Phthalates

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Leah Tait
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Managing Group: Chemicals Group


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Overview


Phthalates are a class of high-volume chemicals that are ubiquitous in the environment. They are plasticizers that, when added to plastics, impart a softening characteristic lending flexibility to the plastic. These water-insoluble, synthetic organic chemicals are usually added to polyvinyl chloride (PVC) plastics and have a wide expanse of uses, including in many common household items, cosmetics, and medical devices. As phthalates are not chemically bound to the plastics in which they are used, they can leach out into the environment.

Human exposure to phthalates begins in utero, and some levels of exposure are nearly unavoidable. Each year, more than 18 billion pounds of phthalates are used worldwide. (CDC). (#Latini et al 2008)

Uses


Phthalates are used as plasticizing agents to make rigid plastics into flexible vinyl (#Green, 2000). They are ubiquitously found in the environment. They are also listed as "inert" ingredients in many sprays including pesticides, cosmetics, and wood finishes.

Phthalates are found in:

  • PVC products
  • vinyl flooring
  • vinyl shower curtains
  • adhesives
  • detergents
  • lubricating oils
  • solvents
  • automotive plastics
  • soap
  • shampoo
  • deodorants
  • hair spray
  • plastic bags
  • garden hoses
  • inflatable recreational toys
  • blood storage bags
  • children's toys
  • perfumes
  • nail polish
  • lotions
  • IV bags
  • automobile interiors
  • our air, water, and soil due to industrial pollution and leaching from consumer products

Above from #Pollution in People Report and (CDC).

Metabolism


The way in which phthalates are metabolized is currently being widely investigated. Phthalates are thought to be disruptors of the endocrine system as anti-androgens. The mechanism appears to be by inhibiting the aromatase enzyme system.

(#Younglai 2007) (#Heudorf et al 2007)

Exposure


Phthalates are so widely used that some level of exposure is impossible to avoid. They are ubiquitous because of their extensive use at high concentrations and because of their ability to migrate from plastics. When used as plasticizers in PVC products, they can dissociate from the PVC and leach into the environment.

Humans are exposed to phthalates in multiple ways:

  • Food contaminated during production, processing, packaging, or storage
  • Cosmetics
  • Environmental exposure
  • Use of medical devices such as i.v. storage bags and tubing

Fetal and infant exposures are of special concern because some phthalates are considered developmental toxicants. Phthalates cross the placental barrier and are excreted in breast milk. Premature infants undergoing hospitalization are exposed to phthalates through medical devices as i.v. tubes, which contain high levels of phthalates.

(#Matsumoto 2008, #Younglai 2007)

Health Effects


Human studies have thus far been limited and inconclusive. There are numerous animal studies in which the health effects of phthalates have been well-documented. Animal studies are not a perfect analog to human health, but are currently the best source of information available regarding the health effects of phthalates.

In laboratory animals, phthalates and their metabolites produce reproductive and developmental toxicities.

Major toxic effects include:

  • Testicular effects
  • Reduced anogenital distance in males
  • Embryolethality
  • Fetal malformations such as cleft palate
  • Abnormal sexual differentiation

While the above toxic effects were found in laboratory animals, it is important to consider that androgen activity during sexual differentiation is well-conserved among mammals. Continued reviews of human exposure is necessary to determine what risks phthalates may pose to humans.

(#Matsumoto 2008)

Regulation


http://www.pvc-toys.com/restrictions
http://pubs.acs.org/cen/news/85/i43/8543news4.html
http://www.sci-tech-today.com/news/Greenpeace--Gaming-Too-Toxic/story.xhtml?story_id=11300DT7SGYT
http://www.prw.com/homePBP_NADetail_UP.aspx?ID_Site=818&ID_Article=24748&mode=1&curpage=0

Precaution


Phthalates are so widely used that to completely avoid them would be nearly impossible. However, it is possible to reduce exposure. Some phthalate-containing cosmetics can be identified through their ingredients list. Some toy companies have released phthalate-free toys and other children's products.

http://health.usnews.com/articles/health/2008/05/07/how-to-limit-your-exposure-to-phthalates.html


References


  • Heudorf U, Mersch-Sundermann V, Angerer J. 2007. Phthalates: toxicology and exposure. Int J Hyg Environ Health. 210(5):623-34.
  • Latini G, Scoditti E, Verrotti A, De Felice C, Massaro M. 2008. Peroxisome proliferator-activated receptors as mediators of phthalate-induced effects in the male and female reproductive tract: epidemiological and experimental evidence. PPAR Res. 2008:359267.
  • Matsumoto M, Hirata-Koizumi M, Ema M. 2008. Potential adverse effects of phthalic acid esters on human health: a review of recent studies on reproduction. Regul Toxicol Pharmacol. 50(1):37-49.
  • Younglai EV, Wu YJ, Foster WG. 2007. Reproductive toxicology of environmental toxicants: emerging issues and concerns. Curr Pharm Des.13(29):3005-19.
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