Water pollution Flashcards
What are the most common final sink for pollutants?
Rivers and oceans
What is pollutant concentration in water influenced by?
Size of emission
Volume of water
Residence time
Degradation by light (photodegradation) or organisms (biodegradation)
Rate of removal (organisms that leave water body)
Flow rate/ dispersal speed (rivers)
What is thermal pollution?
sudden increase or decrease in temperatures of a natural body of water by human influence
Where does thermal pollution normally occur?
when a power station or industrial facility takes water from a natural source, typically for cooling, and returns it at an altered temperature
What changes can thermal water pollution cause?
enzyme function
Metabolism
reproduction
dissolved oxygen levels
Where does oil pollution come from?
vareity of dischrges and accidental release some are point sources while most comes from disperesed sources
What ways can organisms be affected by oil pollution? (General)
Directly coming into contact with oil
Indirectly cause environmental changes
Where does the most visible oil pollution come from?
Oil spills - deepwater horizon (oil rig) and Torrey canyon (tanker)
what are the caues of oil spills?
poor disposal of vehicle lubricants
Damage to or leakage from oil rigs, pipelines or tankers
Discharge of tank washing water from oil tankers
Why do oil tankers have to clean the oil tank of the ship?
to prevent different types of oil contamininating each other and prvent accumulaiton of thick tar
What are the effects of oil pollution?
Reduces dissolution of O2 at the water surface
Smothers and asphyxiates (suffocates) molluscs
Some compounds are toxic
Waterproofing and thermal insulation of bird feathers lost (hypothermia)
Ingested oil prevents digestion (starvation)
Reduced breeding success of birds unable to locate mate by smell
What is dissoluiton of O2?
It is when oil creates a layer above the water preventing the oxyegn form entering the sea
Where is dissolution of oxygen a problem? (Oil)
In enclosed water bodies like lakes where there is a side
What control methods are there for oil pollution?
The waste lubricating oil can be collected, filtered and refined to make new lubricating oil
Better control and maintenance of ships and tankers (fines no one wants to pay so do things properly)
Double hu-hulled tankers to reduce likelihood of rupture of main tank
Twin-engine and fuel tanks to be able to cope with one mechanical failure
Seperate tanks for oil and water so when an empty tankers has to take on water as ballast it doesnt become contaminated with oil which would be relased when docked.
What 2 oil spill case studies do we need to know?
Exxon Valdez
Deepwater horizon
When did the Exxon Valdez disaster happen
24th march 1989
Why/ how did the Exxon Valdez oil spill occur?
Ship struck a reef along Alaskan coast tearing the ships hull
How much oil was spilled at the Exxon Valdez disaster?
11 million gallons of crude oil
Where did the Exxon Valdez oil spill occur?
Prince William Sound, Alaska
What were the impacts of the Exxon Valdez oil spill?
How much coastline was affected by the Exxon Valdez oil spill? (Miles)
1300 miles
What species were killed by the Exxon Valdez oil spill?
Seabirds (250,000)
Sea otters (2800)
Harbour seals (300)
Bald eagles (250)
Killer whales (22)
Salmon and herring eggs (billions)
What were the impacts of the Exxon Valdez oil spill?
Immense impacts for fish, wildlife and their habitats as well as for local industries and communities
How much did the Exxon Valdez oil spill cost?
Clean-up alone- $2.5billion
Total cost (fines, penalties and settlements)- $7billion