Pollution Flashcards
1
Q
What is a pollutant?
A
A substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource.
- Can be naturally forming or anthropogenic forming.
2
Q
Examples of gaseous pollutants:
A
- Sulphur dioxide from fossil fuels
- Carbon dioxide form fossil fuels
- Nitrous oxides from car exhausts
- CFCs from aerosols, fridges etc
3
Q
Examples of liquid pollutants:
A
- Oil form leaks or spills
- Pesticides
- Fertilisers
- Liquid industrial waste
- Sewage
- Hot water form power stations
4
Q
Examples of solid pollutants:
A
- Smoke particles
- Suspended solids in water
- Solids domestic waste (rubbish)
- Mining waste
- Solid industrial waste
5
Q
Examples of energy pollutants:
A
- Noise
- Ionising radiation
- Heat
- Light
6
Q
How does the density of a pollutant affect pollution?
A
The denser the particles of solid the closer to the source they settle.
In gases denser air sinks nearer source
In liquid denser particles sink more quickly
7
Q
How does the source of pollution affect the pollution caused?
A
Point of source - from a definite place has a definite effect e.g. oil spills from a tanker
Diffuse source - from many sources with combined impacts e.g. car exhausts
8
Q
How does persistence/degradability affect pollution?
A
- A measure of the length of time before a material breaks down
- Have to biodegrade within a certain amount of time in the lab to be sold
9
Q
What are POPs and what has been done to reduce them?
A
- Persistent organic pollutants (POP) do not degrade in the environment and have negative health effects
- Stockholm convention 2001 took action to reduce/eliminate production of POPs
10
Q
What are the effects of POPs?
A
- Nearly wiped out the bald eagle
- Transboundary pollution threatening Antarctica
- Decline of wildlife
- Disease and abnormalities on living creatures
- Reproductive impairment
11
Q
How does toxicity affect pollution?
And what is an example of a persistent heavy metal?
A
Toxic chemicals = inhibit enzymes, damage the nervous system and damage organs.
E.g. lead. It is a neurotoxin, accumulates in soft tissues and bones, causes blood and brain disorders
12
Q
How does chemical reactivity affect pollution?
A
- Very reactive chemicals do not last long in the environment, may be highly toxic though
- Chemicals can react to form a secondary pollutant which is WORSE
13
Q
What are PANs?
How are they mad?
What issues do they cause?
A
Peroxy Acetyl Nitrates
- Made from NOx from car exhausts and oxygen in the air and unborn hydrocarbons
- Reacts in sunlight to make PANs
- Toxic and irritating to eyes, lungs and plants
14
Q
How does specificity affect pollution?
And an example?
A
- Specific toxin will affect specific organisms
- Non-specific toxins will affect all organisms
E.g. Pyrethroids
15
Q
How does adsorption affect pollution?
What’s the problem?
A
When molecules stick onto the outside of another particle
E.g. pollutants sticking to soil particles
PROBLEM: they can be releases later on
16
Q
Examples of adsorbents?
A
- Ice clouds adsorb chlorine
- Silica
- Activated carbon/zeolite in H2O purification
- Uranium clean up using polymer resins
- Catalytic converters honey comb shape or platinum to convert pollutants
17
Q
How does solubility in water/lipids affect pollution?
A
- Water soluble pollutants are often mobile in the hydrosphere e.g. nitrates
- Liposoluble pollutants are soluble in fats and are more likely to bioaccumulate e.g. DDT, PCBs and heavy metals
18
Q
How does mobility affect pollution?
A
Mobility is the measure of the degree to which the pollutant is carried by wind, water or organisms.
E.g. smoke, acid rain, CFCs, PCBs
19
Q
What is bioaccumulation and how does it affect pollution?
A
- The absorption and storage of pollutant in the tissues of organisms e.g. heavy metals, DDTs, PCBs
- It occurs when an organism absorbs a toxic substance at a greater rate than that at which the substance is lost.
So the longer the biological half-life of the substance the greater the risk of chronic poisoning.
20
Q
What is biomagnification and how does it affect pollution?
A
It is the increase in concentration as a pollutant passes along a food chain, up the tropic levels.
E.g. heavy metals, chlorinated organic compounds, the chlorine makes them resistant to degradation.
21
Q
What is synergism and how does it affect pollution?
And what is an example of this?
A
- When two or more pollutants effects interact to create a different effect, usually a more serious one.
E.g. ozone damages leaf cuticles which enables sulphur dioxide to cause more damage to the newly exposed cells.
22
Q
What is mutagenic action and how does it affect pollution?
A
- Agents which cause changes in the chemical structure of DNA by damaging chromosomes by rearrangement of the DNA structure (mutations)
- Gonadic effects = birth abnormality in the offspring produced.
- Somatic effects = most are harmless, can cause cancer, where uncontrolled cell division produced a tumour.
E.g.s ionising radiation, UV light, Chlorinated organic substances, cadmium, asbestos.
23
Q
What is carcinogenic action?
A
- Mutagens that cause cancer, creating tumours that can prevent normal tissue function.
24
Q
What is teratogenic action?
A
- Causes birth abnormalities by preventing normal gene expression.
- Do not change DNA but inhibit the function of proteins and enzymes that the DNA would normally have controlled
- Cannot be inherited by future generations because the DNA structure is not affected.
25
How does temperature affect degradation?
Chemical reactions will speed up as temp increase, so degradable pollutants will break down more rapidly at higher temperate, but more rapid degradation can lead to problems like deoxygenating.
26
How does light levels affect degradation?
Provide the activation energy that drives chemical reactions involving pollutants e.g. photochemical smogs and the photo-degradation of some pesticides.
27
How does oxygen affect degradation?
Aerobic bacterial decomposition of sewage, oxidation of sulphide ores producing sulphur dioxide, oxidation state affects the solubility if many metals.
28
How does pH affect degradation?
Affects the solubility of substances, many heavy metals are more soluble and therefore mobile under more acidic conditions.
29
How do pollutant interactions affect degradation?
Behaviour of a pollutant may be affected by the presence of other pollutants e.g. interaction of NOx and hydrocarbons in photochemical smogs, the combined effect of phosphates and and nitrates in eutrophication.
30
How does water and wind currents affect dispersal?
Velocity and direction of air and water currents will affect how far a pollutant is dispersed and how much it is diluted.
31
How do temperature inversions affect dispersal?
Temperature inversion traps pollution close to the ground especially smog.
32
How does presence of an adsorbent material help to reduce pollution?
- Pollutants may adsorb onto materials such as clay particles or organic materials in aquatic sediments.
- It may immobilise the pollutant and stop it causing problems
33
What is CPS and how does it help to control pollution?
- Predict the movement of potential pollutants in the environment to assess the severity and location of the pollution that may occur
Factors that may be included in CPA:
- Properties of pollutant = state of matter, density, solubility in water/lipids, chemical stability
- Features of the environment = wind and water currents, geology, pH, oxygen availability, temperature
34
What is CGM and how does it help to control pollution?
