Pesticides

Pesticides

• Used to get rid of pests of all kinds.• If it is toxic to other life forms, it may be

toxic to us.– Also may be toxic to other organism that we

don’t want them to harm.

• Must be used with care– ~20,000/year in US receive emergency

medical care from perceived or actual exposure

– ~30/year die from above

Pesticides

• Most important are insecticides, herbicides, and fungicides

• Persistent pesticides remain in environment and spread.– Most recent research has been for short-lived

pesticides– Most persistent ones have been removed

from use.• Like DDT

DDT• Hailed as “miraculous” in 1945 by Sir

Winston Churchill– Saved millions of lives

• Malaria – mosquitoes• Yellow fever – mosquitoes• Typhus – body lice• Fleas – bubonic plague

• Banned in the late 1960’s in developed countries– Still being used in underdeveloped countries

• Still saving millions of lives/year – imported foods?

Organochlorine insecticides

Bioaccumulation + bioconcentration = biomagnification

.000003 ppm in water

More soluble in fats than in water

Organophosphate and CarbamateInsecticides

• Non-persistant – break down quickly in the environment.– Don’t bioaccumulate

• More immediately toxic to humans and mammals

• Examples:– Malathion – will soon be restricted– Diazinone – no longer available

Pyrethrin, an natural insecticide

Most – unstable in sunlight

H23 – C10

• 24 - 27, 29, 30, 63, 64, 66, 69, 70, 72, 87, 88