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
How was the Exxon Valdez spill cleaned up?
Skimmed oil form the waters surface
Sprayed oil disinfectants in the water and on shore
Washed oiled beaches with hot water
Rescued and cleaned animals trapped in oil
How long did it take to clean up the Exxon Valdez?
Around 3 years from 89-92
with the area still being monitored by scientists
How many people helped clean up from the Exxon Valdez oil spill?
11,000
What machinal clean up methods were used for Exxon Valdez?
booms and skimmers
What was the problem with skimmers in the Exxon Valdez spill?
Not readily available for first 24hrs
Thick oil kelp blocked equipment
When did the Deepwater horizon disaster occur?
20th April 2010
Why/ how did the Deepwater Horizon disaster occur?
a surge of natural gas blasted through a concrete core recently installed to seal an oil well for later use.
When the gas reached the rig it ignited
How much of the oil was actually cleaned up form the Exxon Valdez oil spill?
Only about 10%
Where did the Deepwater horizon disaster occur?
Gulf of Mexico
What were the effects of the Deepwater horizon oil spill?
Reproductive failure and organ damage
650 dolphins stranded
Lesions and physical damage to species
Chemicals entered food chain via zooplankton
Trapped in shells of fish
Mutations to species
Bird deaths
How much oil was released form the Deepwater Horizon oil spill?
134 million gallons (200 Olympic sized swimming pools)
How large was the area affected by the Deepwater Horizon spill?
Over 1000 miles of shore line
How long did it take for the oil leak to be fully capped? (Deepwater horizon)
3 months
How many people were hired to assists with the Deepwater Horizon clean-up?
48000
How long did the effects of the Deepwater Horizon disaster last?
still evident 10yrs later
How was the Deepwater Horizon oil spill cleaned-up?
Treated oil with over 1.4 million gallons of various chemical dispersants
Floating booms to stop oil spreading
Skimmers
Sorbents
controlled burning
How much of the oil was recovered by skimming? (Deep water)
2-4%
What are sorbents?
absorb oil like a sponge or adsorb it (stick to surface)
How much of the Deepwater horizon oil spill was cleaned-up by controlled burning?
5-6%
How many turtles died form the Deepwater Horizon oil spill?
167,600
How many birds died from the Deepwater Horizon disaster?
800,000 coastal birds
200,000 offshore birds
What is a pesticide?
Any substance used to protect plants or plants products from harmful organisms to regulate growth of plants (insecticides, herbicides and fungicides)
Why do farmers use pesticides?
Protect crops from insects pests, weeds and fungal diseases
What are the characteristics of an ideal pesticide?
Specific
Non-persistent
Incapable of bioaccumulating or bio-magnifying
What are the 4 types of pesticide?
Organo-chlorine
Organo-phosphate
Pyrethroid
Neonicitinoid
What is an example of organo-chlorine?
DDT (banned)
What are some examples of organo -phosphates?
Malathion
Parathion
What are some examples of pyrethroid insecticides?
Pyrethrum
Permethrin
What are the characteristics of organo-chlorine?
-very persistent
-liposoluble
- bioaccumulate & bio-magnify
- high insect toxicity, low mammal toxicity
What are the characteristics of organo-phosphates?
-low persistence
-low liposolubility: minimal bioaccumulation & bio-magnification
-high insect and mammal toxicity
What are the characteristics of pyrethroid insecticides?
-not persistent
- toxic to insect and fish
- low mammal toxicity
What type of action are neonicitinoids?
Systemic action
Where do neonicitinoids chemically remain after application?
Seeds
Leaves
Water
Soil
Pollen
Nectar
What are neonicitinoids chemically similar to?
Nicotine affecting the ability of the neurotransmitter acetylcholine from functioning
What are the characteristics of neonicitinoids?
High insect toxicity but lower in in vertebrates as cannot cross blood brain barrier
Persistent enough to remain in soil long enough for roots to pick them up (into plants)
What control methods are there for pesticides?
Bans (DDT)
Avoid using any persistent types that bioaccumulate or bio magnify
Avoid spraying on windy days or near water courses (reduce dispersal)
Use alternative techniques (cover crops) to stop weed germination, biological control using natural predators)
What biological control can be done to reduce pests?
Increase/ make conditions more favourable for beetles (beetle banks)
What are beetle banks?
2 metre wide grass mounds that run right across the middle or large arable fields
What aren’t inorganic nutrients?
Pesticides
What is the difference between organic and inorganic nutrients? (water pollution)
Organic contain a carbon atom (living)
Inorganic don’t contain a carbon atom (non-living)
What are some examples of inorganic nutrients?
