Labelling transformers containing PCBs.

Polychlorinated biphenyls (PCBs) are a class of organic compounds with 1 to 10 chlorine atoms attached to biphenyl which is a molecule composed of two benzene rings each containing six carbon atoms. The chemical formula for all PCBs is C₁₂H_10-xCl_x. Labelling PCB-containing transformers. ... Labelling PCB-containing transformers. ... Benzene is the simplest of the arenes, a family of organic compounds An organic compound is any member of a large class of chemical compounds whose molecules contain carbon. ... General Name, symbol, number chlorine, Cl, 17 Chemical series halogens Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... Biphenyl (or Diphenyl or 1,1-Biphenyl or lemonene) is a solid compound that forms colourless to yellowish crystals. ... Benzene, C6H6, PhH, or benzol is a colorless and flammable liquid with a pleasant, sweet smell. ... A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... For other uses, see Carbon (disambiguation). ... This article is about the chemistry of hydrogen. ... General Name, symbol, number chlorine, Cl, 17 Chemical series halogens Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ...

PCBs were used as coolants and insulating fluids for transformers and capacitors (askarels), stabilizing additives in flexible PVC coatings of electrical wiring and electronic components, pesticide extenders, cutting oils, flame retardants, hydraulic fluids, sealants (used in caulking, etc), adhesives, wood floor finishes,^[1] paints, de-dusting agents, and in carbonless copy paper.^[2] A coolant, or heat transfer fluid, is a fluid which flows through a device in order to prevent its overheating, transferring the heat produced by the device to other devices that utilize or dissipate it. ... PVC may refer to the following: Polyvinyl chloride, a plastic Premature ventricular contraction, irregular heartbeat Permanent virtual circuit, a term used in telecommunications and computer networks Param Vir Chakra, Indias highest military honor. ... A cropduster spreading pesticide. ... Cutting fluid or coolant is liquid used to cool and lubricate the cutting edges of machine tools and the pieces they are shaping. ... Socks made from flame retardant cotton. ... Hydraulic fluids are a large group of mineral oils, water-based or water used as the medium in hydraulic systems. ... Self-leveling silicone firestop system used around pipe through-penetration in a two-hour fire-resistance rated concrete floor assembly. ... Caulking - Wikipedia /**/ @import /w/skins-1. ... For the band, see Adhesive (band). ... For other uses, see Paint (disambiguation). ... Carbonless copy paper or NCR (no carbon required) is an alternative to carbon paper. ...

PCB production was banned in the 1970s due to the high toxicity of most PCB congeners and mixtures. PCBs are classified as persistent organic pollutants which bioaccumulate in animals. // Toxic and Intoxicated redirect here – toxic has other uses, which can be found at Toxicity (disambiguation); for the state of being intoxicated by alcohol see Drunkenness. ... A congener (from Latin roots meaning born together or within the same race or kind) is applied in biology to mean organisms within the same genus; in chemistry to mean a chemical that is in some way related to another e. ... Persistent organic pollutants (POPs) are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. ... To bioaccumulate literally means to accumulate in a biological system. ...

Chemical structure of PCBs. The possible positions of chlorine atoms on the benzene rings are denoted by numbers assigned to the carbon atoms.

Image File history File links Polychlorinated_biphenyl_structure. ... Image File history File links Polychlorinated_biphenyl_structure. ... General Name, symbol, number chlorine, Cl, 17 Chemical series halogens Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... Benzene, C6H6, PhH, or benzol is a colorless and flammable liquid with a pleasant, sweet smell. ... For other uses, see Carbon (disambiguation). ...

Physical and chemical properties

PCB congeners are odorless, tasteless, clear to pale-yellow, viscous liquids. They are formed by electrophilic chlorination of biphenyl with chlorine gas. There are theoretically 209 different PCB congeners, although only about 130 of these were found in commercial PCB mixtures.^[3] Commercial PCBs preparations are usually mixtures of 50 or more PCB congeners.^[3] Commercial PCB mixtures are clear to pale-yellow, viscous liquids (the more highly chlorinated mixtures are more viscous and more yellow - for example, Aroclor 1260 is a sticky yellowish resin). PCBs have low water solubilities — 0.0027-0.42 ng/L for Aroclors,^[2] and low vapor pressures at room temperature, but they have high solubilities in most organic solvents, oils, and fats. They have high dielectric constants, very high thermal conductivity,^[2] high flash points (170-380°C)^[2] and are chemically almost inert, being extremely resistant to oxidation, reduction, addition, elimination, and electrophilic substitution.^[4] The density varies from 1.182 to 1.566 kg/L.^[2] Other physical and chemical properties vary widely across the class. As the degree of chlorination increases, melting point and lipophilicity increase, but vapour pressure and water solubility decrease.^[2] A congener (from Latin roots meaning born together or within the same race or kind) has several different meanings depending on the field in which it is used. ... Aroma redirects here. ... For the social and aesthetic aspects of taste, see taste (sociology). ... For other uses, see Viscosity (disambiguation). ... For other uses, see Liquid (disambiguation). ... In organic chemistry, an electrophilic aromatic halogenation is a type of halogenation. ... Biphenyl (or Diphenyl or 1,1-Biphenyl or lemonene) is a solid compound that forms colourless to yellowish crystals. ... General Name, symbol, number chlorine, Cl, 17 Chemical series halogens Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... This article does not cite any references or sources. ... H2O and HOH redirect here. ... Solubility is a chemical property referring to the ability for a given substance, the solute, to dissolve in a solvent. ... The nanogram is an SI unit of mass (symbol ng) defined as: 1 ng = 1 × 10-12 kilogram (1 × 10-9 gram) A nanogram is one billionth (1/1,000,000,000) of a gram. ... The litre or liter (see spelling differences) is a unit of volume. ... Vapor pressure is the pressure of a vapor in equilibrium with its non-vapor phases. ... For other uses, see Solvent (disambiguation). ... For other uses, see FAT. Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. ... The relative dielectric constant of a material under given conditions is a measure of the extent to which it concentrates electrostatic lines of flux. ... K value redirects here. ... For other uses, see Flash point (disambiguation). ... The most fundamental reactions in chemistry are the redox processes. ... The most fundamental reactions in chemistry are the redox processes. ... An addition reaction, in chemistry, is in its simplest terms an organic reaction where two or more molecules combine to form a larger one. ... An elimination reaction is a type of organic reaction in which two substituents are removed from a molecule in either a one or two-step mechanism. ... Electrophilic substitution reactions are chemical reactions in which an electrophile displaces another group, typically but not always hydrogen. ... Kg redirects here. ... The litre or liter (see spelling differences) is a unit of volume. ... ...

