Phthalate

From Wikipedia, the free encyclopedia

 This article may require cleanup to meet Wikipedia's quality standards.
Please improve this article if you can. (January 2007)
General chemical structure of phthalates. R and R' = CnH2n+1; n = 4-15
General chemical structure of phthalates. R and R' = CnH2n+1; n = 4-15

Phthalates, or phthalate esters, are esters of phthalic acid and are mainly used as plasticizers (substances added to plastics to increase their flexibility). They are chiefly used to turn polyvinyl chloride from a hard plastic into a flexible plastic.

Contents

[edit] Properties

Phthalate esters are the dialkyl or alkyl aryl esters of phthalic acid (also called 1,2-benzenedicarboxylic acid, not be confused with the isomeric terephthalic or isophthalic acids ); the name phthalate derives from phthalic acid, which itself is derived from word "naphthalene". When added to plastics, phthalates allow the long polyvinyl molecules to slide against one another. The phthalates 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 with an appropriate alcohol (usually 6 to 13 carbon).

As of 2004, manufacturers produce about 363 thousand metric tonnes (800 million pounds or 400 000 short tons) of phthalates each year. They were first produced during the 1920s, and have been produced in large quantities since the 1950s, when PVC was introduced. The most widely-used phthalates are di-2-ethyl hexyl phthalate (DEHP), diisodecyl phthalate (DIDP) and diisononyl phthalate (DINP). DEHP is the dominant plasticizer used in PVC, due to its low cost. Benzylbutylphthalate (BBzP) 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 solvents in perfumes and pesticides.

Phthalates are also frequently used in soft plastic fishing lures, nail polish, adhesives, caulk, paint pigments, and sex toys made of so-called "jelly rubber." Some vendors of jelly rubber sex toys advise covering them in condoms when used internally, due to the possible health risks. Other vendors do not carry jelly rubber sex toys, in favor of phthalate-free varieties.[1] The Dutch office of Greenpeace UK sought to encourage the European Union to ban sex toys that contained phthalates.[2]

Though controversial, phthalates are still being used in a variety of household applications (shower curtains, adhesives, perfume), modern pop-culture electronics and medical applications such as catheters. Notable recent examples include Apple Inc.'s iPhone and iPod, and personal computers. The company has been criticized by environmental supporters claiming that tests on a commercially-purchased iPhone returned "toxic" levels of the chemical, prompting public declarations for change due to its associated hazards.[3].

[edit] Table of more common phthalates

Name Acronym Structural formula CAS No.
Dimethyl phthalate DMP C6H4(COOCH3)2 131-11-3
Diethyl phthalate 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 DBP C6H4[COO(CH2)3CH3]2 84-74-2
Diisobutyl phthalate 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 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
Diisodecyl phthalate 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

[edit] Health effects

People are commonly exposed to phthalates, and the majority of Americans tested by the Centers for Disease Control and Prevention have metabolites of multiple phthalates in their urine. High doses of many phthalates have shown hormonal activity in rodent studies. Studies on rodents involving large amounts of phthalates have shown damage to the liver and testes and cause birth defects.[4] In addition, 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.[5]

Initial rodent studies on carcinogenity indicated hepatocarcinogenity. Following this result, diethyl hexyl phthalate was listed as a possible carcinogen by IARC, EC and WHO. Later studies on primates showed that the mechanism was specific to rodents - humans are resistant to the effect.[6] The carcinogen classification was subsequently withdrawn.

