Is polychlorinated biphenyl water soluble?
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).
Why are polychlorinated biphenyls so harmful?
PCBs have been demonstrated to cause a variety of adverse health effects. They have been shown to cause cancer in animals as well as a number of serious non-cancer health effects in animals, including: effects on the immune system, reproductive system, nervous system, endocrine system and other health effects.
What is the chemical formula for polychlorinated biphenyls?
The chemical formula of PCBs is C12H10-nCln, where n ranges from 1 to 10. Theoretically, 209 different congeners are possible, but only about 130 of these have been identified in commercial products.
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).
How long does it take PCBs to break down?
3.5 to 83 days
The time it takes for half of the amount of PCBs (initially) present to be broken down ranges from 3.5 to 83 days for molecules with 1 to 5 chlorine atoms. In water, PCBs are essentially broken down by the effect of sunlight (photolysis).
Where do polychlorinated biphenyls come from?
Most people are exposed to PCBs by eating contaminated fish, meat, and dairy products. Catfish, buffalo fish, and carp usually have the highest PCB levels.
How are humans exposed to PCBs?
Since PCBs are found throughout the environment, it is likely that everyone has been exposed to them. Persons living near a hazardous waste site with PCB contamination may be exposed to higher levels. PCBs can enter the body by eating or drinking contaminated food, through the air we breathe, or by skin contact.
How many types of polychlorinated biphenyls are there?
209 different
There are 209 different chemical compounds in which one to ten chlorine atoms can replace hydrogen atoms. PCBs are typically used as mixtures of compounds and are given the single identifying CAS number 1336-36-3 . About 130 different individual PCBs are found in commercial PCB products.
What was Aroclor 1254 for?
Type 1 Aroclor 1254 was one of the commercial PCB mixtures manufactured and sold by the Monsanto Company prior to 1971; a high percentage of its production was used in electrical equipment like transformers and capacitors, smaller amounts were used in other applications like being formulated into building materials ( …
Do PCBs have a high LC50?
PCBs have a low acute toxicity to birds, with 5-day dietary LC50 values in the range of 747 mg/kg diet in quail to >5,000 mg/kg in several species.
How long do PCBs stay in soil?
The time it takes for half of the amount of PCBs (initially) present to be broken down ranges from 3.5 to 83 days for molecules with 1 to 5 chlorine atoms.
Which is the correct formula for polychlorinated biphenyl?
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). PCB warning label on a power transformer known to contain PCBs. A polychlorinated biphenyl ( PCB) is an organic chlorine compound with the formula C 12 H 10−x Cl x.
How are polychlorinated biphenyls resistant to oxidation?
PCB mixtures are resistant to acids, bases, oxidation, hydrolysis, and temperature change. They can generate extremely toxic dibenzodioxins and dibenzofurans through partial oxidation. Intentional degradation as a treatment of unwanted PCBs generally requires high heat or catalysis (see Methods of destruction below).
Why are polychlorinated biphenyls used in industrial applications?
They have a range of toxicity and vary in consistency from thin, light-colored liquids to yellow or black waxy solids. Due to their non-flammability, chemical stability, high boiling point and electrical insulating properties, PCBs were used in hundreds of industrial and commercial applications including:
Where does polychlorinated biphenyl ( PCB ) accumulation take place?
Because of their low vapour pressure, PCBs accumulate primarily in the hydrosphere, despite their hydrophobicity, in the organic fraction of soil, and in organisms. The hydrosphere is the main reservoir. The immense volume of water in the oceans is still capable of dissolving a significant quantity of PCBs.
