envi sci aqa - pollution

• What are all the types of water pollution?

  - thermal pollution

  - oil pollution

  - pesticide pollution

  - inorganic nutrient pollution

  - organic nutrient pollution

  - acid mine drainage

  - heavy metals
• What are the factors affecting dilution and dispersal of pollutants in water?

  dilution

  - amount of pollutant

  - volume of water body

  - residence time of water (low residence time = more likely to be carried away)

  dispersal

  - presence of water currents
• What are the sources of thermal pollution?

  - hot water from power stations

  - some industries
• What is the relationship between temp and dissolved oxygen?

  - increased temp = decreased dissolved oxygen

  - solubility of oxygen declines and temp increases
• What are the effects of thermal pollution?

  - decreased dissolved oxygen making conditions less suitable for fish e.g. salmon

  - can denature enzymes killing aquatic organisms

  - outside range of tolerance

  - deoxygenation

  - non-indigenous species introduced from warmer climates may out compete indigenous species
• How can thermal pollution be controlled?

  - hot water from power stations can be pumped through cooling towers

  - hot water is held in cooling towers where warm air rises out of the cooling tower cooling the hot water down

  - warm water is then released into rivers/sea/lakes
• What are the causes of oil pollution?

  - waste lubrication oil e.g. vehicle engine oil leaks

  - oil tanker accidents

  - oil rig accidents

  - oil pipeline leaks

  - lubrication used for oil drilling
• What are the effects of oil pollution?

  - can be toxic to some organisms e.g. plankton

  - oil can smother organisms preventing birds from flying and feeding there young and stop algae from photosynthesising

  - thin layer of oil can reduce the amount of dissolved oxygen and light penetration

  - can make it hard for species who use sense of smell to find mates

  - food chain impacts
• What environment would have the most severe effects from oil pollution?

  - inshore

  - enclosed body of water

  - low winds

  - low water currents

  - sensitive ecosystems
• How can oil pollution be controlled?

  - oil interceptors

  - recycling of waste oil lubricants

  - improved tanker operation

  - improved tanker design

  - treatment of oil spill
• What is an oil interceptor?

  - separate oil from watery waste removed oil which can be removed and treated
• How can tanker operation be improved to reduce oil pollution?

  - better shipping routes (offshore shipping routes)

  - better navigation systems to avoid collisions

  - when tankers are washed oil can be recirculated in tanks during unloading to be mixed up and removed with the cargo instead of being washed into the sea
• How can tanker design be improved to reduce oil?

  - double haul so if outer layer has a whole oil wont leak out

  - twin engines in case one fails preventing the ship from being carried into rocks

  - multiple separate oil tank so if one has a leak only the oil from that tank will leak
• How can oil spills be treated to reduce oil pollution?

  - booms used to restrict movement of floating oil (do not work with strong currents and waves)

  - skimmers which are rotating metal discs that pick up oil

  - detergents or dispersants e.g. corexit which emulsifies oil into to tiny droplets mobilizing them allowing them to be dispersed in water currents

  - bioremedation e.g. use of bacteria which digest the oil breaking down
• What is the oil spill case study?

  - Deep Water Horizon

  - dolphin migration affected

  - starvation due to oil ingestion
• What are the main properties of pesticides?

  - specificity

  - persistence

  - bioaccumulation

  - biomagnification
• What are all the pesticides used to demonstrate different properties of pollutants?

  - organochlorines e.g. DDT

  - organophosphates

  - pyrethroids

  - neonicotinoids
• What where organochlorines used for?

  - used in 1940s for pest control e.g. mosquitoes

  - properties lead to major environmental problems such as bees being killed

  - killed predators top of the food chain as well
• What are the properties of organochlorines?

  - high toxicity specific to insects (kills insects e.g. bees/butterflies)

  - high persistence (protect crops for long time)

  - high liposolubility and low water solubility (heavy rain doesnt wash them off)

  - bioaccumulates and biomagnifies
• What are organophosphates?

  - developed to decrease use of organochlorines

  - reduced environmental impacts
• What are the properties of organophosphates?

  - low persistence and liposolubility (less biomagnification and bioaccumulation)

  - however reduces specificity being toxic to mammals as well so farm workers were put at risk
• What are pyrethoids?

