PCBs are present as solid particles or as a vapor in the atmosphere. They will eventually return to land and water by settling as dust or in rain and snow. In water, PCBs may be transported by currents, attach to bottom sediment or particles in the water, and evaporate into air.
Full Answer
What is a PCB?
PCBs belong to a broad family of man-made organic chemicals known as chlorinated hydrocarbons. PCBs were domestically manufactured from 1929 until manufacturing was banned in 1979.
What are the combustion products of PCBs?
When conducted properly, the combustion products are water, carbon dioxide, and hydrogen chloride. In some cases, the PCBs are combusted as a solution in kerosene. PCBs have also been destroyed by pyrolysis in the presence of alkali metal carbonates.
What is the history of PCB toxicity?
In the 1930s, the toxicity associated with PCBs and other chlorinated hydrocarbons, including polychlorinated naphthalenes, was recognized because of a variety of industrial incidents. Between 1936 and 1937, there were several medical cases and papers released on the possible link between PCBs and its detrimental health effects.
Which PCB waste codes are eligible for exemption from PCB regulations?
Second, only the PCB wastes which exhibit the toxicity characteristic for an organic constituent (waste codes D018-43) may qualify for the exemption (§261.8). States may also have a regulatory program which is more stringent or broader in scope than the Federal program.
What is a PCB congener?
What are PCBs made of?
What are PCB homologs?
How do PCBs affect animals?
What products contain PCBs?
Where are PCB regulations found?
When was the first PCB assessment done?
See more
About this website
What does PCB on a vape mean?
My Smok Alien displays the temperature of the primary circuit board(PCB) and I've always wondered when I should stop and let the device cool down.
What does PCB too hot mean?
1." PCB Too Hot"warning (1)Normal circumstance:When you vape for a long time(eg：chain-vapes more than 10puffs with high wattage),it would give a "PCB Too Hot"warning to protect the device itself. Please take out the batteries（if it's replaceable） and let it cool for 15 mins.
Why is my Smok vape overheating?
By far the most common reason for a hot vape is that you've been vaping too frequently. Don't feel ashamed however, as it's likely that most vapers have been guilty of this on more than one occasion! To put it simply, chain-vaping causes the coil to get too hot without allowing it the time to cool down.
Why is my vape hot on my lips?
It all comes down to the fact that part of your mod or vaping device is literally designed to get hot. Electricity going to your coil and heating it up is what turns your e-liquid into vapour. The vast majority of the time, a hot vape is going to come down to this simple point.
How hot can PCB get?
Medium Tg PCBs generally have a maximum temperature of above 150°C while high Tg PCBs are rated above 170°C. PCBs with higher Tg value also demonstrate better moisture and chemical resistance, as well as sturdier physical structure in heat.
Why does my vape crackle?
When inhaling on your device, vape juice is drawn into the coil. It is then the coils job to heat up the e-liquid and turn it into vapour. Like with most liquid when it is heated rapidly it will make a crackling noise as it turns into vapour.
Does vaping make you lose weight?
Vaping nicotine may well keep your metabolism up and suppress your appetite, so in addition to a healthy diet, vaping nicotine may encourage your body into a caloric deficit, and this will help you lose weight.
Can my vape explode?
Although these incidents appear uncommon, vape fires and explosions are dangerous to the person using the vaping product and others around them. There may be added dangers, for example, if a vape battery catches fire or explodes near flammable gasses or liquids, such as oxygen, propane, or gasoline.
Polychlorinated Biphenyls (PCBs) Fact Sheet - US EPA
PCB-filled capacitors, caulking materials, elastic sealants, and heat insulation have also been known to contain PCBs. Contact with PCBs at hazardous waste sites can happen
Policy and Guidance for Polychlorinated Biphenyl (PCBs) | US EPA
The PCB Question and Answer (Q&A) Manual covers the breadth of EPA's PCB regulations, including the use, cleanup, and disposal of PCBs.. The Manual is revised and updated periodically.. Future updates will be posted here, and each update will be noted in the revision date of the Manual. The Manual also provides PCB responses to comment documents that were developed for several rulemakings, as ...
What Are The Human Health Effects Of PCBs?