- Assessing the risk of public exposure to pollutants
- It assess the risk to members of the public who are most at risk
- If their risk is acceptably low, then it is assumed that all other members of public have an even lower risk
35
How does control of emissions location help to control pollution?
Severity of pollution is affected by the location where the discharges are released.
E.g. water currents will dilute and disperse emissions, emissions downwind of urban areas, not discharging waste onto permeable rock above an aquifer.
36
How does control of emission timing help to control pollution?
Changes in the timing of emissions can affect the severity of pollution e.g. tidal cycle and temperature inversion
37
What is the polluter pays principle?
Organisation or person that causes pollution is responsible for any problems caused, giving them an obligation to prevent it
38
What is the precautionary principle?
Assumes that a waste will cause pollution if released, until research confirms it is unlikely to do so when release may be permitted. It is safer than releasing waste that has not been analysed on the hope it is safe.
39
What is selection of the control methods?
Production prevention, prevention of release, post-release remediation, alternative processes.
40
What is the problem with efficiency of pollution control?
- Can be expensive
- ALARA approach = emissions should be As Low As Reasonably Achieved
E.g. selecting new equipment that is BATNEEC - Best Available Technology, Not Entailing Excessive Costs
41
What does photochemical smogs need to form?
When the ultraviolet light from the sun reacts with nitrogen oxides or VOCs present in the atmosphere.
42
What are PANs?
Peroxyacetyl nitrates = a group of chemicals formed when pollution soup reacts with sunlight
- It is a secondary pollutant
- Serves as a carrier for oxides of nitrogen into rural regions and causes tropospheric ozone formation.
43
What is lapse rate?
The atmospheric lapse rate - the change of an atmospheric variable with a change of altitude, the variable concerned is temperature.
44
How do temperature inversions occur?
The normal temperature gradient in the atmosphere is altered as the air temperature at the earth’s surface is cooler than the air at higher altitudes.
- this traps pollution close to the ground.
45
What are the favourable conditions for a temperature conversion?
- Long winter nights
- Cloudless and clear sky
- Dry air near the ground surface
- Slow movement of air that reduces mixing of heat in the lower layers of the atmosphere
Ground surface covered with snow that reflects light
46
How can VOCs be reduced?
Bans/legislation
47
How can reduced combustion be achieved?
Electric vehicles/heating , reduce temperature of industrial processes
48
How can reduction of solid emissions (PM10) be achieved?
Catch and filter pollutants, catalytic converters, use of smokeless fuels
49
How do Electrostatic Precipitators work?
By changing the smoke particles:
- electrodes cause particles to become negatively charged
- the negatively charged particles are attracted to the walls made of positively charged plates
50
What are the advantages of electrostatic precipitators?
- Good for very fine particles
- Don’t constrict air flow = so factory doesn’t overheat and fill with smoke, or catch on fire
- Filter doesn’t need replacing so the process doesn’t need to stop
51
How do cyclone separators work?
Centrifugal and inertial forces are used in a cyclone to separate particulate from the contaminated gas stream as it spirals through the cyclone
52
What are the advantages of cyclone separators?
- For larger particles
- Simple
- Cost effective
- Low every needed
53
How does a Wet Scrubber work?
- Sodium sulphite reacts with the acidic gases making sodium hydrogen sulphite.
- This can be heated to release the sulphur dioxide
- Can be used to make solid sulphur or sulphuric acid.
54
How does a Dry Scrubber work?
- Calcium carbonate reacts with the sulphur dioxide to form Calcium sulphate.
- This is known as gypsum and key ingredient in making plaster
55
How can coal be treated before burning?
- Heated the coal vaporises the tar, and thus makes smokeless coal
- Bag filters - they trap the PM10 in a fabric bag
56
How about fuel burning the fuel more efficiently?
- Burning fuel in O2 so it burns more cleanly.
- Fitting a turbo charger to burn diesel more efficiently.
57
What is acid rain and how does it form?
Acid rain = any rain with a pH lower than 5.2
- When fossil fuels are burnt they react with water and other solutions to form NOx and SO2.
58
59
How is sulphuric acid formed?
- Hydrocarbons containing sulphur compounds in them are burnt the sulphur reacts with oxygen to form sulphur dioxide gas (SO2)
- This then dissolves in water to form sulphurous acid (H2SO3)
- Sulphurous acid is then oxidised by oxygen in the air to from sulphuric acid (H2SO4)
60
How are oxides of nitrogen formed?
Nitrogen and oxygen in the atmosphere —> car engines ‘internal combustion’ —> fuel is mixed with the air and is ignited —> nitrogen and oxygen react —> NOx + water in clouds forms dilute acid
61
What is nitrogen dioxide?
What problems does it cause?
And how can they be reduced?
- Nitrogen dioxide is a toxic red-brown gas, and it causes respiratory diseases such as bronchitis.
- Catalytic converters in cars convert most of the NOx in exhaust gases into harmless nitrogen.
62
What are the three important legislations?
- The Clean Air Act 1956
- Roland and Molina 1974
- Kyoto protocol 1997
63
What is emissions trading?
Countries are able to trade ‘excess’ carbon = this is the amount that they have saved through efficiency measures e.g. legislations and amount of forests
64
What is the EU trading scheme?
January 2005, where companies are issued with pieces of paper that grant them permission to emit a certain quantity of CO2 into the atmosphere in a a year.
Companies that don’t have enough permissions to cover their emissions can buy them from someone who does.
65
How can attitude to pollution emissions change change as countries become more developed?
More affluent countries = more money individually so can afford more cars increasing pollution. But can also pay for offshoring where other counties have the factories and cause the pollution elsewhere.
More developed countries = more education, more money for research so make action plans to reduce emissions and can afford to be more sustainable.
66
How does carbon tax work?
- Industries which emit carbon dioxide will have to pay a tax of up to $12 a tonne of carbon dioxide emissions from 2007.
- This results in raise of petroleum price by 12% and gas/electricity prices by 8%.
- The tax revenue obtained would be used to offset other taxes and into climate change.
67
How is the UK trying to reduce carbon emissions?
- UK climate change levy 2001, a domestic objective to reduce carbon dioxide emissions by 20% by 2010 and 60% by 2050
68
What’s a biotic indicator?
- Species which have narrow range of tolerance
- Can only live in specific conditions
69
What is an example of a biotic indicator?
Lichens as they are very intolerant of pollution specifically SO2 and acid rain
Lichens are a partnership between fungi and algae
70
What are the types of lichen?
- Crusty lichen = most tolerant of polluted air
- Frilly, shrubby, leafy = clean air spaces
- String of sausages = super clean air spaces
71
How does degradation influence pollutant concentration?
- Pollutant concentration decreases if it is chemically broken.
- The rate can be increased by light or living organisms.
72
How does residence time of water affect pollutant concentration?
- Pollutants in a lake with short residence time will reach lower concentration than in one where the inputs and outputs of water are lower.
73
How does volume of water affect pollutant concentration?
