Bromobenzene is used for organic synthesis, especially in the production of the synthetic intermediate phenyl magnesium bromide (a Grignard reagent). Bromobenzene is also used as an additive to motor oils and as a crystallizing solvent. Release of bromobenzene to the environment may occur during its production and the production of phenyl magnesium bromide, as well as in its use as a solvent and as an additive in motor oil (HSDB, 2003). It has been detected at low frequencies and at low concentrations in samples of food, ambient air, and finished water.
The hepatotoxicity of bromobenzene is due to the production of reactive metabolites that modify or alkylated DNA, RNA and proteins. These reactive metabolites arise from the action of the CYP enzymes that are concentrated in the liver that lead to the production of cytotoxic compounds such as the 2,3- and 3,4-oxides of bromobenzene, the oxides of the bromophenols, 1,4-benzoquinone, and the radicals and quinones derived from redox cycling of the 2- and 4-bromocatechols. Similar reactive metabolites lead to renal damage, albeit at higher doses.
Metabolism
Bromobenzene is converted to either the 3,4-oxide derivative catalyzed primarily by phenobarbital-induced cytochrome isozymes (e.g., CYP 450 1A2, 2A6, 2B6, and 3A4), or the 2,3-oxide derivative catalyzed primarily by 3-methylcholanthrene and β-naphthoflavone-induced CYP isozymes (e.g., CYP 450 1A1, 1A2, and 1B1). This is followed by urinary excretion as premercapturic and mercapturic acids.
No indication of carcinogenicity to humans (not listed by IARC).
Uses/Sources
Used as an industrial chemical for production of Grignard reagents. Also used as an additive in certain motor oils.
Minimum Risk Level
Not Available
Health Effects
The toxic effects of bromobenzene following acute exposure have been extensively studied in animals. Liver, kidney, and lung have been identified as the target organs for this chemical by a variety of routes. It can cause liver and nervous system damage if inhaled, ingested, or absorbed through the skin (4).
Symptoms
If inhaled, bromobenzene causes irritation to the respiratory tract. Symptoms may include coughing, shortness of breath. Affects central nervous system causing dizziness, incoordination and unconsciousness. May be absorbed into the bloodstream with symptoms similar to ingestion. If the compound is ingested it can cause abdominal pain, nausea, vomiting, diarrhea, headache, dullness, central nervous system effects and liver damage. Estimated lethal human dose is 50 - 500 mg/kg. Contact with skin or eyes causes irritation, redness and pain.
Treatment
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.
