Pollution Flashcards
What are the properties of pollutants?
State of matter, energy form, density, persistence, toxicity, reactivity, adsorption, solubility in lipids/water, bioaccumulation, biomagnification, synergism, mutagenic action, carcinogenic action and teratogenic action
What is pollution?
Energy or matter released into the environment with the potential to cause adverse changes to an ecosystem
How can pollutants be categorised?
Direct v Indirect
Anthropogenic v Natural
Primary v Secondary
What are the major types of pollution?
Air, water, thermal and soil or land
How does state of matter impact a pollutant?
Affects the ability to be dispersed by moving water or air
How does density impact a pollutant?
Affects what happens to the particles of a solid, the more dense they are the closer to the source they will settle out
Gases denser than air will sink if the wind is sufficient to disperse them
Liquids will sink quicker if they are more dense
How are sources of pollution categorised?
Point: from a defined place with a definite affect e.g. oil spills from a tanker
Diffuse: from many sources with combined impacts e.g. car exhausts
How is persistence measured?
The time taken for half a pollutant to break down, this is known as environmental half life (Tl ENV)
What environmental conditions can impact the rate of breakdown of pollutants?
Light, temp, oxygen levels, pH or the presence of bacteria
What are some pollutants with high persistence?
CFCs and organochlorine insecticides (DDT)
What are some pollutants with low persistence?
Sewage and pyrethroid insecticides
What does POP stand for and what are they?
Persistent Organic Pollutants and they do not degrade in the environment
Why are POPs bad?
Have negative health effects, they nearly wiped out the bald eagle, transboundary pollution threatening Antarctica, decline of wildlife, disease and abnormalities in living creatures and reproductive impairment
How many main POPs are there and name a few?
21 main: aldrin, chlordane, dichlorodiphenyl trichloroethane (DDT), PCBs and dioxins
What impacts can lead have as a pollutant?
Persistent heavy metal, neurotoxin, it accumulates in the soft tissues and bones, it can cause blood and brain disorders, it affects all organs but especially the nervous system
What are some of the symptoms of lead poisoning?
Abdominal pain, weakness, impaired cognitive function, brain damage, kidney damage and death
What are some other toxic pollutants?
Carbon monoxide, acids and cyanide
How is cyanide toxic?
Inhibits enzymes involved in aerobic respiration
What are PANs?
PeroxyAcetyl Nitrates are made from nitrous oxides with oxygen in the air and unburnt hydrocarbons when reacted in sunlight
How are PANs toxic?
Irritating to eyes and lungs and they kill plants
How does specificity impact pollutants?
Variations in toxicity to different groups of organisms
How does specificity affect use of pyrethroid insecticides?
High toxicity to insects and low toxicity to mammals so safe for use, however they have high toxicity to fish so shouldn’t be used near lakes or rivers
How does adsorption impact pollution?
Immobilise them so they cannot cause pollution problems, but it’s also possible they may be released later to cause other problems e.g. the disturbance of lake sediments by storms may release phosphates or PCBs
What’s the harm of water soluble pollutants?
Very mobile and can lead to eutrophication
What’s the harm of liposoluble pollutants?
Mor soluble in fats so they can pass through phospholipid membranes and stored as oil or fat in cells, allowing biomaginification
What are some lipid soluble pollutants?
DDT, PCBs and heavy metals e.g. Mercury
What are the negative effects of DDT?
Cancer, poisoning wildlife (especially birds) and poisoning aquatic animals
What are PCBs used for?
Coolants, insulating fluids, plasticisers, pesticides, flame retardants, adhesives, paints etc
What is mobility?
The measure of the degree to which a pollutant can be carried by wind, water or organisms
How does mobility impact a pollutant?
High mobility may mean it impacts larger area however dilution means impact may not be as strong
What is bioaccumulation.
The absorption and storage of pollutants in the tissues of organisms, the amount of substance increases over time
How does biological half life impact bioaccumulation?
Greater half life means greater risk of chronic poisoning
What is biomagnification?
The increase in concentration as a pollutant passes along a food chain, becoming concentrated into a progressively smaller biomass with each successive trophic level
How does biomagnification link to the food chain?
Many of the producers are eaten by the primary consumers and the toxins move from originally dispersed area to one organism
What is synergy?
When the combined effects of different pollutants has a much worse effect, they DO NOT combine to create a new pollutant
What’s an example of ozone in synergy?
Ozone damages leaf surface cuticle so sulphur dioxide can access the newly exposed living cells and accuse more damage
What’s an example of synergy in heavy metals?
Lead and cadmium, the impact of one allows the impact of the other to be even stronger but unclear which starts
What are some of the toxic effects of cadmium?
Carcinogenic, linked to osteoporosis, heart disease and learning difficulties
Where can cadmium poisoning come from?
Pigments, steel plating, batteries, smoking or the environment
What are some mutagens?
Ionising radiation, UV light, asbestos, cadmium, chlorinated organic substances
What are some examples of carcinogens?
Asbestos, DDT, cadmium and cigarette smoke
What are teratogens?
Chemicals or energy that cause non-inherited birth abnormalities
What do teratogens do?
Inhibit the function of proteins and enzymes that the DNA would have normally controlled
What is an example of teratogen?
Herbicide 2,4,5T (Agent Orange)
What are some key facts about dioxins?
POPs, bioaccumulate, 90% of human exposure is through food, highly toxic, reproductive and developmental problems, damage immunity, interfere with hormones, carcinogenic, background exposure won’t affect human health and prevention is done via source directed measures
What environmental factors affect the rate of degradation?
Temp, light, pH, oxygen levels, the presence of other chemicals, temperature inversions and the presence fo absorbent material
What abiotic factors affect the dispersal of pollutants?
Velocity/direction of air and water currents
What’s a problem with fast degradation?
Deoxygenation
When does light impact degradability?
Photochemical smogs, photo-degradation of some pesticides
When does oxygen impact degradation?
Aerobic bacterial decomposition and oxidation of sulphide ores producing sulphur dioxide
What happens when warm pollutants are released at higher colder altitudes?
They are less dense and more buoyant than the cooling surrounding air, this allows them to rise disperse and become diluted, they cool but surrounding air is still cooler so they continues to rise and disperse
How does normal temperatures cause the dispersal of pollutants?
As they are warmer than the surrounding air they continue to rise and are dispersed
How do temperature inversions prevent the dispersal of pollutant gases?
When the layer of air closest to the ground is colder than normal, the pollutants become colder and more dense quicker, they cannot disperse easily and become concentrated
What factors allows a temperature inversion to form?
Low wind velocity, valleys, cloudless skies and mist or fog during the day
Why are low wind velocities needed for temperature inversions?
So the two layers of air do not mix
Why are valleys needed for temperature inversions?
Colder denser air can collect
Why are cloudless skies desired for temperature inversions?
IR energy can be radiated from the ground allowing the ground to cool
Why does mist or fog during the day allows for temperature inversions?