Nitrates (no3)
Phosphates (po4)
what is a oligotrophic lake?
A lake or water body in balance
Nutrient and oxygen levels in dynamic equilibrium
What can happen to a oligotrophic water body?
may become eutrophic when nutrient levels become excessive
What is a eutrophicated water body?
When the nutrient levels are too high
What is the process for eutrophication?
Farmer applies fertiliser to nearby soil
Nutrients leached by surface runoff into water body
High algal growth stimulated (algal bloom)
Sunlight penetration through algae reduced reducing photosynthesis (plants die)
Lake becomes anoxic
Invertebrates (mayfly nymph) die
Bacteria use O2 in decomposition, lots of DOM, so O2 drops further
What will oxygen levels typically look like in the summer of a oligotrophic water body?
Deep water will be reduced as bacteria activity increased by warm temp thus sing more oxygen
What 3 methods are there to control inorganic nutrients?
Riparian buffer strips
Lake sediment dredging
Binding agent
What is a riparian buffer strip?
Area of natural vegetation grown around the edge of a water body/river usually at least 2m wide
What is the aim of riparian buffer strips?
the vegetation should take up excess nutrients and prevent water contamination
What are the positives of riparian buffer strips?
Inexpensive
Provision of natural habitat
Biological corridor
Helps prevent nitrate/ phosphate pollution
What are the negatives of riparian buffer strips?
Spaces required reducing crop space
Weed competition/ spread
Takes time to establish/ be effective
What is dredging?
involves removing excess sediments/ DOM and inorganic nutrients from the water body
What is the positives of dredging?
Doesn’t rely on a number of farmers to prevent eutrophication
Increases lake capacity/ increasing potential species diversity
Quick solution
Sediments can be used as fertiliser
What are the negatives of dredging?
Expensive process
Takes time (has to be done periodically based on build up rate)
Might damage habitats
Harm sediment dwelling invertebrates (food chain impacts)
What is a binding agent? (water pollution- inorganic nutrients)
Chemicals added to a pond or lake to prevent phosphates from being taken up be plants- phosphate is a limiting nutrient
What is a limiting nutrient?
nutrient which is present in the least quantity in an ecosystem
What are the the positives of binding agents? (inorganic nutrients)
easy method
Relatively cheap
Long term solution
What are the negatives of a binding agent? (inorganic nutrients)
Doesn’t prevent the pollution just controls impacts
Fossil fuels used in production (process may cause pollution)
What elements are stably bound in minerals when locked underground? (Acid mine drainage)
Lead
Zinc
Copper
What process occurs that means elements locked under ground are exposed to air?
Mining
What happens when stable elements locked underground are exposed to air?
They become mobile as a result of a chemical reaction (oxidation)
What happens when elements locked underground are oxidised?
They are converted (sulphides to sulphates)
What happens when sulphuric acid is produced? (Acid mine drainage)
Oxidise other metal sulphides and/or leach further metals from the surrounding rocks
What are adits?
Horizontal tunnels that are in mines that go to the surface
What happens to acidic water in mines?
Rise through adits and pick up the dissolved metals and transport them to nearby rivers
What is the result of acid mine drainage reaching river?
High and toxic concentrations of metal ions
What do acid wastes do to water?
Reduce water pH to below biologically viable limits (<4 is unhealthy)
At what pH will ferric ions precipitate out?
4-7
What are the effects of iron and aluminium being leached out of the soil?
Coats plants and blocks stomata preventing respiration
Clogs gills and lungs suffocating animals
Prevents spawning of fish
Dissolved metal ions are more readily absorbed and accumulated by plants and animals and are therefore more toxic when in solid form
What are the 2 types of treatment method for acid mine drainage?
Passive
Active
What is active treatment? (Acid mine drainage)
Chemical treatment
Involves the use of a mine water treatment plant
Flocculant
What is passive treatment?
Use of plants -reeds- encourage metals to precipitate out of solution
What is the process for passive treatment? (Acid mine drainage)
Utilises natural biological processes and is sustainable
style of treatment involves creating an area of natural wetland which trap and precipitate the metals
Usually involves construction of shallow lined lagoons or cells
What is the process for active treatment? (Acid mine drainage)
Mine water enters tank and added sludge begins the initial process of settling the solids
Lime added to raise pH and cause precipitation of metal hydroxides
Flocculant added to coagulate the metal solids and sludge settles out of the clarifier tank
Sludge recirculated
