L2 - Definitions and Types of Pollution and Pollutants Flashcards
How does Mellanby define environmental pollution (environmentalist view)?
“…the introduction of foreign materials into the environment should be kept at a level at which no detectable biological change results.” - outlines perspective about foreign materials and biological change
What is the economic view of environmental pollution?
“Discharge or other actions which occasions economic damage to man” - things that cause damage to man
What is Holdgate’s definition of pollution (1979)?
“The introduction by man into the environment of substances or energy liable to cause hazards to human health, harm to living resources and ecological systems, damage to structures or amenity, or interferences with legitimate uses of the environment.”
Describe Holdgate’s definition of environmental pollution
- More detail
- Detects humans as the cause of environmental pollution, hazards to human health
- More of a full definition
- More key terms
What is the U.S. President Advisory Committee in Environmental Pollution definition of EP (1965)?
“…environmental pollution is the unfavourable alteration of our surroundings wholly or largely as a by-product of man’s actions, through direct or indirect effects of the change of patterns, radiation levels, chemical and physical constitution and abundance of organisms. These changes may affect man directly through his supplies of water and agricultural or other bodies, his physical objects or his opportunities to recreation and appreciation of nature.”
Describe the definition of environmental pollution by US President Advisory Committee on Environmental Pollution (1965)
- 1965 = midst of the Cold War - radiation levels
- Energy patterns - thermal? (amongst others)
- Reference to populations of organisms (“abundance”)
What is the current definition of environmental pollution from USA Environmental Protection Agency?
“…any substance in water, soil, or air that degrade the natural quality of the environment, offend the senses of sight, taste, or smell, or a health hazard. The usefulness of the natural recourse is usually impaired by the presence of pollutants and contaminants.”
Describe the USA EPA current definition of Environmental Pollution
- A little more brief
- Talks about visual intrusion/taste/smell & health hazards
- Refers to how we use natural resources - by whom or what?
What are the common characteristics of pollution events?
- The pollutant = causes the effect
- The source(s) if the pollutants
- The transport medium (air, water, and/or soil) (could be more than 1)
- The target (organism, ecosystem or object - sometimes receptor)
- Helps identify pollution events and how they work
What is Holdgate’s Pollution Model?
- Model illustrating the processes involved in pollution
- Have 4 common elements represented
- There are additions and extensions to the idea
- Rate of transport is critical
What might happen when a pollutant reaches its target?
- May not have the same chemical form as what was released from the source - May undergo chemical transformations whilst moving through the environment
- Amount of pollutant teaching the target is critical - pollutant undergoes different processes
- When pollutant reaches the target it may not have a direct effect - could also be processes within the target - organisms may excrete pollutants
What are the common approaches to pollution transport?
- Source (e.g. agriculture)
- Media affected or travelled through (air, water, land)
- Nature and properties of the pollutant (e.g. heavy metals, organic material, sewage)
What are the sources of pollutants?
- Discrete point sources = readily identify exactly where it is released into the environment
- Diffuse (nonpoint) sources = things in which pollutants come from or are applied to a wide area without a specific source point
What are examples of discrete point sources?
- Sewage effluent pipe
- Industrial wastewaters
What are example of diffuse (nonpoint) sources?
- Acid rain
- Fertilisers
- Pesticides
What are sources of pollution?
- Agriculture
- Electricity generation (byproducts from fossil fuel combustion)
- Derelict has works (used to gasify coal)
- Metal mining (chemical residue)
- Metal industries (gaseous discharges, byproducts, metal cocktail)
- Urban & industrial sources (Road runoff = cocktail of pollutants - car tyres, vanadium & fuel hydrocarbon residues)
- Waste disposal (legacy landfills = leachate’s)
- Transport (tyre particles/hydrocarbon residue, carbon di/monoxide)
What are effect-generating properties?
What the effect is of the polluter in the target of the receptor
What are examples of effect-generating properties?
- Toxin = effect is toxic and could be lethal or sub lethal on living organisms
- Corrosion of metals = acidification of rain water corrodes metal structures which runs into ground water
What are pathway-determining properties?
- Properties that determines where a pollutant goes in the environment
- Includes the distance travelled, rate of dispersion
- Where it goes to is determined by the pathway it takes
What are examples of pathway-determining properties?
Primary settlement tank in sewage works:
- Scum on top of water is called FOG (fats, oils & greases) all of these rise to the top because they are hydrophobic - skimmed off the top as it goes through treatment works
- Different properties means where it ends up is different than the rest of the water
What are primary pollutants?
Pollutants that exert harmful effects in the form which they enter the environment
What is an example of a primary pollutant?
Discharge pipe has a direct effect in its primary form
What are secondary pollutants?
Pollutants that are synthesised as a result of chemical processes in the environment, often (not always) from less harmful precursors (chemical change or process) - less harmful precursors are something relatively benign but becomes a problem because it changes as it moves through the environment
- Referred to by a specific part of Holdgate’s model that deals specifically with chemical transformations in environmental media
What is an example of a secondary pollutant?
Microplastics
What are the key aspects of transport and dispersion of pollutants?
- Fluid media = water & air (both behave as fluid in a physical sense)
- Settlement and leaching of liquids (driven by gravitational forces)
- Anthropogenic (transport and placement)
What are the 2 key mechanisms in the transport and dispersion of water?
- Advection (aligns with gravity) = movement of a pollutant with water mass
- Diffusion (driven by turbulence & particle motion) = spreading within water mass
What is an example of advection?
Ink speeding down-stream
What is an example of diffusion
Ink speeding outwards/widening in water
What results from a mixture of advection and diffusion?
A loss in concentration of pollutant in water
What restricts the vertical movement of pollutants in ponds/lakes?
- Depth of water body
- Stratification (layers within water body)
How does accumulation of pollutants in water occur?
- When there are inputs without loss
- Can become sinks for pollution (net accumulation)
- Lakes & seas
- Lakes & sea sediments
How is the oceanic system an example of net accumulation of pollutants?
Things that are delivered don’t tend to be removed e.g. the sea is saline because evaporation doesn’t remove the salts that are washed in
What is stratification?
Layering of water in water body
What is the impact of stratification?
Impacts the way pollutants have an effect on aquatic ecosystems and in the way they move through the system
What does stratification underpin?
Temperature and density of water
What does density of water depend on?
Temperature of water