Water vapour that condenses in the cooler ground layer had a high albedo and will reflect sunlight and slow the heating of the ground that would cause the temperature inversion broken down
What happened to the Caesium-137 at Chernobyl?
Washed out of the atmosphere by rain and adsorbed onto the clay particles in the soil so any radiation is absorbed by the ground
What is the purpose of CPA?
Critical Pathway Analysis predicts the movement of potential pollutants in the environment to assess the severity and location of the pollution that may occur
What factors are included when determine the critical analysis pathway?
Properties of pollutant and features of the environment
What is CPA mainly used for?
Monitor the dispersal of radioactive waste discharges
How can the accuracy of CPA be checked?
Environmental sampling
What is CGM?
Critical Group Monitoring is a specific method of assessing the risk of public exposure to pollutants
What does CGM do?
Assesses the risk to members of the public who , because of their lifestyle, are most likely to be at risk. It monitors exposure to assess potential risks before health impacts occur
What factors affecting the dispersal of pollutants can be managed?
Emission location and timing
What are some examples of controlling emission location?
Marine discharges where currents disperse and dilute emissions, emissions downwind of urban areas and not discharging waste onto permeable rock above an aquifer
What are some examples of controlling the timing of emissions?
Tidal cycles- emissions into tidal rivers when tide is coming is will be carried upstream and when tide is going out will allow dispersal
Temperature inversions- restricting time and area of activity if inversions may happen
What is the precautionary principle?
This assumes a waste will cause pollution if released until research confirms it doesn’t, this is safer than releasing a waste that hasn’t been analysed
What is an example of production prevention?
Desulfurisation of fossil fuels before combustion
What is an example of prevention of release?
Electrostatic precipitators for smoke control, catalytic converters for control of NOx, CO and hydrocarbons in vehicle exhaust emissions
What is an example of post release remediation?
Oil spill clean ups and phytoremediation of land contaminated with heavy metals
What are some examples of alternative processes?
Electric vehicles, pyrethroid pesticides instead of DDT and use of renewables
What is the ALARA approach to emission control?
As low as reasonable achievable, meaning paying a efficient amount to clean up as cleaning all is rarely possible anyway
What is BATNEEC?
Best available technology, not entailing excessive costs
What is smoke made up of?
Atmospheric particulates produced by the incomplete combustion of carbon-based materials
How is smoke categorised?
Size range on the particles e.g. PM10 is less than 10 microns in diameter and PM5, PM1 are commonly used
What are some sources of smoke?
Combustion of coal, diesel, general combustible wastes especially in urban areas and combustion of crop waste, wood fuel, grasslands, forests in rural areas
What are the effects of smoke on humans?
Respiratory disease, e.g. bronchitis, asthma, lung cancer. Chemicals on or in smoke can kill the cilia in the bronchioles which makes it more difficult to clear inhaled particles and bacteria from the lung, this can increase the risk of infection
What are the effects of smoke on other living organisms?
Reduced photosynthesis as smoke blocks light, some substances in the smoke may also be toxic e.g. acids and heavy metals
What are the effects of smoke on non-living objects?
Smoke particles can damage buildings due to the acids and organic solvents they may contain, cleaning dirty buildings is expensive
What are the effects of smoke on the climate?
Large releases of smoke can reduce temperatures because the high albedo of the smoke reflects the light so it does not reach the ground, where it may be absorbed and converted to heat, crops may die, livestock may die and many natural ecosystems would be disrupted
Why do smoke particles remain in the stratosphere longer than the troposphere?
No rain to wash them away
How can smoke damage the stratosphere?
Disruption of ozone
What makes fog more likely?
Temperature inversion
What are the dangers of smoke in fog?
More easily inhaled
How is smoke controlled by legislation?
Clean Air Act (1956), which restricted the use of fuels that do not produce smoke, for example, natural gas, electricity
How are domestic sources of smoke controlled?
Increased use of fuels that do not produce smoke, for example natural gas, electricity
How are diesel transports controlled for smoke?
Diesel Particulate Filters (DPF) fitted in the exhaust pipes of engines that trap up to 80% of smoke particles
What are electrostatic precipitators?
Effluent gases are passed through a chamber with many electrically charges wired or plates, smoke particles within the gases are attracted to the charged wires and plates and collect together, as the particulates accumulate they fall to the floor as ‘fly ash’, this is often used in coal-fired power stations
What are cyclone separators?
Based on the same principle as vacuum cleaners, the effluent gases are forced to rotate in a cylindrical chamber, which throws the suspended particles to then outside surfaces of the chamber where they fall and collect, this cleans the gases which are then discharged via a pipe from the centre of the cylinder
What is a scrubber?
Fine water spray to wash out suspended solid particulate matter and dissolve soluble gaseous pollutants
What is coal treatment?
Heating coal allows the tar that causes smoke production to be drained off
What are bag filters?
Remove smoke particles from effluent gases by trapping them on fabric filter
How are Diesel engines developed to be more efficient and create less smoke?
Turbo chargers enable more air to be delivered to the combustion chamber, to reduce smoke formation and increase efficiency as more of the organic matter is completely burnt when accelerating
When do photochemical smogs occur?
Urban pollution during temperature inversions
How do NOx form in exhaust gases of vehicles?
N2 and O2 form the air react under the high temperature and pressure in the engine, it’s unrelated to the fuel
What are the dangers of PANs?
They are more stable than ozone and act as global formation of global tropospheric ozone as they carry nitrous oxides
What are the effects of nitrous oxides?
Increases the risk of respiratory infections, such as colds, flu and bronchitis, they can also making existing conditions worse
What are the effects of PANs?
Eye irritation, breathing difficulty, emphysema and increased risk of heart disease
What can make cities prone to photochemical smogs?
Topography, heavy vehicle use and climate
Athens, LA, Paris, Beijing and Mexico City
What are control methods for photochemical smogs?
NOx and HCs can be controlled with catalysts such as platinum and palladium
NOx reforms N2 and O2
How are hydrocarbons controlled?
Catalytic converters create carbon dioxide and water by oxidation, unburnt hydrocarbons can be managed by collecting and condensing fumes back into fuel at petrol stations, vapours can also be collected and passed through an activated carbon filter where the hydrocarbons adsorb onto the carbon particles
What is the natural pH of rain?
5.6
What happens when sulphurous and nitrous oxides react with oxygen and water in the atmosphere?
They form secondary pollutants as acids
What other gases can form acid rain?
Hydrogen chlorides and sulphur trioxide (reaction with ozone)
What are the impacts of acid rain on non-living things?
Acid corrodes metal , causing damage to railway lines, metal railings, water pipes, pylons and overhead power lines. Limestone structures such as building and statues are damaged as the acids dissolve the surface layers and weaken the stone structure of porous limestone
What are the direct impacts of acid rain on living things?
Denature proteins in cell membranes and can inhibit enzyme action, exposed living cells likely damaged and invertebrates with exoskeletons may die, the acid dissolves calcium compounds that form the skeleton and lichens are very sensitive
What are biotic indicators?
Species which have a narrow range of tolerance e.g. lichens
What is a lichen?