  - synthetic insecticides
• What are the properties of pyrethoids?

  - high insect toxicity specific to only insects

  - not persistent

  - do not bioaccumulate and biomagnify

  - however are water soluble and can be toxic to fish so if leached can cause damage
• What are neonicotinoids?

  - widely used insecticides
• What are the properties of neonicotinoids?

  - high insect toxicity but low toxicity to invertebrates as they cannot cross the blood-brain barrier of invertebrates

  - relatively persistent

  - water soluble (allows roots to absorb protecting the plant from pests, however can build up in aquifers)

  - however very toxic to bees and have caused large bee decline

  - broken down by sunlight
• What are the direct effects of pesticide pollution?

  - can be toxic to non-target species e.g. bees

  - toxic chemicals can biomagnify up the food chain killing predators top of the food chain

  - higher doses can make species infertile

  - pesticide spray drift can cause neurotoxic problems to people nearby
• What the indirect effects of pesticide pollution?

  - food chain impacts e.g. food supply dies out or predators die out increasing population of another

  - loss of interspecies relationships e.g. impacts of flowers due to loss of pollinators
• How can pesticide pollution be controlled?

  - restrictions and bans on pesticides e.g. organochlorines banned in most countries

  - use of non-persistent pesticides e.g. organophosphates

  - use of more specific pesticides e.g. pyrethroids

  - use of systemic pesticides

  - apply pesticides during low winds, at night and not before heavy rainfall to reduce spray drift, bees affected and run off

  - biological pest control e.g. introduce pest predators

  - cultural pest control e.g. barrier crops
• What are systemic pesticides?

  - pesticides that are absorbed by crops and translocated within protecting the crop from pests

  - means pesticides do not have to be sprayed and do not wash off
• What are the sources of inorganic nutrient pollution?

  - phosphates in sewage effluent

  - nitrates washed off farmland from artificial fertilisers
• What is the main environmental impacts of inorganic pollution?

  - eutrophication (algal blooms)
• What is the process of eutrophication?

  - addition of additional inorganic nutrients

  - algae absorb nutrients and grow faster than other plants

  - eventually algae forms a layer which shades water below reducing light penetration and therefore photosynthesis

  - macrophytes then die and are decomposed by aerobic organisms (increasing BOD and reducing DO) causing deoxygenation

  - algae then also die once nutrients run out and oxygen levels are depleted
• What are the impacts of eutrophication?

  - macrophytes die

  - deoxygenation (anoxic conditions)

  - cyanobacteria in algae release toxins which can affect livestock/people that drink/come into contact with water

  - food web disruption

  - algae are unreliable food source and cant support rich food webs
• What are the human health impacts of inorganic pollution?

  - nitrates can contaminate water supplies leading to blue baby syndrome

  - nitrates can cause stomach cancer
• How can nitrates cause blue baby syndrome?

  - gut bacteria can convert nitrate into nitrites which then react with haemoglobin reducing its ability to carry oxygen

  - high levels can lead to blue baby syndrome in infants as they have more of the required gut bacteria
• How can nitrate inorganic nutrients be controlled?

  - reduced use of nitrate fertilisers

  - reduced application before/during heavy rainfall to reduce run off

  - reduced cultivation of crops with high nitrogen requirements

  - buffer strips

  - Nitrate Vulnerable Zones where use of nitrate fertilisers are highly constricted
• How can phosphate inorganic nutrients be controlled?

  - adding iron sulphur to effluent released by sewage (phosphates stripping)

  - phosphates then precipitate out of the effluence
• What are the sources of organic pollution?

  - nutrients such as carbohydrates, lipids and proteins found in sewage, manure and milk etc
• What are the impacts of organic nutrient pollution?

  - deoxygenation killing aerobic organisms

  - can contain pathogens e.g. in sewage which can contaminate food and water spreading diseases e.g. cholera

  - eutrophication

  - increased turbidity
• How is deoxygenation caused by organic nutrient pollution?

  - when organic pollution enters a water body aerobic bacteria increases increasing the biological oxygen demand

  - increased in biological oxygen demand causes dissolved oxygen to decrease as more if being used up by the aerobic bacteria decomposing the pollution