Fact Sheet 12 What Are The Human Health Effects Of PCBs? Polychlorinated biphenyls are a group of 209 different chemicals which share a common structure but vary in the number of attached chlorine atoms.
Polychlorinated Biphenyls (PCBs) | US EPA
To provide regulatory information to the regulated community (those using, storing, or disposing of PCBs), and to provide risk/background information to those researching PCBs and/or concerned about potential exposure to PCBs.
Polychlorinated Biphenyls (PCB's) (86-111) | NIOSH | CDC
[return to text] *”Potential occupational carcinogen means any substance, or combination or mixture of substances, which causes an increased incidence of benign and/or malignant neoplasms, or a substantial decrease in the latency period between exposure and onset of neoplasms in humans or in one or more experimental mammalian species as the result of any oral, respiratory or dermal exposure ...
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. For example: 4,4'-Dichlorobiphenyl is a congener comprising the biphenyl structure with two chlorine substituents - one on each of the #4 carbons of the two rings. In 1980, a numbering system was developed which assigned a sequential number to each of the 209 PCB congeners.
What are PCBs made of?
What Are PCBs? PCBs are a group of man-made organic chemicals consisting of carbon, hydrogen and chlorine atoms. The number of chlorine atoms and their location in a PCB molecule determine many of its physical and chemical properties.
What are PCB homologs?
PCB Homologs. Homologs are subcategories of PCB congeners that have equal numbers of chlorine substituents. For example, the tetrachlorobiphenyls are all PCB congeners with exactly 4 chlorine substituents that can be in any arrangement. Table of PCB Homologs.
How do PCBs affect animals?
PCBs can affect an animal’s immune system, reproductive system, nervous system and endocrine system. The body's regulation of all of these systems is complex and interrelated. As a result, it is not surprising that PCBs can exert a multitude of serious adverse health effects.
What products contain PCBs?
Products that may contain PCBs include: Transformers and capacitors. Electrical equipment including voltage regulators, switches, re-closers, bushings, and electromagnets.
Where are PCB regulations found?
Current PCB regulations, published pursuant to the TSCA statute, can be found in Title 40 of the Code of Federal Regulations (CFR) in Part 761 . The Government Printing Office maintains the most current version of the CFR. View PCB regulations in the electronic-CFR. For useful interpretation of the regulations as well as answers to frequently asked questions please visit EPA's Policy and Guidance for PCBs page.
When was the first PCB assessment done?
EPA's first assessment of PCB carcinogenicity was completed in 1987. At that time, data was limited to Aroclor 1260. In 1996, at the direction of Congress, EPA completed a reassessment of PCB carcinogenicity titled "PCBs: Cancer Dose-Response Assessment and Application to Environmental Mixtures".
Where can PCBs be found?
In the 1960s, when initial research results were released, traces of PCBs could be detected in people and animals around the world – not only in heavily populated areas such as New York City , but also in remote areas as far as the Arctic .
Why are PCBs sprayed on dirt roads?
PCBs were also sprayed on dirt roads to keep the dust down prior to knowing some of the unintended consequences from widespread use . Prior to the ban in 1979, PCBs entered the air, water, and soil during manufacture and use.
Why were PCBs banned?
Image credit: U.S. Fish and Wildlife Service. PCB chemicals were banned in the U.S. in 1979 because these chemicals harm human and environmental health. From the 1920s until their ban, an estimated 1.5 billion pounds of PCBs were made for things such as microscope oils, electrical insulators, capacitors, and electric appliances such as television ...
How do PCBs degrade?
PCBs can degrade or breakdown in the environment, but the process greatly depends on the chemical makeup of the PCBs. The degrading process also depends on where the PCBs are in the environment. Typically, PCBs are either broken down in the environment by sunlight or by microorganisms.
What is the role of sunlight in the breakdown of PCBs?
Sunlight plays an important role in the breakdown of PCBs when they are in the air, shallow water, or surface soils. Microorganisms, such as bacteria, algae, or fungi, biodegrade PCBs when found in soil or sediments.
What are PCBs made of?
PCBs are derived from biphenyl, which has the formula C 12 H 10, sometimes written (C 6 H 5) 2. In PCBs, some of the hydrogen atoms in biphenyl are replaced by chlorine atoms. 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.