Composite organisms consisting of a fungus (the mycobiont) and a photosynthetic partner (photobiont) growing together in a symbiotic relationship
Which lichens are most tolerant of polluted air?
Crusty lichens
What are the indirect impacts of acid rain on living things?
Low pH makes metal ions more soluble, which may lead to leaching and important plant nutrient (calcium and magnesium ions) are normally lost first, ions such as aluminium and lead become mobile and are no longer adsorbed onto clay, these may inhibit enzyme action, leaching can lead to death of aquatic organisms and consumption by humans (water or animals)
How does fog affect the severity of acid rain?
Can cause acid rain to be in contact with vegetation longer as no water potential gradient leading to more harmful effects
How does soil lime content affect the severity of acid rain?
Neutralises acid pH and minimises effect
How does snow impact the severity of acid rain?
PH of meltwater will be much lower, harming soil and aquatic life in fresh waterways
Why is hydrogen sulphide removed from natural gas?
To prevent corrosion damage to refinery and pipeline equipment and to the appliances in which the gas is used, this also prevent the production of sulphur dioxide when it is burnt
How is hydrogen sulphide removed form natural gas?
Dissolving it in amine solution or reacting it with iron particles
What processes can be used to remove sulphur form power station emissions?
Dry flue gas desulphurisation and wet flue-gas desulphurisation
What happens in dry flue-gas desulphurisation?
Flue gases are passed through a bed of crushed calcium carbonate, the sulphur dioxide reacts with the lime to produce calcium sulphur, if the effluent gases have been cleaned to remove smoke particles, then calcium sulphate may be pure enough to make gypsum building plaster
What happens in wet flue-gas desulphurisation?
Sodium sulphite scrubbing where the flue gases are bubbled through a sodium sulphite solution, the sodium hydrogen sulphite is then heated and breaks down to sodium sulphite and water, which are rescued, and concentrated sulphur dioxide, which is valuable industrial raw material can be converted to solid sulphur or sulphuric acid
What are the control methods for oxides of nitrogen?
Low temperature combustion, lean-burn engines, catalytic converters and urea sprays
Tropospheric ozone- effects, production and control
Toxic to plants, breathing difficulties and increased asthma, produces secondary pollutants (photochemical smog and acid rain)
NO2 broken down by UVA, releasing O radical to react with O2
Reducing NO2 release
Carbon monoxide- effects and control
Binds to haemoglobin causing brain damage and death
Exhaust catalytic converters oxides to carbon dioxide
How does effluent quantity impact water pollution?
The amount of pollutant released affects concentration, if the concentration of pollutant in the water is low many pollutants are not harmful
How does volume of water impact water pollution?
The anger the body of water the more the waste will be diluted
How does the residence time of the water impact water pollution?
The shorter the residence time of the water the more likely that the pollutant will be carried away by flowing water and not accumulate
What factors affect the rate of degradation in water?
Light levels, temperatures, environmental conditions making new substances by oxidation or reduction
How can reduction of pollutants be harmful?
Inorganic mercury wastes can be reduced to methyl mercury which is much more hazardous
How do sediments within the water impact water pollution?
Pollutants may absorb onto the sediments which effectively removes them from the water
What factors can be considered when locating suitable sites for effluent discharge?
Dispersal by currents, however if pollutants don’t degrade large water bodies can make problems harder to solve later
How can warm effluent water impact ecology?
Lower the possible dissolved oxygen level, denatures proteins in aquatic organisms
How can warm effluent water cause physiological changes?
Increased metabolic rate of many organisms, so more energy is used leaving less surplus energy for growth, increased rate of development of eggs so they hatch sooner, non-indigenous species may thrive and outcompete indigenous, toxins can be metabolised more rapidly, resistance to disease may be reduced
What are some of the control methods used for thermal pollution?
Cooling towers are used to cool power station effluent water so that it does not cause deoxygenation, water used to condense steam in a power station is taken from a nearby water source, after absorbing heat the water is returned to the natural source at higher temperatures
How do cooling towers work?
Spray hot water from shower floor, the air absorbs the heat from the water and rises up the tower, escaping into the open atmosphere, this causes an up-draught, which draws more air through the shower spray.
How much higher is the temperature of the water returned?
5 to 8 degrees Celsius
Where are cooling ponds used?
In places with sufficient land
What is the water in a cooling pond used for?
Reused by the plant
What are the causes of oil pollution?
Waste lubricating oil, accidental releases and oil exploitation
What are some accidental releases?
Shipping accidents, oil rig accidents, oil pipeline leaks, storage tank leakage and discharge of waste water from washing tanks on ship tankers
What are the effects of oil pollution?
Reduced dissolution of O2, smothers and asphyxiates molluscs, some components are toxic, waterproofing and thermal insulation of bird feathers lost leads to hypothermia, ingested oil prevents digestion and reduced breeding success as birds are unable to locate mated by sense of smell
What are drill pipes lubricated with?
Fine clay suspended in water (mud)
What are the effects of oil pollution?
Planktonic organisms killed by toxicity Algae cannot access sunlight or carbon dioxide for photosynthesis
Bird feathers stick so they drown
Less O2 can dissolve from atmosphere
How can waste lubrication oil be reused?
Contaminants can be removed and chemical reforming and distillation can produce commercially valuable lubricant again
How can oil pollution be controlled by improving tanker operation?
Better shipping routes, better navigation systems, inert gas systems, tank washing procedures and oily waster water disposal
What is the AIS and what does it do?
Automatic Identification System allows the position of other ships to be monitored to avoid collisions
Why are inert gas systems used?
Using air to fill the tankers can cause an explosive mix of air and oil vapours
Why must oil tanks be washed?
To prevent the build up of tar sludges
How were tanks previously washed?
Washed with sea water which was then discharged back into the sea
How is oily waste water disposed of?
Unloaded at an oil terminal when the tanker docks
How can tanker design be improved to control oil pollution?
Double hull, double rudder, double engine, double fuel tanks, separate oil and ballast tanks, oil interceptors and bund walls
What is the hull and how does doubling it help?
The layer of steel between the oil and sea, doubling it means any damage to the outer hull doesn’t release any oil as there is typically a 2m gap
How can doubling engine/rudder/fuel tanks prevent pollution?
Any mechanical failure on a tanker that affects propulsion/steering can be serious as the ship could be carried by wind or currents onto a rocky coastline
How do separate oil and ballast tanks help prevent oil pollution?
Ballast water pumped back into the sea can carry oil residue with it
What do oil interceptors do?
Separate oil from watery waste, the water flows to the main drainage system or river but the oil is retained and can be removed for later treatment
What do bund walls do?
Contains the oil if the tank were to split, the volume enclosed by the bund wall is greater than the tank so it cannot overflow
What happens to the oil in spill?
Light fractions can evaporate, medium fractions will be digested by bacteria, but heavier fractions will remain as tar balls for many years
When is oil pollution most serious?
