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Dwight Causey
DDT
DDE
DDD
Chemical Properties
DDT
DDE
DDD
Molecular
Weight
354.49
318.03
320.05
Appearance/
Physical State
Colorless
Crystals, white
powder
Crystalline Solid
Colorless
Crystals, white
powder
Melting Point
(oC)
109
89
109-110
Solubility (at
25oC)
0.025 mg/L
0.12 mg/L
0.090 mg/L
Log Kow
6.91
6.51
6.02
Log Koc
5.18
4.7
5.18
Henry’s Law
constant
8.3x10-6 atmm3/mol
2.5x10-5 atmm3/mol
4.0x10-6 atmm3/mol
History


First synthesized in 1874
Insecticidal properties discovered in 1939 by
Paul Hermann Müller
 Won Noble Prize in Physiology and Medicine in 1948


Used to control insect-borne diseases (i.e.
malaria and typhus)
Peak of usage in 1962
 Registered for use on 334 agricultural commodities
 85,000 tons produced

Cumulative estimated world usage is 2 million
tons
History



Used in homes for
mothproofing and lice
control
Still used today in
developing countries
to control malaria and
lice
Silent Spring by
Rachel Carson in
1962, questioned the
widespread use of
DDT
Mode of Entry into Water

Indirectly
 Agricultural runoff
○ Binds strongly to soil and organic matter
 Volatized into the atmosphere
○ Redistributed through particulate matter

Directly
 Water pollution plants (sewer pipes to the
ocean)
 1,000,000 kg (~227 tons) from Montrose
Chemical Company to Palos Verdes shelf
Reactivity
Slightly soluble in water
 Very lipophillic
 Physical Half-life: 2-15 years

 Increases with time
 Sequestered in micropores
Biological Half-life: 8 years
 Biodegraded into DDE and DDD under
aerobic and anaerobic conditions,
respectively

DDT Derivatives
DDE is the major metabolite
 Both resist to biodegradation in aerobic
and anaerobic conditions
 Very long half-lives in water
 Hydrolysis is a minor process in
degradation
 Photolysis of DDE is a major process

 Half-life: 15-26 hours
DDD Toxicity

96 hour LC50:
 Glass shrimp: 2.4 µg/L
 Rainbow trout: 70 µg/L
 Largemouth bass: 42 µg/L
 Walleye: 14 µg/L

48 hour LC50:
 Daphnid: 4.5 µg/L
DDE Toxicity

96 hour LC50:
 Rainbow trout: 32 µg/L
 Atlantic Salmon: 96 µg/L
 Bluegill: 240 µg/L

Egg shell thinning
 Mallard: 3 µg/g
 Brown pelican: 3 µg/g
Toxic Effects
Weak estrogenic activities
 In the brain:

 Inhibition of ATP-based reactions
 Hepatic enzyme induction
 Disruption of hormonal mechanisms
Inhibition of Na+/K+ ATPases in the gills
 Thinning of egg shells in raptors
 Reduction in cortisol production

Mode of Entry into Organisms
Majority enters through food
 Some enters through absorption from
water through body surfaces (i.e. gills),
not believed to be significant when
compared to amount entering through
food
 Very Lipophillic, bioaccumulates
 Some organisms retain 90%+ of ΣDDT
in their food source

Molecular Mode of Interaction

Egg shell thinning in Raptors, 2 possibilities:
 DDE inhibits prostaglandin synthesis in the shell
gland mucosa, limiting calcium and bicarbonate
transport across the mucosa
 Embryonic exposure alters shell gland carbonic
anhydrase expression, causing eggshell thinning

In fish, no known molecular mechanism is
known
 Believed to involve ATPases in the central nervous
system and gills

In Insects, causes the irreversible opening of
voltage gated Na+ channels along the axon
Biochemical Metabolism and
Breakdown
DDT metabolized into DDE and DDD by
microorganisms
 Mixed-function oxidases may induce the
dechlorination of DDT to DDE in fishes
 In some mammals, DDE is converted to 2methylsulfonyl-DDE and 3-methylsulfonylDDE

 Acted on by phase I CYP2B enzymes
 Followed by conjugation with glutathione during
phase II
 Then through the mercapturic acid pathway, 2SH-DDE and 3-SH-DDE are formed
Detoxification
Up-regulation of CYP6G1 gene in
Drosophila melanogaster
 Secretion through urine, feces, semen, and
breast milk
 Clams shown to dechlorinate DDE to
DDMU under methanogenic or sulfidogenic
conditions
 Dried and ground seaweed has been
shown to increase DDT biodegradation by
80% after 6 weeks, further degradation of
DDD also seen

Bibliography












Cal/Ecotox Toxicity Data for Brown Pelican (Pelecanus occidentalis) . Office of Environmental Health
Hazard Assessment. 1999. http://www.oehha.ca.gov/cal_ecotox/report/pelectox.pdf
The Comparative Toxicogenomics Database. Mount Desert Island Biological Laboratory. 2008.
http://ctd.mdibl.org/
Denholm I, Devine GJ, Williamson MS (2002). Evolutionary genetics. Insecticide resistance on the move.
Science 297 (5590): 2222–3.
Evans, D. H. (1987). The Fish Gill: Site of Action and Model for Toxic Effects of Environmental Pollutants.
Environmental Health Perspectives 71, 47-58.
Hazardous Substances Data Bank. National Library of Medicine TOXNET System. 2008.
http://toxmap.nlm.nih.gov/toxmap/home/welcome.do
Handbook of Acute Toxicity of Chemicals to Fish and Aquatic Invertebrates. U.S. Fish and Wildlife
Services. 1980.
Kantachote D., Naidu R., Williams B., McClure N., Megharaj M., Singleton I. (2004). Bioremediation of
DDT-contaminated soil: enhancement by seaweed addition. Journal of Chemical Technology &
Biotechnology, 79 , 6, 632-638.
Lacroix M., Hontela A. (2003). The organochlorine o,p’-DDD disrupts the adrenal steroidogenic signaling
pathway in rainbow trout (Oncorhynchus mykiss). Toxicology and Applied Pharmacology 190, 197-205.
O’Reilly A.O., Khambay B.P.S., Williamson M.S., Field L.M., Wallace B.A., Emyr Davies T.G. (2006).
Modelling insecticide-binding sites in the voltage-gated sodium channel. Biochemical Journal, 396, 255263.
U.S. Department of Health and Human Services. Toxicological Profile for DDT, DDE, and DDD. Agency
for Toxic Substances and Disease Registry. 2002.
World Health Organization. DDT and its Derivatives – Environmental Aspects. Environmental Health
Criteria 83. 1989. http://www.inchem.org/documents/ehc/ehc/ehc83.htm
World Health Organization. DDT and its Derivatives. Environmental Health Criteria 9. 1979.
http://www.inchem.org/documents/ehc/ehc/ehc009.htm