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Heavy Metals, Ionising Radiation, alpha, high level waste, Contamination:…
Heavy Metals
Other heavy metals
Cadium
source
- disposal of old nickel-cadmium batteries
- incineration of waste containing cadmium pigments eg. some plastics, paints
- drainage water from cadmium and zinc mines
effect
- liposoluble = bioA + bioM
- brain damage and paralysis
- lung cancer
- kidney failure
control
most uses have been restricted or banned
waste should be disposed in a hazardous waste landfill or be recycled
Tin
- used as antifouling paint on boats (stop marine organism growth)
- can damage marine organisms and enter humans when eaten
- paint now replaced with less toxic metals eg. copper
- paint residues now removed to landfill vs. washed out to sea
Iron
Control
spoil heap drainage can be collected and passed over mesh screens - iron is oxidised and deposited on the mesh, solid iron is removed periodically
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Lead
Sources
only the uses of lead that release lead, cause pollution - these uses have been restricted and those that don't, continue, eg. lead-acid batteries
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Acute exposure may cause severe symptoms eg.
- brain damage
- paralysis
- death
These are only likely in industrial accidents and can be prevented by good working practices eg. wearing facemasks, using water sprays, or remote operations
Control
Water pipes:
- lead dissolves in water, leading to chronic exposure
- lead pipes replaced with copper pipes
- where lead still remains, phosphoric acid can be added to produce and insoluble layer of lead phosphate, which prevents lead from dissolving into water
Lead based paint:
- lead compounds added to paint to accelerate drying and increase durability
- dusty, flaky paint poses a much greater risk
- chemical paint strippers + hot air guns can remove paint safely, without producing dust or vapours containing lead
Mercury
Sources
disposal of items containing mercury eg. batteries, fluorescent lights, thermometers
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Ionising Radiation
Noise
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Effects
Non-living objects:
- Acoustic fatigue: sounds that cause objects to vibrate at the resonant frequency can cause stress cracking and structural failure
- Vibration damage: repetitive vibration can cause structural damage to buildings, briders, pipes eg. caused by the vibrations created by the wheels of heavy vehicles
- Shock impacts: sudden, very loud noise eg. sonic booms from aircraft can cause structural damage to buildings eg. broken windows
Living organisms
Humans:
- Hearing damage:
- Stress related health problems eg. high bp, heart disease
- Behavioural changes eg. irritability, aggression, lack of concentration
- Communication problems
Other organisms:
- Livestock: sudden noises may cause animals to panic, leading to injuries of breeding failure
- Disturbance of breeding birds
- Reduced feeding success of animals that use hearing to find food (echolocation) eg. bats, owls, dolphins
- Hearing damage/ behavioural changes: eg. cetaceans (whales, dolphins) - hearing loss or mass strandings
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Aircraft
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Aircraft design
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blended wing aircraft: engine located on the top of their aircraft, body acts as a noise barrier + less turbulence/vibration
lighter aircraft: composite materials eg. carbon fibre makes aircraft lighter, so, less engine thrust is needed/ smaller engines
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Aircraft operation
take off angle: steeper angle to allow aircraft to climb to altitude where it cannot be heard from the ground
constant descent angle: less intrusive, no periods of high thrust - doesn't have to slow down/ use reverse thrusters + steeper descent angle allows aircraft to stay at higher altitudes for longer
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Road traffic
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Engine noise:
Acoustic insulation around the engine, quieter exhaust pipes
General road vehicle noise:
Traffic management (reduces noise from acceleration), walls, embankments, tree planting to absorb noise
Industrial
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general methods of control:
- sound absorbing materials around the equipment
- remote machinery operation
- worker ear protection
Domestic
main sources are domain appliances:
- washing machines, music equipment, garden machinery, barking tools
control:
- appliances with acoustic absorbers
- volume limiters on music equipment
- control of pet dogs
Railway
Wheel vibration: track polishing, sound absorbing ballast
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Solid waste
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Properties
- degradability
- flammability
- release of radioactivity
- toxicity
Affluence
affluent people have more waste as they..
