Phthalates

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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 a group of chemical compounds that 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.

Phthalate esters are the dialkyl or alkyl aryl esters of 1,2-benzenedicarboxylic acid; the name phthalate derives from phthalic acid. 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 400,000 tons (one billion pounds or 363 millions kilograms) 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 nail polish, fishing lures, 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. The Dutch office of Greenpeace UK sought to encourage the European Union to ban sex toys that contained phthalates.[1]

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[edit] Health effects

Phthalates are controversial because 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, the kidneys, the lungs and the developing testes. On the other hand, one Japanese study involving juvenile primates (marmosets) did not observe testicular effects (Tomonari et al, The Toxicologist, 2003). Research published in 2006 by Joint Research Centre Institute for Health and Consumer Protection European Chemicals Bureau has found that two of the suspected dangerous phthalates banned by EU legislation - diisononyl phthalate (DINP) and diisodecyl phthalate (DIDP) - show no risks to human health or the environment for any current use.[citation needed]

2004 - a joint Swedish-Danish research team found a very strong link between allergies in children and the phthalates DEHP and BBzP.[2]

2004 - On the other hand, a study by Children's National Medical Center and George Washington University was found no adverse effects in adolescents who had been exposed to phthalates as neonates. The study measured both physical characteristics and chemical characteristics of the subjects.[3]

2005 - study reported that phthalates may mimic the female hormone oestrogen (see xenoestrogens), and cause "feminisation" of baby boys. Phthalates and Baby Boys: Potential Disruption of Human Genital Development. Barrett JR. Environ Health Perspect. 2005 Aug; 113(8): A542.

In the study by the University of Missouri in Columbia, urine samples were collected from pregnant women in four United States cities. All of the women were found to have levels of phthalate residues in their urine[citation needed]. 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.[4]There was also a correlation between heightened residue levels and smaller penis sizes. The testes of boys with smaller penises were more likely to have testes that didn't descend properly into the scrotum.

The reaction of the public to the results study has been criticized[5]by STATS, a non-profit research organization affiliated with George Mason University. Critics claim that the methodology used, including a small, homogeneous study group that was not pulled from a wide variety of regions, can not be used to definitively claim widespread problems related to phthalates. The criticism also states that the media overstated the findings in the report.

2006 - Two of the most commonly used phthalates (DINP and DIDP) are declared "safe" at current levels of use by EU research scientists.[6][7] Environmental impact, chronic and acute health effects in consumers (both adults and infants) and in chemical workers, have all been assessed and found to pose no risk. The rigorous EU risk assessments, which include a high degree of conservatism and built-in safety factors, have been carried out under the strict supervision of the European Commission and provide a clear scientific evaluation on which to judge whether or not a particular substance can be safely used. The research is the culmination of ten years of study into the suspect phthalates and goes against the previous conclusions and precautionary measures adopted by the EU government.

[edit] See also

[edit] References

  1. ^ http://www.news24.com/News24/World/News/0,,2-10-1462_1995778,00.html
  2. ^ 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. 
  3. ^ Khodayar Rais-Bahrami,1 Susan Nunez,2 Mary E. Revenis,1 Naomi L.C. Luban,3 and Billie L. Short (2004). "Follow-Up Study of Adolescents Exposed to Di(2-Ethylhexyl) Phthalate (DEHP) as Neonates on Extracorporeal Membrane Oxygenation (ECMO) Support". Environ Health Perspect 112 (14): 1393–1397. DOI:10.1289/ehp.6901. 
  4. ^ 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.
  5. ^ Rebecca Goldin Ph.D (2006-01-30). Toy Tantrums - The Debate Over the Safety of Phthalates. STATS.org. Retrieved on 2007-01-24.
  6. ^ 1,2-benzenedicarboxylic acid, di-c9-11 branched alkyl esthers, c10 rich, and Di-"isodectyl phthalate (DIDP) summary assesment report (pdf) 26. European commision joint research center (2003). Retrieved on 2007-01-25.
  7. ^ 1,2-benzenedicarboxylic acid, di-c8-10 branched alkyl esthers, c10 rich, and Di-"isodectyl phthalate (DIDP) summary assesment report (pdf) 26. European commision joint research center (2003). Retrieved on 2007-01-25.
  • 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. Oct. 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:<100::AID-AJIM10>3.0.CO;2-Q 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

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