Research
o Introduction to DDT
o DDT stands for Dichlorodiphenyltrichloroethane
o DDT is a compound made up of:
o Hydrogen
o Carbon
o Chlorine
o It is prepared chemically in reactions between Chloral (CCI3CHO) and Chlorobenzene (C6H5CI)
o Physical and Chemical Properties Of DDT
o Physical Properties
o Colourless crystalline
o White powdery material
o Slight aromatic odour
o Insoluble in water
o Soluble in fats
o Density at 20 degrees is 1.016kg/L
o Boiling Point: 185oC
o Chemical Properties
o Made up of hydrogen, carbon, and chlorine
o Chemical Formula: C14H9Cl5 à so in every molecule, there are
o 14 Carbon atoms
o 8 Hydrogen atoms
o 5 Chlorine atoms
o Reactions with:
o Oil: DDT dissolves in
o H2O: DDT doesn’t mix, since its insoluble in water
o Physical and Chemical Properties Of DDT That Makes it Ideal for Pesticides
o Physical Properties
o Insoluble in water
o When farmers water their plants, or when it rains; DDT won't wash away à so we need less pesticide, saving money
o Soluble in fats
o Once it gets into the pest, DDT will contact the nerve cell’s plasma membrane (the outer part)
o The membrane is made up mostly of fats, so DDT will dissolve
o As it enters the cell, it create a large opening
o Potassium ions and sodium ions à two essential substances in order for a nerve cell to operate properly
o If nerve cells don’t work, creatures (such as pests) will either suffer convulsion or paralysis and they will die
o Chemical Properties
o Reactions with:
o Oil: DDT dissolved in: Since it dissolves in oils, it dissolves in fats of animals
(especially tiny insects) and kills them by damaging their nervous system
o H2O: DDT doesn’t mix, since its insoluble in water: DIssolves only in the animal fats
o Physical and Chemical Properties Of DDT That Makes it a Problem
o Physical Properties
o Insoluble in water
o If DDT gets into oceans, it will be like an oil spill
o It doesn’t get off sea creature easily
o It will poison lots of sea life
o It will dissolve only inside the animals; killing them
o Creature who rely on seafood (seagulls, people, polar bears) will also be poisoned
o Creature who rely on creature who rely on sea food will be poisoned, and so on
o Soluble in fats
o This is an ethical issue, since we are knowingly killing animals in a slow, painful way à we poison their nervous system, disabling it work properly
o The creature at the top of the food chain will suffer the highest concentration, since everything they eat has some DDT. Who is at the top? Humans.
o Chemical Properties
o Reactions with:
o Oil: DDT dissolves in
o This is an ethical issue, since we are knowingly paralyse animals
o The creature at the top of the food chain will suffer the highest contamination
o H2O: DDT doesn’t mix, since its insoluble in water
o It doesn’t wash away
o If DDT gets into oceans, it will be like an oil spill
o It will poison lots of sea life
o It will dissolve only inside the animals; killing them
o Creatures who rely on seafood (seagulls, people, polar bears), will all be contaminated
o Interesting Facts About DDT
o Harmful effects on humans:
o Mild- serious damage to the liver, kidney, or central nervous system
o On the other hand, there is little scientific evidence to conclude that DDT is a serious health threat
o In one experiment people took capsules with some DDT everyday for 18 months
o There were no measurable health concerns
