10: Pollution Flashcards
what properties of pollutents affect its impact? (14)
1) state of matter
2) energy form (radiation/light/thermal)
3) density
4) persistence
5) toxicity
6) specificity
7) reactivity
8) adsorption u big silly
9) solubility in lipids/water
10) bio accumulation/magnification
11) synergism
12) mutagenic action
13) Teratogenic action
14) mobility
How does density affect a pollutants environmental impact?
denser materials require more kinetic energy to move. Lighter materials will spread quicker
How does solubility in lipids affect the impact of a pollutant?
Being liposoluble enables pollutants to pass through cell membranes and bioaccumulate and bio magnify up the food chain.
what is synergism?
When two or more pollutants interact to create a different, more serious effect
What is mutagenic action?
Gonadic effects: a mutation in the egg, sperm or embryo
Somatic effects: a mutation within general just cells
Carcinogenic: causes cancer
What is the name for a substance which can cause birth defects?
Teratogens
They do not change the DNA so cant be inherited, but rather inhibit protein function.
Why are CFCs so persistent?
They are chemically stable, and have low solubility in water.
What environment/abiotic factors effect the impact of a pollutant.
- Temperature
- Light levels
- Oxygen
- pH
- Pollutant interactions
How does oxygen levels affect the impact of a pollutant?
- aerobic bacterial decomposition of sewage
- oxidation of sulphide ores producing sulphur dioxide, which can dissolve in water as sulphuric acid
What examples of pollutant interactions are there?
- Interaction of NOx and hydrocarbons in photo chemical smog
- The combined effects of phosphate and nitrates in eutrophication
What features make a good biotic indicator?
- abundant
- easy to identify
- wide range of different species
What factors allow for temperature inversions to form?
- Valleys, where colder denser air can collect
- Low wind velocity, so air layers with different temperatures don’t mix
- Mist or fog during the day which has a higher albedo so reflects sunlight and prevents the warming of the ground
What is CPA
A strategies used to control pollution
Critical Pathway Analysis
Predicts the movement of potential pollutants in the environment to assess the severity and where the pollution may occur.
If a pollutant is expected to be concentrated in a sensitive area, then it may be necessary to control the release
What Is CGM?
A Strategy used to control pollution
Critical Group Monitoring
A method of assessing the risk of a pollutant to public health. They assess the risk for the group most at risk from the pollutant due to factors such as lifestyle.
If the risk to the Critical group is low, then its assumed all other members are at even lower risk.
What are the two methods used to asses the risk of pollution?
CPA and CGM
What emission control strategies are there?
Control of emission location
- downwind of urban areas
- where marine currents can disperse
- not above an unconfined aquifer
Control Of emission timing
- Tidal differences, out to sea will disperse
- Avoiding pollution during temperature inversions
What are the four principles that affect the decision of how to control pollution?
1) Polluter pays
2) Precautionary principle (Assumes all waste causes pollution until research confirms otherwise, so release is not permitted)
3) Selection of the control method (Prevention, post release, alternative process)
4) The efficiency of pollution control (ALARA using BATNEEC)
What are the 4 different control methods?
With Examples
1) Production prevention (Desulphurisation of fossil fuels)
2) Prevention of release (Electrostatic precipitators)
3) Post-release remediation (Post-release remediation)
4) Alternative processes (Use of electric cars instead of petrol)
What is another pollutant that smoke often acts synergistically with?
Sulphur dioxide
What are the effects of smoke pollution?
- Respiratory diseases
- reduced photosynthesis due to smoke blocking the light
- Eroding buildings due to the acids that may be contained
- Cooling affect due to the high albedo
- Depletion of the ozone layer
What are smoke smogs?
A mix of smoke and fog when temperatures are cool (often in a temperature inversion)
E.g. the London smog
What legislation is in place to reduce smoke pollution control measures?
Clean air act 1956
Restricted use of fuels that produce smoke in large urban areas of the UK
What 5 different smoke cleaning devices are used in industry?
1) Electrostatic precipitators
2) Cyclone Separators
3) Scrubber
4) Coal treatment
5) Bag filters
What is an electrostatic precipitator?
Effluent gasses are passed through a chamber with positively charged wires that attract the smoke particles and the clean gas flows out.
As the smoke accumulates it falls down as ash
What is a cyclone separator?
The Effluent gas is passed into a cylinder which spins, causing the heavy smoke particles to fall to the edges and accumulate.
What is a scrubber?
A scrubber uses a fine water spray to was out soluble pollutants from the gas
How can coal be made cleaner?
Producing smokeless coal by heating the coal and letting the tar run off.
Name an example of an improvement in the efficiency of combustion engines?
Turbo chargers
These improve the oxygen delivery to the engines to allow more complete combustion
What is a photochemical smog?
The interaction of NOX with other secondary pollutants in the presence of UV light.
The combination of NOx with 03 and unburnt hydrocarbons can interact to create PANs, one of the more toxic elements of a photochemical smog.
What are the effects of PANs?
What are the causes?
PANs are made when NOX, ozone and unburnt hydrocarbons interact in the presence of UV light.
- Eye irritation
- breathing difficulty
- asthma
- increased risk of heart attacks
Toxic at lower concentrations than other pollutants
How are photochemical smogs controlled?
