Insecticide DDT
Václav Szmek
Jiří Šido
Physical and chemical properties
DDT
Chemical
name
4,4'-(2,2,2-trichloroethane1,1-diyl)bis(chlorobenzene)
Chemical
formula
C14H9Cl5
Molecular
mass
354.49 g/mol
Melting point 108.5 °C
Boiling point
260 °C
• DDT is a white, crystalline powder with a weak
odour.
• It shows low solubility in water and high
soubility in organic solvents, fat and oils.
• It doesn't break down in the environment or in
organisms.
Powder – prášek
odour – zápach
environment – okolí,
ovzduší
Preparation of DDT and its qualities
• DDT is created by the reaction of trichloroethanol with
chlorbenzene (C6H5Cl). Trade or other names for DDT
include Anofex, Cesarex, Chlorophenothane.
• DDT has potent insecticidal properties; it kills by opening
sodium channels in insect neurons, causing the neuron to
fire spontaneously.
• DDT was responsible for eradicating malaria from Europe
and North America, and was also extensively used as an
agricultural insecticide after 1945
Quality – vlastnost
Extensively – rozsáhle
potent – silný, účinný
eredicate - vyhubit
History of DDT
• DDT was the first modern pesticide, was first synthesized in
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1873 by Othmar Ziedler .
Insecticidal properties were discovered in 1939, by the Swiss
scientist Paul Hermann Paul Hermann Müller
It was used extensively during World war II by Allied troops
and certain civilian populations to control insect typhus and
malaria vectors (as a result nearly eliminating typhus).
DDT was also extensively used as an agricultural insecticide
after 1945.
By the 1950s, in some uses, doses of DDT and other
insecticides had to be doubled or tripled as resistant insect
strains developed.
Properties – vlastnosti
Certain – zaručený, spolehlivý
extensive – často
strain – namáhat, napínat
Environmental impact
• DDT is a Persistent Organic Pollutant and very highly
persistent in the environment. Routes of loss and
degradation include runoff, volatilization, photolysis and
biodegradation (aerobic and anaerobic). These processes
generally occur slowly. Breakdown products in the soil
environment are DDE (1,1-dichloro-2,2-bis(pdichlorodiphenyl)ethylene) and DDD (1,1-dichloro-2,2bis(p-chlorophenyl)ethane), which are also highly
persistent and have similar chemical and physical
properties.
Persistent – odolná
Pollutant-spad, znečišťující látka
Occur – přihodit se
Route – směr
Loss – ztráta
Runoff-odtok, splach
Volatilization- těkání,
vyprchání, vypaření
• DDT is highly toxic to aquatic
life, including crayfish,
daphnids, sea shrimp and
many species of fish. DDT may
be moderately toxic to some
amphibian species, especially
in the larval stages. In addition
to acute toxic effects, DDT
may bioaccumulate
significantly in fish and other
aquatic species, leading to
long-term exposure.
• DDT is not particularly toxic to humans, compared to
other widely used pesticides.
Crayfish – rak
daphnids-plankton sea shrimp-kreveta Amphibian- obojživelný
Arguments for and against DDT
• Since the ban, two million people a year have died
•
unnecessarily from malaria, mostly children. The ban
has caused more than fifty million needless deaths.
Banning DDT killed more people than Hitler
One of the pro-DDT arguments is that the treatment
was used long enough to eliminate insect-borne
diseases in the West but now that it's only needed in
poorer countries in Africa, Asia and elsewhere it's been
banned.
Ban – zákaz
Caused – způsobil
Treatment – léčba, zacházení
Thank you for attention