Propylene glycol, also called
1,2-propanediol or
propane-1,2-diol, is an
organic compoundAn organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
(a
diolA diol or glycol is a chemical compound containing two hydroxyl groups A geminal diol has two hydroxyl groups bonded to the same atom...
or double
alcoholIn chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
) with formula C
3H
8O
2 or HO-CH
2-CHOH-CH
3. It is a colorless, nearly odorless, clear, viscous liquid with a faintly sweet taste, hygroscopic and miscible with
waterWater is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
,
acetoneAcetone is the organic compound with the formula 2CO, a colorless, mobile, flammable liquid, the simplest example of the ketones.Acetone is miscible with water and serves as an important solvent in its own right, typically as the solvent of choice for cleaning purposes in the laboratory...
, and
chloroformChloroform is an organic compound with formula CHCl3. It is one of the four chloromethanes. The colorless, sweet-smelling, dense liquid is a trihalomethane, and is considered somewhat hazardous...
.
The compound is sometimes called
α-propylene glycol to distinguish it from the isomer
propane-1,3-diol1,3-Propanediol is the organic compound with the formula CH22. This three-carbon diol is a colorless viscous liquid that is miscible with water.-Products:...
HO-(CH
2)
3-OH, also called
β-propylene glycol.
Chirality
Propylene glycol contains an asymmetrical carbon atom, so it exists in two stereoisomers. The commercial product is a
racemicIn chemistry, a racemic mixture, or racemate , is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule. The first known racemic mixture was "racemic acid", which Louis Pasteur found to be a mixture of the two enantiomeric isomers of tartaric acid.- Nomenclature :A...
mixture. Pure optical isomers can be obtained by hydration of optically pure
propylene oxidePropylene oxide is an organic compound with the molecular formula CH3CHCH2O. This colourless volatile liquid is produced on a large scale industrially, its major application being its use for the production of polyether polyols for use in making polyurethane plastics...
.
Production
Industrially, propylene glycol is produced from
propylene oxidePropylene oxide is an organic compound with the molecular formula CH3CHCH2O. This colourless volatile liquid is produced on a large scale industrially, its major application being its use for the production of polyether polyols for use in making polyurethane plastics...
. Different manufacturers use either non-catalytic high-temperature process at 200 °C (392 °F) to 220 °C (428 °F), or a catalytic method, which proceeds at 150 °C (302 °F) to 180 °C (356 °F) in the presence of ion exchange resin or a small amount of sulfuric acid or alkali.
Final products contain 20% 1,2-propanediol, 1.5% of
dipropylene glycolDipropylene glycol is a mixture of three isomeric chemical compounds, 4-oxa-2,6-heptandiol, 2--propan-1-ol, and 2--propan-1-ol...
and small amounts of other
polypropylene glycolPolypropylene glycol or polypropylene oxide is the polymer of propylene glycol. Chemically it is a polyether. The term polypropylene glycol or PPG is reserved for low to medium range molar mass polymer when the nature of the end-group, which is usually a hydroxyl group, still matters...
s. Further purification produces finished industrial grade or USP/JP/EP/BP grade propylene glycol that is typically 99.5% or greater. Propylene glycol can also be converted from
glycerolGlycerol is a simple polyol compound. It is a colorless, odorless, viscous liquid that is widely used in pharmaceutical formulations. Glycerol has three hydroxyl groups that are responsible for its solubility in water and its hygroscopic nature. The glycerol backbone is central to all lipids...
, a
biodieselBiodiesel refers to a vegetable oil- or animal fat-based diesel fuel consisting of long-chain alkyl esters. Biodiesel is typically made by chemically reacting lipids with an alcohol....
byproduct.
Applications
Propylene glycol is used:
- As an ingredient in the oil dispersant Corexit
Corexit is a product line of solvents primarily used as a dispersant for breaking up oil slicks. It is produced by Nalco Holding Company which is associated with BP and Exxon. Corexit was the most-used dispersant in the Deepwater Horizon oil spill in the Gulf of Mexico, with COREXIT 9527 having...
, used in great quantities during the Deepwater Horizon oil spillThe Deepwater Horizon oil spill is an oil spill in the Gulf of Mexico which flowed unabated for three months in 2010, and continues to leak fresh oil. It is the largest accidental marine oil spill in the history of the petroleum industry...