In 2004, a joint Swedish-Danish research team found a very strong link between allergies in children and the phthalates DEHP and BBzP.[7]

A 2005 study by Swan et al. reported that human phthalate exposure during pregnancy changed an anogenital measurement in the baby boys later born, a change that in rodents exposed to phthalates is associated with genital abnormalities. In this study urine samples were collected from pregnant women in four United States cities. All were found to have levels of phthalate residues in their urine. Upon birth of the children whose mother's urine had been previously measured, the genital features and anogenital distance were measured and correlated with the residue levels in the mother's urine. In boys, the highest levels of residue were seven times more likely to have a shortened anogenital distance.[8] The science behind this study was questioned by chemical industry advocates,[9] 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.[10] As of June, 2008, there have only been 5 published studies in which this distance was measured in male infants, and none of these studies addressed reproduction.[11] recent study of anogenital distance states "Whether anogenital distance measurements in humans relate to clinically important outcomes, however, remains to be determined".[12]

The reporting by the media of the Swan study has been criticized by STATS.[13] They claim that the methodology used, including a small, homogeneous study group that was not pulled from a wide variety of regions, cannot be used to definitively claim widespread problems related to phthalates. The criticism also states that the media overstated the findings in the report.

In addition, in a 2004 study by the Children's National Medical Center and The George Washington University School of Medicine in Washington, D.C, it was found that "adolescents exposed to significant quantities of DEHP as neonates showed no significant adverse effects on their physical growth and pubertal maturity."[14]There was no correlation between heightened residue levels and smaller penis sizes. It should be noted, however, that this study examined children exposed intravenously to phthalate diester, and intravenous phthalate diester exposure results in relatively little metabolic conversion of the relatively nontoxic phthalate diester to its toxic metabolite (phthalate monoester).[15]

The authors of a study of Finnish boys with undescended testis hypothesized, based on their findings, that exposure to a combination of phthalates and anti-androgenic pesticides may have contributed to their condition.[16]

In 2007, a cross-sectional study of U.S. males conducted by researchers at Rochester School of Medicine and Dentistry concluded that urine concentrations of four phthalate metabolites correlate with waist size and three phthalate metabolites correlate with the cellular resistance to insulin, a precursor to Type II diabetes. The authors note the need for follow-up longitudinal studies,[17] as waist size is known to correlate with insulin resistance.

Research on phthalates in the environment published in 2008 reported that baby care products containing phthalates are source of exposure for infants. The authors "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."[18]

[edit] Legal status

[edit] United States

 Please help improve this article or section by expanding it.
Further information might be found on the talk page or at requests for expansion. (March 2008)

Some phthalates will be restricted in the U.S. state of California (for children's toys) starting in 2009.[19] In Connecticut, state legislators are considering a bill that would ban phthalates in children's products.[20]

[edit] European Union

The use of some phthalates is restricted in the European Union for use in children's toys.[21] 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.

There are no other specific restrictions in the European Union, and the phthalates mentioned are allowed in any concentration in other products. Other phthalates are not restricted.

[edit] Identification in plastics

Some type 3 plastics may leach phthalates
Some type 3 plastics may leach phthalates

PVC plastics - for recycling reasons are labelled "Type 3" - are typically used for various containers and hard packaging, medical tubing and bags may contain and leach phthalates.

