What is congeners in PCB?
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.
Who PCB congener list?
| IUPAC Name | BZ Congener Number | CASNR |
|---|---|---|
| 2,3′,4,4′-Tetrachlorobiphenyl | 66 | 32598-10-0 |
| 2,3′,4,5-Tetrachlorobiphenyl | 67 | 73575-53-8 |
| 2,3′,4,5′-Tetrachlorobiphenyl | 68 | 73575-52-7 |
| 2,3′,4,6-Tetrachlorobiphenyl | 69 | 60233-24-1 |
How do you calculate PCBs?
Total PCB, calculated by multiplying the sum of the three indicator congeners by 2, showed a strong and highly significant correlation to the sum of all 209 measured congeners for each sample.
What is definition of congeners?
Definition of congener 1 : a member of the same taxonomic genus as another plant or animal. 2 : a person, organism, or thing resembling another in nature or action the New England private schools and their congeners west of the Alleghenies— Oliver La Farge. 3 : a chemical substance related to another.
What are congeners in chemistry?
Congeners can refer to similar compounds that substitute other elements with similar valences, yielding molecules having similar structures. Examples: potassium chloride and sodium chloride may be considered congeners; also potassium chloride and potassium fluoride.
What are PCBs used for?
PCBs have been used as coolants and lubricants in transformers, capacitors, and other electrical equipment because they don’t burn easily and are good insulators. The manufacture of PCBs was stopped in the U.S. in 1977 because of evidence they build up in the environment and can cause harmful health effects.
What is PCB water?
PCBs, or polychlorinated biphenyls, are industrial products or chemicals. PCB contamination is high in the Housatonic River and New Bedford Harbor in Massachusetts. According to the EPA, PCBs belong to a broad family of human-created organic chemicals known as chlorinated hydrocarbons.
What replaced PCBs in transformers?
Silicone oil as replacement fluid for PCBs in transformers.
When were PCBs used in transformers?
What is a PCB transformer? Polychlorinated biphenyls (PCBs) were used in electrical transformers manufactured between 1929 and 1977, with the majority being installed in residential and commercial buildings and industrial facilities prior to 1978.
What are congeners examples?
Congeners refer to the various oxidation states of a given element in a compound. For example, titanium(II) chloride (titanium dichloride), titanium(III) chloride (titanium trichloride), and titanium(IV) chloride (titanium tetrachloride) may be considered congeners.
How many PCB congeners are detected in this study?
Method 1628 detects all 209 PCB congeners and quantifies them either directly or indirectly. A total of 29 carbon-13 labeled PCB congeners are used as isotope dilution quantification standards. An additional 19 congeners are quantified by an extracted internal standard procedure, using one of the isotope dilution standards.
How do environmental conditions affect the congener composition of PCBs?
Air samples, sediment samples, biota samples and water samples are the ones most likely to have had their congener composition changed by environmental conditions. This can happen because the PCB congeners with fewer chlorine atoms tend to partition into air and water more readily than those with more chlorine atoms.
Why do PCB congeners with fewer chlorine atoms partition more easily?
This can happen because the PCB congeners with fewer chlorine atoms tend to partition into air and water more readily than those with more chlorine atoms. For this reason air and water samples are likely to be “enriched” with congeners with fewer chlorine atoms.
What is the best method for measuring PCBs?
Overall, in most instances measuring PCBs using the Aroclor method will be the best choice. Where that method is inappropriate, looking at homologs is likely to be a good option, and where even more detailed results are needed, looking for PCB congeners will be necessary.