- Releases of pollutants into small bodies will produce a higher concentration.
74
How does removal rate of a pollutant affect pollutant concentration?
Removal of the pollutant from a particular location by degradation or moving air or water will reduce the concentration.
75
How does dispersal affect pollutant concentration?
Dispersal by air, water or living organisms will reduce the local concentration but may increase the area that is affected.
76
How does size of emissions affect pollutant concentration?
Larger emissions will produce higher concentrations.
77
78
What’s the EU trading scheme?
- January 2005 companies were issued pieces of paper that grant them permission to emit a certain quantity of CO2 in a year
- If they don’t have enough permissions to cover their emissions they will have to buy them from someone who does
79
80
How can attitude to pollution emissions change as a country becomes more developed?
More affluent countries - have more money individually so can afford more cars which increases pollution, however they can also afford to pay for offshoring, where other countries have the factories and are causing the pollution elsewhere where.
More developed countries - more education, more money for research so can make action plans to reduce emissions and can afford to be more sustainable.
81
How does carbon tax work?
- Industries which emit carbon dioxide will have to pay a tax of up to $12 a tonne of carbon dioxide emissions from 2007.
- This results in raise of petroleum price by 12% and gas/electricity prices by 8%.
- The tax revenue obtained would be used to offset other taxes and into climate change.
82
How is the Uk trying to reduce carbon emissions?
- UK Climate Change Levy 2001 = domestic objective to reduce carbon dioxide emissions by 20% by 2010 and 60% by 2050
83
What is a biotic indicator?
- A species with a narrow range of tolerance
- Can only live in specific conditions
84
What is an example of a good biotic indicator?
Lichens = very intolerant of pollution, specifically so2 and acid rain
They are a partnership between fungi and algae
85
What are the three types of lichen?
Crusty = most tolerant
Frilly, shrubby, leafy = clean air
String of sausages = very super clean air
86
How does degradation influence pollutant concentration?
87
How does volume of water influence pollutant concentration?
88
How does size of emissions influence pollutant concentration?
89
How does removal rate of pollutant influence pollutant concentration?
90
How does dispersal influence pollutant concentration?
91
How does residence time of water influence pollutant concentration?
92
What happens to aquatic animals at higher water temperatures?
- Not enough O2 to survive
- Increases their metabolic rate so they will need more oxygen
- Grow to fast
- Eggs hatch earlier
- Warmer climate species may invade
- Toxicity greater of some pollutants
- Resistance to disease may reduce
93
What is thermal pollution?
- Heat pollution mainly caused by hot condense water from power stations
94
What are the ecological consequences of thermal pollution?
- Many species have a limited range of tolerance, rlly high temps may cause enzymes to denature.
- Temp-dependent of gas solubility in water means that the concentration of dissolved gases such as oxygen is lower at higher temps.
- May kill sensitive species
- Increased rates of chemical reactions occur at higher temps
95
How does a cooling tower work?
- Water needs to be low mineral content, neutral pH , zero particulates = internal circuit of water.
- Hot water sprayed down.
- Cold air is wafted up.
- Cold water collects at bottom.
- Hot air and steam leaves at top.
96
What are the main causes of oil pollution?
- Poor disposal of vehicle lubricants
- Damage to or leakage from oil rigs, pipelines, tankers, etc
- Discharge of tank washing water (to prevent accumulation of tarry residues) from oil tankers
97
What are the effects of oil pollution?
(Indirect)
- Reduces dissolution of O2 at water surface
- reduced breeding success as birds unable to locate mates by sense of smell - affects pheromones
98
What are the effects if pollution?
(Direct)
- Smothers and asphyxiates molluscs
- Some components are toxic - carcinogen
- Water proofing and thermal insulation of bird feathers lost -> hypothermia
- Ingested oil prevents digestion -> starvation
99
What ways are there of treating oil pollution?
- Detergents will break up the oil into smaller droplets which disperses it.
- Absorbent materials e.g. straw picks up oil
- Skimmers use rotating wheels to which the oil sticks and can be scraped off.
- Oil-digesting bacteria can be sprayed on the oil
- Floating booms
- Steam washing can clean contaminated shorelines - heats the oil makes it less viscous = runny
100
What are the adaptations made to an oil tanker?
- Multiple engines + navigation systems
- Multiple propellers and rudders
- Double hull
- Smoke/exhaust gas back filing to stop explosion
- Separate water ballast tank -> to stop ship from capsizing so it keeps the ship as a balanced weight
101
What are the adaptations of liquid oil storage?
- Impermeable oversight
- Volume inside bund wall must be equal to the storage tank
102
What are the properties of a pesticides?
- Mixed specificity
- Poisonous, carcinogenic, toxic, neurotoxic to humans
- Toxic to non target species = bees and butterflies
- Enters water ways = Kills water plants and invertebrates
- Persistent = low water solubility
- Lipid soluble = go into organisms = bioaccumulation = biomagnification
- Synthetic = often not biodegradable
103
What does MDAF stand for ?
Minimum does always fatal = the least you can use which kills everything
104
What does MDNF stand for?
Maximum dose never fatal = the most you can use which doesn’t kill anything
105
What is the correct dose control to not kill non-target species?
MDAF less than MDNF of the non target species
No overlap = not accidental killing of non target species.
106
What are the main sources of inorganic nutrients?
- Phosphates in sewage effluent and eroded soil particles
- Nitrates washed off farmland from manure and artificial fertilisers
107
What is cultural eutrophication and the process?
Eutrophication is the enrichment of a water body with nutrients, usually with an excess amount of nutrients.
108
What causes cultural eutrophication?
- Human activities such as the discharge of phosphate-containing detergents, fertilisers, or sewage.
- Clearing of land and runoff
109
What is an Oliotrophic lake?
Few nutrients, little plant growths e.g. Mountain lakes
110
What is an eutrophic lake?
Rich in nutrients, abundant plant growth e.g. Lowland lakes
111
What happens during eutrophication?
- Influx of nutrients results in algal bloom
- Floating algae shade the submerged macrophytes so they cannot photosynthesise = death = anaerobic respiration = deoxygenation
- Death and decay of algae = deoxygenation
- Cyanobacteria can release harmful toxins = affects livestock, pets and people in contact/drinking the water
112
What are the human health effects of of nitrates?
Nitrates are very soluble and may be ingested from water sources, where the bacteria in the gut converts it into nitrites which react with haemoglobin and reduce its ability to carry oxygen.
113
What are the effects of nitrates on babies?
Babies have high levels of the bacteria so it can cause diseases such as methaemoglobinaemia AKA blue baby syndrome
114
How can nitrates cause cancer?
Gut bacteria can convert nitrates into nitrosamines which are carcinogenic and can cause stomach cancer.
115
What ways can we control inorganic nutrients?
- Reduced use of nitrate fertilisers
- reduced ploughing at times of heavy rain
- Use soluble, rapid-release fertilisers
- the deposition of waste manure where the nutrients will not leach into the ground or be washed into a river
- Reduce high nitrogen requiring crops
- reduce reliance on artificial fertilisers
116
What are NVZs?
