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Phthalates

Phthalates

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Phthalates or phthalate esters, are esters of phthalic acid
Phthalic acid
Phthalic acid is an aromatic dicarboxylic acid, with formula C6H42. It is an isomer of isophthalic acid and terephthalic acid. Although phthalic acid is of modest commercial importance, the closely related derivative phthalic anhydride is a commodity chemical produced on a large...

 and are mainly used as plasticizer
Plasticizer
Plasticizers or dispersants are additives that increase the plasticity or fluidity of the material to which they are added; these include plastics, cement, concrete, wallboard, and clay. Although the same compounds are often used for both plastics and concretes the desired effects and results are...

s (substances added to plastic
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...

s to increase their flexibility, transparency, durability, and longevity). They are used primarily to soften polyvinyl chloride
Polyvinyl chloride
Polyvinyl chloride, commonly abbreviated PVC, is a thermoplastic polymer. It is a vinyl polymer constructed of repeating vinyl groups having one hydrogen replaced by chloride. Polyvinyl chloride is the third most widely produced plastic, after polyethylene and polypropylene. PVC is widely used in...

. Phthalates are being phased out of many products in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

, and European Union
European Union
The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...

 over health concerns.

Phthalates are used in a large variety of products, from enteric coating
Enteric coating
An enteric coating is a barrier applied to oral medication that controls the location in the digestive system, where it is absorbed. Enteric refers to the small intestine, therefore enteric coatings prevent release of medication before it reaches the small intestine.Most enteric coatings work by...

s of pharmaceutical pills and nutritional supplements to viscosity
Viscosity
Viscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity...

 control agents, gelling agents, film formers, stabilizer
Stabilizer (chemistry)
In chemistry a stabilizer is a chemical which tends to inhibit the reaction between two or more other chemicals. It can be thought of as the antonym to a catalyst...

s, dispersant
Dispersant
A dispersant or a dispersing agent or a plasticizer or a superplasticizer is either a non-surface active polymer or a surface-active substance added to a suspension, usually a colloid, to improve the separation of particles and to prevent settling or clumping...

s, lubricant
Lubricant
A lubricant is a substance introduced to reduce friction between moving surfaces. It may also have the function of transporting foreign particles and of distributing heat...

s, binders, emulsifying agents, and suspending agents. End-applications include adhesives and glues, electronics, agricultural adjuvants, building materials, personal-care products, medical devices, detergents and surfactants, packaging, children's toys, modelling clay
Modelling clay
You can use modelling clay to create items with it. The material compositions and production processes vary considerably. -Ceramic clay:...

, waxes, paints, printing inks and coatings, pharmaceuticals, food products, and textiles.

Phthalates are easily released into the environment because there is no covalent bond
Covalent bond
A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. The stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding....

 between the phthalates and plastic
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...

s in which they are mixed. As plastics age and break down, the release of phthalates accelerates. People are commonly exposed to phthalates, and most Americans tested by the Centers for Disease Control and Prevention
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...

 have metabolite
Metabolite
Metabolites are the intermediates and products of metabolism. The term metabolite is usually restricted to small molecules. A primary metabolite is directly involved in normal growth, development, and reproduction. Alcohol is an example of a primary metabolite produced in large-scale by industrial...

s of multiple phthalates in their urine. Because phthalate plasticizers are not chemically bound to PVC, they can easily leach and evaporate into food or the atmosphere. Phthalate exposure can be through direct use or by indirect means through leaching and general environmental contamination. Diet
Diet (nutrition)
In nutrition, diet is the sum of food consumed by a person or other organism. Dietary habits are the habitual decisions an individual or culture makes when choosing what foods to eat. With the word diet, it is often implied the use of specific intake of nutrition for health or weight-management...

 is believed to be the main source of DEHP and other phthalates in the general population. Fatty foods such as milk, butter, and meats are a major source.

In studies of rodents exposed to certain phthalates, high doses have been shown to change hormone levels and cause birth defects.

Uses


Phthalates are used in a large variety of products, from enteric coating
Enteric coating
An enteric coating is a barrier applied to oral medication that controls the location in the digestive system, where it is absorbed. Enteric refers to the small intestine, therefore enteric coatings prevent release of medication before it reaches the small intestine.Most enteric coatings work by...

s of pharmaceutical pills and nutritional supplements to viscosity
Viscosity
Viscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity...

 control agents, gelling agents, film formers, stabilizer
Stabilizer (chemistry)
In chemistry a stabilizer is a chemical which tends to inhibit the reaction between two or more other chemicals. It can be thought of as the antonym to a catalyst...

s, dispersant
Dispersant
A dispersant or a dispersing agent or a plasticizer or a superplasticizer is either a non-surface active polymer or a surface-active substance added to a suspension, usually a colloid, to improve the separation of particles and to prevent settling or clumping...

s, lubricant
Lubricant
A lubricant is a substance introduced to reduce friction between moving surfaces. It may also have the function of transporting foreign particles and of distributing heat...

s, binders, emulsifying agents, and suspending agents. End-applications include adhesives and glues, agricultural adjuvants, building materials, personal-care products, medical devices, detergents and surfactants, packaging, children's toys, modelling clay
Modelling clay
You can use modelling clay to create items with it. The material compositions and production processes vary considerably. -Ceramic clay:...