PCBs readily penetrate skin, PVC (polyvinyl chloride), and latex (natural rubber); organic solvents such as kerosene increase the rate of skin absorption.^[5] PCB-resistant materials include Viton, polyethylene, polyvinyl acetate (PVA), polytetrafluoroethylene (PTFE), butyl rubber, nitrile rubber, and Neoprene.^[5] Absorption is a route by which substances can enter the body through the skin. ... PVC may refer to the following: Polyvinyl chloride, a plastic Premature ventricular contraction, irregular heartbeat Permanent virtual circuit, a term used in telecommunications and computer networks Param Vir Chakra, Indias highest military honor. ... This article is about the typesetting system. ... Viton® is a synthetic rubber and fluoropolymer elastomer commanly used in o-rings. ... This article does not cite any references or sources. ... Polyvinyl acetate formula Polyvinyl acetate or PVA is a rubbery synthetic polymer. ... In chemistry, polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer which finds numerous applications. ... Butyl rubber is a synthetic rubber, a random copolymer of about 98% of isobutylene with about 2% of isoprene. ... Nitrile rubber is a synthetic rubber co-polymer of acrylonitrile (ACN) and butadiene. ... Neoprene is the DuPont Chemical trade name for a family of synthetic rubbers based on polychloroprene. ...

PCBs are very stable compounds and do not degrade readily. They may be destroyed by chemical, thermal, and biochemical processes, though it is extremely difficult to achieve full destruction, and there is the risk of creating extremely toxic dibenzodioxins and dibenzofurans through partial oxidation. Because of the high thermodynamic stability of PCBs, all degradation mechanisms are difficult to sustain. Intentional degradation as a treatment of unwanted PCBs generally requires high heat or catalysis. Environmental and metabolic degradation generally proceeds quite slowly relative to most other compounds. Chemical decomposition or analysis is the fragmentation of a chemical compound into elements or smaller compounds. ... Dioxins form a family of toxic chlorinated organic compounds that bioaccumulate in humans and wildlife due to their fat solubility. ... Categories: Chemistry stubs ... Catalyst redirects here. ...

Alternative names

Commercial PCB mixtures were marketed as Apirolio in Italy, Aroclor by Monsanto in USA and UK, Asbestol in USA, Askarel in USA and UK, Bakola131 in USA, Chlorextol in USA, Clophen by Bayer in Germany, Delor in Czechoslovakia, Fenclor in Italy, Hydol in USA, Inerteen by Westinghouse in the USA, Kanechlor by Kanegafuchi in Japan, Noflamol in USA, Phenoclor and Pyralene by Prodolec in France, Pyranol and Pyrenol by General Electric in USA, Pyroclor in UK, Saft-Kuhl in USA, Santotherm by Mitsubishi in Japan, Sovol and Sovtol in the former USSR, and Therminol in USA.^[2][6] The Monsanto Company (NYSE: MON) is a multinational agricultural biotechnology corporation. ... Bayer AG (IPA pronunciation //) (ISIN: DE0005752000, NYSE: BAY, TYO: 4863 ) is a German chemical and pharmaceutical company founded in Barmen, Germany in 1863. ... The name Westinghouse can refer to any number of devices and independent businesses that trace their roots to the work of George Westinghouse: People George Westinghouse, founder of Westinghouse Electric Corporation Places George Westinghouse Bridge in East Pittsburgh, Pennsylvania Westinghouse Park in Pittsburgh, Pennsylvania Devices Westinghouse air brake, patented by... “GE” redirects here. ... For information on Mitsubishi brand computer monitors, see NEC-Mitsubishi Electronics Display of America Inc. ...

Applications

PCBs were used as coolants and insulating fluids for transformers and capacitors, plasticizers in paints and cements, stabilizing additives in flexible PVC coatings of electrical wiring and electronic components, pesticide extenders, cutting oils, reactive flame retardants, lubricating oils, hydraulic fluids, sealants (for caulking in schools and commercial buildings^[1]), adhesives, wood floor finishes (such as Fabulon and other products of Halowax in the U.S.),^[1] paints, de-dusting agents, water-proofing compounds, casting agents, vacuum pump fluids, fixatives in microscopy, surgical implants, and in carbonless copy ("NCR") paper.^[2] A coolant, or heat transfer fluid, is a fluid which flows through a device in order to prevent its overheating, transferring the heat produced by the device to other devices that utilize or dissipate it. ... For other uses, see Transformer (disambiguation). ... See Capacitor (component) for a discussion of specific types. ... Plasticizers are additives that soften the materials (usually a plastic or a concrete mix) they are added to. ... PVC may refer to the following: Polyvinyl chloride, a plastic Premature ventricular contraction, irregular heartbeat Permanent virtual circuit, a term used in telecommunications and computer networks Param Vir Chakra, Indias highest military honor. ... A cropduster spreading pesticide. ... Cutting fluid or coolant is liquid used to cool and lubricate the cutting edges of machine tools and the pieces they are shaping. ... Socks made from flame retardant cotton. ... A lubricant (colloquially, lube) is a substance (often a liquid) introduced between two moving surfaces to reduce the friction and wear between them. ... Hydraulic fluids are a large group of mineral oils, water-based or water used as the medium in hydraulic systems. ... Self-leveling silicone firestop system used around pipe through-penetration in a two-hour fire-resistance rated concrete floor assembly. ... Caulking - Wikipedia /**/ @import /w/skins-1. ... For the band, see Adhesive (band). ... Polychlorinated naphthalene (PCN) products are made by chemically binding chlorine with naphthalene, a soft, pungent solid made from coal or petroleum and often used for mothproofing. ... For other uses, see United States (disambiguation) and US (disambiguation). ... For other uses, see Paint (disambiguation). ... The Roots blower is one example of a vacuum pump A vacuum pump is a pump that removes gas molecules from a sealed volume in order to leave behind a partial vacuum. ... A fixative is a liquid, similar to varnish, which is usually sprayed over a finished piece of artwork to better preserve it and prevent smudging. ... Carbonless copy paper or NCR (no carbon required) is an alternative to carbon paper. ...

History

PCBs, originally termed "chlorinated diphenyls," were commercially produced as complex mixtures containing multiple isomers at different degrees of chlorination. In the United States, commercial production of PCBs was taken over in 1929 by Monsanto from Swann Chemical Company. Manufacturing levels increased in response to the electrical industry's need for a "safer" cooling and insulating fluid for industrial transformers and capacitors. PCBs were also commonly used as stabilizing additives in the manufacture of flexible PVC coatings for electrical wiring and electronic components to enhance the heat and fire resistance of the PVC.^[7] In chemistry, isomers are molecules with the same chemical formula and often with the same kinds of chemical bonds between atoms, but in which the atoms are arranged differently (analogous to a chemical anagram). ...

The toxicity associated with PCBs and other chlorinated hydrocarbons, including polychlorinated naphthalenes was recognized very early due to a variety of industrial incidents ^[8]. A conference about the hazards was organized at Harvard School of Public Health in 1937, and a number of publications referring to the toxicity of various chlorinated hydrocarbons were published before 1940 ^[9]. Robert Brown reminded chemists in 1947 that Arochlors were "objectionably toxic. Thus the maximum permissible concentration for an 8-hr. day is 1 mg. per cu.m. of air. They also produce a serious and disfiguring dermatitis."^[10] However, PCB manufacture and use continued with few restraints until the 1970s. Polychlorinated naphthalene (PCN) products are made by chemically binding chlorine with naphthalene, a soft, pungent solid made from coal or petroleum and often used for mothproofing. ... Harvard School of Public Health The Harvard School of Public Health (HSPH) is Harvard Universitys School of Public Health. ...