Nitrate Vulnerable Zones = where aquifers may be exposed at the surface and can become contaminated
117
What are other ways to mange and limit the effects of inorganic nutrients?
- Adding iron (III) sulphate to remove phosphates from liquid effluents released by sewage treatment works, the phosphates are precipitated as a fine sediment of iron phosphate.
- Dredgin
G lakes and rivers that have phosphate rich sediment from past pollution or adding iron (III) sulphur to reduce the solubility of the phosphates
118
What are the main sources of organic nutrients?
Sewage works, manure disposal, silage storage, leather tanneries, paper mills and food processing plants.
- Carbohydrates, lipids and proteins.
119
What are the effects of organic nutrient pollution?
- Deoxygenation: organic nutrients provide food for microorganisms in the water. Their aerobic digestion deoxygenates the water and may kill aerobic organisms such as fish and insects. Eutrophication can also occur with organic nutrient pollution as microbial decay releases inorganic nutrients.
- Pathogens: Sewage can contain pathogens from infected people. This can allow diseases to spread through sewage and water e.g. cholera, typhoid and dysentery.
- Inorganic nutrient release: organic nutrients do not cause eutrophication directly as they provide nutrients for heterotrophs not nutrients for photo autotrophs. However, as they decay they may release inorganic nutrients which can cause eutrophication.
120
What ways can we treat organic effluents?
- Ban on dumping sewage into rivers
- The effluent received by a sewage works so the concentration of sewage in the water is low.
121
What are the main groups of treatment processes involving activated sludge treatment?
- Pre-treatment = the removal of solid objects such as paper, plastic, road grit.
- Primary treatment = the separation of most organic solids from fluids.
- Secondary treatment = the digestion and break down of the remains organic matter in the fluids.
- Tertiary treatment = additional treatment to remove phosphates or bacteria
- Sludge treatment
122
What are pre-treatment methods?
- Screens: metal grills or sieves are used to trap floating and suspended items.
- Grit traps: for stones and grit traps. Wide channels reduce the velocity of the effluent so the grit sinks and doesn’t flow with the effluent,
- Comminutors: chop up suspended faecal solids, increasing the exposed surface area and speeding up later processes.
123
What is primary treatment?
Sedimentation: effluent is left to stand in large tanks where the faecal solids sink to bottom so that they can removed separately. Removing 95% of the organic matter.
124
What is secondary treatment?
- Destroys the small amount of organic matter that remains in the effluent from the primary sedimentation tank.
- Aeration tanks/oxidation pods: remaining organic matter broken down by bacteria, air is mixed in by paddle wheels or air stones.
- Secondary sedimentation tanks: removes suspended bacteria
- Trickling filter beds: four rotating arms spray liquid effluents over large cylindrical tanks, contains lumps of solid material such as gravel, coke or blast furnace.
125
What is tertiary treatment?
- Used if the discharge site for the treated effluent is particularly ecologically sensitive or important to humans.
- Phophates can be removed by adding solution of iron (III) sulphate producing insoluble iron phosphate as fine as sediments which can be used as a fertiliser
- can be strained through micro-strainers, the remains bacteria killed by UV light
126
What is sludge treatment?
- Sludge removed from primary sedimentation tanks probably contains pathogens.
- Anaerobic microbes digest the sludge in a warm digestion tank for about four weeks
- Killing most pathogens and the odours are reduced.
127
How can the remains after sludge treatment be disposed of?
- Landfill: cheap and simple but wastes nutrient content
- Dispersal in the sea: pollution
- incineration: expensive and needs a lot of fuel, creating further waste
- Agriculture use: used as a fertiliser
- Anaerobic respiration also produced biogas which can be used as a fuel.
128
What is acid mine drainage?
Many igneous metal ores are sulphides. In spoil heaps chemical reactions take place between the small amounts of remaining sulfide ores and oxygen from air in the spaces between the waste particles. This may leave metal oxides and oxides of sulfur which dissolve in drainage water to produced sulfuric acid.
129
What are the effects of acid mine drainage?
Acidic solutions that leach put of the spoil heap have a similar effect to acid rain. The pH of the solutions is often very low and may contain toxic metals if they were present in the mine waste.
130
How can we control acid mine drainage?
The pH of the drainage water can be increased by passing it through crushed limestone to neutralise the acids. This will also reduce the solubility of many toxic metals.
131
Describe the logarithmic nature of the dB scale:
- each bel is divided into ten decibels
- an increase in volume of 10dB represents a tenfold increase in sound volume
- an increase of 3dB represents a doubling volume
132
What is the frequency range of human hearing?
20-20000Hz
133
What is acoustic fatigue?
- some objects have a frequency at which they will naturally vibrate = natural resonant frequency
- if exposed to a sound of this frequency then they will vibrate, which may cause stress cracking and structural failure
134
What is vibration damage?
- repetitive vibration can cause structural damage to buildings, bridges and underground pipes
- this can be caused by the vibrations created by the wheels of heavy vehicles
135
What are shock impacts?
- force of the impact of a sudden very loud noise can cause damage such as the sonic boom of supersonic aircraft jet engines causing structural damage to buildings
136
What are the effects of noise on humans?
- hearing damage: long-term exposure to loud machinery
- stress-related health problems: ulcers, high blood pressure, heart disease
- behavioural changes: irritability, aggression, lack of concentration
- communication problems: difficult to hear others talking
137
What are the effects of noise on other living organisms?
- livestock: sudden noises may cause panic leading to injuries or failure to breed
- disturbance of breeding birds: birds that sing to establish their territories or attract mates may have difficulties in urban areas because of noise levels, may be sacred away by noise abandoning their nests
- reduced feeding success: animals that use hearing to find food e.g. bats, owls, dolphins may not be able to do so
- hearing damage/behavioural changes: cetaceans such as whales and dolphins can be harmed by noises like military sonar to detect submarines, cause it mass stranding of cetaceans
138
How do airforces plan low flying training flights to minimise noise nuisance problems?
- major urban areas are avoided
- UK has 13 major avoidance areas
- flight paths are varied
- UK divided into 20 low flying areas of which three are tactical training areas
- it is possible to request a temporary stop to low flying e.g. for horse shows
- low flying times are published when practical
- compensation may be paid for damage caused to livestock
- flight may avoid ecologically sensitive sites such as seabird cliff breeding colonies
139
How are civil aircraft flights kept to reduce as much noise as possible?
- civil aircraft cruise altitude is high enough that little or no sound reaches the ground
- many airports are located close to urban areas to reduce travel times to and from the airport
140
Why are airports located away from major population centres?
- minimise the number of people affected
141
Why’s re taxi areas away from residential areas?
- taxiing before takeoff can increase noise levels for nearby residents
142
What are engine test areas?
- where engines are tested on the ground at high thrust, are located away from residential area, are only used during the day and are surrounded by acoustic screens
143
What is acoustics insulation?