[edit] See also

[edit] References

  1. ^ Sustainable Kink. A local couple explores the last eco-frontier: sex toys. by Ethan Smith, "Willamette Week" 18 April 2007.
  2. ^ News24
  3. ^ Greenpeace
  4. ^ Third National Report on Human Exposure to Environmental Chemicals, U.S. CDC, July 2005.
  5. ^ Hallmark N, Walker M, McKinnell C, Mahood IK, Scott H, Bayne R, Coutts S, Anderson RA, Greig I, Morris K, Sharpe RM. (2007). "Effects of monobutyl and di(n-butyl) phthalate in vitro on steroidogenesis and Leydig cell aggregation in fetal testis explants from the rat: comparison with effects in vivo in the fetal rat and neonatal marmoset and in vitro in the human.". Environ Health Perspect. 115 (3): 390-6.. 
  6. ^ http://www.cpsc.gov/library/foia/foia01/os/dinp.pdf p. 87.
  7. ^ C.-G. Bornehag, J. Sundell, C. J. Weschler, T. Sigsgaard, B. Lundgren, M. Hasselgren, L. Hägerhed-Engman (2004). "The Association between Asthma and Allergic Symptoms in Children and Phthalates in House Dust: A Nested Case–Control Study". Environ Health Perspect. 112 (13): 1319–1340. doi:10.1289/ehp.7187. 
  8. ^ Swan, S.H. et al. 2005. PMID 16079079 An overview of this paper is given in the same volume: Julia R. Barrett, Phthalates and Baby Boys: Potential Disruption of Human Genital Development, Environ Health Perspect. 2005 Aug; 113(8): A542. [1]
  9. ^ McEwen, GN. Validity of anogenital distance as a marker of in vitro phthalate exposure. Retrieved on 2008-02-06.PMID 16393642
  10. ^ Kaiser J. Toxicology. Panel finds no proof that phthalates harm infant reproductive systems Science 2005 Oct 21;310(5747):422 PMID 16239449
  11. ^ Postellon, Daniel C. (2008). "Baby Care Products" (letter). Pediatrics (6 (June)): 1292. 
  12. ^ Romano-Riquer SP, Hernández-Avila M, Gladen BC, Cupul-Uicab LA, Longnecker MP (2007). "Reliability and determinants of anogenital distance and penis dimensions in male newborns from Chiapas, Mexico". Paediatr Perinat Epidemiol 21 (3): 219–28. doi:10.1111/j.1365-3016.2007.00810.x. PMID 17439530. 
  13. ^ Rebecca Goldin Ph.D (2006-01-30). Toy Tantrums - The Debate Over the Safety of Phthalates. STATS.org. Retrieved on 2007-01-24.
  14. ^ Khodayar Rais-Bahram (9 2004). Follow-Up Study of Adolescents Exposed to Di(2-Ethylhexyl) Phthalate (DEHP) as Neonates on Extracorporeal Membrane Oxygenation (ECMO) Support (pdf) 2. Environmental Health Perspectives. Retrieved on 2007 - 01 - 25.
  15. ^ Huber WW, Grasl-Kraupp B, Schulte-Hermann R. (1996). "Hepatocarcinogenic potential of di(2-ethylhexyl)phthalate in rodents and its implications on human risk". Crit Rev Toxicol 26 (4): 365–481. PMID 8817083. 
  16. ^ Toppari J, Virtanen H, Skakkebaek NE, Main KM (2006). "Environmental effects on hormonal regulation of testicular descent". J Steroid Biochem Mol Biol 102 (1-5): 184-6. PMID 17049842. 
  17. ^ Stahlhut RW, van Wijngaarden E, Dye TD, Cook S, Swan SH. (2007). "Concentrations of urinary phthalate metabolites are associated with increased waist circumference and insulin resistance in adult u.s. Males". Environ Health Perspect 115 (6): 876-82. PMID 17589594. 
  18. ^ Sathyanarayana, Sheela. Baby Care Products:Possible sources of infant phthalate exposure PMID 18245401 (full text article). Retrieved on 2008-02-12.
  19. ^ California Bans Phthalates In Toys For Children, Bette Hileman, Chemical and Engineering News, OCT. 22, 2007, P. 12.
  20. ^ Weil, William (April 23, 2008), “Debate In A Bottle”, Hartford Courant, <http://www.courant.com/features/lifestyle/green/hc-bottled.art0apr23,0,5170837.story> .
  21. ^ EU Restrictions on the use of phthalates in toys, European Council for Plasticisers and Intermediates (ECPI)