PCBs are persistent organic pollutants and have entered the environment through both use and disposal. The environmental transport of PCBs is complex and nearly global in scale. The public, legal, and scientific concerns about PCBs arose from research indicating they were likely carcinogens having the potential to adversely impact the environment and therefore undesirable as commercial products. Despite active research spanning five decades, extensive regulatory actions, and an effective ban on their production since the 1970s, PCBs still persist in the environment and remain a focus of attention.^[2] Persistent organic pollutants (POPs) are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. ... In pathology, a carcinogen is any substance or agent that promotes cancer. ...

The only North American producer, Monsanto, marketed PCBs under the trade name Aroclor from 1930 to 1977. These were sold under trade names followed by a 4 digit number. The first two digits generally refer to the number of carbon atoms in the biphenyl skeleton (for PCBs this is 12), the second two numbers indicate the percentage of chlorine by mass in the mixture. Thus, Aroclor 1260 has 12 carbon atoms and contains 60% chlorine by mass. An exception is Aroclor 1016, which also has 12 carbon atoms, but has 42% chlorine by mass. Different Aroclors were used at different times and for different applications. In electrical equipment manufacturing in the USA, Aroclor 1260 and Aroclor 1254 were the main mixtures used before 1950, Aroclor 1242 was the main mixture used in the 1950s and 1960s until it was phased out in 1971 and replaced by Aroclor 1016.^[2] The Monsanto Company (NYSE: MON) is a multinational agricultural biotechnology corporation. ...

Manufacture peaked in the 1960s, by which time the electrical industry had lobbied the U.S. Congress to make them mandatory safety equipment, knowing all the while that they were extremely toxic^{[citation needed]}. In 1966, they were determined by Swedish chemist Dr. Soren Jensen to be an environmental contaminant^[11], and it was Dr. Jensen, according to a 1994 article in Sierra, who named them. Previously, they had simply been called "phenols" or referred to by various trade names, such as Aroclor, Kennechlor, Pyrenol, Chlorinol and others. However, Arochlors (chlorinated biphenyls) were known toxins by 1947. Their commercial utility was based largely on their chemical stability, including low flammability, and desirable physical properties, including electrical insulating properties. Their chemical and physical stability has also been responsible for their continuing persistence in the environment, and the lingering interest decades after regulations were imposed to control environmental contamination. Look up sierra in Wiktionary, the free dictionary. ... For other uses, see Fire (disambiguation). ...

In 1972, PCB production plants existed in Austria, then Federal Republic of Germany, France, Great Britain, Italy, Japan, Spain, USSR, and USA.^[2]

From 1973 the use of PCBs was banned in "open" or "dissipative" sources, such as: In physics, dissipation embodies the concept of a dynamical system where important mechanical modes, such as waves or oscillations, lose energy over time, typically due to the action of friction or turbulence. ...

• plasticisers in paints and cements
• casting agents
• fire retardant fabric treatments and heat stabilizing additives for PVC electrical insulation
• adhesives
• paints and water-proofing
• railway sleepers

However, they continued to be allowed in "totally enclosed uses" such as transformers and capacitors, which, in certain failure modes or out-of-specification conditions, can leak, catch fire, or explode. It was Ward B. Stone of the New York State Department of Environmental Conservation who first published his findings in the early 1970s that PCBs were leaking from transformers and had contaminated the soil at the bottom of utility poles. Concern over the toxicity and persistence (chemical stability) of PCBs in the environment led the United States Congress to ban their domestic production in 1977, although some use continues in closed systems such as capacitors and transformers. Plasticizers are plastic additives, most commonly phthalates, that give plastics flexibility and durability. ... A fire retardant is a substance that helps to delay or prevent combustion. ... In chemistry a stabilizer is a chemical which tends to inhibit the reaction between two or more other chemicals. ... An adhesive is a compound that adheres or bonds two items together. ... Ferroconcrete sleepers A variant fastening of rails to wooden sleepers A railroad tie or sleeper is an oblong object used as a base for railroad tracks. ...

The use of PCBs in "closed" uses include:

• capacitors
• insulating fluids in transformers
• vacuum pump fluids
• hydraulic fluids

In the UK, closed uses of PCBs in new equipment were banned from 1981, when nearly all UK PCB synthesis ceased, but closed uses in existing equipment containing in excess of 5 litres of PCBs were not stopped until December 2000.^[12] See Capacitor (component) for a discussion of specific types. ... The Roots blower is one example of a vacuum pump A vacuum pump is a pump that removes gas molecules from a sealed volume in order to leave behind a partial vacuum. ... Hydraulic fluids are a large group of mineral oils, water-based or water used as the medium in hydraulic systems. ... The liter (spelled liter in American English and litre in Commonwealth English) is a unit of volume. ...

In Japan, PCBs were first produced by Kanegafuchi Chemical Co. Ltd. (Kaneka) in 1954 and production continued until 1972 when the Japanese government banned the production, use, and import of PCBs.^[2]

Estimates have put the total global production of PCBs on the order of 1.5 million tons. The United States was the single largest producer with over 600,000 tons produced between 1930 and 1977. The European region follows with nearly 450,000 tons through 1984. It is unlikely that a full inventory of global PCB production will ever be accurately tallied, as there were factories in Poland, East Germany, and Austria that produced unknown amounts of PCBs.^[13]

Large-scale environmental contamination incidents

New York State

In the United States of America, the General Electric Company (GE) released up to 1,300,000 pounds (590,000 kg) of PCBs into the Hudson River between approximately 1947 and 1977.^[14] The PCBs came from the company's two capacitor manufacturing plants at Hudson Falls and Fort Edward in New York State.^[14] Motto: (traditional) In God We Trust (official, 1956–present) Anthem: The Star-Spangled Banner Capital Washington, D.C. Largest city New York City Official language(s) None at the federal level; English de facto Government Federal Republic  - President George W. Bush (R)  - Vice President Dick Cheney (R) Independence - Declared - Recognized... The name General Electric Company refers to two companies: An American multinational, General Electric A defunct British company, The General Electric Company plc, now a part of Telent plc Category: ... The Hudson River, called Muh-he-kun-ne-tuk in Mahican or as the Lenape Native Americans called it in Unami, Muhheakantuck, is a river that runs through the eastern portion of New York State and, along its southern terminus, demarcates the border between the states of New York and... See Capacitor (component) for a discussion of specific types. ... Hudson Falls is a village located in Washington County, New York. ... Fort Edward is a town located in Washington County, New York. ... State nickname: Empire State Other U.S. States Capital Albany Largest city New York Governor George Pataki Official languages None Area 141,205 km² (27th)  - Land 122,409 km²  - Water 18,795 km² (13. ...