- buildings affected by aircraft noise may have free acoustic insulation provided e.g. double glazing
144
What are land use restrictions?
- may be restrictions on land-uses near airports allowing industry but not housing developments
145
What is noise deflection/absorption?
- baffle mounds and acoustic barriers can deflect or absorb noise around a busy airport
146
What are the point of multiple landing runaways?
- allows for more time for slowing down, so the wheel brakes can be used which are quieter then reverse thrusters
147
What’s are high bypass-ratio engines?
Modern jet engines have a second cowling and a turbofan on the front of the jet that forces ‘bypass air’ around the inner cowling
- the bypass air smooths the flow of the exhaust air and reduces noise levels, the bypass ratio is the ratio of bypass air: jet exhaust gases, the higher the ratio the quieter the engine
148
What are chevron nozzles?
- used on high bypass engines to make them even quieter
- a serrated trailing edge on the outer cowling mixes the bypass air with the surrounding air more smoothly
149
What are engine hush kits?
- work like chevron nozzles and can be fitted to low bypass ratio engines to make them quieter
150
What are engine acoustic liners?
- used inside the outer cowling and around the inner cowling to absorb noise
151
What is a blended wing aircraft?
- engines are located on the top of the aircraft so the body acts as a barrier reducing the noise that reaches the ground
152
What are aerodynamics?
- fairings on the undercarriage reduce turbulence around the wheels and leg struts
- fairings covering wing flap hinges reduce turbulence around
- riveted construction creates surface indentations which create turbulence and noise, welded panels create less turbulence
153
How are aircraft’s made lighter?
- using composite materials such as carbon fibre, makes aircraft lighter so less engine thrust is needed
154
How can take of angle reduce noise?
- aircraft’s are nosier when taking off then landing as the engines are running at a higher power so if the take off angle is steep it allows the aircraft to climb more rapidly where it reaches an altitude where it isn’t heard on ground
155
How can flight path planning reduce noise?
- flight path routes are planned to avoid densely populated areas whenever possible
156
How does a constant decent angle reduce noise?
- constant angle for the final decent before landing makes the engine noise less intrusive, no periods of high thrust as there are with a stepped decent
- steeper decent angles allows aircraft’s to stay at greater altitudes for longer, so ground level noise is further reduced
157
How do night flight restrictions reduce noise?
Most airports near large residential areas restrict the number of night flights especially take offs
158
How do noises limits help to control noisier aircraft’s?
- aircrafts are categorised into groups according to whether they meet increasingly strict noise limits
159
How do charges for nosier aircraft reduce noise?
- aircraft pay charges do using airports, at many airports the charge is based on noise levels, at Heathrow noisiest aircrafts pay 10 times as much as similar sized quieter ones.
- night flights cost nearly three times as much as day flights
- fines for breaking noise limits
160
His do restricted flight times reduce noise?
- airports near high population density areas often restricts or ban night flights
- takeoffs are controlled more than landings because they are nosier
161
What is a quota count system?
- airports encourage airlines to operate quieter aircraft’s by resting flight times for nosier aircraft’s or using a points system
- aircraft types are allocated points, each airline are allocated a certain number of points, the total point score of the actual fights must not exceed their allocation
162
How does control of supersonic flights reduce noise?
- no longer any supersonic civil airlines
163
How is wheel vibration from trains controlled?
Track polishing and sound absorbing ballast
164
How is engine noise from trains controlled?
Sound absorbing suspension
165
How is pantograph turbulence from trains controlled?
Aerodynamic fairing
166
How is wheel squeal on corners from trains controlled?
Lubrication of wheels/track
167
How is breaking squeal from trains controlled?
Use of composite material breaks
168
How is wheel noise from trains controlled?
Good carriage suspension
169
How is wheel noise from road traffic controlled?
Sound absorbing road materials such as porous asphalt or asphalt that includes shredded rubber from old vehicles
170
How is vehicle air turbulence from road traffic controlled?
Improved vehicle aerodynamics
171
How is engine noise from road traffic controlled?
Acoustic insulation around the engine = quieter exhaust pipes
172
How is general road vehicle noise from road traffic controlled?
- traffic may be rerouted to avoid more sensitive areas
- fences, embankments, walls and dense tree planting can reduce noise
- double glazing windows
173
How industrial noises controlled?
Air compressors and pumps = silences to reduce explosive expansion of air
Stamping machines = alternative processes
Metal conveyers = use of nylon bearings, wheels or rollers
Mine blasting = regular timing, baffle mounds
Pile driving on land = drilling instead
Pile driving at sea = air bubble curtains
Marine seismic surveys = acoustic survey decides to detect cetaceans before use
174
What are general methods used to control industrial noise?
- sound absorbing surfaces in the room
- sound absorbing materials around equipment
- machinery placed on acoustic mat
- sound absorbing materials as part of the equipment
- remote machinery operation
- worker ear protection
175
How is domestic noise controlled?
- domestic appliances with acoustic absorbers
- wearing ear defenders while using power tools
- volume limiters on music equipment
- selection of quieter domestic appliances
- control of pet dogs
176
What modifications are being made to the dB scale?
It takes into account the sensitivity of human hearing by weighing sounds between 1000 and 4000Hz
177
How can road traffic noise levels be measured?
LA10 = measures noise exceeded for 10% in any set period = good for noisiest
LA90 = measures noise level exceeded for 90% in any set period = good for quiet
Traffic Noise Index (TNI) = produces a representative measure of traffic noise using LA10 and LA90
L10 (18h) = measure assumes that noise is only a problem during the 18 hours between 6am and midnight
178
How can aircraft noise levels be measured?
Effective Perceived Noise Levels (EPNL) = estimate of the relative loudness of a particular type of aircraft during takeoff and landing
Noise and Number Index (NNI) = combines the number of flights and the noise levels of aircrafts above 80dB as it is presumed that aircraft below 80dB do not cause serious annoyance
Let 57 dB: let is an average sound level over a particular period, for UK airports and average of 57dB between 7am and 11pm in the summer is used, levels above this are considered annoying
179
What factors determine what method of monitoring water pollution is used?
- speed of data collection
- level of expertise required
- degree of accuracy
- indication of long-term historical pollutant levels
- methods that are specific to individual pollutants
- measurement of the effects of pollution rather than the levels of pollutant itself
180
What is biochemical oxygen demand (BOD)?
- organic materials of plant or animal origin can provide food for bacteria and lead to deoxygenation as they respire anaerobically
- organic pollution is monitored through the level of deoxygenation that is caused, the amount of oxygen being used is measured under standardised conditions
181
What are the standardised conditions for BOD?
1 litre of water
20’C
5 days long
In the dark = to prevent oxygen replacement by photosynthesis
182
What is chemical oxygen demand?
COD = measures the amount of oxygen needed to chemically oxidise all the organic and inorganic substances in a water sample
183
What is a coliforms count?
- E.coli is a common gut bacteria, presence in water is taken as confirmation of faecal matter
- the health risk can be determined by measuring the number of coliform bacteria in a sample as this indicates how serious the contamination is
184
What are biotic indices?