- Catalytic converters (NOx and hydrocarbons)
- Recollecting vapours from petrol stations etc
- vapours can be passed through a carbon filter where hydrocarbons absorb onto the carbon
What are the main gasses involved in acid rain?
1) Sulfur dioxides (sulfurous acid or sulfuric acid)
2) Oxides of nitrogen (Nitrous and nitric acids)
3) Ozone
What are the impacts of acid rain on non-living things?
- Erodes metal infrastructure
- Erodes limestone structures` such as buildings and statues
What are the impacts of acid rain on living organisms?
Direct
- Denature proteins/inhibit enzymes
- dissolve living cells exposed to environment such as stomata, root hairs, fish eggs
- respiratory problems
Indirect
- Increased solubility of metal ions leading to leaching of important metal ions such as Ca2+ and Mg2+
- releases toxic metal ions such as lead out into the soi
- Toxic ions inhibit enzyme action in root hair cells and other organisms
- Toxic ions may leach into river systems
How can acid rain be controlled?
Sulfur
Removal of sulfur dioxide
- from gas: reacting with iron particles
- from oil: during distillation
- from coal: washing and steaming to remove iron pyrites
- Dry flue gas: Passed through a bed of crushed calcium carbonate
- Wet flue gas: Sodium sulfate scrubbing
How can acid rain be controlled?
NOx
- Low temp combustion as less NOx is produced at a lower temp
- Catalytic converters reduce NOx to nitrogen and oxygen
- Urea sprays where the NOx is removed by reacting it with urea
How does carbon monoxide affect the body?
Binds to haemoglobin to prevent oxygen being carried around the body
What factors affect the degradation of a pollutant?
- High levels of UV can increase photochemical degradation
- High levels of dissolved oxygen increase the rate at which aerobic bacteria break down some pollutants
- higher temperatures which increase the rate of most reactions
- Dispersal through currents or wind
- removal rate via adsorption to sediment
What are the effects of thermal pollution?
- Warm effluent water can reduce dissolved oxygen concentrations
- Most aquatic organisms will be killed by high temperatures due to enzymes denaturing
- migration of non-indigenous species
- pollutant toxicity increases as they are metabolised quicker
- reduced resistance to disease
How is thermal pollution controlled?
-Cooling towers in power stations where water is sprayed down, and the hot air escapes as water vapour
What causes soil pollution?
1) Waste lubricating oil
- vehicle engine oil
- machine oil
2) Accidental releases
- Shipping/oil rig/oil pipeline accidents
- leakage from storage tanks
- discharge of wastewater
3) Oil drilling lubricating oil-based clay
Effects of oil pollution
- Toxic to organisms
- Cover aquatic life such as molluscs or algae
- Cause birds to drown
- reduce oxygenation of water when a thin film forms
- effect marine organisms which use scent for feeding or mating
How is oil pollution controlled?
1) Prevent release
2) improved oil tanker operation
3) Improved tanker design
How is Oil tanker operation improved to prevent oil pollution?
- better shipping routes to prevent collisions
- better navigation systems
- inert gas systems which prevent oxygen mix and explosions
- leaving tank washing liquid and any oily wastewater at oil terminal when the tanker docks
How is deliberate release of oil now prevented?
-recycling of waste lube oil (reforming, fuel)
How is tanker design improved to reduce oil pollution?
- Double hull
- twin-engine/rudder/fuel tanks
- separate oil and ballast tanks, so know residual oil from tanks is washed back into the sea
- oil interceptors that prevent water from flowing into the main drainage system
- Bund walls around oil tanks to contain oil if the tank were to split
How are oil spills treated?
1) Booms restricting the movement of oil
2) Skimmers and high surface area materials (adsorb oil to its surface)
3) Polymerising agents that cause oil to agglutinate
4) Steam washing of sensitive habitats, but may harm unaffected organisms
5) Bioremediation
What is bioremediation?
Using bacteria to break down hydrocarbons and remove the residual pollution.
What are the polymerising agents?
Chemicals which cause the hydrocarbons to form a solid mass which is easier to clean up.
What properties of pesticides make them difficult?
1) Specificity
pesticides also harm non target species
2) Persistence
persistent pesticides will remain in the environment longer and cause more damage
3) Bioaccumulation
liposoluble pesticides can accumulate in the body and and build up to produce toxic concentrations
4) Biomagnification
Pesticides can concentrate up the food chain
What specific insecticides have we looked at?
- Organochlorines
- Organophosphates
- Pyrethroids
- Neonicotinoids
What is an example of an organochlorine and why are they a problem?
DDT
- High persistence
- High Liposolubility
- Low water solubility
How can domestic noise pollution be reduced?
- Acoustic shock absorbers on noisy appliances
- wearing ear defenders when using power tools
- Volume limiters on music
- control of dogs
How can industrial noise be reduced?
- Acoustic sound absorbing material room, around machinery and inside the machinery
- Remote machinery operation
- Worker ear protection
- Regular timing of mine blasting
What are the sources of mercury pollution?
- Disposal of items containing mercury, for example, batteries
- chemical plants that produce chlorine using mercury electrodes
- combustion of coal