, waxes, paints, printing inks and coatings, pharmaceuticals, food products, and textiles. Phthalates are also frequently used in soft plastic fishing lures, caulk, paint
Paint
Paint is any liquid, liquefiable, or mastic composition which after application to a substrate in a thin layer is converted to an opaque solid film. One may also consider the digital mimicry thereof...

 pigments, and sex toys made of so-called "jelly rubber". Phthalates are used in a variety of household applications such as shower curtains, vinyl upholstery, adhesives, floor tiles, food containers and wrappers, and cleaning materials. Personal-care items containing phthalates include perfume, eye shadow, moisturizer, nail polish, liquid soap, and hair spray.
They are also found in modern electronics and medical applications such as catheters and blood transfusion devices. The most widely used phthalates are the di-2-ethyl hexyl phthalate (DEHP), the diisodecyl phthalate
Diisodecyl phthalate
Diisodecyl phthalate is a commonly used plasticizer used in the production of plastic and plastic coating to increase flexibility...

 (DIDP), and the diisononyl phthalate (DINP). DEHP is the dominant plasticizer used in PVC
PVC
Polyvinyl chloride is a plastic.PVC may also refer to:*Param Vir Chakra, India's highest military honor*Peripheral venous catheter, a small, flexible tube placed into a peripheral vein in order to administer medication or fluids...

 due to its low cost. Benzylbutylphthalate (BBP) is used in the manufacture of foamed PVC, which is mostly used as a flooring material. Phthalates with small R and R' groups are used as solvent
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...

s in perfume
Perfume
Perfume is a mixture of fragrant essential oils and/or aroma compounds, fixatives, and solvents used to give the human body, animals, objects, and living spaces "a pleasant scent"...

s and pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...

s.

Globally, approximately six million tonnes of plasticisers are consumed every year, of which European consumption accounts for approximately 1 million tonneshttp://Globally,%20approximately%20six%20million%20tonnes%20of%20plasticisers%20are%20consumed%20every%20year,%20of%20which%20European%20consumption%20accounts%20for%20approximately%201%20million%20tonnes. They contribute 10-60% of plastic products by weight. More recently in Europe, regulatory developments have resulted in a change in phthalate consumption, with the higher phthalates (DINP and DIDP) replacing DEHP as the plasticiser of choice owing to the fact that DIDP and DIP are not classified as hazardous. DEHP, although most applications are shown to pose no risk when studied using recognsied methods of risk assessment, has been classified as a Category 1A reprotoxin and is now on the Annex XIV of the EU REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) legislation which means that producers and users will need to submit authorisation requests to the European Chemicals Agency in Helsinki to continue to use DEHP. Analysis of such applications will involve studies on alternatives and, given the wide number of compounds that have been used as plasticisers, such eveluations are likely to be far reaching.

History


The development of cellulose nitrate in 1846 led to the patent of castor oil
Castor oil
Castor oil is a vegetable oil obtained from the castor bean . Castor oil is a colorless to very pale yellow liquid with mild or no odor or taste. Its boiling point is and its density is 961 kg/m3...

 in 1856 for use as the first plasticizer. In 1870, camphor
Camphor
Camphor is a waxy, white or transparent solid with a strong, aromatic odor. It is a terpenoid with the chemical formula C10H16O. It is found in wood of the camphor laurel , a large evergreen tree found in Asia and also of Dryobalanops aromatica, a giant of the Bornean forests...

 became the more favored plasticizer for cellulose nitrate. Phthalates were first introduced in the 1920s and quickly replaced the volatile and odorous camphor. In 1931, the commercial availability of polyvinyl chloride and the development of di-2-ethylhexyl phthalate began the boom of the plasticizer PVC
PVC
Polyvinyl chloride is a plastic.PVC may also refer to:*Param Vir Chakra, India's highest military honor*Peripheral venous catheter, a small, flexible tube placed into a peripheral vein in order to administer medication or fluids...

 industry.

Properties



Phthalate ester
Ester
Esters are chemical compounds derived by reacting an oxoacid with a hydroxyl compound such as an alcohol or phenol. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH group is replaced by an -O-alkyl group, and most commonly from carboxylic acids and...

s are the dialkyl or alkyl aryl
Aryl
In the context of organic molecules, aryl refers to any functional group or substituent derived from an aromatic ring, be it phenyl, naphthyl, thienyl, indolyl, etc....

 esters of phthalic acid
Phthalic acid
Phthalic acid is an aromatic dicarboxylic acid, with formula C6H42. It is an isomer of isophthalic acid and terephthalic acid. Although phthalic acid is of modest commercial importance, the closely related derivative phthalic anhydride is a commodity chemical produced on a large...

 (also called 1,2-benzenedicarboxylic acid, not be confused with the structurally isomeric terephthalic
Terephthalic acid
Terephthalic acid is the organic compound with formula C6H42. This colourless solid is a commodity chemical, used principally as a precursor to the polyester PET, used to make clothing and plastic bottles. Several billion kilograms are produced annually...

 or isophthalic
Isophthalic acid
Isophthalic acid is an organic compound with the formula C6H42. This colourless solid is an isomer of phthalic acid and terephthalic acid. These aromatic dicarboxylic acids are used as precursors to commercially important polymers, e.g. the fire-resistant material Nomex...

 acids ); the name phthalate derives from phthalic acid
Phthalic acid
Phthalic acid is an aromatic dicarboxylic acid, with formula C6H42. It is an isomer of isophthalic acid and terephthalic acid. Although phthalic acid is of modest commercial importance, the closely related derivative phthalic anhydride is a commodity chemical produced on a large...

, which itself is derived from word "naphthalene
Naphthalene
Naphthalene is an organic compound with formula . It is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromatic hydrocarbon, naphthalene's structure consists of a fused pair of benzene rings...

