Dichlorodiphenyldichloroethylene

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Dichlorodiphenyldichloroethylene
Dichlorodiphenyldichloroethylene
Dichlorodiphenyldichloroethylene
Names
IUPAC name
1,1-bis-(4-chlorophenyl)-2,2-dichloroethene
Other names
Dichlorodiphenyldichloroethylene
Identifiers
3D model (JSmol)
Abbreviations p,p'-DDE
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.000.713
KEGG
Properties
C14H8Cl4
Molar mass 318.02 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Dichlorodiphenyldichloroethylene (DDE) is a chemical compound formed by the loss of hydrogen chloride (dehydrohalogenation) from DDT, of which it is one of the more common breakdown products.[1] Due to DDT’s massive prevalence in society and agriculture during the mid 20th century, DDT and DDE are still widely seen in animal tissue samples.[2] DDE is particularly dangerous because it is fat-soluble like other organochlorines; thus, it is rarely excreted from the body, and concentrations tend to increase throughout life. The major exception is the excretion of DDE in breast milk, which transfers a substantial portion of the mother's DDE burden to the young animal or child.[3] Along with accumulation over an organism's lifetime, this stability leads to bioaccumulation in the environment, which amplifies DDE’s negative effects.

Synthesis[edit]

DDE is created by dehydrohalogenation of DDT. The loss of HCl results in a double bond on the central (previously quaternary) carbon atoms.

Degradation of DDT to form DDE by an elimination of HCl

Toxicity[edit]

DDE has been shown to be toxic to rats at 79.6 mg/kg.[4] DDE and its parent, DDT, are reproductive toxicants for certain birds species, and major reasons for the decline of the bald eagle,[5] brown pelican[6] peregrine falcon, and osprey.[7] These compounds cause egg shell thinning in susceptible species, which leads to the birds’ crushing their eggs instead of incubating them, due to the latter’s lack of resistance.[8] Birds of prey, waterfowl, and song birds are more susceptible to eggshell thinning than chickens and related species, and DDE appears to be more potent than DDT.[7]

Mechanism[edit]

The biological mechanism for the thinning is not entirely known, but it is believed that p,p'-DDE impairs the shell gland's ability to excrete calcium carbonate onto the developing egg.[7][9][10][11][12] Multiple mechanisms may be at work, or different mechanisms may operate in different species.[7] Some studies have shown that although DDE levels have fallen dramatically, eggshell thickness remains 10–12 percent thinner than before DDT was first used.[13]

Some studies have indicated that DDE is an endocrine disruptor[14] and contributes to breast cancer, but more recent studies provide strong evidence that there is no relationship between DDE exposure and breast cancer.[15] What is more clear is that DDE is a weak androgen receptor antagonist and can produce male genital tract abnormalities.[16][17]

Animal studies show that organochlorine pesticides—such as DDE—are neurotoxic, cause oxidative stress, and damage the brain's dopaminergic system.[18]

See also[edit]

References[edit]

  1. ^ ATSDR - Public Health Statement: DDT, DDE, and DDD
  2. ^ Walker, K. C.; Goette, M. B.; Batchelor, G. S. (1954). "Pesticide Residues in Foods, Dichlorodiphenyltrichloroethane and Dichlorodiphenyldichloroethylene Content in Prepared Foods". Journal of Agricultural and Food Chemistry. 2: 1034–1037. doi:10.1021/jf60040a006.
  3. ^ Waliszewski, SM; Melo-Santiesteban, G; Villalobos-Pietrini, R; Gómez-Arroyo, S; Amador-Muñoz, O; Herrero-Mercado, M; Carvajal, O (2009). "Breast milk excretion Kinetic of b-HCH, pp'DDE and pp'DDT". Bull Environ Contam Toxicol. 83: 869–73. doi:10.1007/s00128-009-9796-3. PMID 19551328.
  4. ^ NIST DDE MSDS
  5. ^ Stokstad, E (2007). "Species conservation. Can the bald eagle still soar after it is delisted?". Science. 316 (5832): 1689–90. doi:10.1126/science.316.5832.1689. PMID 17588911.
  6. ^ "Endangered and Threatened Wildlife and Plants; 12-Month Petition Finding and Proposed Rule To Remove the Brown Pelican (Pelecanus occidentalis) From the Federal List of Endangered and Threatened Wildlife; Proposed Rule," Fish and Wildlife Service, U.S. Department of the Interior, February 20, 2008. 73 FR 9407
  7. ^ a b c d ATSDR - Toxicological Profile: DDT, DDE, DDD
  8. ^ California Wild Spring 1994 - Peregrine Falcons
  9. ^ Recovery Plan for the California Condor, U.S. Fish and Wildlife Service, April 1996, page 23
  10. ^ DDE concentration and percent eggshell thinning in Double-crested Conmorant eggs(North Channel, Lake Huron, Ont.)
  11. ^ Guillette, Louis J., Jr. (2006). "Endocrine Disrupting Contaminants" (PDF). Archived from the original (PDF) on 2010-11-18. Retrieved 2007-02-02.
  12. ^ Lundholm, C.E. (1997). "DDE-Induced eggshell thinning in birds". Comp Biochem Physiol C Pharmacol Toxicol Endocrinol. 118 (2): 113–28. doi:10.1016/S0742-8413(97)00105-9. PMID 9490182.
  13. ^ Division of Environmental Quality Archived 2008-03-03 at the Wayback Machine.
  14. ^ Chemical fact sheet: Organochlorine - The Breast Cancer Fund Archived 2006-10-09 at the Wayback Machine.
  15. ^ Questions about Endocrine Disruptors
  16. ^ Longnecker, M. P.; Gladen, B. C.; Cupul-Uicab, L. A.; Romano-Riquer, S. P.; Weber, J.-P.; Chapin, R. E.; Hernandez-Avila, M. (2007). "In utero exposure to the antiandrogen 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) in relation to anogenital distance in male newborns from Chiapas, México". American Journal of Epidemiology. 165 (9): 1015–22. doi:10.1093/aje/kwk109. PMC 1852527. PMID 17272288.
  17. ^ Hejmej, Anna; Kotula-Balak, Magorzata; Bilinsk, Barbara (2011). "Antiandrogenic and Estrogenic Compounds: Effect on Development and Function of Male Reproductive System". Steroids - Clinical Aspect. doi:10.5772/28538.
  18. ^ Pesticide Exposure Linked to Parkinson's, Alzheimer's Disease