[edit] Further reading

  • Hauser R, Meeker JD, Singh NP, et al (March 2007). "DNA damage in human sperm is related to urinary levels of phthalate monoester and oxidative metabolites". Hum. Reprod. 22 (3): 688–95. doi:10.1093/humrep/del428. PMID 17090632. 
  • Susan M. Duty, Narendra P. Singh, Manori J. Silva, Dana B. Barr, John W. Brock, Louise Ryan, Robert F. Herrick, David C. Christiani, and Russ Hauser (2003). "The relationship between environmental exposures to phthalates and DNA damage in human sperm using the neutral comet assay". Environmental Health Perspectives 111 (July): 1164-1169 Abstract. 
  • Shanna H. Swan, Katharina M. Main, Fan Liu, Sara L. Stewart, Robin L. Kruse, Antonia M. Calafat, Catherine S. Mao, J. Bruce Redmon, Christine L. Ternand, Shannon Sullivan, J. Lynn Teague, and the Study for Future Families Research Team (2005). "Decrease in anogenital distance among male infants with prenatal phthalate exposure". Environmental Health Perspectives In press: Abstract. 
  • Swan, S.H. 2004. Phthalates in pregnant women and children. e.hormone 2004 conference. October 27-30. New Orleans.
  • Swan, S.H. et al. 2005. Decrease in anogenital distance among male infants with prenatal phthalate exposure. Environmental Health Perspectives 113:1056--1061.
  • Barbara J. Davis, Tara Lovekamp-Swant (2003). "Mechanisms of Phthalate Ester Toxicity in the Female Reproductive System". Environmental Health Perspectives 111. doi:10.1289/ehp.5658. 
  • L. Earl Gray, Jr.*,1, Joseph Ostby*, Johnathan Furr*, Matthew Price*, D. N. Rao Veeramachaneni{dagger} and Louise Parks (2000). "Perinatal Exposure to the Phthalates DEHP, BBP, and DINP, but Not DEP, DMP, or DOTP, Alters Sexual Differentiation of the Male Rat". Toxicological Sciences 58: 350-365. 
  • Joel A. Tickner, ScD 1 *, Ted Schettler, MD, MPH 2, Tee Guidotti, MD, MPH 3, Michael McCally, MD, MPH 4, Mark Rossi, MA 5. "Health risks posed by use of Di-2-ethylhexyl phthalate (DEHP) in PVC medical devices: A critical review". American Journal of Industrial Medicine 39 (1): 100 - 111. doi:10.1002/1097-0274(200101)39:1<100::AID-AJIM10>3.0.CO;2-Q. 
  • Shanna H. Swan,1 Katharina M. Main,2 Fan Liu,3 Sara L. Stewart,3 Robin L. Kruse,3 Antonia M. Calafat,4 Catherine S. Mao,5 J. Bruce Redmon,6 Christine L. Ternand,7 Shannon Sullivan,8 and J. Lynn Teague9 (2005). "Decrease in Anogenital Distance among Male Infants with Prenatal Phthalate Exposure". Environmental Health Perspectives 113 (8): 1056–1061. doi:10.1289/ehp.8100. 
  • Michael C. Kohn; Frederick Parham; Scott A. Masten; Christopher J. Portier; Michael D. Shelby; John W. Brock; Larry L. Needham (2000). "Human Exposure Estimates for Phthalates". Environmental Health Perspectives 108 (10): A440-A442. 
  • Carl-Gustaf Bornehag,1,2,3 Jan Sundell,2 Charles J. Weschler,2,4 Torben Sigsgaard,5 Björn Lundgren,1 Mikael Hasselgren,3 and Linda Hägerhed-Engman1 (2004). "The Association between Asthma and Allergic Symptoms in Children and Phthalates in House Dust: A Nested Case–Control Study". Environmental Health Perspectives 112 (14): 1393–1397. doi:10.1289/ehp.7187. 
  • Richard W Stahlhut, Edwin van Wijngaarden, Timothy D Dye, Stephen Cook and Shanna H Swan (2007). "Concentrations of Urinary Phthalate Metabolites are Associated with Increased Waist Circumference and Insulin Resistance in Adult U.S. Males". Environmental Health Perspectives. doi:10.1289/ehp.9882. 

[edit] External links

[edit] Media

[edit] Research

[edit] Sources suggesting low/no health risks