- purchase more consumer goods
- purchase more disposable items
- throw items away rather than repairing them
industrys may also try and increase sales by:
- built in obsolescence
- disposable products
- over-packaging
solid waste disposal
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Landfill
Advantages:
- simplest
- requires little to no treatment of the waste itself
Disadvantages:
- potential resource value lost (metals, glass, plastics)
- large areas of land - loss of habitats + farmland
- OM decays anaerobically, releasing methane + CO2
- leakage of toxic leachate
- contaminants may still prevent later development for the sites eg. housing, agriculture
- transport + infrastructure delivering waste generates noise and congestion locally
Features of a well managed site:
- separation of different waste types
- polymer liners to prevent escape of leachate fluids
- regular covering of soil to reduce pest problems
- collection and treatment of leachate fluids
- collection (+use) of methane
- potentially reacting chemicals not dumped together
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Incineration
Involves the destruction of waste by high temperature oxidation
For flammable domestic/ Industrial waste
Advantages:
- volume of ash produced is much less than original waste
- heat produced can be used for district heating or electricity generation
- no sorting or complicated management needed
- flammable materials eg. plastics, can be separated and burnt in power stations or used for industrial heat
- large quantities of a single flammable waste can create a fuel
Disadvantages:
- resource value of recyclable materials lost
- organic wastes + chlorine = potential production of toxic dioxins
- fuel to maintain combustion of wet or non-flammable wastes = expensive
- wastes need to be separated (to removed wet wastes) = increased cost
- treatment of atmospheric pollutants in the effluent gases = increased cost
Features of a well-managed site:
- removal of recyclable waste before incineration
- removal of high water content wastes eg. compostable wastes
- removal of heavy metals by scrubbing, and then stored in solid form at high ph (so less soluble and less mobile)
- heat produced is harnessed for use
- atmospheric pollution is controlled: so2, Nox, HCl, Co2, smoke/PM10
- additional treatment of some produced materials after incineration
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Spoil Heaps
Contamination: phytoremediation (plants absorb and store pollutants eg. heavy metals), bioremediation (for petrochemical waste eg. oil)
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Lack of nutrients: addition of topsoil, sewage sludge, fertilisers, leguminous plants
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Instability: compaction, planting vegetation, drainage, landscaping to reduce gradients
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Uses
Industry
- oil and gas exploration
- Strengthening polymers
Healthcare:
- cancer treatment
- X-ray photography and CT scans
- sterilising heat-sensitive surgical equipment
Agriculture:
- sterile male insect pest control
- production of mutations in crop breeding programmes
Scientific research:
- radio-labelled tracers to track the movement of materials within organisms or the environment
Nuclear fission and fusion:
- nuclear weapons
- nuclear electricity
- ship propulsion
Factors affecting Impact
Properties of different types of radiation:
eg. power of penetration, distance of travel, ease of absorption
- poor penetrating power = more easily absorbed
- denser material = easier absorption of radiation
- RBE (relative biological effectiveness): measure of the comparative effects of different types on ionising radiation on living tissues (higher = worser)
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Activation products
exposure to neutrons may cause previously stable nuclei to become radioactive as its converted into a new isotope
(most types of radiation do not cause the material to become radioactive because the nuclei are unaltered
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Risk:Benefit analysis
Assessing risks and benefits can be difficult because:
- symptoms may take a long time to develop (especially those from chronic exposure)
- different causes which cause the same symptoms makes identification difficult
- accurate data on the impacts on humans or exposure often not available
- risks may be offset by the reduction of other risks eg. x-ray vs. invasive surgery
alpha
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very easily absorbed, travels short distances
absorbed by clothing and dead skin so emission outside the body is safe. BUT: very dangerous when ingested and the particles are all absorbed in a small mass of tissue = concentrated damage
high level waste
Intermediate level waste
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low level waste (solid)
sealed in thick polythene bags, inside steel drums in concrete lined landfill site
low level waste(liquid)
filtered, ion exchange, discharged
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Contamination: physically carrying radioactive materials, which, when the release radiation, may cause exposure
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NOTE: inorganic mercury that enters anaerobic sediments can by changed into organic mercury compounds, eg. methyl mercury by anaerobic microbes
large amounts of solid wastes are deliberately or accidentally dumped into the environment - eg. litter, choking wildlife
biomagnification = increased concentration, along a food chain !!! ingestion in food and storage
bioaccumulation = absorption, increased concentration within an organism, due to storage of many small doses
liposolubility: dissolves in fats/ lipids, allows storage in fish, humans, etc.
noise NOT sound: noise = disturbing, unwanted + may cause harm
(frequency, duration, strength)
(each Bel divided into 10 decibels - increase is 10dB represents a ten-fold increase in sound volume)
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