, such as cigarette smoke, coal tar, coal tar pitch, and bitumens, have been associated with increased incidences of lung cancer in humans. /Polycyclic aromatic hydrocarbons/

Dermal exposure to coal tar and shale oils containing PAHs have been associated with increased incidences of skin tumors in humans ... . /Polycyclic aromatic hydrocarbons/

An estimated BCF of 123,000 was calculated for 6-bromobenzo(a)pyrene(SRC), using an estimated log Kow of 7.0(1,SRC) and a recommended regression-derived equation(2). According to a classification scheme(3), this BCF suggests that bioconcentration in aquatic organisms is very high(SRC).

The Henry's Law constant for 6-bromobenzo(a)pyrene is estimated as 8.48X10-8 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This value indicates that 6-bromobenzo(a)pyrene is expected to be essentially nonvolatile from water surfaces(2,SRC). 6-Bromobenzo(a)pyrene's Henry's Law constant(1,SRC) indicates that volatilization from moist soil surfaces should not occur(SRC). 6-Bromobenzo(a)pyrene is not expected to volatilize from dry soil surfaces based on an estimated vapor pressure of 2.18X10-9 mm Hg (SRC), determined from a fragment constant method(3).

A GROUP OF B(A)P DERIVATIVES INCL 6-BROMOBENZO(A)PYRENE WAS TESTED IN FEMALE SWISS MICE 4 TIMES/WK FOR 20 WK. 6-BROMOBENZO(A)PYRENE WAS NOT AN ACTIVE CARCINOGEN.

MICE RECEIVING INJECTION OF 0.2 ML SOLN PROPYLENE GLYCOL CONTAINING 1 MG 6-BROMOBENZO[A]PYRENE SHOWED 5.5% TUMOR INCIDENCE OVER 2 YR. ALL WERE FIBROSARCOMAS AT OR AROUND INJECTION SITE. COMPD SHOWED WEAK OR NO ELECTRON DONOR PROPERTIES.

6-BROMOBENZO[A]PYRENE DECR LIVER GLYCOGEN LEVEL IN MICE FOR 2 DAYS AFTER INJECTION. NO EFFECT ON LIVER WT COULD BE SEEN OVER 9-DAY PERIOD.

Benz(a)anthracene (BA), dibenz(a,h)anthracene (DBA) and dibenzo[a,i]pyrene (DBP) are polycyclic aromatic hydrocarbons (PAHs) found in incomplete combustion products of fossil fuels, coal tar, and other organic materials. Workers in related industries may be exposed to these chemicals by inhalation. The information related to the potential health hazards of these chemicals to the exposed workers, however, is very limited. In the present study, micronucleus (MN) formation in rat bone marrow and spleen polychromatic erythrocytes (PCEs) was determined following three intratracheal instillations within a 24-hr period with either benz(a)anthracene, dibenz(a,h)anthracene or dibenzo[a,i]pyrene. Three doses with five rats per dose were used for each chemical. Bone marrow and spleen cells were harvested 24 hr after the first dosing. Results showed that the order of toxicity for the three polycyclic aromatic hydrocarbons was dibenzo[a,i]pyrene > dibenz(a,h)anthracene > benz(a)anthracene. Benz(a)anthracene induced micronucleus in a dose-related manner in both bone marrow and spleen polychromatic erythrocytes at doses above 25 mg/kg. Dibenz(a,h)anthracene caused significant increases in the frequencies of micronucleus in both spleen and bone marrow polychromatic erythrocytes at the dose of 8.5 mg/kg or higher. At 10 mg/kg, dibenzo[a,i]pyrene significantly increased micronucleus frequency in spleen polychromatic erythrocytes, but the increase in bone marrow polychromatic erythrocytes was not significantly different from the control. These results indicate that: (1) all three polycyclic aromatic hydrocarbons studied are absorbed through the respiratory tract and their genotoxic metabolites reach the bone marrow and/or spleen; (2) except for dibenzo[a,i]pyrene which does not induce micronucleus in the bone marrow, all three polycyclic aromatic hydrocarbons induced micronucleus in both bone marrow and spleen polychromatic erythrocytes; and (3) the sensitivity of the spleen to the three polycyclic aromatic hydrocarbons is comparable to or higher than that of the bone marrow.

The rate constant for any vapor-phase reaction of 6-bromobenzo(a)pyrene with photochemically-produced hydroxyl radicals has been estimated as 3.15X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1,SRC). This corresponds to an atmospheric half-life of about 12.2 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1,SRC). 6-Bromobenzo(a)pyrene is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(3). Due to similar structure and characteristics to benzo(a)pyrene, which absorbs in the UV spectrum above 290 nm(3), 6-bromobenzo(a)pyrene will be expected to directly photolyze in the environmental UV spectrum as well(SRC).

6-Bromobenzo(a)pyrene occurrs in fly ash from waste incineration. If released into the atmosphere, 6-bromobenzo(a)pyrene is expected to exist solely in the particulate phase in the ambient atmosphere, based on an estimated vapor pressure of 2.18X10-9 mm Hg at 25 °C. An estimated Koc value of 153,000 suggests that 6-bromobenzo(a)pyrene will be immobile in soil. Volatilization from moist soil is not expected based upon an estimated Henry's Law constant of 8.48X10-8 atm-cu m/mole. Volatilization from dry soil surfaces should not be important given the vapor pressure of this compound. Limited data are present in the scientific literature regarding the biodegradation of 6-bromobenzo(a)pyrene, but degradation is expected to be slow since 6-bromobenzo(a)pyrene contains more than three aromatic rings. In water, 6-bromobenzo(a)pyrene is expected to adsorb to sediment or particulate matter based on its Koc value. This compound is not expected to volatilize from water surfaces given its estimated Henry's Law constant. Bioconcentration in aquatic organisms should be very high based upon an estimated BCF value of 123,000. Occupational exposure to 6-bromobenzo(a)pyrene may occur through inhalation of dust particles with this compound at workplaces where 6-bromobenzo(a)pyrene is generated. (SRC)