". When added to plastics, phthalates allow the long polyvinyl molecules to slide against one another. The phthalates have a clear syrupy liquid consistency and show low water solubility, high oil solubility, and low volatility. The polar carboxyl group contributes little to the physical properties of the phthalates, except when R and R' are very small (such as ethyl or methyl groups). They are colorless, odorless liquids produced by reacting phthalic anhydride
Phthalic anhydride
Phthalic anhydride is the organic compound with the formula C6H42O. It is the anhydride of phthalic acid. This colourless solid is an important industrial chemical, especially for the large-scale production of plasticizers for plastics. In 2002, approximately 4.6 billion kilograms were...

 with an appropriate alcohol
Alcohol
In 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....

 (usually 6- to 13-carbon).

The mechanism by which phthalates and other molecules afford plasticisation to polar polymers has been a subject of intense study since the 1960s. The mechanism is one of a polar interactions between the polar centres of the phthalate molecule (the C=O functionality) and the positively charged areas of the vinyl chain, typically residing on the carbon atom of the carbon-chlorine bond. In order for this to be established, the polymer needs to be heated in the presence of the plasticiser, first above the Tg of the polymer and then into a melt state. This enables an intimate mix of polymer and plasticiser to be formed, and for these interactions to occur. When cooled, these interactions remain and the network of PVC chains cannot reform (as is present in unplasticised PVC, or PVC-U). The alkyl chains of the phthalate then screen the PVC chains from each other as well. This explains why small changes in the length of these chains produce small changes in the level of plasticisation.

Table of the most common phthalates

Name Acronym Structural formula
Structural formula
The structural formula of a chemical compound is a graphical representation of the molecular structure, showing how the atoms are arranged. The chemical bonding within the molecule is also shown, either explicitly or implicitly...

CAS No.
CAS registry number
CAS Registry Numbersare unique numerical identifiers assigned by the "Chemical Abstracts Service" toevery chemical described in the...

Dimethyl phthalate
Dimethyl phthalate
Dimethyl phthalate is a phthalate with molecular formula 2. It is the methyl ester of phthalic acid.Dimethyl phthalate is an ectoparasiticide and has many other uses, including in solid rocket propellants, plastics, and insect repellents....

DMP C6H4(COOCH3)2 131-11-3
Diethyl phthalate
Diethyl phthalate
Diethyl phthalate is a phthalate ester, namely the diethyl ester of phthalic acid. It is a clear substance that is liquid at room temperature and which does not occur in nature. It has a faint, disagreeable odor and can be transferred from the plastics that contain it...

DEP C6H4(COOC2H5)2 84-66-2
Diallyl phthalate DAP C6H4(COOCH2CH=CH2)2 131-17-9
Di-n-propyl phthalate DPP C6H4[COO(CH2)2CH3]2 131-16-8
Di-n-butyl phthalate
Dibutyl phthalate
Dibutyl phthalate is a commonly used plasticizer. It is also used as an additive to adhesives or printing inks. It is soluble in various organic solvents, e.g. in alcohol, ether and benzene...

DBP C6H4[COO(CH2)3CH3]2 84-74-2
Diisobutyl phthalate
Diisobutyl phthalate
Diisobutyl Phthalate is prepared by esterification process of isobutanol and phthalic anhydride. Its structural formula is C6H42. Refractive index is 1.488 - 1.492 ....

DIBP C6H4[COOCH2CH(CH3)2]2 84-69-5
Butyl cyclohexyl phthalate BCP CH3(CH2)3OOCC6H4COOC6H11 84-64-0
Di-n-pentyl phthalate DNPP C6H4[COO(CH2)4CH3]2 131-18-0
Dicyclohexyl phthalate DCP C6H4[COOC6H11]2 84-61-7
Butyl benzyl phthalate BBP CH3(CH2)3OOCC6H4COOCH2C6H5 85-68-7
Di-n-hexyl phthalate DNHP C6H4[COO(CH2)5CH3]2 84-75-3
Diisohexyl phthalate DIHxP C6H4[COO(CH2)3CH(CH3)2]2 146-50-9
Diisoheptyl phthalate
Diisoheptyl phthalate
Diisoheptyl phthalate is a phthalate used as a plasticizer. Diisoheptyl phthalate is typically a mixture of chemical compounds consisting of various isoheptyl esters of phthalic acid with the chemical formula C22H34O4....

DIHpP C6H4[COO(CH2)4CH(CH3)2]2 41451-28-9
Butyl decyl phthalate BDP CH3(CH2)3OOCC6H4COO(CH2)9CH3 89-19-0
Di(2-ethylhexyl) phthalate DEHP, DOP C6H4[COOCH2CH(C2H5)(CH2)3CH3]2 117-81-7
Di(n-octyl) phthalate DNOP C6H4[COO(CH2)7CH3]2 117-84-0
Diisooctyl phthalate DIOP C6H4[COO(CH2)5CH(CH3)2]2 27554-26-3
n-Octyl n-decyl phthalate ODP CH3(CH2)7OOCC6H4COO(CH2)9CH3 119-07-3
Diisononyl phthalate DINP C6H4[COO(CH2)6CH(CH3)2]2 28553-12-0
Di(2-Propyl Heptyl) phthalate DPHP C6H4[COOCH2CH(CH2CH2CH3)(CH2)4CH3]2 53306-54-0
Diisodecyl phthalate
Diisodecyl phthalate
Diisodecyl phthalate is a commonly used plasticizer used in the production of plastic and plastic coating to increase flexibility...

DIDP C6H4[COO(CH2)7CH(CH3)2]2 26761-40-0
Diundecyl phthalate DUP C6H4[COO(CH2)10CH3]2 3648-20-2
Diisoundecyl phthalate DIUP C6H4[COO(CH2)8CH(CH3)2]2 85507-79-5
Ditridecyl phthalate DTDP C6H4[COO(CH2)12CH3]2 119-06-2
Diisotridecyl phthalate DIUP C6H4[COO(CH2)10CH(CH3)2]2 68515-47-9

Exposure


Phthalates are easily released into the environment because there is no covalent bond
Covalent bond
A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. The stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding....

 between the phthalates and plastic
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...

s in which they are mixed. As plastics age and break down, the release of phthalates accelerates. Phthalates in the environment are subject to biodegradation
Biodegradation
Biodegradation or biotic degradation or biotic decomposition is the chemical dissolution of materials by bacteria or other biological means...