Why are PCBs used in electronics?
PCBs were also commonly used as heat stabilizer in cables and electronic components to enhance the heat and fire resistance of PVC. In the 1930s, the toxicity associated with PCBs and other chlorinated hydrocarbons, including polychlorinated naphthalenes, was recognized because of a variety of industrial incidents.
Why are PCBs so attractive?
PCBs are technically attractive because of their inertness, which includes their resistance to combustion. Nonetheless, they can be effectively destroyed by incineration at 1000 °C. When combusted at lower temperatures, they convert in part to more hazardous materials, including dibenzofurans and dibenzodioxins. When conducted properly, the combustion products are water, carbon dioxide, and hydrogen chloride. In some cases, the PCBs are combusted as a solution in kerosene. PCBs have also been destroyed by pyrolysis in the presence of alkali metal carbonates.
Why are PCBs still used?
Because of their longevity , PCBs are still widely in use, even though their manufacture has declined drastically since the 1960s, when a host of problems were identified.
How do PCBs undergo xenobiotic biotransformation?
PCBs undergo xenobiotic biotransformation, a mechanism used to make lipophilic toxins more polar and more easily excreted from the body. The biotransformation is dependent on the number of chlorine atoms present, along with their position on the rings. Phase I reactions occur by adding an oxygen to either of the benzene rings by Cytochrome P450. The type of P450 present also determines where the oxygen will be added; phenobarbital (PB)-induced P450s catalyze oxygenation to the meta-para positions of PCBs while 3-methylcholanthrene (3MC)-induced P450s add oxygens to the ortho – meta positions. PCBs containing ortho – meta and meta – para protons can be metabolized by either enzyme, making them the most likely to leave the organism. However, some metabolites of PCBs containing ortho – meta protons have increased steric hindrance from the oxygen, causing increased stability and an increased chance of accumulation.
Where are polychlorinated biphenyls found?
Polychlorinated biphenyls have been discovered in organisms living in the Mariana trench in the Pacific Ocean. Levels were as high as 1,900 nanograms per gram of amphipod tissue in the organisms analyzed.
When did PCBs become banned?
With the discovery of PCBs' environmental toxicity, and classification as persistent organic pollutants, their production was banned by United States federal law in 1978, and by the Stockholm Convention on Persistent Organic Pollutants in 2001.
What are the main components of an e-cigarette?
The main components. E-cigarette liquids, at the bare minimum, have three main components: flavors, sweeteners and solvents. Solvents are substances used to dissolve either nicotine or marijuana-derived compounds including THC or CBD so those ingredients can be inhaled.
What is the condition that a woman developed after vaping?
And a 2012 case report involved a woman who developed a condition called exogenous lipoid pneumonia after vaping for about six months. Doctors said her e-cigarette's oil-based solvents were the likely cause, and her condition improved when she quit vaping.
What are the ingredients in e-liquid?
Sweeteners include sucralose and ethyl maltol. E-liquid flavors are wide-ranging, and can read like a wine tasting: "notes of vanilla" or "berries and herbal notes.". All of those ingredients — the solvents, the sweeteners and the flavors — are considered "generally recognized as safe" by the Food and Drug Administration.
How do e-cigarettes produce aerosols?
E-cigarettes produce an aerosol by heating the e-liquid with metal coils. Those metal coils can be composed of a variety of substances, including an alloy of iron, chromium and aluminum called kanthal, or a combination of nickel and chromium.
What is the chemical in vanilla bean?
One recent study from Yale University found that vanillin — an extract of the vanilla bean — transforms into chemicals called acetals when aerosolized. Those chemicals, the researchers said, may be especially irritating to the lungs and cause damage when inhaled.
Can I buy vapes on the street?
Last week, the FDA and CDC warned the public not to buy vapes or vape ingredients on the street, and said "e-cigarette products should not be used by youth, young adults, pregnant women, as well as adults who do not currently use tobacco products.". Follow NBC HEALTH on Twitter & Facebook.
Is nicotine a carcinogen?
By itself, it's not known to be carcinogenic, but some lab research has suggested nicotine could promote tumor growth.