.
- As a solvent in many pharmaceuticals, including oral
Oral administration is a route of administration where a substance is taken through the mouth.-Terminology:Per os is an adverbial phrase meaning literally from Latin "by mouth" or "by way of the mouth." The expression is used in medicine to describe a treatment that is taken orally. The...
, injectable and topicalIn medicine, a topical medication is applied to body surfaces such as the skin or mucous membranes such as the vagina, anus, throat, eyes and ears.Many topical medications are epicutaneous, meaning that they are applied directly to the skin...
formulations. Notably, diazepamDiazepam , first marketed as Valium by Hoffmann-La Roche is a benzodiazepine drug. Diazepam is also marketed in Australia as Antenex. It is commonly used for treating anxiety, insomnia, seizures including status epilepticus, muscle spasms , restless legs syndrome, alcohol withdrawal,...
, which is insoluble in water, uses propylene glycol as its solvent in its clinicA clinic is a health care facility that is primarily devoted to the care of outpatients...
al, injectable form.
- As a humectant
A humectant is a hygroscopic substance. It is often a molecule with several hydrophilic groups, most often hydroxyl groups, but amines and carboxyl groups, sometimes esterified, can be encountered as well; the affinity to form hydrogen bonds with molecules of water is crucial here.Since...
food additiveFood additives are substances added to food to preserve flavor or enhance its taste and appearance.Some additives have been used for centuries; for example, preserving food by pickling , salting, as with bacon, preserving sweets or using sulfur dioxide as in some wines...
, labeled as E numberE numbers are number codes for food additives that have been assessed for use within the European Union . They are commonly found on food labels throughout the European Union. Safety assessment and approval are the responsibility of the European Food Safety Authority...
E1520
- As an emulsification agent in Angostura
Angostura bitters, often simply referred to as angostura, is a concentrated bitters made of water, 44.7% alcohol, gentian root, and vegetable flavoring extracts by House of Angostura in Trinidad and Tobago. They are typically used for flavoring beverages, or food...
and orange bittersA bitters is an alcoholic beverage that is flavored with herbal essences and has a bitter or bittersweet flavor. There are numerous brands of bitters that were formerly marketed as patent medicines but are now considered to be digestifs, rather than medicines...
- As a moisturizer
Moisturizers or emollients are complex mixtures of chemical agents specially designed to make the external layers of the skin softer and more pliable, by increasing its hydration by reducing evaporation. Naturally occurring skin lipids and sterols as well as artificial or natural oils,...
in medicinesA pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...
, cosmeticsCosmetics are substances used to enhance the appearance or odor of the human body. Cosmetics include skin-care creams, lotions, powders, perfumes, lipsticks, fingernail and toe nail polish, eye and facial makeup, towelettes, permanent waves, colored contact lenses, hair colors, hair sprays and...
, foodFood is any substance consumed to provide nutritional support for the body. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals...
, toothpasteToothpaste is a paste or gel dentifrice used with a toothbrush as an accessory to clean and maintain the aesthetics and health of teeth. Toothpaste is used to promote oral hygiene: it serves as an abrasive that aids in removing the dental plaque and food from the teeth, assists in suppressing...
, shampooShampoo is a hair care product used for the removal of oils, dirt, skin particles, dandruff, environmental pollutants and other contaminant particles that gradually build up in hair...
, mouth wash, hair careHair care is an overall term for parts of hygiene and cosmetology involving the hair on the human head. Hair care will differ according to one's hair type and according to various processes that can be applied to hair...
and tobaccoTobacco is an agricultural product processed from the leaves of plants in the genus Nicotiana. It can be consumed, used as a pesticide and, in the form of nicotine tartrate, used in some medicines...
products
- As a carrier in fragrance oil
Fragrance oil, also known as aroma oils, aromatic oils, and flavor oils, are blended synthetic aroma compounds or natural essential oils that are diluted with a carrier like propylene glycol, vegetable oil, or mineral oil...
