pesticides. used to get rid of pests of all kinds. if it is toxic to other life forms, it may be...
Post on 20-Dec-2015
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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?
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