, photodegradation
Photodegradation
Photodegradation is degradation of a photodegradable molecule caused by the absorption of photons, particularly those wavelengths found in sunlight, such as infrared radiation, visible light, and ultraviolet light. However, other forms of electromagnetic radiation can cause photodegradation...

, and anaerobic degradation; therefore, in general, they do not persist in the outdoor environment. Outdoor air concentrations are higher in urban
City
A city is a relatively large and permanent settlement. Although there is no agreement on how a city is distinguished from a town within general English language meanings, many cities have a particular administrative, legal, or historical status based on local law.For example, in the U.S...

 and suburb
Suburb
The word suburb mostly refers to a residential area, either existing as part of a city or as a separate residential community within commuting distance of a city . Some suburbs have a degree of administrative autonomy, and most have lower population density than inner city neighborhoods...

an areas than in rural and remote areas.

In general, indoor air concentrations are higher than outdoor air concentrations due to the nature of the sources. Because of their volatility
Volatility (chemistry)
In chemistry and physics, volatility is the tendency of a substance to vaporize. Volatility is directly related to a substance's vapor pressure. At a given temperature, a substance with higher vapor pressure vaporizes more readily than a substance with a lower vapor pressure.The term is primarily...

, DEP
Diethyl phthalate
Diethyl phthalate is a phthalate ester, namely the diethyl ester of phthalic acid. It is a clear substance that is liquid at room temperature and which does not occur in nature. It has a faint, disagreeable odor and can be transferred from the plastics that contain it...

 and DMP
Dimethyl phthalate
Dimethyl phthalate is a phthalate with molecular formula 2. It is the methyl ester of phthalic acid.Dimethyl phthalate is an ectoparasiticide and has many other uses, including in solid rocket propellants, plastics, and insect repellents....

 are present in higher concentrations in air in comparison with the heavier and less volatile DEHP
Bis(2-ethylhexyl) phthalate
Bisphthalate, commonly abbreviated DEHP, is an organic compound with the formula C6H42. It is sometimes called dioctyl phthalate and abbreviated DOP. It is the most important "phthalate," being the diester of phthalic acid and the branched-chain 2-ethylhexanol. This colourless viscous liquid is...

. Higher air temperatures result in higher concentrations of phthalates in the air. PVC
PVC
Polyvinyl chloride is a plastic.PVC may also refer to:*Param Vir Chakra, India's highest military honor*Peripheral venous catheter, a small, flexible tube placed into a peripheral vein in order to administer medication or fluids...

 flooring leads to higher concentrations of BBP and DEHP, which are more prevalent in dust.

People are commonly exposed to phthalates, and most Americans tested by the Centers for Disease Control and Prevention
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...

 have metabolite
Metabolite
Metabolites are the intermediates and products of metabolism. The term metabolite is usually restricted to small molecules. A primary metabolite is directly involved in normal growth, development, and reproduction. Alcohol is an example of a primary metabolite produced in large-scale by industrial...

s of multiple phthalates in their urine. Because phthalate plasticizers are not chemically bound to PVC, they can easily leach and evaporate into food or the atmosphere. Phthalate exposure can be through direct use or by indirect means through leaching and general environmental contamination. Diet
Diet (nutrition)
In nutrition, diet is the sum of food consumed by a person or other organism. Dietary habits are the habitual decisions an individual or culture makes when choosing what foods to eat. With the word diet, it is often implied the use of specific intake of nutrition for health or weight-management...

 is believed to be the main source of DEHP and other phthalates in the general population. Fatty foods such as milk, butter, and meats are a major source. Low-molecular-weight phthalates such as DEP, DBP, BBzP may be dermally absorbed. Inhalational exposure is also significant with the more volatile phthalates.

In a 2008 Bulgarian study, higher dust concentrations of DEHP were found in homes of children with asthma and allergies, compared with healthy children's homes. The author of the study stated, "The concentration of DEHP was found to be significantly associated with wheezing in the last 12 months as reported by the parents." Phthalates were found in almost every sampled home in Bulgaria. The same study found that DEHP, BBzP, and DnOP were in significantly higher concentrations in dust samples collected in homes where polishing agents were used. Data on flooring materials was collected, but there was not a significant difference in concentrations between homes where no polish was used that have balatum (PVC or linoleum) flooring and homes with wood. High frequency of dusting did decrease the concentration.

In general, children's exposure to phthalates is greater than that of adults. In a 1990s Canadian study that modeled ambient exposures, it was estimated that daily exposure to DEHP was 9 μg / kg bodyweight / day in infants, 19 μg / kg bodyweight / day in toddlers, 14 μg / kg bodyweight / day in children, and 6 μg / kg bodyweight/day in adults. Infants and toddlers are at the greatest risk of exposure, because of their mouthing behavior. Body-care products containing phthalates are a source of exposure for infants. The authors of a 2008 study "observed that reported use of infant lotion, infant powder, and infant shampoo were associated with increased infant urine concentrations of [phthalate metabolites], and this association is strongest in younger infants. These findings suggest that dermal exposures may contribute significantly to phthalate body burden in this population." Though they did not examine health outcomes, they noted that "Young infants are more vulnerable to the potential adverse effects of phthalates given their increased dosage per unit body surface area, metabolic capabilities, and developing endocrine and reproductive systems."