- To produce polyester compounds
- As a base in deicing solution
- As an ingredient in massage oils
- In hand sanitizers, antibacterial
Antiseptics are antimicrobial substances that are applied to living tissue/skin to reduce the possibility of infection, sepsis, or putrefaction...
lotions, and saline solutions
- In smoke machines to make artificial smoke
Smoke is a collection of airborne solid and liquid particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-product of fires , but may also be used for pest...
for use in firefighterFirefighters are rescuers extensively trained primarily to put out hazardous fires that threaten civilian populations and property, to rescue people from car incidents, collapsed and burning buildings and other such situations...
s' training and theatrical productions
- In electronic cigarettes, as a vaporizable base for diluting the nicotine liquid
- As a solvent
A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
for food colorsFood coloring is a substance, liquid or powder, that is added to food or drink to change its color. Food coloring is used both in commercial food production and in domestic cooking...
and flavorings
- As an ingredient, along with wax and gelatin, in the production of paintballs
- As a moisture stabilizer (humectant) for snus
Snus , or Swedish snuff, is a moist powder tobacco product originated from a variant of dry snuff in the early 19th century in Sweden, consumed by placing it under the lip for extended periods of time. The precursor of snus, the dry form of snuff inhaled through the nose, was introduced in Europe...
(Swedish style snuff).
- As a cooling agent for beer
Beer is the world's most widely consumed andprobably oldest alcoholic beverage; it is the third most popular drink overall, after water and tea. It is produced by the brewing and fermentation of sugars, mainly derived from malted cereal grains, most commonly malted barley and malted wheat...
and wineWine is an alcoholic beverage, made of fermented fruit juice, usually from grapes. The natural chemical balance of grapes lets them ferment without the addition of sugars, acids, enzymes, or other nutrients. Grape wine is produced by fermenting crushed grapes using various types of yeast. Yeast...
glycol jacketed fermentation tanks
- As a non-toxic antifreeze
Antifreeze is a freeze preventive used in internal combustion engines and other heat transfer applications, such as HVAC chillers and solar water heaters....
for winterizing drinking water systems, and in applications where the used antifreeze eventually will be drained into the soil, water, or a septic system.
- As a less-toxic
In the context of biology, poisons are substances that can cause disturbances to organisms, usually by chemical reaction or other activity on the molecular scale, when a sufficient quantity is absorbed by an organism....
antifreezeAntifreeze is a freeze preventive used in internal combustion engines and other heat transfer applications, such as HVAC chillers and solar water heaters....
in solar water heatingSolar water heating or solar hot water systems comprise several innovations and many mature renewable energy technologies that have been well established for many years...
systems
- As a solvent
A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
used in mixing photographic chemicals, such as film developers
- In cryonics
Cryonics is the low-temperature preservation of humans and animals who can no longer be sustained by contemporary medicine, with the hope that healing and resuscitation may be possible in the future. Cryopreservation of people or large animals is not reversible with current technology...
- As a working fluid in hydraulic presses
- As a coolant
A coolant is a fluid which flows through a device to prevent its overheating, transferring the heat produced by the device to other devices that use or dissipate it. An ideal coolant has high thermal capacity, low viscosity, is low-cost, non-toxic, and chemically inert, neither causing nor...
in liquid cooling systems
- To regulate humidity in a cigar humidor
A humidor is any kind of box or room with constant humidity, and ideal temperature, used to store cigars, cigarettes, or pipe tobacco. For private use, small wooden or acrylic glass humidor boxes for a few dozen cigars are used, while cigar shops may have walk-in humidors, sometimes consisting of a...
- As the killing and preserving agent in pitfall traps, usually used to capture ground beetles
- As an additive to pipe tobacco to prevent dehydration.
- To treat livestock ketosis
Ketosis is a state of elevated levels of ketone bodies in the body. It is almost always generalized throughout the body, with hyperketonemia, that is, an elevated level of ketone bodies in the blood. Ketone bodies are formed by ketogenesis when the liver glycogen stores are depleted...
- As the main ingredient in deodorant
Deodorants are substances applied to the body to affect body odor caused by bacterial growth and the smell associated with bacterial breakdown of perspiration in armpits, feet and other areas of the body. A subgroup of deodorants, antiperspirants, affect odor as well as prevent sweating by...
sticks.
- To de-ice aircraft.