In 1976, because of concern over continuing high levels of PCBs in local fish and other aquatic organisms, and the unacceptable risk to the health of consumers of such fish, the New York State Department of Environmental Conservation banned all fishing in the Upper Hudson River, as well as commercial fishing of striped bass and several other species in the Lower Hudson River,^[15][14] and also issued advisories restricting the consumption of fish caught within a 20-mile (30 km) long segment of the Hudson River from Hudson Falls to Troy.^[14][16] The New York State Department of Environmental Conservation (NYSDEC or DEC) is responsible for the conservation, improvement, and protection of natural resources within the U.S. state of New York. ... Binomial name Morone saxatilis (Walbaum, 1792) The striped bass Morone saxatilis is a member of the temperate bass family native to North America but widely introduced elsewhere. ... Looking west down Broadway at downtown Troy. ...

There have been many programs of remediation work to reduce the PCB pollution, mostly paid for by GE. In 1984, approximately 200 miles (320 km) of the Hudson River was designated a Superfund site, and attempts to cleanup the Upper Hudson River began, including the removal in 1977-8 of 180,000 cubic yards (140,000 m³) of contaminated river sediments near Fort Edward.^[15] In 1991, further PCB pollution was found at Bakers Falls near the former GE Hudson Falls factory, and a program of remediation was started.^[15] In August 1995, a 40-mile (64 km) reach of the Upper Hudson was re-opened to fishing but only on a catch-and-release basis.^[15] Removal of contaminated soil from Rogers Island was completed in December 1999.^[15] In 2002, the United States Environmental Protection Agency announced a further 2,650,000 cubic yards (2,030,000 m³) of contaminated sediments in the Upper Hudson River would be removed. Checking the status of a cleanup site Superfund is the common name for the United States environmental law that is officially known as the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), 42 U.S.C. §§ 9601 to 9675, which was enacted by the United States Congress on December 11... Rogers Island is an island on the Hudson River, in Washington County, New York, that once formed part of the third largest city in colonial North America, and is considered the spiritual home of the United States Special Forces, particularly the United States Rangers[1]. // Rogers Island is located in... EPA redirects here. ...

Indiana

From the late 1950s through 1977, Westinghouse Electric used PCBs in the manufacture of capacitors in its Bloomington, Indiana plant. Reject capacitors were hauled and dumped in area salvage yards and landfills. Workers also dumped PCB oil down factory drains which contaminated the city sewage treatment plant.^{[citation needed]} The City of Bloomington gave away the sludge to area farmers and gardeners, creating anywhere from 200 to 2000 sites which remain unaddressed. Over 2 million pounds of PCBs were estimated to have been dumped in Monroe and Owen Counties, making it the biggest concentration of PCBs in the world.^{[citation needed]} Although federal and state authorities have been working on the site remediations, many areas remain contaminated. Concerns have been raised regarding the removal of PCBs from the karst limestone topography, and regarding the possible disposal options. To date, the Westinghouse Bloomington PCB Superfund site case does not have a RI/FS (Remedial Investigation/Feasibility Study) and ROD (Record of Decision), although Westinghouse signed a US Department of Justice Consent Decree in 1985.^{[citation needed]} On February 15, 2008, Monroe County approved a plan to clean up the 3 remaining contaminated sites in the City of Bloomington, at a cost of $9.6m to CBS Corp., the successor of Westinghouse. ^[17] Image File history File links Question_book-3. ... The Westinghouse Electric Corporation was an organization founded by George Westinghouse in 1886 as Westinghouse Electric & Manufacturing Company. ... Location in the state of Indiana Coordinates: County Monroe Mayor Mark Kruzan Area    - City 51. ... Karst topography occurs when a landscape is marked by underground drainage patterns. ... is the 46th day of the year in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... CBS Corporation (NYSE: CBS, NYSE: CBSA) is an American media conglomerate focused on broadcasting, publishing, billboards, and television production, with most of its operations in the United States. ...

The Great Lakes

Much of the Great Lakes area is still heavily polluted with PCBs, despite extensive remediation work.^[18] Locally caught fresh water fish and shellfish are contaminated with PCBs and their consumption is restricted. The Great Lakes from space The Laurentian Great Lakes are a group of five large lakes in North America on or near the Canada-United States border. ...

Global transport through atmospheric pollution

PCBs have been detected globally in the atmosphere, from the most urbanized areas that are the centers for PCB pollution, to regions north of the Arctic Circle. The atmosphere serves as the primary route for global transport of PCBs, particularly for those congeners with 1 to 4 chlorine atoms.

Atmospheric concentrations of PCBs tend to be lowest in rural areas, where they are typically in the picogram per cubic meter range, higher in suburban and urban areas, and highest in city centres, where they can reach 1 ng/m³ or more. In Milwaukee, an atmospheric concentration of 1.9 ng/m³ has been measured, and this source alone was estimated to account for 120 kg/year of PCBs entering Lake Michigan.^[19] Concentrations as high as 35 ng/m³, 10 times higher than the EPA guideline limit of 3.4 ng/m³, have been found inside some houses in the U.S.^[1] The picogram is an SI unit of mass (symbol pg) defined as: 1 pg = 1 × 10-15 kilogram (1 × 10-12 gram) A picogram is one trillionth (1/1000000000000) of a gram. ... The nanogram is an SI unit of mass (symbol ng) defined as: 1 ng = 1 × 10-12 kilogram (1 × 10-9 gram) A nanogram is one billionth (1/1,000,000,000) of a gram. ... This article is about the unit of length. ... This article is about Milwaukee in Wisconsin. ... Kg redirects here. ... Lake Michigan is one of the five Great Lakes of North America, and the only one located entirely within the United States. ... The nanogram is an SI unit of mass (symbol ng) defined as: 1 ng = 1 × 10-12 kilogram (1 × 10-9 gram) A nanogram is one billionth (1/1,000,000,000) of a gram. ... This article is about the unit of length. ... EPA redirects here. ...

Volatilization of PCBs in soil was thought to be the primary source of PCBs in the atmosphere, but recent research suggests that ventilation of PCB-contaminated indoor air from buildings is the primary source of PCB contamination in the atmosphere.^[20]

Health effects

The toxicity of PCBs to animals was first noticed in the 1970s when emaciated seabird corpses with very high PCB body burdens were washed up on beaches. The sources of the PCBs were unknown though, because seabirds may die at sea and be washed ashore from a very wide area. Where they were found was no reliable indicator of where they had died. // Toxic and Intoxicated redirect here – toxic has other uses, which can be found at Toxicity (disambiguation); for the state of being intoxicated by alcohol see Drunkenness. ...

The toxicity of PCBs varies considerably among congeners. The coplanar PCBs, known as non-ortho PCBs because they are not substituted at the ring positions ortho to (next to) the other ring, (i.e. PCBs 77, 126, 169, etc), tend to have dioxin-like properties, and generally are among the most toxic congeners. Because PCBs are almost invariably found in complex mixtures, the concept of toxic equivalency factors (TEFs) has been developed to facilitate risk assessment and regulatory control, where more toxic PCB congeners are assigned higher TEF values. One of the most toxic compounds known, 2,3,7,8-tetrachlorodibenzo[p]dioxin, is assigned a TEF of 1. ^[21] In organic chemistry, ortho (along with meta and para) is used to distinguish the three types of isomer of disubstituted benzenes: it indicates that the substituents are at locants 1 and 2. ... Dioxin is the common name for the group of compounds classified as polychlorinated dibenzodioxins (PCDDs). ... Dioxin is the common name for the group of compounds classified as polychlorinated dibenzodioxins (PCDDs). ...

