Pollution - Pesticides Flashcards
Organochlorines: past uses
DDT
used on malaria mosquito swamps
has saved millions of lives
later used as an agricultural insecticide due to its desirable properties
Organochlorines: specific actions
neurotoxin
overstimulates to death
common use in malaria swamps
Organochlorines: properties
persistent - toxic to insects but not humans, continued to protect crops long after application
high liposolubility - bioaccumulative and biomagnifing
low water solubility - not washed off in rain
Organochlorines: enviro impacts
kill non target species
thin egg shells
decades long residence time
use now banned or heavily restricted
Organophosphates: past uses
Sarin
Agent Orange
^gas bombs used in WW2
Round Up weed killer
Organophosphates: specific action
neurotoxin
inactivates enzymes
nerve function damaged
poisons mammals - acute exposure by farmers at toxic levels causes death
impaired memory, Alzheimer’s, depression, ADHD, behavioural changes
possible carcinogen
Organophosphates: properties
low persistence - degrades quicky
low liposolubilty - does not bioaccumulate/ magnify
high mammal toxicity e.g to farmers
Organophosphates: enviro impacts
water soluble - found in drinking water
kills wild mammals (non target species)
Pyrethroids: specific action
toxic to fish
safe for humans, domestic insecticides
disrupts nervous system of insect causing paralysis
Pyrethroids: properties
high insect toxicity
not persistent - do not bioaccumulate or magnify
Pyrethroids: enviro impacts
toxic to fish, do not use near rivers or fish farms
Neonicotinoids: uses
most widely used insecticide, chemically similar to nicotine
Neonicotinoids: specific action
neurotoxin - inhibit action of neurotransmitters
BUT can be used as coated seed treatment to minimise harmful impacts of non target species
Neonicotinoids: properites
high insect toxicity
low vertebrates toxicity (cannot cross blood- brain barrier)
relatively persistent
water soluble
remain in soil long enough to be absorbed by roots and translocated with crops that are then protected from insect pests
synergetic with some fungicides when present together
Neonicotinoids: enviro impacts
may build up in aquifers, cause problems in future
toxic to bees
linked to decline of many bee populations
neurotoxic effect - reduce ability to navigate, reduce immunity to disease
most dangerous when neonicotinoid dust carried in wind
