2,2',3,3',4,5,5',6,6'-Nonabromobiphenyl belongs to the biphenyls and derivatives, a subclass of benzene and substituted derivatives within the organic compounds. With an average molecular weight of 864.27 g/mol, 2,2',3,3',4,5,5',6,6'-Nonabromobiphenyl is a heavy molecule. This exogenous compound with the formula C12HBr9 exists as a solid at room temperature. It is a polybrominated biphenyl, a group of synthetic organic compounds used as flame retardants in textiles, plastic foams, and plastics for televisions and computer monitors.
The compound targets the aryl hydrocarbon receptor (AhR). Binding and activation of AhR initiates transcriptional upregulation of genes, including cytochrome P-450-dependent monooxygenases CYP1A1 and CYP1A2. This process affects cell cycle regulation, endocrine pathways, morphogenesis, and oxidative stress response, resulting in toxic responses.
belongs to the class of organic compounds known as polybrominated biphenyls. These are organic aromatic compounds containing a biphenyl moiety, which is substituted at two or more ring positions by a bromine atom.
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. (3)
Metabolism
PBBs can be absorbed via oral, inhalation, and dermal routes. Due to their lipophilic nature, PBBs, especially the highly brominated congeners, tend to accumulate in lipid-rich tissues such as the liver, adipose, skin, and breast milk. Certain PBB compounds are metabolized by the microsomal monooxygenase system catalyzed by cytochrome P-450 of the type induced by phenobarbital. The rate of metabolism may depends on the bromine substitution pattern. PBB congeners of low bromine content are transformed into hydroxylated derivatives that are predominately eliminated in the urine. Highly brominated congeners are either retained or excreted unchanged in the feces. (3)
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. (3, 4)
PBB exposure may cause weight loss, skin disorders (such as acne), nervous and immune systems effects, and effects on the liver, kidneys, and thyroid gland. (3)
Symptoms
Symptoms of PBB exposure may include nausea, abdominal pain, loss of appetite, joint pain, fatigue, and weakness. (4)
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.