Infants and hospitalized children are particularly susceptible to phthalate exposure. Medical devices and tubing may contain 20-40% Di-2-ethylhexyl phthalate (DEHP) by weight, which “easily leach out of tubing when heated (as with warm saline/blood)”. Several medical devices contain phthalates including, but not limited to, IV tubing, gloves, nasogastric tubes and respiratory tubing. The Food and Drug Administration did an extensive risk assessment of phthalates in the medical setting and found that neonates may be exposed to five times greater than the allowed daily tolerable intake. This finding led to the conclusion by the FDA that, “Children undergoing certain medical procedures may represent a population at increased risk for the effects of DEHP.”

In 2008, the Danish Environmental Protection Agency (EPA) found a variety of phthalates in eraser
Eraser
An eraser or rubber is an article of stationery that is used for rubbing out pencil markings. Erasers have a rubbery consistency and are often white or pink, although modern materials allow them to be made in any color. Many pencils are equipped with an eraser on one end...

s and warned of health risks when children regularly suck and chew on them. The European Commission Scientific Committee on Health and Environmental Risks
Scientific Committee on Health and Environmental Risks
The Scientific Committee on Health and Environmental Risks is one of the independent scientific committees managed by the Directorate-General for Health and Consumer Protection of the European Commission, which provide scientific advice to the Commission on issues related to consumer products.-...

 (SCHER), however, considers that, even in the case when children bite off pieces from erasers and swallow them, it is unlikely that this exposure leads to health consequences.

Phthalates are also found in medications, where they are used as inactive ingredients in producing enteric coating
Enteric coating
An enteric coating is a barrier applied to oral medication that controls the location in the digestive system, where it is absorbed. Enteric refers to the small intestine, therefore enteric coatings prevent release of medication before it reaches the small intestine.Most enteric coatings work by...

s. It is not known how many medications are made using phthalates, but some include omeprazole
Omeprazole
Omeprazole is a proton pump inhibitor used in the treatment of dyspepsia, peptic ulcer disease , gastroesophageal reflux disease , laryngopharyngeal reflux and Zollinger–Ellison syndrome...

, didanosine
Didanosine
Didanosine is sold under the trade names Videx and Videx EC. It is a reverse transcriptase inhibitor, effective against HIV and used in combination with other antiretroviral drug therapy as part of highly active antiretroviral therapy .-History:The related pro-drug of didanosine,...

, mesalamine
Mesalazine
Mesalazine , also known as Mesalamine or 5-aminosalicylic acid , is an anti-inflammatory drug used to treat inflammation of the digestive tract ulcerative colitis and mild-to-moderate Crohn's disease...

, and theophylline
Theophylline
Theophylline, also known as dimethylxanthine, is a methylxanthine drug used in therapy for respiratory diseases such as COPD and asthma under a variety of brand names. Because of its numerous side-effects, the drug is now rarely administered for clinical use. As a member of the xanthine family, it...

. A recent study found that urinary concentrations of monobutyl phthalate, the DBP metabolite, of mesalamine users was 50 times higher than the mean of nonusers (some formulations of mesalamine do not contain phthalates). The study showed that exposures from phthalate-containing medications can far exceed population levels from other sources. DBP in medications raises concern about health risks due to the high level of exposures associated with taking these medications, especially in vulnerable segments of the population, including pregnant women and children.

In 2008, the United States National Research Council
United States National Research Council
The National Research Council of the USA is the working arm of the United States National Academies, carrying out most of the studies done in their names.The National Academies include:* National Academy of Sciences...

 recommended that the cumulative effects of phthalates and other antiandrogens be investigated. It criticized US EPA guidances, which stipulate that, when examining cumulative effects, the chemicals examined should have similar mechanisms of action or similar structures, as too restrictive. It recommended instead that the effects of chemicals that cause similar adverse outcomes should be examined cumulatively. Thus, the effect of phthalates should be examined together with other antiandrogens, which otherwise may have been excluded because their mechanisms or structure are different.

Studies of girls have found correlations between precocious puberty
Precocious puberty
As a medical term, precocious puberty describes puberty occurring at an unusually early age. In most of these children, the process is normal in every respect except the unusually early age, and simply represents a variation of normal development. In a minority of children, the early development is...

 and exposure to phthalates, although a single study reported no link and concluded differently.

Much of the current research on effects of phthalate exposure has been focused towards children and men’s health, however, women may be at higher risk for potential adverse health effects of phthalates due to increased cosmetic use. Diethyl phthalate and dibutyl phthalate are especially ubiquitous in cosmetics
Cosmetics
Cosmetics 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...

 and personal care products. According to in vivo and observational studies by Davis et al. (1994) and Lopez-Carillo et al. (2010), there is an association between phthalate exposure and endocrine disruption leading to development of breast cancer. Furthermore, it has been well documented that endocrine disruptors such as phthalates can be additive, so even very small amounts can interact with other chemicals to have cumulative, adverse “cocktail effects” Though the number of studies on phthalate and breast cancer is limited, this should not be reason enough to allow their use in personal care products.

Phthalate parent compounds and/or their metabolites have recently been implicated as a cause of breast cancer (BC). A 2010 study published in Environmental Health Perspectives for the first time implicated that the exposure to diethyl phthalates (DEP), a parent compound of the monoethyl phthalate (MEP) metabolite, may be associated with increased risk of BC (Odds Ratio of 2.20, p value for trend, p<0.003). The case-control study was age matched to 233 BC cases residing in northern Mexico. The phthalate level was determined in urine samples collected pretreatment from the cases. This is only a preliminary finding therefore additional research is required. Interestingly, exposure to the parent phthalate, butylbenzyl phthalate (BBzP) of the monobenzyl phthalate (MBzP) metabolite showed a negative association with breast cancer (Odds ratio=0.46, p value for trend, p<.008). This finding may be associated with the demethylation of the estrogen receptor complex in breast cancer cells of this particular phthalate resulting in a negative effect. This explanation will require further confirmatory research since confounders may be playing an unknown role. It is also known that DEP is found in a high proportion of personal care products, deodorants and perfumes whereas in contrast, BBzP is not detected in most deodorants and hair products and in less than one-third of all products tested , so degree of exposure may also be influencing results. A higher phthalate tertile (microgram/g creatinine) of DEP/MEP was compared to a lower phthalate tertile of BBzP/MBzP in this study.