- As an ingredient in UV or blacklight tattoo ink
UV tattoos or blacklight tattoos are tattoos made with a special ink that is visible under an ultraviolet light . Depending upon the ink, they can be nearly invisible in non-UV environments, thus they are a popular consideration for people seeking a subtler tattoo...
- As a lubricant in air conditioning compressors.
- As a wetting agent, used to determine drying time in paints and coatings
Propylene glycol has properties similar to those of highly toxic
ethylene glycolEthylene glycol is an organic compound widely used as an automotive antifreeze and a precursor to polymers. In its pure form, it is an odorless, colorless, syrupy, sweet-tasting liquid...
(monoethylene glycol, or MEG). (Note: Infrequently propylene glycol may also use the acronym MEG, but as an abbreviation of methyl ethyl glycol- the industry standard acronym for propylene glycol is PG or MPG (monopropylene glycol)). The industrial norm is to replace ethylene glycol with propylene glycol when safer properties are desired.
Properties
Propylene glycol is a component in newer automotive antifreezes and de-icers used at airports. Like
ethylene glycolEthylene glycol is an organic compound widely used as an automotive antifreeze and a precursor to polymers. In its pure form, it is an odorless, colorless, syrupy, sweet-tasting liquid...
, the freezing point of propylene glycol is depressed when mixed with water due to disruption of hydrogen bonding. Unlike ethylene glycol, propylene glycol is of very low toxicity. Both are readily biodegradable.
Freezing Points of Propylene Glycol – Water Mixtures
| Percent Propylene Glycol (wt. %) |
Freezing Point (°F) |
Freezing Point (°C) |
| 0 |
32 |
0 |
| 10 |
26 |
-3 |
| 20 |
20 |
-7 |
| 30 |
10 |
-12 |
| 36 |
0 |
-18 |
| 40 |
-5 |
-20 |
| 43 |
-10 |
-23 |
| 48 |
-20 |
-29 |
| 52 |
-30 |
-34 |
| 55 |
-40 |
-40 |
| 58 |
-50 |
-46 |
| 60 |
-60 |
-51 |
Humans
The acute oral toxicity of propylene glycol is very low, and large quantities are required to cause perceptible health damage in humans; propylene glycol is metabolized in the human body into
pyruvic acidPyruvic acid is an organic acid, a ketone, as well as the simplest of the alpha-keto acids. The carboxylate ion of pyruvic acid, CH3COCOO−, is known as pyruvate, and is a key intersection in several metabolic pathways....
(a normal part of the glucose-metabolism process, readily converted to energy),
acetic acidAcetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...
(handled by ethanol-metabolism),
lactic acidLactic acid, also known as milk acid, is a chemical compound that plays a role in various biochemical processes and was first isolated in 1780 by the Swedish chemist Carl Wilhelm Scheele. Lactic acid is a carboxylic acid with the chemical formula C3H6O3...
(a normal acid generally abundant during digestion), and
propionaldehydePropionaldehyde or propanal is the organic compound with the formula CH3CH2CHO. It is a saturated 3-carbon aldehyde and is a structural isomer of acetone...
(a highly toxic substance).
Serious toxicity generally occurs only at plasma concentrations over 1 g/L, which requires extremely high intake over a relatively short period of time. It would be nearly impossible to reach toxic levels by consuming foods or supplements, which contain at most 1 g/kg of PG. Cases of propylene glycol poisoning are usually related to either inappropriate intravenous administration or accidental ingestion of large quantities by children. The potential for long-term oral toxicity is also low. In one study, rats were provided with feed containing as much as 5% PG in feed over a period of 104 weeks and they showed no apparent ill effects. Because of its low chronic oral toxicity, propylene glycol was classified by the U. S.
Food and Drug AdministrationThe Food and Drug Administration is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments...
as "
generally recognized as safeGenerally recognized as safe is an American Food and Drug Administration designation that a chemical or substance added to food is considered safe by experts, and so is exempted from the usual Federal Food, Drug, and Cosmetic Act food additive tolerance requirements.-History:On January 1, 1958,...
" (GRAS) for use as a direct food additive.