When soil or sand samples are collected, should you consider whether the PCBs are on the soil surface or
When soil or sand samples are collected, you should consider whether the PCBs are on the soil surface or if they could be located deeper in the soil. An example of when PCBs might be on the soil surface would be if fragments of weathered caulking were deposited on undisturbed soil surfaces.
Can PCBs migrate into porous surfaces?
Porous surface samples - Because PCBs can migrate into porous surfaces (e.g., brick, masonry, concrete or wood) surface wipe sampling is not adequate to characterize the PCB concentration of porous surfaces. Instead, core samples should be collected on a bulk basis (i.e., mg/kg) to collect the top 0.5 to 2 cm of the porous surface.
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. For example: 4,4'-Dichlorobiphenyl is a congener comprising the biphenyl structure with two chlorine substituents - one on each of the #4 carbons of the two rings. In 1980, a numbering system was developed which assigned a sequential number to each of the 209 PCB congeners.
What are PCBs made of?
What Are PCBs? PCBs are a group of man-made organic chemicals consisting of carbon, hydrogen and chlorine atoms. The number of chlorine atoms and their location in a PCB molecule determine many of its physical and chemical properties.
What are PCB homologs?
PCB Homologs. Homologs are subcategories of PCB congeners that have equal numbers of chlorine substituents. For example, the tetrachlorobiphenyls are all PCB congeners with exactly 4 chlorine substituents that can be in any arrangement. Table of PCB Homologs.
How do PCBs affect animals?
PCBs can affect an animal’s immune system, reproductive system, nervous system and endocrine system. The body's regulation of all of these systems is complex and interrelated. As a result, it is not surprising that PCBs can exert a multitude of serious adverse health effects.
What products contain PCBs?
Products that may contain PCBs include: Transformers and capacitors. Electrical equipment including voltage regulators, switches, re-closers, bushings, and electromagnets.
Where are PCB regulations found?
Current PCB regulations, published pursuant to the TSCA statute, can be found in Title 40 of the Code of Federal Regulations (CFR) in Part 761 . The Government Printing Office maintains the most current version of the CFR. View PCB regulations in the electronic-CFR. For useful interpretation of the regulations as well as answers to frequently asked questions please visit EPA's Policy and Guidance for PCBs page.
When was the first PCB assessment done?
EPA's first assessment of PCB carcinogenicity was completed in 1987. At that time, data was limited to Aroclor 1260. In 1996, at the direction of Congress, EPA completed a reassessment of PCB carcinogenicity titled "PCBs: Cancer Dose-Response Assessment and Application to Environmental Mixtures".
What Are PCBs?
- PCBs are a group of man-made organic chemicals consisting of carbon, hydrogen and chlorine atoms. The number of chlorine atoms and their location in a PCB molecule determine many of its physical and chemical properties. PCBs have no known taste or smell, and range in consistency from an oil to a waxy solid. PCBs belong to a broad family of man-made...
Inadvertent PCBs
- In the United States, PCBs were commercially manufactured from 1929 until production was banned in 1979 by the Toxic Substances Control Act (TSCA). However, EPA’s regulations implementing TSCA for PCBs allow some inadvertent generation of PCBs to occur in excluded manufacturing processes, as defined in title 40 of the Code of Federal Regulations (CFR) sectio…
Commercial Uses For PCBs
- Although no longer commercially produced in the United States, PCBs may be present in products and materials produced before the 1979 PCB ban. Products that may contain PCBs include: 1. Transformers and capacitors 2. Electrical equipment including voltage regulators, switches, re-closers, bushings, and electromagnets 3. Oil used in motors and hydraulic systems 4. Old electri…
Release and Exposure of PCBs
- Today, PCBs can still be released into the environment from: 1. Poorly maintained hazardous waste sites that contain PCBs 2. Illegal or improper dumping of PCB wastes 3. Leaks or releases from electrical transformers containing PCBs 4. Disposal of PCB-containing consumer products into municipal or other landfills not designed to handle hazardous waste 5. Burning some waste…
PCB Congeners
- 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 substituentsand the position of each chlorine. For example: 4,4'-Dichlorobiphenyl is a congener comprising the biphenyl structure with two chlorine substituents - one on each of the #4 carbons of the two rings. In 1980, a numberin…
PCB Homologs