When it occurs inshore, or in an enclosed body of water, where dispersal is prevented, where there are more sensitive ecosystems, where there are more concentrated human activities to be effected
What are booms and how are they used?
Inflatable tubes that restrict movement of floating oil, a skirt below the boom can retain oil if there is a water current
Where are booms mainly used?
Sheltered areas where they can reduce the dispersal of oil as open currents are too strong
What are skimmers?
Rotating metal discs that pick up oil that can be scraped off and stored for later disposal by incineration or landfill
How are absorbent materials used for oil treatment?
High surface area materials such as textile mops can help to absorb oil, the absorbent material and oil can be removed and disposed of by incineration or in landfill sites
How can detergents and dispersants be used in oil treatment?
Break up the oil to produce and emulsion of oil droplets in water, they allows the oil to become more mobile and disperse , possible to be broken down by bacteria but they do not reduce the amount of pollution themselves.
How can polymerising agents be used for oil treatment?
Chemicals have been developed that cause the oil molecules to join together, producing more solid materials that can be collected more easily
How can steam washing be used in oil treatment?
Oil on beaches can be washed off using sprays of steam and hot water, this does not destroy the oil, but it can remove it from particularly sensitive habitats, however, the steam jets may kill organisms deeper in the beach sediments that were not affected by the oil
How does bioremediation impact oil treatment?
Some bacteria break down hydrocarbons and helps to remove the residual pollution left after the other clean-up methods have been used, bioremediation of the soil may be accelerated by irrigation, the addition of nutrients and ploughing of the soil
What are some oil spill treatment methods?
Booms, skimmers, absorbent material, detergents, polymerising agents, steam washing and bioremediation
What are some types of pesticides?
Insecticides, herbicides and fungicides
What would the characteristics of an ideal pesticide be?
Specific, non-persistent and incapable of bioaccumulation and biomagnification
How can harm to non-target species be controlled?
Dosage
What is MDAF?
Minimum dose always fatal
What is MDNF?
Maximum dose never fatal
How did DDT impact birds?
Caused thin shells of the eggs at low doses, meaning they broke easily, higher doses caused sterility and much higher doses caused death
What are some indirect effects of pesticides on organisms?
Reduction in the population of one species can affect another inter-dependent species, some species become rarer because they have lost a food supply or an ecosystem service ugh as pollination or seed dispersal, other species may become more common because they have fewer predators or competitors
Organochlorines (DDT)
Highly toxic to insects, low toxicity to mammals and invertebrates, high persistence, high liposolubility and low solubility
Death of bees, butterflies and beetles
Bioaccumulate and biomagnify
Pyrethroids
Not persistent, toxic to insects and fish, low mammal and bird toxicity, requires low doses to kill insects, fast-acting, bind tightly to soil and organic matter and dissolved very poorly in water
Neonicotinoids
Relatively persistent and water soluble, toxic to insects (especially bees) and lower mammal toxicity, neurotoxin to bees reducing navigation and immunity
What is DDT still used for and why is it acceptable?
Control malaria mosquitoes in houses, should not cause toxic exposure or lead to DDT entering the human food chain where it could biomagnify
What does chronic exposure of organophosphate increase?
Impaired memory, depression, behavioural changes, ADHD and Alzheimer’s disease
How can the impacts of neonicotinoids be minimised?
Coated seed treatment minimises impact on non-target species
How can the harmful effect of all pesticides be reduced?
Restricting use, use of non-persistent pesticides, use of specific pesticides, use of systemic pesticides, application timing, non-pesticide techniques
What are systemic pesticides?
Absorbed by the crop and translocated within it, they do not need to be sprayed onto all surfaces, they may be eaten by humans though if they are still present in the plant tissue
How does application timing reduce harmful effects of pesticides?
Spraying on still days results in less spray drift, spraying at night or when plants aren’t flowering reduces impacts to bees and newer spraying techniques use smaller droplets to produce even more coverage which reduces the amount required to adequately cover all areas of the crop leaves
What are some of the sources of phosphates?
Sewage effluent and eroded soil particles
What are some of the sources of nitrates?
Washed off farmland from manure and leachate from artificial fertilisers
What are the inorganic nutrients that can cause pollution?
Nitrates and phosphates
What are the characteristics of oligotrophic lakes?
Few nutrients, little plant growth for example mountain lakes
What are the characteristics of eutrophic lakes?
Rich in nutrient, abundant plant growth, for example lowland lakes
How does the growth fo Cyanobacteria lead to problems?
Release harmful toxins which can affect livestock, pets and people who drink or are in contact with the water, algae are also an unreliable food source as they can die off quickly if the right conditions are not met
What effects can leaching and eutrophication has on biodiversity?
Change species diversity, change species abundance and species may become present or absent
How are nitrates linked to cancer?
Gut bacteria convert nitrates to nitrites, these may then be converted tin the gut to nitrosamines which are carcinogenic and may cause stomach cancer, most research has been arrived out on rats and the link is not conclusive
Where are nitrites used?
Added to bacon to give it the smokey flavour
What are the effects of nitrates on babies?
Nitrites react with haemoglobin in the blood and reduce its ability to transport oxygen, high levels may cause the disease methaemoglobinaemia or ‘blue baby syndrome’, infants are especially at risk as they have more of the necessary bacteria and their haemoglobin reacts more rapidly with nitrites
What other products have food additives as nitrites?
Meat, fish and cheese
What are the control methods for reducing inorganic nutrients?
Reduced use of nitrate fertilisers, reduced ploughing/tilling, use of soluble, rapid release fertilisers or insoluble fertilisers depending on the location, the deposition of waste manure where the nutrient will not leach into the ground, reducing the cultivation of crops that have higher nitrogen requirements, reducing the reliance on artificial fertilisers and adding more denitrifying bacteria to areas
What’s an NVZ?
Nitrogen Vulnerable Zone, where aquifers may be exposed at the surface and can easily become contaminated
What are some ways to specifically remove or limit the effects of phosphate?
Adding iron (III) sulphate to remove the phosphates from liquid effluents released by sewage treatment works, the phosphates are precipitated as a fine sediment of iron phosphate, this is called phosphate stripping
Dredging lakes and rivers that have phosphate-rich sediments from past pollution or adding iron (III) sulphur to reduce solubility of the phosphates
How much of the uk is currently a NVZ?
55%
What impact can buffer strips have on NVZ?
Reduce the risk and have nitrate and phosphate control areas
How does absorbent properties impact phosphate?
Phoslock binds to free reactive phosphate and locks permanently and the compound falls to the floor
What are some of the sources of organic nutrient pollution?
Sewage works, manure disposal, silage storage, leather tanneries, paper mills and food processing plants
What are some organic pollutions that’s aren’t biodegradable?
Plastic and some man-made chemicals
What is sewage?
A mix of domestic and industrial waste in liquid form
What can sewage contain?
Dissolved organic material (bacteria, urine, soap), water (99.9%), particulate organic waste (food, goldfish), debris (plastics) and dissolved inorganic material (N and P)
How does organic pollution of water lead to deoxygenation?