Prolonged contact with propylene glycol is essentially non-irritating to the skin. Undiluted propylene glycol is minimally irritating to the eye, and can produce slight transient conjunctivitis (the eye recovers after the exposure is removed). Exposure to mists may cause eye irritation, as well as upper respiratory tract irritation. Inhalation of the propylene glycol vapors appears to present no significant hazard in ordinary applications. However, limited human experience indicates that inhalation of propylene glycol mists could be irritating to some individuals. Some research has suggested that propylene glycol not be used in applications where inhalation exposure or human eye contact with the spray mists of these materials is likely, such as fogs for theatrical productions or antifreeze solutions for emergency eye wash stations.
Propylene glycol does not cause sensitization and it shows no evidence of being a carcinogen or of being genotoxic.
Adverse responses to intravenous administration of drugs which use PG as an
excipientAn excipient is generally a pharmacologically inactive substance used as a carrier for the active ingredients of a medication. In many cases, an "active" substance may not be easily administered and absorbed by the human body; in such cases the substance in question may be dissolved into or...
have been seen in a number of people, particularly with large dosages thereof. Responses may include "hypotension[,] bradycardia... QRS and T abnormalities on the ECG[,] arrhythmia[,] cardiac arrest[,] serum hyperosmolality[,] lactic acidosis[,] and haemolysis". A high percentage (12% to 42%) of directly-injected propylene glycol is eliminated/secreted in urine unaltered depending on dosage, with the remainder appearing in its glucuronide-form. The speed of renal filtration decreases as dosage increases, which may be due to propylene glycol's mild anesthetic / CNS-depressant -properties as an alcohol.
In one case, administration via IV of PG-suspended nitroglycerin to an elderly man may have induced coma and acidosis.
According to a 2010 study by
Karlstad UniversityKarlstad University is a state university in Karlstad, Sweden. The university, being a former university college was granted university status in 1999 by the Government of Sweden. Originally it was a branch of the University of Gothenburg...
, the concentrations of PGEs, propylene glycol and glycol ethers in indoor air, particularly bedroom air, has been linked to increased risk of developing numerous respiratory and immune disorders in children, including
asthmaAsthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
,
hay feverHay Fever is a comic play written by Noël Coward in 1924 and first produced in 1925 with Marie Tempest as the first Judith Bliss. Laura Hope Crews played the role in New York...
,
eczemaEczema is a form of dermatitis, or inflammation of the epidermis . In England, an estimated 5.7 million or about one in every nine people have been diagnosed with the disease by a clinician at some point in their lives.The term eczema is broadly applied to a range of persistent skin conditions...
, and allergies, with increased risk ranging from 50% to 180%. This concentration has been linked to use of water-based paints and water-based cleansers.
Animals
Propylene glycol is an approved food additive for dog food under the category of animal feed and is generally recognized as safe (GRAS) for dogs. Similarly, propylene glycol is an approved food additive for human food as well. The exception is that it is prohibited for use in food for cats because of a species-specific reaction in the body, as noted in 21 CFR 582.1666.
Veterinary data indicate that propylene glycol is toxic to dogs with a 50% chance of being lethal at doses of 9mL/kg, although the figure is higher for most laboratory animals (LD
50 at levels of 20mL/kg).
However, propylene glycol may be toxic to cats in ways not seen in other animals. The U.S. Food and Drug Administration has determined that its presence in or on cat food has not been shown by adequate scientific data to be safe for use. Any such use is considered an adulteration of the cat food and a violation of the Federal Food, Drug, and Cosmetic Act.
Allergic reaction
Research has suggested that individuals who cannot tolerate propylene glycol probably experience a special form of irritation, but that they only rarely develop allergic contact dermatitis. Other investigators believe that the incidence of allergic contact dermatitis to propylene glycol may be greater than 2% in patients with eczema.
Patients with
vulvodyniaVulvodynia is a chronic pain syndrome that affects the vulvar area and occurs without an identifiable cause or visible pathology categorized in the ICD-9 group 625—specifically ICD-9 625.7, which is for pain and other disorders of the female genital organs...
and
interstitial cystitisInterstitial cystitis or bladder pain syndrome is a chronic, oftentimes severely debilitating disease of the urinary bladder...
may be especially sensitive to propylene glycol. Women struggling with yeast infections may also notice that some OTC creams can cause intense burning. Post menopausal women who require the use of an estrogen cream may notice that brand name creams made with propylene glycol often create extreme, uncomfortable burning along the vulva and perianal area. In these cases, patients can request that a local
compounding pharmacyCompounding is the mixing of drugs by a compounding pharmacist to fit the unique needs of a patient...
make a "propylene glycol free" cream.