In most cases of breast cancer the cause is unknown and less than 25% of patients have a history of commonly associated risk factors. such as: early menarche, later age at first childbirth, nulliparity, family history of BC, or history of benign breast biopsy Environmental and genetic factors may play a role in breast cancer and should be evaluated by conducting further research.

Endocrine disruption


In studies of rodents exposed to certain phthalates, high doses have been shown to change hormone levels and cause birth defects. A recent British study showed that the phthalate di(n-butyl) phthalate (DBP) or its metabolite monobutyl phthalate (MBP) suppresses steroidogenesis by fetal-type Leydig cells in primates as in rodents.

In a study published in 2005, lead investigator Dr. Shanna Swan reported in the "Swan Study" that human phthalate exposure during pregnancy results in decreased anogenital distance
Anogenital distance
Anogenital distance is the distance from the anus to the genitalia, the base of the penis or vagina. It is considered medically significant for a number of reasons, in both humans and animals. It is regulated by dihydrotestosterone, which can be disrupted by phthalates common in plastics...

 among baby boys. In this study, phthalate metabolites were measured in urine samples collected from the pregnant women who gave birth to the infants. After birth, the genital features and anogenital distance of these women's babies were measured and correlated with the residue levels in the mother's urine. Boys born to mothers with the highest levels of phthalates were 7 times more likely to have a shortened anogenital distance. An editorial
Editorial
An opinion piece is an article, published in a newspaper or magazine, that mainly reflects the author's opinion about the subject. Opinion pieces are featured in many periodicals.-Editorials:...

 concerning this paper in the same volume stated that the study population was small, and "needs to be investigated more thoroughly in a larger, more diverse population". While anogenital distance is routinely used as a measure of fetal exposure to endocrine disruptors in animals, this parameter is rarely assessed in humans, and its significance is unknown. One paper states that "Whether anogenital distance measurements in humans relate to clinically important outcomes remains to be determined," and a National Toxicology Program expert panel concluded that anogenital distance is a "'novel index' whose relevance in humans 'has not been established,'" and that there is "insufficient evidence in humans" that DEHP causes harm. The Swan study is thought by some to "suggest that male reproductive development in humans could be affected by prenatal exposure to environmentally relevant levels of phthalates". Authors of a more recent study of boys with undescended testis
Cryptorchidism
Cryptorchidism is the absence of one or both testes from the scrotum. It is the most common birth defect regarding male genitalia. In unique cases, cryptorchidism can develop later in life, often as late as young adulthood. About 3% of full-term and 30% of premature infant boys are born with at...

 hypothesized that exposure to a combination of phthalates and anti-androgenic pesticides may have contributed to that condition.

In contrast to the Swan study, an earlier study found that "adolescents exposed to significant quantities of DEHP as neonates showed no significant adverse effects on their physical growth and pubertal maturity." This study, however, examined children exposed intravenously to phthalate diesters, and intravenous exposure results in little metabolic conversion of the relatively nontoxic phthalate diester to its more toxic monoester metabolite.

In November 2009, Swan et al., in the International Journal of Andrology, in a paper titled "Prenatal phthalate exposure and reduced masculine play in boys",
"... suggest that prenatal exposure to antiandrogenic phthalates may be associated with less male-typical play behaviour in boys. ... [and] ... suggest that these ubiquitous environmental chemicals have the potential to alter androgen-responsive brain development in humans."

Other effects


There may be link between the obesity
Obesity
Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...

 epidemic and endocrine disruption and metabolic interference. Studies conducted on mice exposed to phthalates in utero did not result in metabolic disorder in adults. However, "in a national cross-section of U.S. men, concentrations of several prevalent phthalate metabolites showed statistically significant correlations with abnormal obesity and insulin resistance." Mono-ethyl-hexyl-phthalate, a metabolite of DEHP
Bis(2-ethylhexyl) phthalate
Bisphthalate, commonly abbreviated DEHP, is an organic compound with the formula C6H42. It is sometimes called dioctyl phthalate and abbreviated DOP. It is the most important "phthalate," being the diester of phthalic acid and the branched-chain 2-ethylhexanol. This colourless viscous liquid is...

, has been found to interact with all three peroxisome proliferator-activated receptors (PPARs). PPARs are members of the nuclear receptor superfamily. The author of the study stated "The roles of PPARs in lipid and carbohydrate metabolism raise the question of their activation by a sub-class of pollutants, tentatively named metabolic disrupters." Phthalates belong to this class of metabolic disruptors. It is a possibility that, over many years of exposure to these metabolic disruptors, they are able to deregulate complex metabolic pathways in a subtle manner.

Large amounts of specific phthalates fed to rodents have been shown to damage their liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

 and testes, and initial rodent studies also indicated hepatocarcinogenicity
Liver cancer
Liver tumors or hepatic tumors are tumors or growths on or in the liver . Several distinct types of tumors can develop in the liver because the liver is made up of various cell types. These growths can be benign or malignant...