Microorganism respire aerobically to breakdown matter, which deoxygenated the water
What is biochemical oxygen demand?
The amount of oxygen consumed by bacteria and other microorganisms while they decompose organic matter under aerobic (oxygen is present) conditions at a specified temperature
How is sewage impacted by pathogens?
Can contain pathogens from infected people, these can be passed onto other people in they come into contact with the pathogen either directly of in contaminated water and food
What types of diseases spread from sewage pollution?
Cholera, typhoid and dysentery
What nutrients do organic materials provide?
Nutrients for heterotrophs, not for autotrophs
How can sewage cause a release of inorganic nutrients?
Decaying of heterotrophs will release them
What is the concentration of sewage?
2-3kg of sewage/person/day in 250kg of water
What are the main groups of treatment processes in activated sludge treatment?
Pretreatment, primary, secondary and tertiary
What happens in pretreatment in activated sludge treatment?
The removal of solid objects such as paper, plastic and road grit
What happens in primary treatment in activated sludge treatment?
The separation of most organic solids from fluids
What happens in secondary treatment in activated sludge treatment?
The digestion and breakdown of the remaining organism matter in the fluids
What happens in the tertiary treatment in activated sludge treatment?
Additional treatment to remove phosphates or bacteria; sludge treatment
What are the stages in pretreatment in activated sludge treatment?
Screens, grit traps for stones and road grit and comminutors
What happens to the plastic and paper items that the screens trap?
Treated by incineration or disposed of in a landfill site
How are stones and road grit removed in grit traps?
The channel widen to slow the flow rate and the kinetic energy that carries grit drops to the bottom and is deposited as sediment
What happen to the grit removed in grit traps?
Disposed of in landfill site or by sterilisation and reuse
What do comminutors do?
Chop us suspended faecal solids, increasing the exposed surface area and speeding up later processes
What happens in the primary treatment in activated sludge treatment?
The effluent is left and all the organic matter forms a sediment in the bottom
How is the sludge from primary sedimentation treated?
Anaerobic digestion in warm tank for about 4 weeks, this kill most pathogens and the odours are reduced, the sludge is then dried on drying beds
How is the dry sludge removed?
Landfill, matter dispersal in the sea, incineration or agricultural use
What are the disadvantages of incineration of dry sludge?
A lot of fuel (usually natural gas) is required and is therefore expensive, this also creates further waste in the form of gas and a small amount of ash which is deposited in landfill sites
How can the sludge from primary treatment be used in agriculture?
Agricultural fertiliser
Why is it important to time the spreading of sludge in agriculture?
Application during the growing season would cover the crops, while application during the winter can cause damage to the damp soils as farm vehicles compact the soil
What are some of the disadvantages of using sludge in agriculture?
Heavy metal from urban wastes and road runoff maybe present in the sludge and could be absorbed by crops and then consumed with food, this can be reduced by adding lime to reduce the solubility of the heavy metals
What are the stages of secondary sedimentation?
Aeration tanks, secondary sedimentation tanks and trickling filter beds
What happens in the aeration tanks in secondary treatment?
The remaining organic matter in the fluid effluent is broken down by bacteria, shortage of oxygen can be limiting factor as it slows down this aerobic process, to stop this, large amounts of air are mixed by paddle wheels, or air stones
What happens in the secondary sedimentation tanks?
The effluent from the aeration tanks contains suspended bacteria which must not be wasted, these are collected in the secondary sedimentation tank and returned to the aeration tank as ‘activated sludge’, in most sewage works, the clear effluent from secondary treatment is discharged into the river, lake or sea, it should contain no pathogens, or other organic materials, but it may contain some dissolved inorganic nutrients which could cause cultural eutrophication
How are trickling filter beds used in secondary treatment?
An alternative process to aeration tanks, it is an older process that has mainly been replaced by the use of aeration tanks in activated sludge treatment, four rotating arms spray the liquid effluent over large cylindrical tanks containing lumps of a solid material such as gravel, coke, or blast furnace clinker
Why is the surface area of trickling filter beds increased?
Bacteria, fungi, invertebrates, algae, worms and fly larvae to digest the remaining organic matter
How can nitrates also be reduced?
Denitrified by bacteria so the liquid effluent will cause less eutrophication
When is tertiary treatment used?
If the discharge site for the treated effluent is particularly ecologically sensitive or important for humans
What are some methods used in tertiary treatment?
Phosphate stripping, microfiltration, chlorination, filter beds, reed beds, bioremediation, co-metabolism and land farming techniques
What is phosphate stripping?
Adding iron (III) sulphate to the phosphates to create insoluble iron phosphate as fine sediment which can be used as an agricultural fertilisers
What is microfiltration?
The effluent can be strained through fine sieves called micro-strainers
What is chlorination?
The addition of chlorine, UV or ozone to kill any remaining bacteria in the effluent
What is co-metabolism?
Breaking down a contaminant by using an enzyme that is produced by microbes oxidising or reducing other compounds (metabolites) for energy and carbon
How does the weather impact flow volume of effluent?
Droughts or storms
How do sewage works overcome extra effluent?
Most sewage works have storm overflow tanks, however these cannot overcome the maximum possible effluent, this can cause great expense
What systems are used to collect the sewage (UK)?
One system collects only foul waste from toilets which requires full treatment but the smaller volume involved allows the construction of smaller, therefore cheaper, sewage treatment works
The second system collects the larger volumes of cleaner water, this requires little treatment before discharge
How is acid mine drainage defined?
A metal-bearing acidic solution formed from the oxidation of suffixes e.g. iron pyrite
How is acid mine drainage created?
Elements are stably bound in minerals, they become exposed to air in the mining, they are converted form sulfides to sulfates, sulphuric acid can oxidise other metals, the dissolved metals can be leached into nearby rivers
What are some of the ecological impacts of acid mine drainage?
Coats plants and blocks up stomata prevention respiration
Clogs gills and lungs, suffocating animals
Prevents the spawning of fish
Dissolved metal ions are more readily absorbed and bioaccumulated
Increased turbidity prevent respiration
Combine with enzymes so they cannot function
Combine chemically with the constituents of cells
What are the two types of treatment of acid mine drainage?
Active: chemical treatment involves the use of mine water treatment of plant
Passive: the use of plants, such as reeds to encourage metals to precipitate out of solution
What happens in the stages of active acid mine drainage treatment?
Minewater enter the tank and added sludge begins the initial process of settling the solid
Lime is added to raise the pH, neutralising the acids and causes precipitation of the metal hydroxides
A flocculant is added to coagulate the metal solids and sludge settles out in the clarifier tank
What are the 2 main styles of passive treatment?
Aerobic cell- using reed beds or trickle bed to remove heavy metals
Anaerobic cell- underground tunnels
What factors determine the data collection method used?
Speed of data collection, level of expertise required, degree of accuracy, indication of long-term historical pollutants levels, methods that are specific to individual pollutants and measurement of the effects of pollution rather than the levels of the pollutant itself
How is organic pollution monitored?