Biotic index is a scale for showing the quality of an environment by indicating the types of organisms that are present
185
What characteristics of species are used in biotic indices?
- have different sensitivities to pollution
- are easy to find
- are easy to identify
- are normally present
- are usually common
- are generally distributed
186
What are the advantages and disadvantages of biotic indices?
ADV:
- rapid assessment of current and recent pollution can be made
- equipment needed is not expensive
DIS:
- sorting samples is time consuming
- identification involves skill
- further tests are required using other techniques to detect the specific pollutant present
187
What are two commonly used biotic indices?
Lichens to monitor atmospheric acidic pollution
Aquatic invertebrates to monitor water pollution
188
What are the key properties of heavy metals?
- heavy metals inhibit enzyme function esp. in three nervous system
- heavy metals are liposoluble meaning they may be stored in fat, which can cause bioaccumulation, which can pass along the food chain and may lead to biomagnification
- if they act in conjunction with other pollutants it can cause synergism
- they are more soluble at low pH, therefore pollution caused by heavy metals can be reduced by increasing pH
189
What are the sources of lead pollution?
- lead-acid batteries, lead flashing used in building construction
- industrial workers may inhale lead or dust or absorb it through their skin if it dissolves in sweat
190
What are the effects of acute lead exposure?
- brain damage, paralysis, death, very high doses can kill by causing liver and kidney failure
191
How can water pipes control lead pollution?
Small amounts of lead dissolve into the water so people drinking the water may suffer chronic exposure
- in high risk areas small amount s of phosphoric acid are added to the water supply, this produces an insoluble layer of lead phosphate in the pipes which prevents lead dissolving into the water
192
How can petrol additives control lead pollution?
Anti-knock agents such as tetra ethyl lead were added to petrol to smooth the explosion of combustion and reduce engine wear, however, lead particulates were released into the atmosphere which created a public health threat
193
How can electrical solder control lead pollution?
Lead-based solder in electrical connections can be vaporised and inhaled when it is melted during soldering or if it is melted during recycling after use
194
How can lead-based paint control lead pollution?
Lead-based solder in electrical connections can be vaporised and inhaled when it is melted during soldering or if it is melted during recycling after use
195
How can fishing weights control lead pollution?
Used on fishing lines that may be discarded or lost and then swallowed by water fowl such as swans, causing lead poisoning
196
How can shotgun pellets control lead pollution?
Most shotgun pellets miss their targets and lay on the ground where animals may ingest them and can be poisoned
197
What are the sources of mercury?
- disposal of items containing mercury e.g. batteries, thermometers
- chemical plants that produce chlorine using mercury electrodes
- combustion of coal
198
What are the effects of chemical form on the toxicity of mercury?
- liquid mercury is not easily absorbed through the skin or gut, although vapours may be absorbed in the lungs if they are inhaled
- inorganic mercury can be absorbed in the gut
- organic mercury e.g. methyl mercury are absorbed easily through the skin, gut and as vapours, they are liposoluble so can affect the brain, kidneys, placenta to harm unborn babies.
199
How is mercury pollution controlled?
- mercury thermometers have been replaced with alcohol or electronic
- mercury can be removed from effluents by reverse osmosis or activated carbon filters
- ion exchange filters
- disposal at high pH to reduce solubility
200
What are the sources of cadmium?
- disposal of old nickel-cadmium batteries
- incineration of wastes containing cadmium pigments
- drainage water from cadmium and zinc mines
201
What are the effects of cadmium?
Liposoluble and bioaccumulates so chronic exposure can lead to toxic concentrations which:
- brain damage and paralysis
- lung cancer
- kidney failure
- skeletal collapse caused by bone decalcification
202
How is cadmium pollution controlled?
- restriction or bans on cadmium such as its use in pigments
- cadmium waste should be disposed of in a hazardous waste landfill site or may be recycled
203
What were the previous uses/sources of tin?
- antifouling paint on the bottom of boats to control growth of marine organisms that create friction
- the chemical was tri-butyl tin TBT which is an endocrine disruptor that alters the growth and reproductive philology of marine organisms which can pass to humans when they eat them
- it is now prohibited and replaced with copper
204
What are the effects of iron pollution?
- iron is not toxic but it can cause deoxygenation when it is oxidised in water
- it is soluble in its chemically reduced form
205
How is iron pollution controlled?
Spoil heap drainage water is collected and passed over mesh screens where the iron becomes oxidised and is deposited on the mesh when the water flows into the river there is no longer a risk of deoxygenation
206
What solid waste is produced from mining and construction?
Mine overburden heaps = usually non toxic
Mine spoil heaps = may contain toxic metals
Demolition waste = may contain hazardous materials such as asbestos
207
What solid waste can be produced from domestic and commercial municipal uses?
- packaging and containers
- paper
- domestic appliances
- organic materials = food and garden waste
- clothing and textiles
208
What are some waste management problems?
- large quantities of waste are produced
- every household produces waste making collection labour intensive and expensive
- mix of waste varies throughout the year
- many different types of waste are mixed together
209
What are the properties of solid waste?
- degradability = how rapidly the waste breaks down
- conditions after degradation e.g. pH, temp, oxygen, bacteria
- flammability
- release of radioactivity
- toxicity
210
How is waste production liked to affluence?
More affluent people:
- purchase more consumer goods
- purchase more trivia
- purchase more disposable items
- throw items away rather than repair them
211
How do companies increase single use and waste?
- built in obsolescence = items designed to have a short lifespan, fast fashion
- disposable products = items with a limited usable lifespan
- over-packaging = to make items more attractive
212
How is solid waste often disposed of?
- dumped into the environment
- plastics can degrade to become smaller particles which can choke sea organisms or release chemicals that may be endocrine disruptors
213
What factors affect waste disposal methods?
- population density = collection costs are higher where fewer people and more dispersed
- mass of waste produced per capita
- properties of the wastes e.g. toxicity and flammability
- land availability
- availability of recycling technology
- degree of environmental awareness and willingness of people to recycle, reuse and repair
- regulator framework and legislation
- household income
- waste processing costs for labour or machinery
214
What are features of a good landfill site?
- separation of different waste types and recording their locations
- polymer liner to prevent the escape of leachate fluids
- perimeter fence to trap litter blown by winds
- regular covering with soil to reduce pest problems
- collection and treatment of leachate fluids
- collection of methane and using it as a fuel
- impermeable cap to prevent water entering
- deodorising spray
- dispersal of flammable materials
- chemicals that could react need to be dispersed away from each other
215
What are the disadvantages of landfill?
- potential resource value is lost
- large areas of land used
- organic matter decays anaerobically releasing methane and CO2
- toxic leachate can leak
- wildlife habitats and farmland lost
- contaminants in the landfill site = can’t be used form farming
- transport delivering the waste to the site and the infrastructure around it can generate noise and congestion
216
What are spoil heaps and how are they made?