Signs and symptoms

• Humans

The most commonly observed health effects in people exposed to PCBs are skin conditions such as chloracne and rashes, but these were known to be symptoms of systemic poisoning dating back to the 1920s. Studies in workers exposed to PCBs have shown changes in blood and urine that may indicate liver damage. In 1968 in Japan, PCB contamination in rice bran oil caused a mass poisoning known as Yushō Disease in over 14000 people.^[22] Common symptoms included dermal and ocular lesions, irregular menstrual cycles and a lowered immune response.^[23][24][25] Other symptoms included fatigue, headache, cough, and unusual skin sores.^[26] Additionally, in children, there were reports of poor cognitive development.^[23][25][26]

There have also been studies of the health effects of PCBs in the general population and in children of mothers who were exposed to PCBs.

• Animals

Animals that eat PCB-contaminated food even for short periods of time get liver damage and may die. In 1968 in Japan, 400,000 birds died after eating poultry feed that was contaminated with PCBs.^[22] Animals that eat smaller amounts of PCBs in food over several weeks or months develop various kinds of health effects, including anemia; acne-like skin conditions (chloracne); and liver, stomach, and thyroid gland injuries (including hepatocarcinoma). Other effects of PCBs in animals include changes in the immune system, behavioral alterations, and impaired reproduction. PCBs are not known to cause birth defects in humans, although those that have dioxin-like activity are known to cause a variety of teratogenic effects in animals.

• Effects during pregnancy/breastfeeding

Women who were exposed to relatively high levels of PCBs in the workplace or ate large amounts of fish contaminated with PCBs had babies that weighed slightly less than babies from women who did not have these exposures. Babies born to women who ate PCB-contaminated fish also showed abnormal responses in tests of infant behavior. Some of these behaviors, such as problems with motor skills and a decrease in short-term memory, lasted for several years. Other studies suggest that the immune system was affected in children born to and nursed by mothers exposed to increased levels of PCBs. The most likely way infants will be exposed to PCBs is from breast milk. Transplacental transfers of PCBs were also reported.

Studies have shown that PCBs alter estrogen levels in the body and contribute to reproduction problems. In the womb, males can be feminized or the baby may be intersex, neither a male nor a female. Also, both sets of reproductive organs may develop. More instances of this are being reported. Biological magnification of PCBs has also led to polar bears and whales that have both male and female sex organs and males that cannot reproduce. This effect is also known as endocrine disruption. Endocrine Disrupting Chemicals (EDC's) pose a serious threat to reproduction in top-level predators.

Health effects, health impacts or health risks are an important consideration in many areas, such as hygiene, pollution studies, workplace safety, nutrition and health sciences in general. ... Chloracne is an acne-like eruption of blackheads, cysts, and pustules associated with over-exposure to certain halogenic aromatic hydrocarbons, such as chlorinated dioxins and dibenzofurans. ... A rash is a change in skin which affects its color, appearance, or texture. ... For other uses, see Blood (disambiguation). ... This article is about the urine of animals generally. ... For the bird, see Liver bird. ... Bran is the hard outer layer of cereal grains, and consists of combined aleurone and pericarp. ... Skin lesions caused by Chickenpox A lesion is any abnormal tissue found on or in an organism, usually damaged by disease or trauma. ... Menstrual cycle In the female reproductive system, the menstrual cycle is a recurring cycle of physiologic changes that occurs in reproductive age females of several mammals, including human beings and other apes. ... A request has been made on Wikipedia for this article to be deleted in accordance with the deletion policy. ... This article discusses the medical condition. ... Chloracne is an acne-like eruption of blackheads, cysts, and pustules associated with over-exposure to certain halogenic aromatic hydrocarbons, such as chlorinated dioxins and dibenzofurans. ... In anatomy, the stomach is a bean-shaped hollow muscular organ of the gastrointestinal tract involved in the second phase of digestion, following mastication. ... A scanning electron microscope image of a single neutrophil (yellow), engulfing anthrax bacteria (orange). ... Dioxin is the common name for the group of compounds classified as polychlorinated dibenzodioxins (PCDDs). ... Teratogenesis is a medical term from the Greek, literally meaning monster making. ... A glass of cows milk. ... Endocrine disruptors are substances which interfere with the endocrine system by mimicking, blocking or otherwise disrupting the function of hormones. ... EDC has the following meanings: European Defence Community endocrine disrupting chemical 1-ethyl-3-3(3-dimethylaminopropyl) carbodiimide hydrochloride Ethylene dichloride Economic Development Corporation Export Development Canada Electronic Data Capture Electronic Diesel Control Every Day Carry This page concerning a three-letter acronym or abbreviation is a disambiguation page — a...

Cancer link

A few studies of workers indicate that PCBs were associated with specific kinds of cancer in humans, such as cancer of the liver and biliary tract. Rats that ate food containing high levels of PCBs for two years developed liver cancer. The Department of Health and Human Services (DHHS) has concluded that PCBs may reasonably be anticipated to be carcinogens. The US Environmental Protection Agency (EPA) and the International Agency for Research on Cancer (IARC) have determined that PCBs are probably carcinogenic to humans. PCBs are also classified as probable human carcinogens by the National Cancer Institute, World Health Organization, and the Agency for Toxic Substances and Disease Registry. Recent research by the National Toxicology Program has confirmed that PCB126 (Technical Report 520) and a binary mixture of PCB126 and PCB153 (Technical Report 531) are carcinogens. Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these to spread, either by direct growth into adjacent tissue through invasion, or by implantation into distant sites by metastasis (where cancer cells are transported through the bloodstream or lymphatic system). ... A bile duct is any of a number of long tube-like structures that carry bile. ... The United States Department of Health and Human Services, often abbreviated HHS, is a Cabinet department of the United States government with the goal of protecting the health of all Americans and providing essential human services. ... Look up carcinogen in Wiktionary, the free dictionary. ... EPA redirects here. ... The International Agency for Research on Cancer (IARC, or CIRC in its French acronym) is an intergovernmental agency forming part of the World Health Organisation of the United Nations. ... The National Cancer Institute (NCI) is part of the United States Federal governments National Institutes of Health. ... WHO redirects here. ... The United States Agency for Toxic Substances and Disease Registry, (ATSDR), is directed by congressional mandate to perform specific functions concerning the effect on public health of hazardous substances in the environment. ... The purpose of the National Institute of Environmental Health Sciences (NIEHS), as part of the U.S. National Institutes of Health, is to reduce the burden of human illness and dysfunction from environmental causes by understanding each of these elements and how they interrelate. ... In pathology, a carcinogen is any substance or agent that promotes cancer. ...