The level of deoxygenation in a water body
What are the standard conditions for Biological Oxygen Demand?
1 litre of water, 20C, 5 days and in the dark so algae cannot photosynthesise
What is chemical oxygen demand?
Measurement of oxygen required to oxidise soluble and particulate organic matter in water
What does it mean if the chemical oxygen demand is high?
Greater amounts of oxidisable organic material in the sample, which will reduce the dissolved oxygen levels
What is the benefit of using COD over BOD?
COD only takes 2-3 hours to do the test whereas BOD takes 5 days
What is the benefit of using COD over BOD?
COD only takes 2-3 hours to do the test whereas BOD takes 5 days
How are E.coli used in water monitoring?
Their presence in water is usually taken as an indication of faecal contamination, the health risk can be assessed using the size of the population
How is E.coli count impacted by temperate regions?
They do not survive long in temperate regions, so the presence is usually a sign of persistent or recent contamination
What is the boundary for water containing E.coli to be considered contaminated?
Water with <200 per 100ml is safe for swimming, any higher means the water is polluted
What is the maximum E.coli count for safe drinking water?
<1 per 100ml
What are the characteristics of species used for ionic indices?
Have different sensitivities to pollution, easy to find, easy to identify, normally present, usually common and generally distributed
What are some common biotic indices?
Lichens to monitor atmospheric acidic pollution
Aquatic vertebrates to monitor water pollution
What are the advantages of using biotic indices?
A rapid assessment of current and recent pollution can be made, expensive equipment is not required
What are some of the disadvantages of biotic indices?
Sorting samples can be time-consuming, identification of different taxa involves some skill and further tests are required using other techniques to detect the specific pollutants present
What compounds can chemical tests test for?
Nitrates, ammonia and phosphates
What is the process for chemical testing?
Water is placed within the container, the crushed tablets are added and left for 10 minutes, if the water changes colour then there are chemicals present in the water, this form of test can also be performed using an electric calorimeter
How is turbidity measures?
A secchi disc or by water being poured into a turbidity tube
What are some of the main sources of solid waste?
Mining and processing, domestic, industry and manufacturing
What are some solid wastes produced by mining and construction?
Mine overburden heaps- usually non-toxic
Mine spoil heaps- may contain toxic metals
Demolition waste- may contain hazardous material e.g. asbestos
How much of UK waste goes to landfill?
70%
What pollution properties do solid wastes typically have?
Degradability, conditions that affect degradation, flammability, radioactivity and toxicity
How does affluence impact waste?
More goods purchased, more disposable items purchased, tend to dispose of item rather than repair, more ‘non-essential goods’ purchased
How does manufacturing/ retail impact waste?
Built in obsolescence: to change fashions, upgrading models
Disposable products: razors, cigarette lighters, ballpoint pens
Over-packaging: items may be made more attractive
What factors can impact waste disposal?
Mass of waste, properties of waste, land availability, recycling technology, degree of environmental awareness, local and national regulatory framework/legislation, household income, waste processing costs for labour and population density (collection costs are higher where there are fewer people)
What comes into good landfill management?
Separation of different waste types, polymer liner to prevent the escape of leachate fluids, impermeable cap to prevent water entering once the site is complete, dispersing flammable materials, collection of methane for use as fuel, perimeter fence to trap litter blown by winds, regular covering with soil to reduce pest problems, collection and treatment of leachate fluids, deodorising spray to control odours and ensuring chemicals that could react with each other are no placed together
How is waste placed?
Compacted to 3m thick
Why is clay/sand placed on top of landfill at the end of the day?
Minimises the infiltration of rainwater, isolate the waste from birds and vermin and reduce odours
What are the two types of gas management for landfill gas?
Active: systems involve the active extraction of the gas, this includes pumping air into and under the landfill to displace the methane
Passive: systems comprise of wells with perforated tops to allow the gas to vent into the atmosphere
What are the disadvantages of landfill?
Loss of resources value (e.g. glass, plastics, metals), large land take, anaerobic decay of organic matter, toxic leachate may leak, farmland and habitats lost, contaminants in the site may prevent later development of landfill sites for housing or agriculture and transport delivering the waste to the site and the infrastructure around it to generate noise and congestion in the local area
What produces spoil?
Coal-fired power station and incineration produces ash, iron blast furnaces produce slag and mining/quarrying (coal, china clay metal ores)
What factors of landfill must be overcome for the land to be reused by a later date?
Stability, drainage, lack of nutrients, pH, contamination, topography, toxic leachate, heavy metals and flammability wastes
How have these factors that limit landfill reuse been overcome?
Stability- planting trees
Lack of nutrients- adding topsoil, sludge and fertilisers
PH- adding lime
Contamination- phytoremediation, bioremediation
Topography- landscaping
Toxic leachate- collected and treated
Heavy metals- kept alkaline, disposed when solid
Flammable waste- regular layers of fine grained arterial to reduce air flow
What are the advantages of incineration?
The volumes of ash produced is much less than the original waste, no sorting needed, heat produced may be used for district heating or the generation of electricity, flammable material can be used in industrial heat
What are the disadvantages of incineration?
Valuable recyclable material is lost, toxic dioxins may be produced by reaction of organic wastes and chlorine, the fuel used to maintain combustion is expensive, wastes may need to be serrated increasing processing costs and treatment of atmospheric pollutants in the effluent gases increases costs
What types of wastes are removed before incineration of domestic material?
Wastes with high water content, recyclable wastes
What are some factors in making good domestic incinerators?
Heat produced is harnessed to be used, waste gases are cooled rapidly to reduce dioxin production, control of atmospheric pollutants and heavy metals can be removed by scrubbing then stored in solid form at high pH
What are impacts of asbestos on human heath?
If inhaled, they cause irritation and lead to asbestosis, scar tissue also develops and reduces gas exchange, it can lead to mesothelioma (a type of cancer)
What is asbestos used for?
Strengthening cement roof panels, it’s found in textured ceilings coverings, as long as the asbestos is encapsulated and remain intact it is not dangerous
How is asbestos waste removed?
Double wrapped in heavy duty polyethene bags in a specialised landfill site where the waste contents are recorded
How is cyanide disposed of?
Incineration to break the carbon-nitrogen bond, the NOx and CO2 produced are much smaller pollution problems
What is the method used for encapsulation?
Pollutant is mixed with cement slurry which is poured into containers made of an impermeable and unreactive material
What is vitrificaction?
A specialist encapsulation technique used for the storage of high level radioactive waste that has been extracted from used nuclear fuel
What is the process for vitrification?
Powdered radioactive waste is mixed with molten glass and poured into stainless steel containers which are then sealed, the glass solidifies encapsulating the waste
What properties affect heavy metal pollution?
Liposolubility,, synergism and solubility
What is lead used for?
Car batteries, pipes, solder, paint, antiknock petrol additives and flashing for roofs and windows on building
How has the use of lead changed?
The uses of lead that do cause pollution have slowed or stopped, but the uses that don’t (flashing and batteries) are still widely used
What are some of the symptoms of lead poisoning?