Large quantities of non-toxic solids that can produce polluting leachate fluids
- mining and quarrying = coal, clay
- coal-fired power stations = ash
- iron blast furnace = slag
217
How can spoil heaps be made more stable?
Surface erosion can be reduced by establishing vegetation so the roots hold the spoil together
Compaction from buildings on concrete rafts to reduce uneven settling, reducing the danger of subsidence and landslides
218
How can spoil heaps have better drainage?
Natural or artificial drainage may be essential where spoil heaps are tall or on hillsides to reduce the risk of landslides following heavy rain
219
How can lack of nutrients be fixed in spoil heaps?
Addition of top soil, sewage sludge and fertilisers are common techniques to improve the nutrient content and increase plant growth
220
How can pH of spoil heaps be changed?
Additional of lime can reduced acidity of spoil
Rarely too alkaline
221
How can contamination of spoil heaps be fixed?
Phytoremediation can be used where plants absorb and store pollutants such as heavy metals
Petrochemical waste like oil can be treated by bioremediation, where certain species of bacteria will digest the oil in the right conditions
222
How can topography of spoil heaps be changed?
Spoil heaps can be unattractive, landscaping can be used to reshape the heap, although may require getting more land
223
How can toxic leachates be removed from spoil heaps?
Collected and treated to prevent them entering water courses
Deeper layers of soil should be applied during restoration so that plant roots cannot reach the layer containing toxic metals
They’d an bring toxins to the surface and cause their dispersal into the wider environment
224
How can heavy metals be extracted from spoil heaps?
Disposing of them in solid form under alkaline conditions, so the remaining metals are insoluble
To reduce dust particles, heavy metals should be covered so they cannot become airborne
225
How can flammable wastes be reduced in spoil heaps?
Coal of shale oil production can contain high proportions of hydrocarbons which can result in spontaneous combustion within the heap, reduced with regular layers of fine-grained material to reduce airflow
226
What is incineration?
Destruction of wastes by high temperature oxidation
227
What are the advantages of incineration?
- volume of ash produced is much less then original waste
- heat produced may be used for district heating or generation of electricity
- no sorting or complicated management is needed
- flammable materials can be separated and burnt in purpose built power stations which an be used as a fuel
228
What is Refuse-Derived Fuel (RDF)?
Pellets of shredded compacted flammable municipal waste
229
What is Tyre-Derived Fuel (TDF)?
Shredded vehicle tyres, sometimes mixed with coal, wood or other fuels
230
What a re the disadvantages of incineration?
- resource value of recyclable material lost
- toxic dioxins may be produced by reaction of organic wastes and chlorine
- fuel used to maintain combustion of wet or non-flammable wastes = expensive
- wastes may need to be separated
- treatment of atmospheric pollutants in the effluent gasses increases costs
231
What are the features of good domestic waste incinerators?
- recyclable wastes removed before
- high water content wastes removed
- the combustion temperature is kept high and waste gases are cooled rapidly to reduce dioxin production
- heat produced is harnessed for use
- atmospheric pollution is controlled
- heavy metals removed by scrubbing then stored in solid form under alkaline conditions = insoluble
- some materials need additional treatment
232
How is asbestos disposed of?
Encapsulation and storage
Requires special handling, need to be double wrapped in heavy-duty polythene bags in a specialist landfill site where the watse contents are recorded
233
How are cyanide wastes disposed of?
Incineration is the safest wat to dispose of cyanide wastes so that the carbon and nitrogen are separated and oxidised
Carbon dioxide and oxides of nitrogen produced are a much smaller pollution problem
234
What is encapsulation?
Hazardous wastes are mixed with a cement slurry which is poured into containers made of an impermeable and un-reactive material
The solid cement encapsulates the waste so it is immobilised
235
What is vitrification?
Specialist encapsulation technique used to store high-level radioactive waste that has been extracted from nuclear fuel
Powdered radioactive waste that has been mixed with molten glass and poured into stainless steel containers which are sealed
Glass solidifies encapsulating the waste, the steel containers are placed in cylindrical passages inside a concrete building, which are ventilated to remove the heat generated within the waste
236
What is the logarithmic nature of the dB scale?
Each Bel is divided into ten decibels, an increase in volume of 10dB represents a ten-fold increase in sound volume, an increase of 3dB represent a doubling in volume
0dB at 1000Hz is the threshold of human hearing
237
How is ionising radiation and nuclear power used in industry?
- measuring the thickness of rolled metals and paper
- testing aircraft jet engines
- strengthening polymers, radiation can create cross-links in molecules, used to improve latex surgical gloves and balloons
- in oil and gas exploration to test rock porosity
238
How is ionising radiation and nuclear power used in healthcare?
- sterilising heat-sensitive surgical equipment
- cancer treatment
- x-ray and CT scans
239
How is ionising radiation and nuclear power used in agriculture?
- pest control = stored food sterilisation
- sterile male pest control
- production of mutations in crop breeding programmes
240
How is ionising radiation and nuclear power used in scientific research?
- radio-labelled tracers to track movements of Mattel’s within organism or the environment
241
How is ionising radiation and nuclear power used in nuclear fission and fusion?
- nuclear weapons use fission and fusion, 500 nuclear test explosions took place in the atmosphere up to 1980
- nuclear electricity = nuclear fission using uranium and plutonium is used in nuclear reactors to generate electricity
- ship propulsion = high energy density of nuclear fuel means ships propelled by nuclear reactors rarely need to be refuelled and don’t need air for combustion = good fro submarines
242
Why can assessing the risks and benefits if using ionising radiation be difficult?
- symptoms may take a long time to develop
- some effects of exposure may be diffficult to identify as there may be alternative causes of the same sympotoms
- accurate data on impacts on humans is often not avalible
- accurate data on exposure do often not available during accidental releases
- the people of benefit and those who take risks may not be in the same place
243
What is cosmic radiation?
Large amounts of charged subatomic particles are released by natural processes that occur in the sun, when they reach earth they are absorbed releasing high-energy electromagnetic radiation, including gamma rays
244
What are gamma rays from the lithosphere?
- radioactive isotopes in the lithosphere, release different types of radiation when their atoms decay, only gamma rays penetrate well enough to travel from underground to reach the earths surface
245
What is internal radiation from the body?
Activation products form the upper atmosphere and radioisotopes form the ground can enter the body via food and water or by being inhaled, which can decay inside the body releasing radiation
246
What is radon from the ground?
Radioisotopes in underground rocks decay, releasing radiation which is usually absorbed by the surrounding rocks, when some uranium atoms decay the gaseous radionuclide radon is produced.
Radon is unstable and releases alpha radiation
247
What is medical exposure radiation?
- x-rays on bones and teeth
- x-rays with radio-opaque dyes to find blockages e.g. kidney stones
- high does of radiation to kill cancerous tissue
- radio-labelled substances to track the passage of that substance in the body
248
What is occupational exposure?