- Homologs are subcategories of PCB congeners that have equal numbers of chlorine substituents. For example, the tetrachlorobiphenyls are all PCB congeners with exactly 4 chlorine substituents that can be in any arrangement. 1. Table of PCB Homologs
PCB Mixtures and Trade Names
- With few exceptions, PCBs were manufactured as a mixture of individual PCB congeners. These mixtures were created by adding progressively more chlorine to batches of biphenyl until a certain target percentage of chlorine by weight was achieved. Commercial mixtures with higher percentages of chlorine contained higher proportions of the more heavily chlorinated congeners…
PCB Trade Names
- PCBs were manufactured and sold under many different names. The names in the following table have been used to refer to PCBs or to products containing PCBs. Please note: 1. Some of these names may be used for substances or mixtures not containing PCBs. 2. Many of these names were used with distinguishing suffixes, indicating degree of chlorination, type of formulation, or …
Health Effects of PCBs
- 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. Studies in humans support evidence for potential car…
Laws and Regulations
- Statute: Toxic Substances Control Act
The Toxic Substances Control Act of 1976 provides EPA with authority to require reporting, record-keeping and testing requirements, and restrictions relating to chemical substances and/or mixtures, including PCBs. Some substances are generally excluded from TSCA, including but no… - PCB Regulations: Part 761 in Title 40 of the Code of Federal Regulations
Current PCB regulations, published pursuant to the TSCA statute, can be found in Title 40 of the Code of Federal Regulations (CFR) in Part 761. The Government Printing Office maintains the most current version of the CFR. View PCB regulations in the electronic-CFR. For useful interpret…
Overview
Polychlorinated biphenyls (PCBs) are highly carcinogenic chemical compounds, formerly used in industrial and consumer products, whose production was banned by United States federal law in 1978 and by the Stockholm Convention on Persistent Organic Pollutants in 2001. They are organic chlorine compounds with the formula C12H10−xClx; they were once widely used in the manufactur…
Physical and chemical properties
The compounds are pale-yellow viscous liquids. They are hydrophobic, with low water solubilities: 0.0027–0.42 ng/L for Aroclors brand, but they have high solubilities in most organic solvents, oils, and fats. They have low vapor pressures at room temperature. They have dielectric constants of 2.5–2.7, very high thermal conductivity, and high flash points (from 170 to 380 °C).
Alternative names
Commercial PCB mixtures were marketed under the following names:
• Ascarel
• Delor
• Phenoclor
• Pyralène (both used by Prodolec)
Production
One estimate (2006) suggested that 1 million tonnes of PCBs had been produced. 40% of this material was thought to remain in use. Another estimate put the total global production of PCBs on the order of 1.5 million tonnes. The United States was the single largest producer with over 600,000 tonnes produced between 1930 and 1977. The European region follows with nearly 450,000 tonnes through 1984. It is unlikely that a full inventory of global PCB production will eve…
Applications
The utility of PCBs is based largely on their chemical stability, including low flammability and high dielectric constant. In an electric arc, PCBs generate incombustible gases.
Use of PCBs is commonly divided into closed and open applications. Examples of closed applications include coolants and insulating fluids (transformer oil) for transformers and capacitors, such as those used in old fluorescent light ballasts, hydraulic fluids, lubricating and cutting oils, a…
Environmental transport and transformations
PCBs have entered the environment through both use and disposal. The environmental fate of PCBs is complex and global in scale.
Because of their low vapour pressure, PCBs accumulate primarily in the hydrosphere, despite their hydrophobicity, in the organic fraction of soil, and in organisms including the human body. The hydrosphere is the main reservoir. T…
Biochemical metabolism
PCBs undergo xenobiotic biotransformation, a mechanism used to make lipophilic toxins more polar and more easily excreted from the body. The biotransformation is dependent on the number of chlorine atoms present, along with their position on the rings. Phase I reactions occur by adding an oxygen to either of the benzene rings by Cytochrome P450. The type of P450 present also determines where the oxygen will be added; phenobarbital (PB)-induced P450s catalyze oxy…
Health effects
The toxicity of PCBs varies considerably among congeners. The coplanar PCBs, known as nonortho PCBs because they are not substituted at the ring positions ortho to (next to) the other ring, (such as PCBs 77, 126 and 169), 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 o…