Brian damage, paralysis and eventually death, very high doses can cause death by kidney or liver failure
How does lead pollution link to water pipes in the UK?
Most lead piping was replaced in the 20th century by copper piping, however lead solder was used to keep the pipes together
What is done in areas with high risk of lead poisoning?
Small amounts of phosphoric acid are added to the water to create an insoluble layer of lead phosphate in the pipes which prevents lead dissolving in the water
What has replaced lead in anti-knock agents for petrol?
Benzene
Why is lead solder considered a threat and how is it controlled?
Lead-based solder used in electrical connections is not a significant threat to public health during use, however the lead can be vaporised and inhaled when melted during the manufacturing or recycling process, so lead-free solder is now widely used
What are some other controls for lead pollution?
Shotgun pellets (wildlife ingestion), lead-based paint (vapours produced and ingestion by babies) and fishing weights (mistaken for snails)
What are the sources of mercury?
Disposal of items containing mercury (batteries, fluorescent lights, thermometers), chemical plants that produce chlorine using mercury electrodes and combustion of coal
What are the different effects of mercury based on chemical form?
Liquid, inorganic mercury, organic
What impacts does liquid mercury have?
Not easily absorbed through the skin and gut, although vapours may be absorbed in the lungs if inhaled
What impacts does inorganic mercury have?
Mercury oxide (HgO) are absorbed moderately well in the gut
What impacts does organic forms of mercury have?
Methyl mercury are absorbed easily through the skin, by the gut, and as vapours if they are inhaled, they are also liposoluble and can pass thought the blood-brain barrier to be a neurotoxin
What are some of the control methods of mercury?
Replacing mercury thermometers with alcohol or electronic, can be removed from effluents by activated carbo filters or reverse osmosis, ion exchange filters and disposal at high pH to minimise solubility
What are some of the sources of cadmium?
Disposal of old nickel-cadmium batteries, incineration of wastes containing cadmium pigments (plastics and paints), drainage water from cadmium and zinc mines
One new use of cadmium is cadmium-telluride PV solar panels, manufacture and eventual disposal of old panels could cause pollution
What are the effects of cadmium?
Cadmium is liposoluble and bioaccumulate so chronic exposure can lead to toxic concentrations and it can biomagnify in food chains
Symptoms: brain damage, paralysis, lung cancer, kidney failure and bone decalcification
What are the control of cadmium?
Most uses of cadmium have been restricted or banned e.g. pigment use, cadmium waste should be disposed of in a hazardous waste landfill site or may be recycled
What are the sources of tin?
Used in anti fouling paint on the bottom of boats to control the growth of marine organisms that slow boats down due too friction, the active chemical was tributyl tin (TBT), toxic to Marin organisms e.g. molluscs, prevention their growth
What are the effects of tin?
TBT is an endocrine disruptor that alters the growth and reproductive physiology of marine organisms such as oysters and whelks, this can impact the food chains and webs across the ocean
What can ingestion of tin cause in humans?
Stomach ache, anemia and liver and kidney problems
How is tin controlled?
Prohibited in anti-fouling paint and replaced with less toxic metals e.g. copper
Some countries also require paint residues produced by boat cleaning to be disposed of in a chemical waste landfill site rather than being washed into the sea
What are the sources of iron?
Iron is common in nature and can be found in many minerals and rocks, in low oxygen conditions iron will be in its chemically reduced form, in this form it is soluble, iron in mine spoil heaps present the Fe is soluble and can be leached out by river water draining through the spoil heap
What are the effects of iron?
Not a toxic pollutant but it can cause deoxygenation when it is oxidised in water, when oxidised it becomes insoluble, forming an iron oxide sediment, the process of oxygenation may deoxygenate the river causing the death of aerobic organisms
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 and to solid iron is periodically removed from the mesh
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 and to solid iron is periodically removed from the mesh
What are the effects of noise on objects?
If noise causes an object to vibrate at its natural resonant frequency, this may result in stress cracks, an indication of acoustic fatigue, repetitive vibration can structurally damage roads, bridges, buildings and aircraft
What affects can noise have on organisms?
Muscle contraction, increased heart rate/blood pressure, constriction of blood vessels, stress, irritability, headaches and temporary/permanent damage to hearing
How does noise pollution lead to hearing loss?
Loud noise can cause overstimulation and eventual death of the microscopic hair cells which line the organ of Corti in the cochlea of the inner ear, once killed, these hair cells cannot be replaced
How do loud noises disturb wildlife?
Result in nest abandonment and breeding failure
Why is the decibel scale logarithmic?
Humans are sensitive to a very wide range of sound power levels
What does it mean if something is 0Db?
Quietest sound heard at 1000Hz, the lowest threshold for human hearing
What are the effects of noise on humans?
Hearing damage, stress-related health problems (ulcers, high blood pressure and heart disease), behavioural changes and communication problems
How can bats, owls and dolphins be affected by noise?
The use sonar to find food, they may struggles when background noise occurs
How are cetaceans affected by noise?
Sonar can cause hearing loss for navigation and lead to them being stranded
What is a natural resonant frequency?
Frequency at which objects will naturally vibrate
What is acoustic fatigue?
Stress cracking and structural failure, when objects are exposed t sound at their natural resonant frequency for long periods
What can happen with vibrations?
Everything can break and become structurally weak- noise isn’t good
How are airport designed for minimal disturbance?
Located away from major population centres, engine test areas, taxi areas away from residential areas, land-use restrictions, acoustic insulation, noise deflection/absorption, multiple runways
How does noise pollution impact cliff nesting birds?
When startled they may knock off their offspring/eggs into the ocean
How can air forces plan low flying training flights to minimise noise nuisance?
Flight paths are varied, major urban areas are avoided, low flying timetables and compensation for building damage or livestock injury
What do the major avoidance areas include?
Civil airport and certain key industrial or medical sites
Why does having multiple runways reduce noise pollution at airports?
Usually, at busy airports pane will use reverse thrusters (which are very noisy) to slow themselves down if they cannot land as the airstrip is occupied
How has the engine design been improved to reduce noise?
Double cowling and turbofan forces bypass air around the inner cowling
What are some other features to reduce noise of aircraft?
Chevron nozzles, engine hush kits and engine acoustic liners
How is aircraft body design improved?
Blended wing aircraft, aerodynamics, lighter aircraft
What aspects of aircraft operation have the largest impact?
Take-off angle, flight path planning, night flights restrictions, constant descent angle
What is NNI?
Noise and number index
How do chevron nozzles improve engine design?
Used on high bypass engines to make them quieter
How do engine hush kits improve engine design?
Work like chevron nozzles but can be used on low bypass ratio engines to make them quieter
How do engine acoustic liners improve engine design?
Acoustic liners are used inside the outer cowling and around the inner cowling to absorb noise
How could blended wing aircraft improve body design?
Engines can be located on top of the aircraft so the body acts as a barrier reducing the noise that reaches the ground
How could blended wing aircraft improve body design?
