What is a PCB congener?
A PCB congener is any single, unique well-defined chemical compound in the PCB category. The name of a congener specifies the total number of chlorine substituents , and the position of each chlorine.
Can PCBs cause liver damage?
Polychlorinated biphenyls (PCBs) have been associated with abnormal liver enzymes and suspected nonalcoholic fatty liver disease (NAFLD) in cohort studies. NAFLD affects greater than 25% of the global population and may result in liver-related mortality.
What congeners are in Aroclor 1260?
Aroclor 1260, a commercial PCB mixture, is heavily chlorinated and contains a limited amount of coplanar congeners (∼1%). It has predominantly non-coplanar and di-ortho substituted PCBs that have either 5, 6, 7, or 8 chlorines (Supplemental table 1).
What are PCBs soluble in?
In general, PCBs are relatively insoluble in water, and the solubility decreases with increased chlorination (see Table 4-3). PCBs are also freely soluble in nonpolar organic solvents and biological lipids (EPA 1980b).
What are coplanar PCBs?
Chemically, coplanar PCBs usually refer to 12 of the 209 possible PCB molecules that do not have a chlorine atom stuck in what organic chemists refer to as the “ortho” (or number 2 or 6) position (typically the mono-and di-chloro PCBs are not counted as being coplanar).
How many PCB homologs are there?
There are 10 possible PCB homolog groups, organized by the number of chlorine atoms in the molecule. Because of their useful electrical insulation, non-flammability and chemical stability, PCBs were used in a multitude of commercial and industrial products.
What is congener Aroclor 1254?
Aroclors 1016, 1242, 1254, and 1260 are complex mix- tures of polychlorinated biphenyl (PCB) congeners, prepared by the chlorination of biphenyl. For Aroclors 1242, 1254, and 1260, the chlorination reaction was stopped when the weight percent chlorine of the product had reached 42, 54, or 60%, respectively.
Which congeners are most toxic?
Most toxic PCB congeners for humans are dioxin-like or coplanar PCBs.
Who banned PCBs?
Commercial production of PCBs ended in 1977 because of health effects associated with exposure. In 1979, the U.S. Environmental Protection Agency (USEPA) banned the use of PCBs; however, PCBs are still present in many pre-1979 products.
What are the symptoms of PCBs?
Usually there are no immediate symptoms caused by exposure to PCBs, unless it is a massive exposure, such as falling in a tank containing PCBs or ingesting a significant amount of PCBs. In these cases, a worker may experience nausea, vomiting, respiratory irritation (sniffles, cough), and skin irritation (redness).
How do you get PCBs out of your body?
The main PCB elimination routes are through the faeces, urine, and breast milk. Once in the gastrointestinal tract, ingested PCBs diffuse across cell membranes and enter blood vessels and the lymphatic system.
What are PCB homologs?
Homologs are a way of grouping PCB congeners by the number of chlorine atoms they have; this can vary from one to ten. All the PCB chemicals that have the same number of chlorine atoms are said to belong to the same homolog group.
Which PCB congeners are dioxin-like?
The non-ortho dioxin-like PCBs (i.e., PCBs 77, 81, 126 & 169) bind the AHR and cause dioxin-like toxicity in fish, birds and mammals. The mono-ortho chlorinated dioxin-like PCBs are also able to bind the AHR and cause dioxin-like toxicity in birds and mammals, but generally do not cause dioxin-like responses in fish.
What are coplanar PCBs (dioxin-like) PCBs?
Coplanar (aka “dioxin-like”) PCBs. Polychlorinated biphenyls (PCBs) are an environmental contaminant in the news because they have been discovered in schools and other buildings. PCBs are actually a mixture of many different similar chemicals; there are 209 chemically different chlorinated biphenyls that together make up the PCB chemical group.
What are polychlorinated biphenyls (PCBs)?
Polychlorinated biphenyls (PCBs) are an environmental contaminant in the news because they have been discovered in schools and other buildings. PCBs are actually a mixture of many different similar chemicals; there are 209 chemically different chlorinated biphenyls that together make up the PCB chemical group.
What are the different types of PCB chemicals?
The different types of PCB chemicals are known as congeners, which are compounds that are distinguished by the number of chlorine atoms and their location on the biphenyl structure. PCB congeners can be divided into the coplanar, the mono-ortho-substituted PCBs, and other non-dioxin-like PCBs.
This contains a list of all PCB congeners, which is any single, unique well-defined chemical compound in the PCB category. The name of a congener specifies the total number of chlorine substituents and the position of each chlorine.