Dichlorodiphenyldichloroethylene

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Dichlorodiphenyldichloroethylene
Dichlorodiphenyldichloroethylene
Dichlorodiphenyldichloroethylene
Identifiers
CAS number 72-55-9 YesY
PubChem 3035
ChemSpider 2927 YesY
KEGG C04596 YesY
ChEBI CHEBI:16598 YesY
ChEMBL CHEMBL363207 YesY
Jmol-3D images Image 1
Properties
Molecular formula C14H8Cl4
Molar mass 318.02 g/mol
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
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] DDE is fat soluble which tends to build up in the fat of animals. Due to its stability in fat, DDE is rarely excreted from the body, and body levels tend to increase throughout life. The major exception is the excretion of DDE in breast milk, which delivers a substantial portion of the mother's DDE burden to the young animal or child.[2]

Degradation of DDT to form DDE by an elimination of HCl

DDE and its parent, DDT, are reproductive toxicants for certain birds species, and major reasons for the decline of the bald eagle,[3] brown pelican[4] peregrine falcon, and osprey.[5] 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.[6] 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.[5]

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.[5][7][8][9][10] Multiple mechanisms may be at work, or different mechanisms may operate in different species.[5] Some studies have shown that although DDE levels have fallen dramatically, eggshell thickness remains 10–12 percent thinner than before DDT was first used.[11]

Some studies have indicated that DDE is an endocrine disruptor[12] and contributes to breast cancer, but more recent studies provide strong evidence that there is no relationship between DDE exposure and breast cancer.[13] What is more clear is that DDE is a weak antiandrogen.[14]

Animal studies show that organochlorine pesticides—such as DDE—are neurotoxic, cause oxidative stress, and damage the brain's dopaminergic system.[15]

References[edit]

  1. ^ ATSDR - Public Health Statement: DDT, DDE, and DDD
  2. ^ Breast milk excretion Kinetic of b-HCH, pp'DDE and pp'DDT. Bulletin of Environmental Contamination and Toxicology, 2009 Dec;83(6):869-73
  3. ^ 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. 
  4. ^ "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 F.R. 9407
  5. ^ a b c d ATSDR - Toxicological Profile: DDT, DDE, DDD
  6. ^ California Wild Spring 1994 - Peregrine Falcons
  7. ^ Recovery Plan for the California Condor, U.S. Fish and Wildlife Service, April 1996, page 23
  8. ^ DDE concentration and percent eggshell thinning in Double-crested Conmorant eggs(North Channel, Lake Huron, Ont.)
  9. ^ Guillette, Louis J., Jr. (2006). "Endocrine Disrupting Contaminants" (PDF). Retrieved 2007-02-02. 
  10. ^ 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. 
  11. ^ Division of Environmental Quality
  12. ^ Chemical fact sheet: Organochlorine - The Breast Cancer Fund
  13. ^ Questions about Endocrine Disruptors
  14. ^ 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. 
  15. ^ Pesticide Exposure Linked to Parkinson's, Alzheimer's Disease