Engines can be located on top of the aircraft so the body acts as a barrier reducing the noise that reaches the ground
How could aerodynamics be applied to improve the body design of aircraft?
Fairings on the undercarriage reduce turbulence around the wheels and leg struts, fairings covering wing flap hinges reduce turbulence, riveting constructions creates surface indentations which create turbulence and noise, welded panels create less turbulence
How can aircrafts be made lighter?
Using composite materials e.g. carbon fibre, makes engine thrust less needed
How does the NNI scale run?
0-70
What are the noise limits set on airlines?
Older noisiest chapter 2 aircraft were banned from most major airports in 2002, when chapter 3 limits were introduces (15dB reduction) and all new aircraft since 2006 must meet chapter 4 noise limits (10dB lower than 3)
How are limits on noise controlled?
Charges, restriction of flight times, quota count systems
How do railways contribute to noise pollution?
Affects a small proportion of the population but it can be a serious local problem, high speed passenger trains are noisiest but fright trains are often very long and travel slowly, so they can take a long time to pass
How much outside noise is due to traffic?
66%
What is road vehicle noise?
A combination of engine noise, exhaust noise and the vibration of tyres on the road surface
What are some methods to protect workers form noise pollution in industry?
Sound absorbing surfaces in the room, worker ear protection, sounds absorbing materials around the equipment, sound absorbing materials as part for the equipment, machinery placed on an acoustic mat and remote machinery operation
What causes domestic noise pollution?
Speakers, tools, garden machinery, pets, washing machines and dishwasher
What are some of the control methods for domestic noise pollution?
Volume limiters on music equipment, wearing ear defenders when using power tools and machinery, control pets, domestic appliances with acoustic absorbance and selection of quieter domestic appliances
What does LA10 do?
Measure noise exceeded for 10% in any set period, it is a good measure of the noisiest periods
What does LA90 do?
Measures noise exceeded for 90% in nay set period, it is a good measure of the quietest periods
What is TNI?
Traffic Noise Index produces a representative measure of traffic noise using LA10 and LA90
What is EPNL?
Effective Perceived Noise Levels is the estimate of the relative loudness of a particular type of aircraft during take-off, overflight and landing
What is Leq57dB?
Average sound level over a particular period, in the UK during the summer an average 57dB is used from 7am-11pm
Why does gamma radiation have high penetration?
very high velocities and low wavelength
What is beta radiation range in air?
20cm
What factors can influence how damaging the radiation is?
Proximity, type of radiation, PPE, half-life of material, range and penetration of radiation, state and internal/external route into the body
How does ionisation impact humans?
Produces H+ and OH- free radicals from bodily water, this then interferes with enzyme action and can be harmful to DNA
What are some natural sources of radiation?
Radon, space, Earth and human body
What are some man made sources of radiation?
Medical x-rays, consumer products and nuclear medicines
What are some of the causes of radioactive pollution?
Past nuclear weapons testing, nuclear waste disposal, accidents at nuclear power plants, transportation and processing and storage of radioactive materials
What is the main natural source of background radiation?
The igneous rock, granite and uranium rich sedimentary rocks, sandstone
What causes the release of ionising radiation from natural sources?
Weathering of sandstone can release uranium into waterways and release the argon gas from granite
What are the two main sources of human radiation?
Mining of uranium and granite and medical exposure
What radiation is used in medicine?
Gamma
What are the uses of ionising radiation?
Agricultural, medicine, dating rocks, industry, nuclear fusion/fission and research
How is ionising radiation used in industry?
Measuring the thickness of rolled metals and paper, testing aircraft jet engine turbines, strengthening polymers and in oil and gas exploration to test rock porosity
How is ionising radiation used in agriculture?
Production of mutations in crop breeding programmes and pest control: stored food sterilisation, sterile male insect pest control
How is ionising radiation used in medicine?
Cancer treatment, sterilising heat-sensitive surgical equipment and x-ray photography and CT scans, beta radiation is used to prevent artery closure in the form of Sr90
How is ionising radiation used in research?
Radio-labelled tracers to track the movement of materials (pollutant or drug) within organisms or the environment
How is ionising radiation used in nuclear fission/fusion?
Nuclear electricity, nuclear weapons and ship propulsion
What is the risk: benefit analysis?
The analytics of the risk in the use of radiation against the benefits of the function
How can assessing the risk of ionising radiation be difficult?
Symptoms can take a while to develop, the symptoms may ‘match’ with other diagnoses, accurate data on exposure following accidental release is not readily available, accurate data on impacts on humans is not always available, people at risk vs people at benefit and risk of radioactivity in medicine may outweigh risk of surgery
How is ionising radiation used in food industry?
Seed irradiation to kill off any bacteria/fungi, fresh fish fruit and vag may be irradiated before preservation t increase shelf life and radiation may also be used to sterilise male insect pests
What is cosmic radiation?
When charged particles released from the sun are absorbed in the atmosphere, this releases high energy EM radiation including gamma rays
How does radiation enter the body?
Products from the upper atmosphere and radioisotopes from the ground can enter the body via food and water or inhalation
How is radon released and impactful to humans?
Gas is released by decay of uranium atoms, it releases alpha radiation, it travels up cracks and can escape into the atmosphere
How can we prevent radon gas from entering buildings?
Ventilation of foundations
Why is gas less of a problem than a radioactive solid?
They cannot be ingested, therefore there is less residence time
What are the health risks with radon gas?
Alpha radiation released can easily damage lung tissue and is the second leading cause of lung cancer
Who is at high risk of exposure?
Miners, radiographers, dentists and technicians, workers who test thickness of paper and steel, aircraft crew, scientists using radio-labelled tracers, workers in nuclear power generation and manufacturing industry which uses radioactive substances
What’s the negative effects of nuclear weapons?
The wind carried and contaminated the Earth’s surface but the amount of contamination varied greatly
What are some common consumer products that release radiation?
Smoke detectors, camping gas mantles, ceramics, granite worktops and fertilisers
What is relative biological effectiveness?
A measure of the comparative effects of different types of ionising radiation on living tissues
How can strontium 90 impact human health?
It can replace the CA2+ in the bone marrow and lead to leukaemia or bone marrow cancer
What is the difference between acute and chronic poisoning?
Acute is short term, caused by large doses and can lead to haemorrhages, hair loss and death.
Chronic is long term, caused by small doses and can lead to gonadic and somatic effects
What worker receives the highest radiation level and how?
Air crew workers as they receive high levels of cosmic radiation at higher altitude
What are the strategies to reduce exposure of ionising radiation?
Closed sources, remote handling techniques, materials to absorb the radiation, distance from the source, reducing exposure periods and decontamination
How do we monitor the radiation we absorb?
The gray- one gray is the absorption of one joule of radiation energy per kg of matter
What factors should be taken into account for critical pathway analysis?
Weather, food sources and consumption, physical state of effluent, bioaccumulation and biomagnification, river flows and ocean currents, effect of pH and oxygen solubility, density, half lives and the physical nature of the environment