. Following this result, diethyl hexyl phthalate
Bis(2-ethylhexyl) phthalate
Bisphthalate, commonly abbreviated DEHP, is an organic compound with the formula C6H42. It is sometimes called dioctyl phthalate and abbreviated DOP. It is the most important "phthalate," being the diester of phthalic acid and the branched-chain 2-ethylhexanol. This colourless viscous liquid is...

 was listed as a possible carcinogen
Carcinogen
A carcinogen is any substance, radionuclide, or radiation that is an agent directly involved in causing cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes...

 by IARC
International Agency for Research on Cancer
The International Agency for Research on Cancer is an intergovernmental agency forming part of the World Health Organisation of the United Nations....

, EC, and WHO
Who
Who may refer to:* Who , an English-language pronoun* who , a Unix command* Who?, one of the Five Ws in journalism- Art and entertainment :* Who? , a 1958 novel by Algis Budrys...

. Later studies on primates showed that the mechanism is specific to rodents - humans are resistant to the effect. The carcinogen classification was subsequently withdrawn.

In 2004, a joint Swedish-Danish epidemiologic team found a link between allergies in children and the phthalates DEHP
Bis(2-ethylhexyl) phthalate
Bisphthalate, commonly abbreviated DEHP, is an organic compound with the formula C6H42. It is sometimes called dioctyl phthalate and abbreviated DOP. It is the most important "phthalate," being the diester of phthalic acid and the branched-chain 2-ethylhexanol. This colourless viscous liquid is...

 and BBzP. Their review article
Review article
Review articles are an attempt to summarize the current state of understanding on a topic. They analyze or discuss research previously published by others, rather than reporting new experimental results....

 and meta-analysis
Meta-analysis
In statistics, a meta-analysis combines the results of several studies that address a set of related research hypotheses. In its simplest form, this is normally by identification of a common measure of effect size, for which a weighted average might be the output of a meta-analyses. Here the...

 of published data relating to phthalates and asthma found an association between phthalates in the home and asthma, especially in children, but this evidence was limited by imprecise data on levels of exposure.

In 2007, a cross-sectional study
Cross-sectional study
Cross-sectional studies form a class of research methods that involve observation of all of a population, or a representative subset, at one specific point in time...

 of U.S. males concluded that urine concentrations of four phthalate metabolites correlate with waist size and three phthalate metabolites correlate with the cellular resistance to insulin
Insulin
Insulin is a hormone central to regulating carbohydrate and fat metabolism in the body. Insulin causes cells in the liver, muscle, and fat tissue to take up glucose from the blood, storing it as glycogen in the liver and muscle....

, a precursor to Type II diabetes. The authors note the need for follow-up longitudinal studies
Longitudinal study
A longitudinal study is a correlational research study that involves repeated observations of the same variables over long periods of time — often many decades. It is a type of observational study. Longitudinal studies are often used in psychology to study developmental trends across the...

, as waist size is known to correlate with insulin resistance.

A 2009 study published in the Journal of Pediatrics found that prenatal phthalate exposure was related to low birth weight in infants. Low birth weight is the leading cause of death in children under 5 years of age and increases the risk of cardiovascular and metabolic disease in adulthood. Researchers at the University of Michigan School of Public Health found that women who deliver prematurely have, on average, up to three times the phthalate level in their urine compared to women who carry to term.

In 2009, South Korean scientists reported findings of a statistically-significant correlation between urine phthalate concentrations in children and symptoms of ADHD. Although more research is needed in order to conclusively determine the relationship between phthalate and ADHD, the article suggests that consumers should be aware of its potential effects on behavior and neurological disorders. The findings were replicated in The Mount Sinai Children's Environmental Health Study, which enrolled a multiethnic prenatal population in New York City between 1998 and 2002 (n= 404), published in Jan 2010. There was an association of prenatal phthalate exposure with offspring behavior and executive functioning at ages 4 to 9 years.

Alternatives


Currently, there are few alternatives to phthalates in PVC.

Biological alternatives


There are numerous biological alternatives on the market. The problem is that they are typically expensive and not compatible as a primary plasticizer.

A plasticizer based on vegetable oil has been developed which uses single reactor synthesis and is compatible as a primary plasticizer. It is a ready substitute for dioctyl pthalate.

European Union


The use of some phthalates has been restricted in the European Union for use in children's toys since 1999. DEHP, BBP, and DBP are restricted for all toys; DINP, DIDP, and DNOP are restricted only in toys that can be taken into the mouth. The restriction states that the amount of phthalates may not be greater than 0.1% mass percent of the plasticized part of the toy. These phthalates are allowed at any concentration in other products and other phthalates are not restricted.

There are no other specific restrictions in the European Union, although draft proposals have been tabled for the inclusion of BBP, DEHP, and DBP on the Candidate list of Substances for Authorisation under REACH. The Dutch office of Greenpeace
Greenpeace
Greenpeace is a non-governmental environmental organization with offices in over forty countries and with an international coordinating body in Amsterdam, The Netherlands...

 UK sought to encourage the European Union
European Union
The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...

 to ban sex toys that contained phthalates.. This has now been done and DEHP, BBP and DBP are listed in Annex XIV of the REACH regulation (see above)

United States


In August 2008, the United States Congress
United States Congress
The United States Congress is the bicameral legislature of the federal government of the United States, consisting of the Senate and the House of Representatives. The Congress meets in the United States Capitol in Washington, D.C....

 passed and President George W. Bush
George W. Bush
George Walker Bush is an American politician who served as the 43rd President of the United States, from 2001 to 2009. Before that, he was the 46th Governor of Texas, having served from 1995 to 2000....

 signed the Consumer Product Safety Improvement Act
Consumer Product Safety Improvement Act
The Consumer Product Safety Improvement Act of 2008 is a United States law signed on August 14, 2008 by President George W. Bush. The legislative bill was known as HR 4040, sponsored by Congressman Bobby Rush . On December 19, 2007, the U.S. House approved the bill 407-0. On March 6, 2008, the U.S....