Mechanism of action

As discussed, PCBs exhibit a wide range of toxic effects. These effects may vary depending on the specific PCB. Similar to dioxin, toxicity of coplanar PCBs and mono-ortho-PCBs are thought to be primarily mediated via binding to aryl hydrocarbon receptor (AhR).^[27][28] Because AhR is a transcription factor, abnormal activation may disrupt cell function by altering the transcription of genes. The concept of toxic equivalency factors (TEF) is based on the ability of a PCB to activate AhR. Aryl hydrocarbon receptor or AhR is a basic helix-loop-helix (bHLH) transcription factor that binds to HSP90 in the cytoplasm while inactivated. ... In molecular biology, a transcription factor is a protein that binds DNA at a specific promoter or enhancer region or site, where it regulates transcription. ... A micrograph of ongoing gene transcription of ribosomal RNA illustrating the growing primary transcripts. ... For other uses, see Gene (disambiguation). ...

However, not all effects may be mediated by the AhR receptor. For example, di-ortho-substituted non-coplanar PCBs interfere with intracellular signal transduction dependent on calcium; this may lead to neurotoxicity.^[29] Ortho-PCBs may disrupt thyroid hormone transport by binding to transthyretin.^[30] In biology, signal transduction refers to any process by which a cell converts one kind of signal or stimulus into another, most often involving ordered sequences of biochemical reactions inside the cell, that are carried out by enzymes and linked through second messengers resulting in what is thought of as... Calcium (Ca2+) plays a vital role in the anatomy, physiology and biochemistry of organisms and of the cell, particularly in signal transduction pathways. ... Neurotoxicity occurs when the exposure to natural or manmade toxic substances ,which are called neurotoxins, alters the normal activity of the nervous system. ... The thyroid hormones, thyroxine (T4) and triiodothyronine (T3), are tyrosine-based hormones produced by the thyroid gland. ... Transthyretin (TTR) is a serum and cerebrospinal fluid carrier of the thyroid hormone thyroxine (T4). ...

Containment

Landfill – Large quantities of PCBs have been placed in landfill sites, mainly in the form of transformers and capacitors. Many municipal sites are not designed to contain these pollutants and PCBs are able to escape into the atmosphere or ground water. No emissions above background are seen if the landfill is designed correctly. Look up landfill in Wiktionary, the free dictionary. ...

Methods of destruction

These can be separated into three distinct categories: physical, microbial, and chemical destruction.

Physical

Incineration – Although PCBs do not ignite themselves, they can be combusted under extreme and carefully controlled conditions. The current regulations require that PCBs are burnt at a temperature of 1200°C for at least two seconds, in the presence of fuel oil and excess oxygen. A lack of oxygen can result in the formation of PCDDs, PCDFs and dioxins, or the incomplete destruction of the PCBs. Such specific conditions mean that it is extremely expensive to destroy PCBs on a tonnage scale, and it can only be used on PCB containing equipment and contaminated liquid. This method is not suitable for the decontamination of affected soils. For other forms of waste plant that produce energy see waste-to-energy. ... Dioxin is the common name for the group of compounds classified as polychlorinated dibenzodioxins (PCDDs). ...

Ultrasound – In a similar process to combustion, high power ultrasonic waves are applied to water, generating cavitation bubbles. These then implode or fragment, creating microregions of extreme pressures and temperatures where the PCBs are destroyed. Water is thought to undergo thermolysis, oxidising the PCBs to CO, CO₂ and hydrocarbons such as biphenyl, with chlorine present as the inorganic ion 16. The scope of this method is limited to those congeners which are the most water soluble; those isomers with the least chlorine substitution. For other uses, see Ultrasound (disambiguation). ... Thermolysis (from thermo- meaning heat and -lysis meaning break down) is a chemical process by which a substance is decomposed into other substances by use of heat. ...

Irradiation – If a deoxygenated mixture of PCBs in isopropanol or mineral oil is subject to irradiation with gamma rays then the PCBs will be dechlorinated to form inorganic chloride and biphenyl. The reaction works best in isopropanol if potassium hydroxide (caustic potash) is added. Solvated electrons are thought to be responsible for the reaction. If oxygen, nitrous oxide, sulfur hexafluoride or nitrobenzene is present in the mixture then the reaction rate is reduced. This work has been done recently in the US often with used nuclear fuel as the radiation source[1][2]. Irradiation is the process by which an item is exposed to radiation. ... Isopropyl alcohol or isopropanol is a common name for 2-propanol, an alcohol commonly used for application to the skin, and popularly referred to as rubbing alcohol. ... Mineral oil or liquid petrolatum is a by-product in the distillation of petroleum to produce gasoline. ... This article is about electromagnetic radiation. ... The chloride ion is formed when the element chlorine picks up one electron to form an anion (negatively-charged ion) Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. ... Biphenyl (or Diphenyl or 1,1-Biphenyl or lemonene) is a solid compound that forms colourless to yellowish crystals. ... The chemical compound potassium hydroxide, (KOH) sometimes known as caustic potash, potassa, potash lye, and potassium hydrate, is a metallic base. ... The chemical compound potassium hydroxide, (KOH) sometimes known as caustic potash, potassa, potash lye and potassium hydrate, is a metallic base. ... The solvated electron in water and liquid ammonia is blue. ... This article is about the chemical element and its most stable form, or dioxygen. ... For other uses, see Nitrous oxide (disambiguation). ... Sulfur hexafluoride is an inorganic compound with the formula SF6. ... Nitrobenzene, also known as nitrobenzol or oil of mirbane, is a poisonous organic compound with an almond odor and chemical formula C6H5NO2. ... Nuclear Fuel Process A graph comparing nucleon number against binding energy Nuclear fuel is any material that can be consumed to derive nuclear energy, by analogy to chemical fuel that is burned to derive energy. ...

Microbial

Much recent work has centered on the study of micro-organisms that are able to decompose PCBs. Generally, these organisms work in one of two ways: either they use the PCB as a carbon source, or destruction takes place through reductive dechlorination, with the replacement of chlorine with hydrogen on the biphenyl skeleton. However, there are significant problems with this approach. Firstly, these microbes tend to be highly selective in their dechlorination, with lower chlorinated biphenyls being readily transformed, and with preference to dechlorination in the para and meta positions. Secondly, microbial dechlorination tends to be rather slow acting on PCB as a soil contaminant in comparison to other methods. Finally, while microbes work well in laboratory conditions, there is often a problem in transferring a successful laboratory strain to a natural system. This is because the microbes can access other sources of carbon, which they decompose in preference to PCBs. Biodegradation is the process by which organic substances are broken down by living organisms. ... A microorganism or microbe is an organism that is so small that it is microscopic (invisible to the naked eye). ... Excavation of leaking undergound storage tank causing soil contamination Soil contamination is the presence of man-made chemicals or other alteration to the natural soil environment. ...

Further recent developments have focused on testing enzymes and vitamins extracted from microbes which show PCB activity. Especially promising seems to be the use of vitamin B12, in which a cobalt ion is in oxidation state (III) under normal redox conditions. Using titanium (III) citrate as a strong reductant converts the cobalt from Co(III) to Co(I), giving a new vitamin known as B12s, which is a powerful nucleophile and reducing catalyst. This can then be used on PCBs, which it dechlorinates in a rapid and selective manner.^[31] It has been suggested that this article or section be merged into Catalysis. ...

