Insecticide DDTInsecticide DDT

Václav SzmekVáclav Szmek

Jiří ŠidoJiří Šido

Physical and chemical propertiesPhysical and chemical properties

DDTDDTChemicalChemical namename

4,4'-(2,2,2-4,4'-(2,2,2-trichloroethane-trichloroethane-1,1-1,1-diyl)bis(chlorobenzene) diyl)bis(chlorobenzene)

ChemicalChemical formulaformula

CC1414HH99ClCl5 5

MolecularMolecular massmass

354.49 g/mol 354.49 g/mol

MeltingMelting point point

108.5 °C 108.5 °C

BoilingBoiling point point

260 °C 260 °C

Powder – prášekPowder – prášekodour – zápachodour – zápachenvironment – okolí, environment – okolí,

ovzdušíovzduší

• DDT is a white, crystalline powder with a DDT is a white, crystalline powder with a weak odour.weak odour.

• It shows low solubility in water and high It shows low solubility in water and high soubility in organic solvents, fat and oils.soubility in organic solvents, fat and oils.

• It doesn't break down in the environment It doesn't break down in the environment or in organisms. or in organisms.

Preparation of DDT and its qualitiesPreparation of DDT and its qualities

• DDT is created by the reaction of DDT is created by the reaction of trichloroethanoltrichloroethanol with with chlorbenzenechlorbenzene (C (C66HH55Cl). Trade or other names Cl). Trade or other names for DDT include Anofex, Cesarex, for DDT include Anofex, Cesarex, ChlorophenothaneChlorophenothane..

• DDT has potent insecticidal properties; it kills by DDT has potent insecticidal properties; it kills by opening sodium channels in insect neurons, causing opening sodium channels in insect neurons, causing the neuron to fire spontaneously.the neuron to fire spontaneously.

• DDT was responsible for eradicating malaria from DDT was responsible for eradicating malaria from Europe and North America, and was also extensively Europe and North America, and was also extensively used as an agricultural insecticide after used as an agricultural insecticide after 19451945

Quality – vlastnostQuality – vlastnost potent – silný, účinnýpotent – silný, účinný

Extensively – rozsáhleExtensively – rozsáhle eredicate - vyhubiteredicate - vyhubit

History of DDTHistory of DDT

• DDTDDT was the first modern pesticide was the first modern pesticide, , was first synthesized inwas first synthesized in 18731873 by by Othmar ZiedlerOthmar Ziedler . .

• Insecticidal properties were discovered in 1939, by the Insecticidal properties were discovered in 1939, by the Swiss scientist Paul Hermann Swiss scientist Paul Hermann Paul Hermann MüllerPaul Hermann Müller

• It was used extensively during World war II by Allied troops It was used extensively during World war II by Allied troops and certain civilian populations to control insect typhus and and certain civilian populations to control insect typhus and malaria vectors (as a result nearly eliminating typhus).malaria vectors (as a result nearly eliminating typhus).

• DDT was also extensively used as an agricultural insecticide DDT was also extensively used as an agricultural insecticide after 1945.after 1945.

• By the 1950s, in some uses, doses of DDT and other By the 1950s, in some uses, doses of DDT and other insecticides had to be doubled or tripled as resistant insect insecticides had to be doubled or tripled as resistant insect strains developed.strains developed.

Properties – vlastnostiProperties – vlastnosti extensive – častoextensive – často

Certain – zaručený, spolehlivýCertain – zaručený, spolehlivý strain – namáhat, napínatstrain – namáhat, napínat

Environmental impactEnvironmental impact• DDT is a DDT is a Persistent Organic PollutantPersistent Organic Pollutant and very and very

highly persistent in the environment. Routes of highly persistent in the environment. Routes of loss and degradation include runoff, volatilization, loss and degradation include runoff, volatilization, photolysis and photolysis and biodegradationbiodegradation (aerobic and (aerobic and anaerobic). These processes generally occur anaerobic). These processes generally occur slowly. Breakdown products in the soil slowly. Breakdown products in the soil environment are DDE (1,1-dichloro-2,2-bis(p-environment are DDE (1,1-dichloro-2,2-bis(p-dichlorodiphenyl)ethylene) and DDD (1,1-dichloro-dichlorodiphenyl)ethylene) and DDD (1,1-dichloro-2,2-bis(p-chlorophenyl)ethane), which are also 2,2-bis(p-chlorophenyl)ethane), which are also highly persistent and have similar chemical and highly persistent and have similar chemical and physical properties.physical properties.

Persistent – odolnáPersistent – odolná

Pollutant-spad, znečišťující látkaPollutant-spad, znečišťující látka

Occur – přihodit seOccur – přihodit se

Route – směrRoute – směr

Loss – ztrátaLoss – ztráta

Runoff-odtok, splachRunoff-odtok, splach

Volatilization- těkání, Volatilization- těkání, vyprchání, vypařenívyprchání, vypaření

• DDT is highly toxic to DDT is highly toxic to aquatic life, including aquatic life, including crayfishcrayfish, daphnids, sea , daphnids, sea shrimp and many species shrimp and many species of fish. DDT may be of fish. DDT may be moderately toxic to some moderately toxic to some amphibian species, amphibian species, especially in the larval especially in the larval stages. In addition to acute stages. In addition to acute toxic effects, DDT may toxic effects, DDT may bioaccumulate significantly bioaccumulate significantly in fish and other aquatic in fish and other aquatic species, leading to long-species, leading to long-term exposure.term exposure.

• DDT is not particularly toxic to humans, compared to DDT is not particularly toxic to humans, compared to other widely used pesticides. other widely used pesticides.

Crayfish – rakCrayfish – rak daphnids-plankton daphnids-plankton sea shrimp-krevetasea shrimp-kreveta Amphibian- Amphibian- obojživelnýobojživelný

Arguments for and against DDTArguments for and against DDT

• Since the ban, two million people a year have Since the ban, two million people a year have died unnecessarily from malaria, mostly died unnecessarily from malaria, mostly children. The ban has caused more than fifty children. The ban has caused more than fifty million needless deaths. Banning DDT killed million needless deaths. Banning DDT killed more people than Hitlermore people than Hitler

• OOne of the pro-DDT arguments is that the ne of the pro-DDT arguments is that the treatment was used long enough to eliminate treatment was used long enough to eliminate insect-borne diseases in the West but now that insect-borne diseases in the West but now that it's only needed in poorer countries in Africa, it's only needed in poorer countries in Africa, Asia and elsewhere it's been banned.Asia and elsewhere it's been banned.

Ban – zákazBan – zákaz

Caused – způsobilCaused – způsobil

Treatment – léčba, zacházeníTreatment – léčba, zacházení

Thank you for attentionThank you for attention