 (CPSIA), which became public law 110-314. Section 108 of that law specified that as of 10 February 2009, "it shall be unlawful for any person to manufacture for sale, offer for sale, distribute in commerce, or import into the United States any children’s toy or child care article that contains concentrations of more than 0.1 percent of" DEHP, DBP
Dibutyl phthalate
Dibutyl phthalate is a commonly used plasticizer. It is also used as an additive to adhesives or printing inks. It is soluble in various organic solvents, e.g. in alcohol, ether and benzene...

, or BBP
Benzyl butyl phthalate
Benzylbutylphthalate , also called n-butyl benzyl phthalate or benzyl butyl phthalate, is a phthalate, an ester of phthalic acid, benzyl alcohol and n-butanol. It comes under trade names e.g. Palatinol BB, Unimoll BB, Sicol 160, or Santicizer 160. It is mostly used as a plasticizer for PVC...

 and "it shall be unlawful for any person to manufacture for sale, offer for sale, distribute in commerce, or import into the United States any children’s toy that can be placed in a child’s mouth or child care article that contains concentrations of more than 0.1 percent of" DINP, DIDP, DnOP. Furthermore, the law requires the establishment of a permanent review board to determine the safety of other phthalates. Prior to this legislation, the Consumer Product Safety Commission had determined that voluntary withdrawals of DEHP and DINP from teethers, pacifiers, and rattles had eliminated the risk to children, and advised against enacting a phthalate ban.

Some phthalates were restricted in children's toys sold in California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

 starting in 2009.

Australia


In January 2010, the Australian Consumer Affairs Minister Craig Emerson announced a ban on items containing more than one per cent Diethylhexyl phthalate (DEHP) because of international research linking it to reproductive difficulties.

Identification in plastics


Phthalates are used in some but not all PVC
PVC
Polyvinyl chloride is a plastic.PVC may also refer to:*Param Vir Chakra, India's highest military honor*Peripheral venous catheter, a small, flexible tube placed into a peripheral vein in order to administer medication or fluids...

 formulations, and there are no specific labeling requirements for phthalates. PVC plastics are typically used for various containers and hard packaging, medical tubing, and bags, and are labelled "Type 3" for recycling reasons. However, the presence of phthalates rather than other plasticizers is not marked on PVC items. Only unplasticized PVC (uPVC), which is mainly used as a hard construction material, has no plasticizers. If a more accurate test is needed, chemical analysis, for example by gas chromatography or liquid chromatography, can establish the presence of phthalates.

Polyethylene terephthalate ethylene
Polyethylene terephthalate
Polyethylene terephthalate , commonly abbreviated PET, PETE, or the obsolete PETP or PET-P, is a thermoplastic polymer resin of the polyester family and is used in synthetic fibers; beverage, food and other liquid containers; thermoforming applications; and engineering resins often in combination...

 (PETE) is the main substance used to package bottled water
Bottled water
Bottled water is drinking water packaged in plastic or glass water bottles. Bottled water may be carbonated or not...

 and many sodas. Products containing PETE are labeled "Type 1" (with a "1" in the recycle triangle) for recycling purposes. Although the word "phthalate" appears in the name, PETE does not use phthalates as plasticizers. The terephthalate polymer PETE and the phthalate ester plasticizers are chemically different substances.
http://www.plasticsmythbuster.org/s_mythbuster/sec.asp?CID=1985&DID=8371 Despite this, however, a number of studies have found phthalates such as DEHP in bottled water and soda http://ehsehplp03.niehs.nih.gov/article/fetchArticle.action?articleURI=info%3Adoi%2F10.1289%2Fehp.0901253. One hypothesis is that these may have been introduced during plastics recycling. Several studies tested the liquids before they were bottled, in order to make sure the phthalates came from the bottles rather than already being in the water.

Detection in food products



In February 2009, the Joint Research Centre (JRC) of the European Commission published a review of methods to measure phthalates in food.

See also

  • Xenoestrogen
    Xenoestrogen
    Xenoestrogens are a type of xenohormone that imitates estrogen. They are widely used industrial compounds such as PCB, BPA and Phthalates, that have estrogenic effects on a living organism even though they differ chemically from the naturally occurring estrogenic substances internally produced by...

  • Non-phthalate plasticizers such as 1,2-Cyclohexane dicarboxylic acid diisononyl ester and Citrate
    Citrate
    A citrate can refer either to the conjugate base of citric acid, , or to the esters of citric acid. An example of the former, a salt is trisodium citrate; an ester is triethyl citrate.-Other citric acid ions:...

    s

Further reading


  • Swan, S.H. 2004. Phthalates in pregnant women and children. e.hormone 2004 conference. October 27–30. New Orleans.

Research


Sources suggesting low/no health risks

  • Phthalates Information Centre; an initiative of the European Council for Plasticisers and Intermediates (ECPI)
  • Phthalates Information Center; from the American Chemistry Council
    American Chemistry Council
    The American Chemistry Council , formerly known as the Manufacturing Chemists' Association and then as the Chemical Manufacturers' Association , is an industry trade association for American chemical companies, based in Washington, D.C.-Activities:The mission of the American Chemistry Council is...

    , Inc.
  • Phthalates and Human Health, by Kenneth Green, D.Env.; Director of the Environmental Program at Reason Public Policy Institute, Reason Foundation
    Reason Foundation
    The Reason Foundation is an American nonprofit think tank founded in 1978 that also publishes Reason magazine. Based in Los Angeles, Reason is self-described as nonpartisan and publishes a statement of values that can best be described as libertarian...

    , 2000

Media