Chemical

Many chemical methods are available to destroy or reduce the toxicity of PCBs.

Nucleophilic aromatic substitution is a method of destroying low concentration PCB mixtures in oils, such as transformer oil. Substitution of chlorine by polyethylene glycols) occurs in under two hours under a blanket of nitrogen, to prevent oxidation of the oil, to produce aryl polyglycols, which are insoluble in the oil and precipitate out. A nucleophilic substitution is a substitution reaction in organic chemistry in which the nucleophile displaces a good leaving group, such as a halide on an aromatic ring. ... Polyethylene glycol (PEG) and polyethylene oxide (PEO) are polymers composed of repeating subunits of identical structure, called monomers, and are the most commercially important polyethers. ... In the context of organic molecules, aryl refers to any member of the set of functional groups or substituents that are derived from a simple aromatic ring. ...

Between 700 and 925°C, H₂ cleaves the carbon-chlorine bond, and cleaves the biphenyl nucleus into benzene yielding HCl without a catalyst. This can be performed at lower temperatures with a copper catalyst, and to yield biphenyl. However, since both of these routes require an atmosphere of hydrogen gas and relatively high temperatures, they are prohibitively expensive. This article is about the chemistry of hydrogen. ... R-phrases , S-phrases , , , , Flash point non-flammable Supplementary data page Structure and properties n, εr, etc. ... It has been suggested that this article or section be merged into Catalysis. ...

Reaction with highly electropositive metals, or strong reducing agents such as sodium naphthalide, in aprotic solvents results in a transfer of electrons to the PCB, the expulsion of a chloride ion, and a coupling of the PCBs. This is analogous to the Wurtz reaction for coupling halogenoalkanes. The effect is to polymerise many molecules, therefore reducing the volatility, solubility and toxicity of the mixture. This methodology is most successful on low strength PCB mixtures and can also be performed electrochemically in a partly aqueous bicontinuous microemulsion. Electronegativity is a measure of the attraction that an atom has for the bonding pair of electrons in a covalent bond. ... A reducing agent (also called a reductant or reducer) is the element or a compound in a redox (reduction-oxidation) reaction (see electrochemistry) that reduces another species. ... The Wurzt reaction after Charles Adolphe Wurtz is a coupling reaction in organic chemistry and organometallic chemistry where by two alkyl halides are reacted with sodium: 2 R-X + Na → R-R + 2NaX This reaction involves the radical species R.. References A. Wurtz, Ann. ... A. Two immiscible liquids, not emulsified; B. An emulsion of Phase II dispersed in Phase I; C. The unstable emulsion progressively separates; D. The surfactant (purple outline) positions itself on the interfaces between Phase A and Phase B, stabilizing the emulsion An emulsion is a mixture of two immiscible (unblendable...

The solution photochemistry of PCBs is based on the transfer of an electron to a photochemically excited PCB from a species such as an amine, to give a radical anion. This either expels a chloride ion and the resulting aryl radical extracts a hydrogen atom from the solvent, or immediately becomes protonated, leading to the loss of a chlorine atom. It is useful only for water soluble PCBs. Photochemistry is the study of the interaction of light and chemicals. ... The general structure of an amine Amines are organic compounds and a type of functional group that contain nitrogen as the key atom. ... In the context of organic molecules, aryl refers to any member of the set of functional groups or substituents that are derived from a simple aromatic ring. ... Protonation is the addition of a proton (H+) to an atom, molecule, or ion. ...

The major pathway for atmospheric destruction of PCBs is via attack by OH radicals. Direct photolysis can occur in the upper atmosphere, but the ultraviolet wavelengths necessary to excite PCBs are shielded from the troposphere by the ozone layer. It has, however, been shown that higher wavelengths of light (> 300 nm) can degrade PCBs in the presence of a photosensitizer, such as acetone. Hydroxide is a polyatomic ion consisting of oxygen and hydrogen: OH− It has a charge of −1. ... Photolysis refers to any chemical reaction in which a compound is broken down by light. ... Atmosphere diagram showing the mesosphere and other layers. ... The ozone layer is a layer in Earths atmosphere which contains relatively high concentrations of ozone (O3). ... A photosensitizer is a chemical compound, used in the Photodynamic Therapy of cancers, that can be excited by light of a specific wavelength. ...

The Schwartz reaction is the subject of much study, and has significant benefits over other routes. It is advantageous since it proceeds via a reductive process, and thus yields no dioxins through oxidation. The proposed reaction scheme involves the electron transfer from a titanium (III) organometallic species to form a radical anion on the PCB molecule which expels chlorine to eventually form the relatively non-toxic biphenyl. Organometallic have classically been compounds having bonds between one or more metal atoms and one or more carbon atoms of an organyl group. ...

See also

• GE
• Bay mud
• Organochlorine compound
• Polybrominated biphenyls
• Neal Stephenson's novel Zodiac involves PCBs and their impact on the environment.

Ge may refer to: Gê, a group of indigenous Brazilian tribes and their Ge languages Ge (Cyrillic) (Г, г), a letter of the Cyrillic alphabet Ge with upturn (Ґ, ґ), a letter of the Ukrainian alphabet Nikolai Ge, a Russian painter Gē, an ancient Chinese dagger-axe Ge (genus), a genus of butterflies Also... Richardson Bay mudflats of are exposed layers of bay mud Bay mud consists of thick deposits of soft, unconsolidated silty clay, which is saturated with water; these soil layers are situated at the bottom of certain estuaries, which are normally in temperate regions that have experienced cyclical glacial cycles. ... An organochlorine compound is an organic compound of chlorine. ... Polybrominated biphenyls (PBBs), also called brominated biphenyls or polybromobiphenyls, are a group of manufactured chemicals. ... Neal Town Stephenson (born October 31, 1959) is an American writer, known primarily for his science fiction works in the postcyberpunk genre with a penchant for explorations of society, mathematics, currency, and the history of science. ... Zodiac (1988) is Neal Stephensons second novel, which tells the story of an environmentalist, Sangamon Taylor, uncovering a conspiracy involving industrialist pollutors and bicameral minded Satanists in the Boston Harbor. ...