Additionally, some electronic cigarette users who inhale propylene glycol vapor may experience dryness of the throat or shortness of breath . As an alternative, some suppliers will put Vegetable Glycerin in the "e-liquid" for those who are allergic (or have bad reactions) to propylene glycol.
A Swedish study published in 2010 strongly suggests a connection between airbourne concentrations of propylene glycol in houses and development of asthma and allergic reactions, such as rhinitis, in children.
Possible air germicide
Studies conducted in 1942 by Dr. Oswald Hope Robertson of
University of ChicagoThe University of Chicago is a private research university in Chicago, Illinois, USA. It was founded by the American Baptist Education Society with a donation from oil magnate and philanthropist John D. Rockefeller and incorporated in 1890...
's Billings Hospital showed vaporized propylene glycol inhalation in laboratory mice may prevent pneumonia, influenza, and other respiratory diseases. Additional studies in monkeys and other animals were undertaken to determine long-term effects, especially the potential for accumulation in the lungs. After a few months of treatment, no ill effects were discovered.
Environmental
Propylene glycol is known to exert high levels of
biochemical oxygen demandBiochemical oxygen demand or B.O.D. is the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period. The term also refers to a chemical procedure for...
(BOD) during degradation in surface waters. This process can adversely affect aquatic life by consuming oxygen aquatic organisms need to survive. Large quantities of dissolved oxygen (DO) in the water column are consumed when microbial populations decompose propylene glycol.
The oxygen depletion potential of airport deicing operation discharges is many times greater than that of raw sewage. For example, before application, Type I propylene glycol-based deicing fluid is generally diluted to a mixture containing approximately 50% propylene glycol. Pure propylene glycol has a five-day biochemical oxygen demand (BOD5) concentration of approximately 1,000,000 mg/L. A typical diluted propylene-based deicing fluid could therefore have a BOD5 concentration of approximately 500,000 mg/L. In comparison, raw sewage typically has a BOD5 concentration of approximately 200 mg/L. The amount of fluid used to deice a single jet depends on the nature of the precipitation event and the size of the aircraft but can range from several hundred to several thousand gallons. Therefore, deicing a single jet can generate a BOD5 load greater than that of one million gallons of raw sewage. A large hub airport often has several hundred flights each day.
Sufficient DO levels in surface waters are critical for the survival of fish, macroinvertebrates, and other aquatic organisms. If oxygen concentrations drop below a minimum level, organisms emigrate, if able and possible, to areas with higher oxygen levels or eventually die. This effect can drastically reduce the amount of usable aquatic habitat. Reductions in DO levels can reduce or eliminate bottom-feeder populations, create conditions that favor a change in a community’s species profile, or alter critical food-web interactions.
CorexitCorexit is a product line of solvents primarily used as a dispersant for breaking up oil slicks. It is produced by Nalco Holding Company which is associated with BP and Exxon. Corexit was the most-used dispersant in the Deepwater Horizon oil spill in the Gulf of Mexico, with COREXIT 9527 having...
implications
The chemical is an ingredient in the oil dispersant
CorexitCorexit is a product line of solvents primarily used as a dispersant for breaking up oil slicks. It is produced by Nalco Holding Company which is associated with BP and Exxon. Corexit was the most-used dispersant in the Deepwater Horizon oil spill in the Gulf of Mexico, with COREXIT 9527 having...
, used in great quantities during the
Deepwater Horizon oil spillThe Deepwater Horizon oil spill is an oil spill in the Gulf of Mexico which flowed unabated for three months in 2010, and continues to leak fresh oil. It is the largest accidental marine oil spill in the history of the petroleum industry...
. Corexit has come under scrutiny for probable adverse effects on marine life and humans that are exposed to it. Propylene glycol has also come under scrutiny, as it is the chemical that disperses Corexit and the oil to subsurface depths.
External links