BIOL1007 Lecture Notes - Lecture 24: California Condor, Rachel Carson, Lead Poisoning

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19 May 2018
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Pesticides
Manufacturing e.g. by-products
Industrial accidents e.g. Chernobyl
Chemical spills
Atmospheric pollution
Plastics
Nanoparticles e.g. in face scrubs, shampoos
Toxic inputs
1. Review how human activities affect the ecology of natural systems
Chemicals used in food production, accumulating in birds and mammals
Led to decline in bird pop particularly in raptors
When these pesticides were banned many pops recovered
Birds which were poisoned by pesticides -> thinner egg shells -> more prone to breaking -> pop decline
Silent spring by Rachel Carson
2. Understand how the ecological impacts of pollution and how it affects the ecology of
natural systems
Can't break down toxins
Occurs when an organism absorbs a toxic substance at a rate greater than that at which the substance is lost
Persistent and mobile
Accumulate in body tissue
Particularly higher predators
Diverse group of toxins introduced in various ways esp. pesticides
2,4-D and 2,4,5-T (herbicides)
DDT, dieldrin, lindane (organochlorine insecticides)
PCBs (polychlorinated biphenyls)
Heavy metals
Many used because they work short term
Bioaccumulation
Pesticides get used -> washed off into sea (land to sea barrier crossed) -> chemicals accumulate in sea life and can't be
removed from system -> inability to excrete/process toxins -> death
3. Understand how pollutants move into natural systems
PCBs in breast milk of mothers in southern Quebec in mid 80s
Need for a control ("pristine milk")
Obtained milk from Inuit mothers which had 5 times the PCBs
2/3 children had unacceptably high levels of PCBs
Older people had higher levels
Eat a lot of whale meat, fish which has PCBs
Children born to women who ate contaminated fish
Lower IQ
Poor memory
Shortened attention span
Learning difficulties
11 year olds exposed to PCBs in the womb had
Hostility between indigenous people and researchers, inuit had no control over PCBs
e.g. Inuit of northern Canada - PCBs
No agriculture/manufacturing
How did it get there?
L24 - The Human Footprint
Thursday, 26 October 2017
9:05 AM
mod 4 - ecology and ecosystems Page 1
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No agriculture/manufacturing
They use almost every bit of the beluga and narwhal whales caught, having a preference for muktuk (fat)
Toxins accumulate in certain body parts, particularly fat
The Inuit did not used it - banned in Canada for more than 20 years
Global distillation and fractionation
Heavy usage in tropics -> evaporate from soils -> carried on winds -> condense out in cold as toxic snow and rain
Systematic transfer from warm to cold
The more toxic components more mobile
Screen clipping taken: 26/10/2017 9:23 AM
Problem transcends borders and environments
Global solutions, look at bigger picture
Regulation
Hard to automate
Solutions
Lead poisoning
HOW? Condors ingest lead when they feed on the carcasses of animals that hunters have shot -> chronic lead poisoning
High risk of lead contamination
Many had dangerous levels of lead in their bodies
Lead poisoning severely damages birds' nervous systems and impair liver and kidney function
Long term problem
Recovery of the bird after 30 years on the brink, through intensive capture breeding and medical intervention, detoxify
the animals
About 20% had lead levels requiring costly treatment
e.g. California condor
Exxon Valdez 2009
Long term effects
Old thinking: acute mortaility through short term toxic exposure to oil deposited on shore accounts for the
important losses of shoreline plants and invertebrates
Impacts recurring as long as clean up (chemical and physical) continues
e.g. hoses with high pressure water harmful
Strong pervasive biological interactions in rocky intertidal and kelp forest communities contribute to
cascades of delayed, indirect impacts expand the scope of injury well beyond the initial direct losses thereby
also delay recoveries
New: Clean-up attempts can be more damaging than oil
Impact on coastal communities
e.g. Oil spills
We want to make an informed prediction which is not harmful!!!
4. Understand how the ecological impacts of habitat fragmentation
Fragmented landscape
mod 4 - ecology and ecosystems Page 2
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Document Summary

9:05 am: review how human activities affect the ecology of natural systems. Nanoparticles e. g. in face scrubs, shampoos: understand how the ecological impacts of pollution and how it affects the ecology of natural systems. Chemicals used in food production, accumulating in birds and mammals. Led to decline in bird pop particularly in raptors. When these pesticides were banned many pops recovered. Birds which were poisoned by pesticides -> thinner egg shells -> more prone to breaking -> pop decline: understand how pollutants move into natural systems. Occurs when an organism absorbs a toxic substance at a rate greater than that at which the substance is lost. Diverse group of toxins introduced in various ways esp. pesticides. Pesticides get used -> washed off into sea (land to sea barrier crossed) -> chemicals accumulate in sea life and can"t be removed from system -> inability to excrete/process toxins -> death e. g. inuit of northern canada - pcbs.

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