References

1. ^ ^{a b c d} Rudel, R A, Seryak, L M, and Brody, J G (2008). "PCB-containing wood floor finish is a likely source of elevated PCBs in resident's blood, household air and dust: a case study of exposure". Environmental Health.
2. ^ ^{a b c d e f g h i j k l} Proceedings of the Subregional Awareness Raising Workshop on Persistent Organic Pollutants (POPs), Bangkok, Thailand. United Nations Environment Programme (November 25-28th, 1997). Retrieved on 2007-12-11.
3. ^ ^{a b} UNEP Chemicals (1999). Guidelines for the Identification of PCBs and Materials Containing PCBs. United Nations Environment Programme, p.2. Retrieved on 2007-11-07. 
4. ^ Amy Boate, Greg Deleersnyder, Jill Howarth, Anita Mirabelli, and Leanne Peck (2004). Chemistry of PCBs. Retrieved on 2007-11-07.
5. ^ ^{a b} (1997) Identifying PCB-Containing Capacitors. Australian and New Zealand Environment and Conservation Council (ANZECC), pp.4-5. ISBN 0 642 54507 3. Retrieved on 2007-07-07. 
6. ^ Brand names of PCBs — What are PCBs?. Japan Offspring Fund / Center for Marine Environmental Studies (CMES), Ehime University, Japan (2003). Retrieved on 2008-02-11.
7. ^ Karlyn Black Kaley, Jim Carlisle, David Siegel, Julio Salinas (October 2006). Health Concerns and Environmental Issues with PVC-Containing Building Materials in Green Buildings (pdf), Integrated Waste Management Board, California Environmental Protection Agency, USA, p.11. Retrieved on 2007-08-03. 
8. ^ Drinker, C.K., M.F. Warren, and G.A. Bennet (1937). "The problem of possible systemic effects from certain chlorinated hydrocarbons". Journal of Industrial Hygiene and Toxicology 19 (7): 283.
9. ^ Butler, D.A. (2005). "The early history of scientific and medical research on 'agent orange'". Brooklyn Journal of Law and Policy 13 (2): 527.
10. ^ Brown, R. M. (1947). "The toxicity of the 'Arochlors'". Chemist-Analyst 36: 33.
11. ^ S. Jensen (1966). "Report of a new chemical hazard". New Sci. 32: 612.
12. ^ Guidance on municipal waste strategies, Section 5.12 Equipment which contains low volumes of PCBs. UK Department of the Environment, Transport and the Regions (2001). Retrieved on 2008-01-29.
13. ^ Breivik K, Sweetman A, Pacyna JM, Jones KC (2002). "Towards a global historical emission inventory for selected PCB congeners - a mass balance approach 1. Global production and consumption". The Science of the Total Environment 290: 181-198.
14. ^ ^{a b c d} Hudson River PCBs — Background and Site Information. United States Environmental Protection Agency. Retrieved on 2007-12-31.
15. ^ ^{a b c d e} Hudson River PCBs. United States Environmental Protection Agency (2007-06-27). Retrieved on 2007-12-31.
16. ^ "Hudson River Virtual Tour — Chapter 9: PCB Pollution in the Hudson. New York State Department of Environmental Conservation. Retrieved on 2007-12-31.
17. ^ Monroe Co. approves PCB clean up. IndyStar.com. Retrieved on 2008-02-18.
18. ^ Bette Hileman (1988-02-08). "The Great Lakes cleanup effort". Chemistry and Engineering 8: 22-39.
19. ^ Wethington, D M III and Hornbuckle, K C (2005). "Milwaukee, WI, as a Source of Atmospheric PCBs to Lake Michigan". Environmental Science 39 (1): 57-63. doi:10.1021/es048902d.
20. ^ Jamshidi A, Hunter S, Hazrati S, and Harrad S (2007). "Concentrations and Chiral Signatures of Polychlorinated Biphenyls in Outdoor and Indoor Air and Soil in a Major U.K. Conurbation". Environmental Science Technology 41 (7): 2153-2158. doi:10.1021/es062218c.
21. ^ Van den Berg M, Environ Health Perspect. 1998 Dec;106(12):775-92
22. ^ ^{a b} Contamination of rice bran oil with PCB used as the heating medium by leakage through penetration holes at the heating coil tube in deodorization chamber. Japan Science and Technology Agency. Retrieved on 2007-12-11.
23. ^ ^{a b} http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=11386736&dopt=Abstract
24. ^ Disease ID 8326 at NIH's Office of Rare Diseases
25. ^ ^{a b} http://www.foxriverwatch.com/baby_studies_pcbs_2.html
26. ^ ^{a b} http://www.healthgoods.com/Education/Health_Information/General_Health/environmental_diseases.htm
27. ^ Safe S (1984). "Polychlorinated biphenyls (PCBs) and polybrominated biphenyls (PBBs): biochemistry, toxicology, and mechanism of action". Crit. Rev. Toxicol. 13 (4): 319-95. PMID 6091997.
28. ^ Safe S, Bandiera S, Sawyer T, Robertson L, Safe L, Parkinson A, Thomas PE, Ryan DE, Reik LM, Levin W (1985). "PCBs: structure-function relationships and mechanism of action". Environ. Health Perspect. 60: 47-56. PMID 2992927.
29. ^ Simon T, Britt JK, James RC (2007). "Development of a neurotoxic equivalence scheme of relative potency for assessing the risk of PCB mixtures". PMID 17475378.
30. ^ Chauhan KR, Kodavanti PR, McKinney JD (2000). "Assessing the role of ortho-substitution on polychlorinated biphenyl binding to transthyretin, a thyroxine transport protein". Toxicol. Appl. Pharmacol. 162 (1): 10-21. PMID 10631123.
31. ^ Woods SL, Trobaugh DJ (1999). "Polychlorinated Biphenyl Reductive Dechlorination by Vitamin B12s: Thermodynamics and Regiospecificity". Environ. Sci. Technol. 33: 857-863.

Klaus Töpfer, former UNEP Exec. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 345th day of the year (346th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 311th day of the year (312th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 311th day of the year (312th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 188th day of the year (189th in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 42nd day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 215th day of the year (216th in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 29th day of the year in the Gregorian calendar. ... EPA redirects here. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 365th day of the year (366th in leap years) in the Gregorian calendar. ... EPA redirects here. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 178th day of the year (179th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 365th day of the year (366th in leap years) in the Gregorian calendar. ... The New York State Department of Environmental Conservation (NYSDEC or DEC) is responsible for the conservation, improvement, and protection of natural resources within the U.S. state of New York. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 365th day of the year (366th in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 49th day of the year in the Gregorian calendar. ... Year 1988 (MCMLXXXVIII) was a leap year starting on Friday (link displays 1988 Gregorian calendar). ... is the 39th day of the year in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 345th day of the year (346th in leap years) in the Gregorian calendar. ... National Institutes of Health Building 50 at NIH Clinical Center - Building 10 The National Institutes of Health (NIH) is an agency of the United States Department of Health and Human Services and is the primary agency of the United States government responsible for biomedical research. ... A rare disease (sometimes known as an orphan disease) has such a low prevalence in a population that a doctor in a busy general practice would not expect to see more than one case a year. ...

External links

• ATSDR Toxicological Profile U.S. Department of Health and Human Services
• IARC PCB Monograph
• US EPA PCB Homepage
• National Toxicology Program technical reports
• Polychlorinated Byphenyls: Human Health Aspects by the WHO
• Most Common Environmental Toxins

Look up who in Wiktionary, the free dictionary. ...

Appendix

PCB homolog table

For a complete list of PCB congeners, see PCB Congener List. Note that biphenyl, while not technically a PCB congener due to its lack of chlorine substituents, is still typically included in the literature. A complete list of polychlorinated biphenyl (PCB) congeners. ...