- nuclear electricity generation
- manufacturing items containing radioactive material
- mining
- medical radiographers
- dentists
- research scientists
- aircraft flight crews
249
What is atomic weapons fallout?
Testing atomic weapons releases radioactive material, this is carried by winds and contaminates all parts of the earths surface
250
What is consumer product exposure?
Smoke detectors, some camping gas mantels contain radionuclides
- small amounts of radioactive materials may be present in ceramics, granite worktops and fertilisers
251
What are industrial radiation discharges?
Most industries that use radionuclides release some radioactive wastes into the environment, majority form nuclear electricity generation
- use of filters on gaseous emissions and ion-exchange sands in liquid releases have reduced the amount of radioactive materials released
252
What is RBE?
Relative Biological Effectiveness is a measure if the comparative effects of different types of ionising radiation on living tissues, more damaging forms of radiation have higher RBEs
253
What are the properties and health risks of Alpha radiation?
- very easily absorbed, travels short distances, stopped by paper
- RBE = 20
- absorbed by clothing and dead skin so outside the body = safe
- ingested alpha = very dangerous as all particles are absorbed making very concentrated damage
254
What are the properties and health risks of Beta radiation?
- moderately easily absorbed, travels medium distances
- RBE = 1
- moderately dangerous, source near to body still pose risk
255
What are the properties and health risks of gamma and x-rays radiation?
- not easily absorbed, travels long distances
- RBE = 1
- lower danger as less like to make direct hit with nucleus
- longer distances of travel means even distant sources are a risk
256
What are the properties and health risks of neutron radiation?
- moderately easily absorbed, travel medium distances
- RBE = 2-10
- very dangerous
- ionising ration neutrons still pose risk after being absorbed
- some atoms are changed when bombarded by neurons so they become activation products
- stable nuclei become radionuclides when no marked with neutrons and may later decay and release
257
What is half-life?
The length of time it takes for half of the original isotopes to decay, so if a mass is observed for several half-lives then the remaining proportion will be 1/2, 1/4, 1/8, 1/16 etc… of the original amount
- short half-life = release all their radiation quickly, dangerous but do not pose threat for long
- long half-life = pose danger for a long time
258
How does ionising radiation cause damage to the nucleons of the cell?
A change in the DNA = mutation
Rapidly dividing cells such as skin and gut art more easily affected as their cells are more genetically active
259
How does ionising radiation cause damage to other parts of the cell?
- means the cell may not function properly and may die
- lower levels of damage may cause no long term effects as their cells intact nucleus can co-ordinate the repair of the damage
260
How does ionising radiation cause somatic effects?
Damage to general body cells and organs
261
How does ionising radiation cause gonadic effects?
Damage to the cells in ovaries and testes
262
How does ionising radiation cause chronic effects?
Effect which appear slowly and in proportion to the radiation doses received
263
How does ionising radiation cause acute effects?
Collection of health effects which appear quickly, if radiation is received over a short period of time then more damage is likely as there a may be more damaging free-radical interaction and the cells have less time to repair themselves
264
What is exposure?
Involves the absorption of ionising radiation from an external source
265
What is contamination?
Refers to physically carrying radioactive materials which, when they release radiation, may cause exposure, if someone is contaminated then exposure will continue for as long as they carry the source on them or in them
266
What are activation products?
Exposure to neutrons can cause previously stable nuclei to become radionuclides as the absorption of a neutron will convert it into a new isotope
267
What are the two basic principles for managing safety and radioactive material?
ALARA = situation should be managed to the expires is ‘As Low As Reasonably Achievable’
BATNEEC = the low exposure can be achieved using the ‘Best Available Technology Not Entailing Excessive Cost’
268
How can closed sources reduce exposure?
Prevent workers form coming into direct contact with the source by enclosing a radioactive source in a container
- prevent contamination
269
How can materials that absorb the radiation reduce exposure?
Materials should be used as barriers to prevent the radiation from reaching the workers, the choice and thickness of the material used will depend upon the type of radiation involved and the space available
270
How can protective clothing reduce exposure?
Used to minimise contamination
271
How can distance from the source reduce exposure?
Radiation follows the inverse square lore so when distance is increased there is a more than proportional drop in exposure
So doubling the distance from the source reduces the exposure to one quarter of its previous level
1
Dose received = —————
Distance(squared)
272
How can reducing the period of exposure reduce exposure?
Working arrangements e.g. shifts should minimise the time a worker is close to the source
273
How can decontamination reduce exposure?
Washing, scrubbing and exfoliating scrubs remove surface contamination
Swallowing stable potassium iodide tablets prevents uptake of radioactive iodine
274
What is high level waste and how can it be stored
Used uranium fuel rods - split nuclei form highly radioactive isotopes
- vitrification
275
What is intermediate level waste can how can it be stored?
The metal tubes that surrounded the fuel rods become radioactive in the reactor and filters from waste processing
- mixed with cement and stored in stainless steel drums
276
What is low level solid waste and how is it stored?
General equipment and clothing that becomes contaminated by coming in contact with radioactive material
- sealed in thick polythene bags, inside steel drums inside steel truck containers in a concrete-lined landfill site
277
What is low level liquid waste and how is it stored?
Waste solutions from used fuel reprocessing and storage
- filtered, including ion exchanges and then discharged
278
What is low level gas waste and how is it stored?
Gases released from used fuel during storage and reprocessing
- filtered then released
279
What units are used to measure ionising radiation?
- Becquerel measures the activity of the source
- Gray is a measure of absorbed dose, 1 Gy is the absorption of one joule of radiation energy per kilo of matter
- Sivert is a measure of effective dose treat allows for the differing effects of the different types of radiation
No. Of sivert = no. Of Grays x a radiation weightling factor for the type of radiation
280
What is the weighting factor of alpha radiation?
20
281
What is the weighting factor from gamma and beta radiation?
1
282
What monitors can be used to measure workers?
- personal dose meter measure current exposure
- photographic film badges measure long term exposure
- air monitors to detect atmospheric particles
- contamination monitors which monitor workers as they leave premises
283
What is CPA?
Critical pathway analysis = identifies the possible environmental routes that radioactive materials may take in the endowment after release, the analysis makes it possible to predict where discharges could cause problems by becoming more concentrated
284
What does CPA involve?
- physical state of the effluent
- density
- meteorological conditions that affect wind speed and direction
- river flow and ocean currents
- physical nature of the environment e.g. geology
- pH and oxygen availability
- bioaccumulation and food-chain concentration
- food sources and consumption by local people
- half-lives of isotopes
285
What is critical group monitoring?
If the critical group is safe then everyone else should be too
Critical group = most at risk group e.g:
- where individuals live
- time spent outside
- sources of food
- source of water
286
What is environmental monitoring of ions in radiation?
Places in the environment where radioactive materials are likely to be most concentrated are identified and monitored and it is established that levels are found acceptable then it is assumed that everywhere else is safe.
Assuming the pathways have been predicted correctly
- material such as dust, soil, water, grass, milk, meats, and fish are most likely to be contaminated and those that indicate direct risk to humans
